|CERES No. 134 (FAO Ceres, 1992, 50 p.)|
By Vo Quy
Shortly after the war for the reunification of Vietnam ended in 1975, Vietnamese scientists tried to begin replanting what had once been the magnificent Ma Da Forest - 20000 hectares of which had been completely destroyed by the US military's herbicide spraying program.
Initial attempts to re-establish the indigenous trees failed, however, mainly because young saplings were reduced to ashes in constant grass fires sparked during the dry season. The defoliants used by the military had turned the primary forest into a vast field of easily flammable Pennisetum polystachyam, known now to local people as "American grass" (just as similar fields in the Philippines after the Second World War came to be called "Japanese grass").
"We never knew the name of the grass before", explains Tran Ba Dang, director of the Ma Da Forest Farm. "But wherever the Americans went and sprayed. only that grass can grow. After the war ended, we tried to replant Hopea odorata and Dipterocarpus dyer), but the saplings could not grow. The topsoil was very thin and poor, the humidity was very low, the temperature and the light were very high, and at last the seedlings burned up in grass fires. Finally, in 1981, we realized that we needed to establish a forest canopy under which the indigenous species could survive. We had to copy the conditions in which they used to grow in the forest.
"After we remove big areas of pernicious grass, we plant (fast-growing) shade trees, including Indigofera tenesmani, Acacia auriculiformes and Eucalyptus tereticornis. When these shade trees gain sufficient height, which takes about three years, we plant the native trees underneath them".
Today, more than 1 000 ha of Acacia, Indigofera and Eucalyptus trees give shelter to up to three different species of dipterocarp, including Dipterocarpus alatus, D. dyeri and Hopea odorata. Tran Ba Dang adds: "In the nursery, we have created the special conditions that young seedlings require, moisture and shade. This year we have about 100 000 seedlings. We also collect wild saplings and seeds from the untouched patches of the forest and cultivate these in the nursery. But it is not easy to collect the seeds of dipterocarps and reproduce them in this way. We expect the returning birds and other animals will also help the forest by scattering seeds".
The Ma Da Forest experiment offers great promise for Vietnam, but it also demonstrates how difficult, as well as time and labor-consuming, the process of rehabilitating tropical woodland is - and the vast scale of the work still required to heal our war-scarred country. Thousands of hectares that were once cool, moist, temperate and fertile are now characterized by compacted, leached earth and dry, blazing climate.
The period from 1945 to 1975 was one of almost continuous warfare in Vietnam, involving Japanese, French, American and Vietnamese armies. In the American phase, US forces employed deliberate destruction of the environment as a military tactic on a scale never seen before. This included:
spraying 72 million litres of herbicides (Agents Orange, White and Blue) on forests and
croplands (Operation Ranch Hand), resulting in the destruction of vegetation and the
residual contaminant poisoning of the land by dioxin (TCDD). An estimated 22 000
square kilometres of tropical forest and farmland were destroyed, mainly in the south of
clearing large tracts of forest, agricultural land and villages with giant bulldozers (Rome
plows) that removed even the topsoil (Operation Paul Bunyan);
burning flammable Melaleuca forests by napalm bombing in the Mekong Delta;
damaging land and forests via saturation bombing with more than 13 million tons of
bombs, equivalent to 450 times the energy of the Hiroshima atom bomb, or an average
of 265 kilograms per person in Indochina.
These actions resulted in the immediate loss of more than 20 million cubic metres of commercial timber, 300 million kilograms of food, 135 000 ha of rubber plantations, and the elimination of , much of the nation's wildlife | and fisheries. The long-term , effects are more serious, ' because, more than 20 years afterward, the forests have yet to recover.
Defoliation literally changed the face of large swaths of Vietnamese terrain. Some of the most biologically rich, and environmentally fragile, ecosystems in the world were devastated. Millions of hectares of mountainside were once a dense tropical hardwood jungle, where tigers, elephants and gaurs roamed in the forests and beautiful pheasants presented their bright colors and fantastic adornments on their display grounds. Herbicides subverted the environment; now the jungle is transmuted, as at Ma Da Forest, into savannah. The habitats of large mammals, forest birds, and the slower-breeding carnivorous animals and owls - which fed on rats - were destroyed. At the same time, the grasslands favor the breeding of vermin. Rat populations have exploded, and rats have destroyed crops and spread diseases to both cattle and humans. Bubonic plague, the "Black Death" of Europe's history, has spread rapidly in southern Vietnam since 1965.
The damage from 25 million bomb craters, which caused displacement of 3 000 million cubic metres of earth and topsoil, has also caused health hazards, the disruption of water flow, and an increase in erosion. Particles of shrapnel embedded in living trees render their wood less valuable.
Forest cover has declined even more rapidly since hostilities ceased, principally owing to agricultural clearing, forest fires, extraction of timber and firewood, and urban expansion. This has occurred first in the coastal and low-lying areas, and then gradually higher in the hills and mountains. The process is accelerating as a result of population growth. Since 1943, when 43 per cent of the nation's tree cover remained, forest cover has steadily declined - to 29 per cent in 1975-76 and to only 24 per cent by 1983. The consequences of this forest loss are particularly serious, because the country is mountainous. The resultant erosion, changes in water flow, floods and droughts are far more severe than in other countries. Most deforested areas have become barren. Almost 40 per cent of the country is now classified as unproductive wasteland.
A new revolution
But we are plotting a new revolution in Vietnam: to turn the country green again. Recalling a campaign - "Tree Planting Tet (New Year)" - launched by President Ho Chi Minh as long ago as 1959, our people are carrying out a great tree planting program, whose goal is to bring the extent of forest cover back to 50 per cent of the nation by the 21st century, in order to re-establish the ecological balance, preserve biological diversity and do our part in delaying global warming. This re-greening effort is the biggest challenge facing the country since its reunification in 1975.
In 1990,400 million trees are reported to have been planted. At 1 000 trees per hectare, this is equivalent to 400 000 ha. For the entire period 19611990, an area equal to 5.7 million ha is reported to have been planted. Our goal is to replant some 500 million trees each year, but even this is not enough to compensate for ongoing forest destruction. Millions and millions of hectares still await replanting - and we are forced to work on a shoestring budget.
In 1987, the Vietnamese Ministry of Forestry developed a plan to replant 1.5 million ha of barren hills and to step up the rehabilitation of degraded forests. Unfortunately, lack of funding and resources has thwarted these efforts (see "Casualties of Vietnam's Recovery", New Scientist, 14 September 1991).
The mangrove and Melaleuca forests in the Mekong Delta were perhaps more seriously damaged in the war than any other forest type. They were repeatedly sprayed with Agent Orange herbicide and proved particularly susceptible to its effects. In all, defoliants eliminated 124 000 ha of mangrove in southern Vietnam, about 50 per cent of the mangrove forest of the country. Almost all of the Rhizophora, Sonnerata, Bruguiera and Nypa formations died. As a result, the fisheries and shrimp catches also collapsed. University of Montana zoology professor Egbert W. Pfieffer visited the defoliated areas in 1969,1971 and 1973. Of his boat journey through a mangrove area, he said: "It was one of the most shocking experiences of my life. We saw virtually no green living plants anywhere. It was just a solid gray scene of death".
The Melaleuca forests on the peaty soil behind the mangroves proved flammable in the dry season and many were also destroyed by napalm burning.
These two most badly damaged forest ecosystems are in a more advanced state of recovery than the inland tropical forests. After the war, a program was launched to replant the mangrove forests on the areas destroyed by herbicides. Large areas were replanted with seedlings of Rhizophora apiculata, but few trees survived, probably because the soil was too compacted for their roots to take hold. In the early 1980s, a new program replanted the area and today 70000 of these seedlings survive. The mangroves now yield a self-sustaining and profit-making source of fuel and construction wood. The leaves of Rhizophora are an important link in the food chain of fish and shellfish. Fallen leaves, decomposing in the mud or tidal water, supply an enormous amount of nutrients and thus support a great variety of life, especially such invertebrates as snails, crabs, shrimp and molluscs. As a result, the fisheries are coming back and the shrimp catch rises each year. Wetland birds that had completely disappeared from their roosts during the war have also returned. More than seven major bird roosts are now protected, and new roosts appear each year.
Unique flooded forest
Melaleuca, a 10- to 20-metre tall tree with a straight trunk and small, tough leaves, forms a unique type of flooded forest in the Mekong Delta. It once covered an area of 250 000 ha in low-lying, seasonally-inundated areas. But now there are only about 116 000 ha left. Fig palms and myrtle also grew here, and beneath the canopy was a tangle of climbing vines. Years of wanton cutting for fuelwood and land clearing has gradually reduced the Melaleuca forests, leaving stands of fern or bushy Melaleuca mixed with Phragmites and other wild grasses.
During the Vietnam War, US troops attempted to drain the flooded plain area by digging canals and force the resistance army out of its bases in the Plain of Reeds, an X00 000 ha portion of the Mekong Delta. The drainage was partially successful, and once the soil was dried out sulphur rose to the surface, producing dilute sulphuric acid and reducing the soil pH to 3.9 or lower. Crops, especially rice, could not be grown. People were forced to leave.
The residual water in the canals was affected even more than the soil. Its pH was reduced to 2.8. Freshwater fish and floating rice, once rich and important sources of food for local people and wildlife, gradually disappeared. At places where the canals had been dug, water quickly drained out during the dry season. The upper cover of the soil deteriorated. Constant burning further turned the biological carpet into low brush. Finally, the spraying of the plain by US troops with toxic chemicals and napalm destroyed the Melaleuca forests.
When the war ended, local people made tremendous efforts to restore agriculture on the plain. To dilute the acidity of the soil, they dug more canals to bring in fresh water, but progress was too slow at most places to check the continued denuding.
In time, the people came to realize that to make the plain prosper as farmland again, the soil had to be well-watered in the dry season and covered again with Melaleuca. Since then, the local people have built dikes to keep the water in the plain from draining into the canals in the dry season. They have also planted Melaleuca on thousands of hectares of acid soil, since it is the only tree species that can thrive in such conditions.
Now that their habitat has begun to be restored, the natural plants and animals are gradually returning to the plain. Not only freshwater fish, but also turtles, snakes, and especially birds have returned in surprising numbers. They include some rare species, such as the Sarus Crane, Painted Stork and Adjutant. In early 1986, with the help of researchers at Hanoi University, the people of Tam Nong District set up a reserve for the cranes. Now covering about 5 000 ha, it may soon be expanded to about 9 000 ha. The number of returning cranes has increased each year, and now more than 1 000 birds have been counted.
There is a Vietnamese saying: "Birds only stay in good lands". Apparently, the efforts of the people of the Plain of Reeds and Tam Nong District to restore the land of the Tram Chim Reserve have begun to pay off. The crane is a symbol of happiness and longevity in Vietnam, as in China, Japan and many other Asian countries, and its stylized image can be found in almost all pagodas, temples and other Buddhist places of worship in Vietnam. Now that this bird has returned, our country may again become a beautiful land of peace.
By Le Van Lanh
Beginning in 1961 and accelerating into the early 70s, the Vietnamese government resettled hundreds of thousands of Kinh people from the overpopulated lowlands of the Red River Delta into the "new economic zone" of the midlands' bordering the delta's alluvial plain. The goal was to relieve population pressure, while simultaneously developing a hitherto sparsely peopled region where settlement had been held back, partly by fear of once-endemic malaria.
But the road to ruin is paved with good intentions: in this case the result of migration was increased ecological destruction, which mounted as population rose in the new settlement area to its present density of 500-600 persons/km². The process of land degradation was due partly to the geographical and physical character of the midlands themselves, as well as the slash-and-burn agriculture traditionally practiced by local hill peoples. But the farming practices of the newly arrived Kinh people, which had worked well in the lowlands, were not adapted to their new environment and greatly aggravated the destruction. To reverse the damage, a new development model - based on the "agro-ecosystem" concept - had to be created.
Climate, soil and forests
Vinh Phu is the northern midland province of Vietnam, and is characterized by alternating narrow valleys and rounded hills, with relatively gentle grades of eight to 35 degrees, ranging from 10 to 150 metres above sea level. It has a tropical monsoon climate, the May to October rainy season accounting for 85 per cent of a mean annual rainfall of 1 550 to 2 500 mm. The rain often comes in intense showers of 3.7 mm per minute for 10 minutes. In contrast, the November to April dry season is punctuated by frequent droughts.
Most of the hill soils in the area are yellow and red soils, classified as Oxisols (according to the US taxonomy system) or ferralsols (according to the Unesco-FAO classification). In the valleys, the soils are alluvial and colluvial, or fluvisols according to the FAO classification. Due to high temperatures and humidity, the weathering process is rapid, with a weathering crust a dozen metres thick. Basic washout leads to increasing soil acidity, and clay formation in this acidic environment results in kaolinite clays with low absorption capacity. Iron compounds are dissolved and move freely from place to place, accumulating in the form of concretions and plinthite. On the hillsides, slate clay and metamorphic rocks (phyllite, gneiss, mica slate) are common, and the weathering crust in these rocks is rich in aluminum. Due to erosion it is also poor in alkaline and alkaline-earth metals, with a pH of 4.0 to 5.5. In the surface layer, humus content is one to two per cent, nitrogen 0.05 to one per cent, total phosphorus 0.03 to 0.06 per cent, and total kalium 0.15 to 0.5 per cent. The soil formed on rock (such as sandstone) is typically poor in iron, with bad structure. Soils in the valleys are very acid, and iron toxicity may be a major constraint to rice yields there.
Originally, the province was covered by tropical rainforests, with many strata. The indigenous tribal peoples who lived in the hilly areas practiced mainly Sweden (slash-and-burn) agriculture, clearing and burning forest to make space for growing dry rice, corn, cassava and tea, and rotating their fields every few years with fallow periods to protect soil fertility. This farming system can function well only if populations do not rise too quickly, and adequate fallow periods are maintained. If population pressures lead to shortening of the fallow cycle, land degradation is inevitable.
The influx of lowlanders brought fundamental changes, causing an
ecological imbalance. There are at least six ways to create such imbalances and,
together, local and newly arrived farmers in the midlands employed all of
squandering forest resources through deforestation, by clearing forests for land
reclamation and over-exploiting them for timber, fuel-wood and industrial raw materials;
practicing shifting cultivation with insufficient fallow periods;
mono-cultivating annual crops on sloping land;
using inappropriate cultivation methods to grow perennial crops;
Rapid population growth created increasing demand for fuelwood and food. The clearing of forests, both for wood and new cropland, accelerated, and the burning of dry residues destroyed biological activity in the humus of the soil surface layer. This led to deterioration of the soil structure and increased erosion.
The Kinh, though good soil managers on their home grounds, had little experience in farming hilly areas. Cassava, for example, is the second most important crop in the midlands, next to rice. But the Kinh paid little attention to soil conservation when planting it. When cassava is grown as a monocrop on steep slopes, it provides little protection to the soil under it, which is prone to washing away. A particularly heavy rain ( 170 mm) on 9 April 1982, for example, washed away 200 tons of soil from a single hectare of newly-grown cassava. Because of low soil fertility, cassava production was low, at around three to five tons/ha/year.
Tea is another important cash crop. But tea plantations were neglected and not intermixed with other crops. Such plantations develop slowly and tend to become covered with grasses. The soil is more exposed to the sun, increasing erosion. Overgrazing by livestock on the hills further aggravated the erosion problem.
Meanwhile, the Kinh planted paddy rice in the narrow valleys, where it was frequently destroyed by floods and siltation, caused by the erosion in the hills. Rice productivity remained low, decreasing quickly after the first harvest on new land.
The result of all these errors was severe land degradation, increasingly bare hills and steadily decreasing crop yields.
Accelerated erosion, leaching and degeneration of soil structure
all contribute to degradation. So
does formation of the aforementioned concretions and plinthite from aluminum and iron oxides. This is especially serious in soil formed on ancient alluvial deposits and at the foot of hills, where the ground water table is high. The effect of plinthite is to decrease permeability and increase erosion. The thickness of the soil layer on top of the plinthite zone is crucial to the workability of the soil and plant growth - in some places in Vinh Phu these soil horizons disappeared entirely. This made the land barely usable, lowering crop yields.
Human inroads eliminated most of the primary tree species, leaving only secondary forest made up of such species as Canarium album, Litsea cubeba, Liquidamba formosana, Mangletia glauca, Styrax tonkinensis, Cinanmomum album and Oronsia tonkinensis. Most of the region's vegetation became savannah, with bushes and herbs, including Rhodomyrtus tomentosa, Melastoma candidum, Dieranontesis linear-is and Hedyotis auricularia.
Rehabilitation was possible, but only if it was tailored to the natural conditions of Vinh Phu Province, its topography and soil characteristics, and - of crucial importance - the social factors from which poor practices stemmed. There had to be changes in land use and management, as well as water conservation and control of soil erosion. This involved looking at the complex of people and their environment in terms of interlocking systems - more specifically, the agro-ecosystem concept, described by Kanok Rerkasem in his 1989 paper, Agro-ecosystem and rural resource analysis (the SUAN Secretariat, Farming Systems Research Project, Khon Kaen University, Khon Kaen, Thailand) and in Cuc, Gillogly and Rambo's Agro-ecosystems of the midlands of northern Vietnam (see below).
This approach considers several system properties, but especially productivity and sustainability. It assumes that a system will respond as a whole to a given stimulus or change, even if the stimulus is applied to only one part of the system.
Vinh Phu's problems were confronted on a variety of fronts:
Improving land use - Intercropping was a basic tool. Annual crops were planted with leguminous and green manure plants in such combinations as cassava and peanut, cassava and oregon pea, maize and soybean, cassava and Tephrosia candida. With intercropping, crop yields rose to 12-18 tons per hectare of fresh tuber cassava in fertile soil and 510 tons in degraded soil; 1 800 kilograms per ha of maize grain; 500-800 kg per hectare of peanuts in dry nut form; I 000 kg per hectare of soybean seed. There was a mass of fresh green matter to improve the soil: 19 tons per ha from peanut and 12-18 tons per ha from Tephrosia candida. The soil structure improved as its water-holding capacity and permeability increased, and because the soil was covered, losses caused by water erosion diminished.
Manure was allocated first to rice fields and homegardens. If any was left over, it went to upland fields. Cassava fields received 5.4 to 13.5 tons per ha. Chemical fertilizers were also used, but in relatively small amounts.
Redesigning tea plantations - The redesigning of tea plantations started with planting trees. Tephrosia candida was placed on ridges and hill roads to provide shade for the tea plants and soil cover, preventing erosion, holding moisture and fixing nitrogen. The trees' litter was left on the hill to enrich the soil. Cassia siamea and Vernicia montana were scattered through the plantations at a density of 150 to 200 trees per ha to shade the farmers as well as the plants they were tending.
The tea was planted along the contour of the land in rows 50 centimetres wide on the surface of the soil, 40 cm deep and 30 cm wide under the soil. The young plants were covered with rice straw and dry grasses to maintain soil moisture. Urea was applied at the rate of 50 to 135 kg per ha and phosphorus at the rate of 50 to 270 kg per ha. The plantations can yield about six to eight tons of wet tea per ha over 40 to 50 years, but setting them up is not cheap. The design costs US$500 per ha.
Reforestation - Native trees, including Mangletia glauca, Styrax tonkinensis, Cinanmomum album. Melia azedarach, bamboo, jackfruit, persimmon and Iychee, were used for reforestation. They were intercropped with hill rice, cassava, corn, peanut, soybean and pineapple in the early stages, as in the so-called taungya agroforestry system.
Plantations of fast-growing eucalyptus were developed during the 1980s on large sections of barren hill lands, to provide raw material for the paper mills of Vinh Phu Province. But it was found that the soil under the plantations became compact and dry. It was suspected this was because the fallen eucalyptus leaves contained Cinoel, which inhibits development of both flora and soil micro-organisms. To deal with this problem, starting in the late 1980s, legume trees such as Acacia mangium, Acacia auriculiformis and Tephrosia candida were inter-planted with eucalyptus. In such mixed forests, soil humidity is 20 to 30 per cent higher and the humus content 15 to 25 per cent higher than in forests where eucalyptus grew alone.
Homegardens and the (R)VAC system - The rural landscape of Vinh Phu Province is fairly complex, and the pattern of land use reflects this. The three major elements are (1) valleys between hills, (2) household plots and associated homegardens and (3) sloping uplands. The (R)VAC system, an acronym based on four Vietnamese words, consists of R=rung= forest, which is a new component, V=vuon= gardens, A=ao=fish ponds and C=chuong=animal pens. The government has promoted VAC systems since 1981 in recognition of their contribution to household nutrition. In Vinh Phu Province, each family was given lifetime tenure on 300 square metres for a garden, which they could enlarge by paying taxes on the additional land. (R)VAC makes use of all three elements of the landscape:
(1) In the valleys, the principal land-use systems are paddy fields and water re sources. The paddy fields are on moderately flat, terraced and bounded lowland. Farmers used liming to control soil acidity and intercepted the interflow and sediment to alleviate the problem of iron toxicity. The reservoirs, ponds and streams, found mainly in the valleys, are used for irrigation, aquaculture, care of livestock and washing. The fish raised in ponds and reservoirs provide the household with animal protein, and household and animal wastes may go to feed the fish in the ponds.
(2) The homegarden is located on the lower part of a hillside, planted with vegetables, trees to provide fruit and wood and medicinal and decorative plants. Oranges, lemons, pomelo, grapefruit and papaya were interplanted with tea. Bamboo, rattan and other trees planted at the foot of a hill not only provide wood but serve as a fence, which halts landslides and prevents siltation of fish ponds and reservoirs in the valley.
(3) Upper slopes and hilltops were used for agroforestry, collection of wood for fuel and construction, and some grazing. Indigenous, fast-growing tree species like Styrax tonkinensis and Manglietia glauca were planted along with exotics like Eucalyptus camaldulensis mixed with Acacia mangium and Acacia auriculiformis. At the start of the program, perennial trees were mixed with Tephrosia candida to prevent soil erosion and maintain moisture in the soil.
Lower slopes of less than 35 degrees were devoted to tea
plantations. Slight slopes next to the household plot also tended to be planted
with tea or cassava. The tea was intercropped sparsely with trees like Cassia
siamea and Vercinia montana to provide shade and maintain soil moisture and
Tephrosia candida to fix nitrogen.
Water conservation/erosion control -
Broadly speaking, water conservation is the most important part of soil management. Its objective is to increase water penetration into the soil and the capacity of soil to hold water. This is done by decreasing surface runoff and erosion and providing enough water for crops during periods of drought. This was achieved in Vinh Phu by building reservoirs and maintaining cover on the soil surface.
The reservoirs were important both for the water balance in the upland and for flood control in the lowland. Reservoir water can be used for irrigation during the dry season. It also changes the microclimate around the reservoirs, increasing the moisture in the air, lowering the temperature and raising the ground water level. Vegetation near reservoirs grows rapidly.
The soil was covered by mulching with dry grasses, litter and Tephrosia candida, Styloxanthese gumilis and other leguminous plants, using such multiple cropping systems as intercropping, crop rotation and sequent cropping and preserving natural secondary vegetation in fallow areas.
Tephrosia candida - Tephrosia candida, a leguminous tree that grows as a low shrub, played a key role in rehabilitation, improving soil fertility within two to three years and helping to control erosion and conserve water. It decreased evaporation and lowered soil temperature so that soil moisture increased. It prevented soil loss, supplied organic matter and nutrients and improved soil structure. Along with the characteristics common to all leguminous trees, including the capacity to fix nitrogen, produce seeds prolifically and survive under difficult conditions, Tephrosia candida has leaves of a size useful in agroforestry. Most important, it grows rapidly and well in very dry soil where Leucaena glauca, famous throughout Southeast Asia, cannot grow at all.
Tephrosia candida can produce 12 to 18 tons of biomass per hectare per year when mixed with cassava and 20 to 40 tons, sometimes more, in monoculture. Its biomass makes excellent green manure because of the high nutrient content. When it was planted with food crops on bare hills where other species could not grow, nutrients in the soil increased 30 to 35 per cent and the cassava yield 25 per cent. The tree was also planted to shade young eucalyptus and other plants, and its leaves were left to decompose for nutrients.
Social factors - In planning rehabilitation, it was recognized
that social factors - particularly population pressure and landownership - are
crucial to the use and misuse of land. A national family planning program now
aims at lowering the rate of population growth from the
present 2. 1-2.2 per cent to 1.7 per cent by the year 2000.
Long-term land tenure and tax exemption on degraded land are also being used as incentives for rehabilitation and conservation. This is a new departure for Vietnam. During the Colonial period, most land was privately owned, and many peasants were landless laborers. In the land reform program of 1955-56, the state expropriated land and redistributed it to farmers. In 1960, most of the land in North Vietnam was put under the management of cooperatives and state enterprises, which discouraged farmers from paying attention to soil conservation and improvement of soil fertility.
Since 1989, however, paddy fields, forests and hill land with crops have been allocated to households. Land tenure is 25 to 50 years, encouraging farmers to invest in fertilizer and learn advanced agricultural techniques to increase crop yields.
The results have been generally good. Many farmers have used their lands rationally and raised productivity, although some continued to grow cassava alone on steep slopes and eucalyptus in dry soil, often because of a lack of funds. Farmer income is low and adequate credit is not available, so they cannot always afford to invest in rehabilitating their land.
Overall, however, the ecological models created over the last nine years have won local support. Because the objectives satisfied local needs, local people supported them. Truong Trung, chairman of the provincial Science Committee, gave an enthusiastic report on agroforestry models built since 1986 in the Thanh Hoa, Doan Hung and Lap Thach districts:
"This is a widespread, integrated study concerning the environmental ecosystems, cropping systems and rehabilitation of degraded land in Vinh Phu, which has been accepted and widely applied by local people and highly appreciated by local and international visitors", he said. And, he added, not only did the project result in increased production, it also provided for greater collaboration in science and technology between localities and the government.
Much remains to be done, but what appears to be a successful approach is now established, on which future efforts can build.
Conjuring crops from fire, mud and ash
by Paul Icamina
After the smoke, floods and volcanic violence of the erupting Mount Pinatubo finally subsided, all efforts in the Philippines focused on the task of rehabilitation - especially of the scorched and broken farmland surrounding the mountain, on which thousands of families had depended for sustenance (Ceres Nos. 131 and 133).
But when B.S. Vergara, a plant physiologist, and V. Coronel, assistant scientist, at the Philippines-based International Rice Research Institute (IRRI) searched their computer files for information on growing crops in farmlands covered with volcanic ash and lahar (volcanic debris and mud mixed with water), they found nothing. "Althrough the Philippines has several active volcanoes, we have little experiecnce on the controlled revegetation of volcano-affected areas", they admitted. So they, and other researchers to whom the country looked for guidance, turned to the earlier eruptions of Mount Saint Helens in the United States and Mount Galunggung in Indonesia, searching for answers.
From the Mount Saint Helens eruption, they learned that Central Luzon could expect floods because ash lacks continuous pores for capillary and saturated flows. Water tends to remain longer on the surfaces of the ash and lahar-covered soils, and since canals are clogged, lateral drainage is poor. Acting as a surface mulch, the ash layer also reflects solar radiation, and because of its white to pale gray color, it increases photosynthesis, but lowers soil temperature and water evaporation.
Studies near Mount Galunggung show that crop yields are still high in areas covered by up to 20 centimetres of volcanic material, but productivity declines in thicker deposits. Dr A.M. Fagi, a graduate of the University of the Philippines College of Agriculture who worked on crop establishment in the ash and lahar - covered areas around Mount Galunggung in 1982, found that yields of rice and other food crops were high when the proportion of volcanic materials to soil was up to 5:5 and 7:3. The addition of about 20 tons of manure or other organic material per hectare to the volcanic deposits improved the soil for crops. Dumping Manila's organic garbage has been suggested for the Mount Pinatubo area.
The Indonesian experience also indicated that, where the volcanic deposit is under 20 cm deep, the cropping pattern should be rice-rice-corn/soybean or rice-rice-leaf onion. For 20-30 cm deposits, volcanic material should be plowed dry and organic manure mixed during plowing. Food crops can be planted in the early rainy season but rice and corn are not recommended. If the volcanic deposits exceed 50 cm, pineapple would be suitable because it thrives well in sandy soil with a pH range of 4.5-7.5 and requires minimum care and inputs. Hybrid coconuts can also be planted. In Indonesia, fruits like guavas, jackfruit, papaya and banana grew even better than before Mount Galunggung erupted. The Philippine program Building on the knowledge gained from other countries' experiences, the Philippines' post-eruption Agricultural Rehabilitation Program - in effect, a kind of triage system - divided the Mount Pinatubo disaster area into four zones, according to the amount of sand cover and the severity of damage:
* Zone A - Land with more than 15 cm of ash fall and upland
areas deeply covered with sand, which is considered beyond recovery.
* Zone B - Land with 7.5 to 15 cm of ash fall and lowland towns currently inaccessible, which will need clearing for agriculture.
* Zone C - Land with less than 7.5 to 10 cm of ash fall and lowland towns slightly or moderately affected, which will need intensified assistance in order to produce enough food to meet the region's needs.
* Zone D - Land with less than 7.5 cm of ash fall, which is only slightly affected and can easily be rehabilitated.
To reclaim land for agriculture, the three basic considerations are availability of water, the depth of ash and sand deposits and the type of crop to be grown. Most of the areas to be reclaimed are Zone D lowlands, where ash and sand can be mixed into the soil and two crops of rice are possible because water is available to sustain growth over two seasons.
If the water supply during the dry season is insufficient, rice can be grown during the wet season and vegetables or corn during the dry season. Vegetables recommended for affected areas are string beans, mung beans, winged beans, peanuts, asparagus, cabbage, onions, tomatoes, eggplant, okra, cucumbers, watermelon, cantaloupe and garlic.
Corn and sugarcane, which have high tolerance to arid soil conditions, are highly recommended for planting in non-irrigated lowland areas.
In upland areas, mostly Zone C, and particularly where the volcanic deposits are greater than 20 cm, the recommended crops are fruit trees like jackfruit, guyabano, citrus, mango, cashew, guava, coconut and avocado, fruits like pineapple and root crops like cassava and sweet potatoes.
Fodder can be produced in rolling and sloping areas of both Zones C and D, where soil conditions are not suitable for crops. Under prevailing conditions of low soil fertility and poor water-holding capacity, leguminous fodder trees, leguminous crops and other pasture crops are highly recommended.
Growing rice in lahar
According to the Philippines Department of Agriculture, rice - the principal food in the area of Mount Pinatubo's eruption - could also grow well in lahar. In Zambales, Pampanga and Tarlac provinces, where rice is grown over more than half the cultivated areas, 18 per cent of the rice lands were hit by the eruption. About 20 000 ha of rice lands were heavily damaged by lahar and 10 000 ha by ash fall.
The department recommends four early-maturing rice varieties for planting on lowland or rain-fed farms: IR-72, IR-64, IR-66 and IR-61. "But fertilizers, particularly nitrogen fertilizers, may have to be applied in several doses", R.Y. Reyes, head of IRRI's Soil and Water Sciences Division, and H.U. Neue, plant physiologist at IRRI, said.
"Organic matter should be added to increase cation (positively charged ion) exchange capacity as well as water-holding capacity", Reyes said. "Farming practices that minimize water percolation should be studied. The practicality of compaction to increase soil density should be assessed. Compaction has been suggested as a way to get the benefits of puddling (a traditional method of tillage for lowland rice) without puddling".
To ascertain whether rice could be grown on volcanic material, a preliminary study was made in the IRRI greenhouse using four kilograms of lahar set in five-litre pots. Pre-germinated seeds of IR-64 were dibbled into each pot.
Nitrogen fertilizer treatments were applied either as a single basal dose or in three equal doses (basal, 3 WAS, 6 WAS) at the total rate of 50 ppm. To some pots, phosphorus and potassium were added at the rate of 25 ppm as a single basal dose or in three equal doses as in the nitrogen fertilization. An additional treatment involving 10 equal doses of nitrogen applied weekly at the total rate of 50 ppm was included to examine the effect of sustained nitrogen fertilization.
Results: where water is not limited and fertilizer, particularly nitrogen, is added, rice could grow fairly well. It appeared that nitrogen alone boosts rice growth. However, a high rate of nitrogen fertilization is required. Rice plants showed nitrogen deficiency symptoms seven weeks after sowing. Plants fertilized with a single basal dose of nitrogen showed initial better growth. At six weeks after sowing, no apparent difference in growth was observed between the basal nitrogen application and the split applications. There was no further improvement in growth with the addition of phosphorus and potassium.
A field experiment
Percolation of irrigation water and leaching losses of soluble nutrients could not have occurred in the container pots, but field tests on a rice field covered by more than one metre of lahar in Bacolor, Pampanga Province, showed results comparable with the greenhouse experiment. With proper fertilizer management, growth of rice plants is normal both in the greenhouse and in the field. Corn plants planted on lahar in Bacolor exhibited early leaf yellowing, but this was expected because corn normally needs a high nitrogen level.
By and large, if grown to rice, the texture and structure of lahar implies high percolation rates, poor water economy and high soluble nutrient losses. The single-grain loose structure of the volcanic material makes it highly permeable to percolating water. Water would be difficult to impound. Bunds are difficult to stabilize as the material easily slakes in water. High amounts of sodium in the ash favor slaking. When flooded, leaching of applied fertilizers would be high.
IRRI studies show that some rice varieties are better established on the lahar than others. Of the 40 varieties/lines tested, there were seven outstanding entries. The three top entries were those grown in the acidic areas of Indonesia.
One immediate problem is irrigation where there is no water. The Bureau of Soils and Water Management's Soilsearch Centre, which carries out research on soil management, is promoting drip agriculture using two-gallon (7.6-litre) plastic containers.
"Applying lime and organic fertilizer will solve the acidity", Dr Rogelio N. Concepcion, Soilsearch project manager, said. "As soil material, lahar is better than volcanic ash as it is composed of clay soil and volcanic ash".
Areas covered in 5-10 cm of volcanic ash can recover in three weeks, he added. In areas with highly sulphuric soil of more than 300 ppm, the easy solution is to apply "plenty of organic material", about 500 kg per ha, to nurture micro-organisms that remove the sulphur. "In just five days, instead of three weeks, the soil's sulphur content is back to normal", Concepcion said. Trials showed that when fresh ash is incorporated with the original soils the initial increase in the available sulphur content levels off after about 30 days. In good drainage, it may diminish even faster.
Sugarcane, banana and other deep-rooted perennial crops may be grown immediately in areas covered by more than 10 cm of volcanic deposits. With aging and weathering, the plowed ash and sand deposits decompose, producing a very fertile soil for rice.
Ash deposits of up to 15 cm are manageable because plows can reach that depth. "Places covered in one metre or more of lahar should not be treated as a problem but as a resource base", Concepcion said. "For example, use these areas as an anchor for plants, not for tilling". The Department of Agriculture's instructions for do-it-yourself rehabilitation include:
For coconut trees, cut and burn broken or dead leaves. Then apply I kg of table salt per tree for fast recovery. Follow this with 500 grams of urea or four kg of organic fertilizer per tree, applied one metre away from the tree base. Mix fertilizers thoroughly with topsoil.
For mango trees, prune broken or dead branches. Paint the cutoff portion with coal tar.
Replace dead trees, getting planting materials from the Department of Agriculture.
For fish ponds, first collect pond soil and water samples and send them for analysis to the Bureau of Soils and Water Management Laboratory. Tests will show if ash and sand deposits are dangerous to fish stocks. Experts will then recommend the kind and amount of fertilizer needed to enhance the growth of natural fish food like planktons.
The Soilsearch Centre recommends "basket farming" in which plants or trees are planted in biodegradable bamboo baskets filled with healthy soil and transplanted, basket and all, to lahar-covered areas. As the plant matures, it outgrows its basket and takes root in healthy soil beneath the lahar.
Basket farming was developed from planting techniques of local farmers. Some farmers in Cavite Province plant their crops by digging holes several feet deep through adobe layers. Root crop farmers in Bohol Province do the same in farms covered with rocks where plowing is impossible.
Soil manure "basket farming" is recommended in areas where the
scraping of ash is almost impractical because ash-and-lahar deposits are more
than 15 cm deep. It is also a good alternative in areas
where farmers have no access to tractors and in poorly drained upland areas where soil acidity has already set in.
The seedlings are planted in baskets containing 70 per cent soil, 20 per cent organic manure or fertilizer and 10 per cent urea fertilizer. If the crops are vegetables and other annuals, an ordinary native basket about 30 cm high will do. If tree crops are planted, then the container must be at least 45 cm high, the equivalent of a medium-sized native basket or a rice sack cut in half. A fruit tree can be planted in the centre of the basket and one or two legume vegetables added.
A hole large enough to accommodate the soil mixture is dug in the lahar and ash-covered soil, making sure to remove the thin, impermeable layer of fine ash that impedes infiltration of rainwater into the subsoil and to expose the surface of the original soil. The basket's circumference is covered with plastic to prevent further ash and lahar deposits from choking the healthy soil.
Ash fallouts are expected to lower fertility and raise requirements for water and fertilizer, but areas covered with fine, sandy materials in the ash fallouts will have improved water-holding capacity. It is useless to irrigate land covered with lahar or ash deposits more than 30 cm deep until the cover is scraped off. Volcanic ash by itself is unlikely to provide a suitable growth medium for many years because it may be acidic and contain toxic elements.
The Soilsearch Centre recommends a 50:50 ash-soil ratio. Draft animals can turn ash up to about six cm deep into the soil, and tractors about 10 cm.
The major problem with the land around Mount Pinatubo is its high sulphur content, which has toxic effects on young rice plants and other upland crops like eggplants, mung beans, and peanuts on farms with poor soils and poor land drainage, especially irrigated rice lands. The roots of young seedlings cannot penetrate the 2- to 4-cm deep black soil layer where soil and ash mix. In order to avoid damage from sulphide toxicity, planting and transplanting of rice plants must be done two to four weeks after the area has been submerged in irrigation or rainwater. Alternate irrigation and drainage is recommended to flush out toxic sulphides, but the farm must not be drained beyond field capacity or to the point where the soil surface starts to crack.
On lowland rice farms and farms with poorly drained soils, organic fertilizers can be applied about two to four weeks ahead of actual planting/transplanting to speed up the release of sulphides and improve organic matter. On upland farms with good land drainage, two or three applications of organic fertilizer can improve the fertility of areas with ash deposits.
by Bob Petersen
In the 1960s, at great expense, Danish engineers "channelized" the Skjerna River, removing the vegetation that grew alongside it and deepening and straightening the river bed, in order to speed drainage of its adjacent wetlands and claim them for agriculture. The Skjerna's catchment area was the second largest in the country, and hundreds of farms were enlarged as a result.
Thirty years later, however, authorities admit the project was a mistake. The Danish Parliament has voted to restore the Skjerna to "its former channel and ability to overflow its banks", at a cost of some US$10 million. In a stroke of unusual irony, the same engineering firm that originally channelized the river has been assigned to undo its own earlier work.
Denmark isn't the only country where the policies of past decades are being reversed. Throughout the world, small streams and rivers have for years been the object of "improvement" efforts similar to the first Skjerna project. Such projects unquestionably increased the amount of land available for farming. But, it is now realized, they also destroyed many functions natural streams and stream-side vegetation perform that benefit mankind - functions we can ill afford to neglect.
One of these is the ability of streams to absorb urban, industrial and farm waste, something they have been doing for centuries. Not only do streams carry waste away but, if they are not overloaded and their physical structure is not destroyed, they gradually reduce the concentration of nutrients, organic compounds, metals, and toxic pollutants such as pesticides, herbicides and excess chemical fertilizers that run off from farm fields. In some places where the ability of streams to do this has been compromised through channelization, too much nitrate is leaving farms and entering the ground water, where the resulting high nitrate levels pose a health hazard to drinking water.
In addition to this so-called "self-cleaning" ability, a healthy stream provides habitat for fish living in the channel, as well as wildlife and medicinal plants living along its margin. In arid and semiarid areas, the shading canopy of streamside vegetation can effectively reduce water temperatures, thus minimizing moisture loss through evaporation.
Attention throughout Europe is increasingly focused on reversing the loss of these important stream functions, via practical, cost-effective ways that don't disrupt the productivity of surrounding farmlands. (Further catalyzing this trend is the realization that while farmland and farm products were in high demand in the 1960s, too much land was eventually converted to agricultural use, driving down farm prices.) Numerous restoration projects are under way. In Austria hydraulic engineers who were still channelizing streams only a few years ago now say such efforts are a thing of the past. Swedish engineers admit the hydraulic systems they developed to drain water from the landscape were too efficient, taking too much water from the catchment area at too fast a rate. An adequate solution to the resulting problems can only be implemented at landscape level, involving entire catchment areas, and including not only the channels themselves, but streamside vegetation zones as well. A complete change in the structure of the landscape is required, from a patchwork of fields to a mixture of fields and clean-flowing streams protected by a streamside canopy of vegetation.
This necessitates a plan that can take into consideration vast differences in local topography, economic resources, and the personal preferences of individual landowners. As far as possible, such a plan must also be simple, cheap and flexible.
Building Block model
One such approach is to see restoration measures as a series of Building Blocks, which can be combined in different ways over time according to landowner preference, landscape form and available funds. Installed together, these blocks can improve natural habitat, restore self-cleaning capacity, and reduce the loss of important nutrients from the landscape. While some measures are more important or costly than others, all are effective. They can be used individually or together.
The Building Block model can be described as a series of steps in three groups. The first group consists of three measures having to do with reestablishment of streamside vegetation. The second comprises three steps dealing with reducing the steepness of channel banks and changing channel shape. The third includes additional measures that help retain water in the catchment. The restoration measures in question are relatively independent, and, except for ( I ). do not necessarily have to be taken in the order given:
(1) Buffer strips - The first and most important restoration measure is to set aside a minimum 10-metre-wide strip of land between adjacent fields and the water, on both sides of the stream channel, along the entire length of the stream. These "buffer strips" reduce (or buffer) nutrient and sediment loss from the landscape, while also providing bird and plant habitat. They are the chief determinant of small stream physical structure, because their presence protects stream banks and streamside vegetation. They are the foundation for other restoration measures. The cost of setting aside buffer strips depends on land values. In Sweden, good agricultural land runs between US$3 000 and $5 000 per hectare. Assuming 10 metres on each side of the water, two ha/km of stream will have to be purchased for each kilometre of stream channel. Since most farmland is fairly flat, with a drainage density of roughly one km of stream/km² of landscape, setting aside two ha of land for stream restoration requires setting aside 0.2 per cent of the catchment. Actually, most land near streams is difficult for farmers to use, either because it is too wet or too close to steep channel banks. In addition, the cost of setting aside buffer strips has a hidden discount. Channels, in most farm areas, are about five metres wide at the top. That is 0.5 ha, or 5 000 m2 of land/km of stream, that is not being used. The total width of the buffer area will be 25 m, not 20 m, representing an immediate 25 per cent discount on the purchase.
(2) Revegetation - Buffer strips which have been under field crops should be planted first with fast-growing woody shrubs (in Europe, alder. Willow or aspen). Without replanting, buffer strips will still re-seed naturally, but the process would take up to seven years to achieve complete effects. A mixture of native riparian species is recommended for replanting. Exotic species should he avoided. The effect of replanting will be to eventually restore a landscape more in keeping with local architecture and other cultural appearances. Nor should the importance of the natural plant life that will recolonize the strip be underestimated. Vegetation will stabilize stream banks and inhibit erosion, while its canopy will prevent evaporation. Growth of indigenous plants will be stimulated, including medicinal or edible species. For example, sweet flag (Acorus calamus) is a common aquatic plant used in Europe, Asia and North America for its beneficial effects on the stomach, relief of chronic dyspepsia and as a sedative.
(3) Side slope reduction - A major source of sediment and phosphorus discharge into streams are small-scale land failures (caveins) along the channel. Normally they require re-channelizing and cleaning every one to 10 years, depending on soil structure and the discharge character of the stream. A simple method of limiting this is to reduce the channel side slope by half from the commonly used 50 per cent ( 1:1 or 45-degree) slope to a 25 per cent ( 1:3 or 22.5-degree) slope. The amount of soil that must be removed and spread on the surrounding land is slightly more than two cubic metres for every metre of channel restored. Given that 10 m have been set aside on each side of the channels the amount of land required to reduce the side slope to 25 per cent will be five metres, an area well within that already set aside. Side slope reduction brings several positive effects. First. it increases the width of the water channel, creating a small flood plain to dissipate hydraulic energy by flooding, rather than undercutting, side banks (a leading cause of erosion and slope failures). Second, it reduces the need for channel maintenance, conserving both money and the integrity of the stream.
(4) Meanders - Re-creating meanders in a stream that formerly had them will restore its most stable and natural physical state. This will simultaneously reduce nutrient loads by increasing the physical complexity and length of the channel. A meandering channel by definition is one with a channel length at least 1.5 times the length of the down-valley distance. Since many stream processes can be quantified on a length basis, a longer channel automatically has greater self-cleaning properties.
(5) Riffle pools - Where a slightly higher gradient is available, the physical complexity of the stream bottom can be increased by placing rocks at intervals, to produce riffle areas. These should be followed by pool areas. The natural dimensions of riffle-pool associations should be set so as to have one pair - a riffle and a pool - at a downstream distance of five to seven times the stream width. That is, for a one-metre-wide stream, a riffle-pool pair should occur every five to seven metres. The riffles should be about three metres long, followed by a two-metre-long pool. Actual spacing is not critical, however, since streams will re-adjust rocky sediments themselves during the first flood. Alternating riffle-pool sequences are an important aspect of restoring the within-channel habitat of small streams. In addition to stimulating re-oxygenation of the water via the increased turbulence in riffle sections, the clean rocky substrate forms prime habitat for many aquatic invertebrates and a feeding ground for fish. The pools provide rest and refuge areas for fish, as well as storage areas for organic material, which is slowly released into the stream.
(6) Ponds - Small ponds constructed within the flood-plain valley are an economical and multi-use restoration measure. Uses include water retention for irrigation, as well as habitat for raising fish or crayfish. The latter are a particular favorite of Swedish farmers. While ponds may be used for intensive aquaculture requiring fertilization, natural or extensive aquaculture is recommended for sustainable use. Ponds are usually sited off-channel, rather than in the stream itself. A typical small pond will retain organic material and nitrogen, which in turn enhance the value of irrigation water drawn from it.
(7) Riparian wetlands and swamp forests - Along many lowland
channelized streams are areas
which are seasonally difficult for farmers to plow, due to excess water. These swampy areas were often originally wetlands or swamp forests, and once restored will enhance wildlife conservation as well as water and nutrient retention ability of the area. In many European countries where excess nitrogen threatens to pollute surface waters, there is considerable interest in using wetlands as cost-effective nutrient reduction systems. Studies in Sweden, where there is a need to reduce the nitrogen load to the Baltic Sea by 50 per cent, estimate the cost of reducing each kilogram of nitrogen entering the Baltic would be only US$1 for wetland restoration, compared to $53/kgN for remedial measures in agriculture, and US$15 to $31/kgN for an increase in sewage treatment plant efficiency. Thus, stream-side wetlands and swamp forests can be an efficient solution to a regional problem.
The technology required for stream restoration is small-scale and has low maintenance and operating costs. This makes it especially useful for farmers in developing, as well as developed countries. It is based on common sense notions, which anyone living close to the land and depending on its long-term quality can readily comprehend. In Sweden, with its high standard of living and even higher taxation rate, farmers walk a tightrope between effective long-term farming practices and short-term economic constraints. However, in most European countries farmers know that new, simpler land management practices must be adopted. The landscape is currently being used only for short-term, non-sustainable economic gain, and they are concerned at the long-term crises to which this may lead.
When the Building Block model is explained to farmer cooperatives in Sweden, the response is usually positive. "Yes, we have to do something, don't we?" Then the details of how are discussed: "I can build a pond, but there is no place on my land for a swamp forest". This is how the Building Block model was developed - in discussions with farmers, as a "self-serve" system tailored to fit the individual farmer's financial resources and the landscape of his farm. Adopting any of the measures will bring positive benefits.
The orientation of the model and measures described were aimed originally at lowland streams, but the approach can be used to restore any stream and should be seen as a general strategy for both landowners and governments. Other restoration measures specific to regional problems and topography can be added to those already mentioned. The list should not be regarded as exhaustive or final, but as the starting point for many solutions.
Grassroots field work in Latin America
by Miguel A. Altieri
For most rural Latin Americans, the 1980s were an economic "lost decade", a period of crisis that imposed heavy social and environmental costs.
One of the few gains registered in this otherwise dark time may have been the delivery of a body blow to the credibility of many conventional, top-down agricultural strategies - and a corresponding rise of interest in what some call the "agro-ecological" approach. In country after country, farmers and rural villagers, in alliance with grassroots-oriented non-governmental organizations (NGOs), have been working out their own new, local cultivation and farming systems - and testing them successfully in the field. Though adequate methodologies for weighing the results are still lacking, these hundreds of individual efforts hold great promise for the development of more sustainable ways of growing food.
Before looking at some actual examples, which range from no-till farming on hillsides to the reconstruction of all-but-forgotten ancient Inca systems of high-altitude horticulture, let's put them in context:
Lessons from losses
The losses of the 1980s taught Latin Americans several lessons:
conventional, top-down development strategies are fundamentally limited in their ability
to promote equitable, sustainable development. Despite a succession of internationally
and state-sponsored development projects, poverty, food scarcity, malnutrition, poor
health and degradation of the environment are still common everywhere in the region;
agricultural modernization emphasizing high-input technologies, and proceeding without
effective land distribution, exacerbates environmental problems;
simultaneously, the failure of conventional development projects has legitimized the role
of NGOs, whose grassroots efforts directly target the poor and challenge top-down
food production requirements can no longer be considered apart from environmental
ones. Agricultural development cannot compromise the resource base.
Sustainability is emerging as a central development theme in the region, in government and international circles as well as among NGOs. The goal is to maintain agricultural productivity with minimal environmental impact, assuring adequate returns while providing for the social needs of the entire population. Unfortunately, there are no jiffy recipes for achieving sustainability, and both policy-makers and development workers seem caught up in a series of rhetorical arguments over such key questions as: should farm production for export or domestic use be stressed? Should efforts concentrate on boosting productivity on optimal or marginal lands? Should high- or low-input technologies be emphasized? Should high-yield or traditional varieties be planted? Should local farmers be included in research and development work, or not?
Dilemmas abound, while top-down projects sponsored by the state or international organizations often don't address pressing economic, environmental or regional production needs. or provide viable options for the mass of resource-poor peasants.
There are some 200 NGOs in the region, most of which have gone beyond the mere rhetoric of sustainability to concentrate on promoting technologies which are sensitive to the complexity of local farming systems. Many build on traditional farming knowledge, combining it with elements of modern agricultural science to boost production, while striving to achieve food security, biological stability, resource conservation and equity.
Of course, their efforts are not free of obstacles. Most NGOs are aware of their knowledge and technical gaps, and are interested in strengthening the technical capability of their personnel. While this want is being partly met by training and information exchange efforts coordinated by the Latin American Consortium on Agro-ecology and Development (GLADES), help is urgently needed.
The macro-economic conditions under which peasant production must operate also limit profitability at household level. NGOs must promote alternatives that are profitable, as well as ecologically sound, and the right socio-economic conditions are crucial for new strategies to be successfully repeated. The state's role is thus fundamental.
NGOs in the region have been actively trying out new farming strategies, based on local participation, skills and resources. Their approach gives unprecedented significance to local farmers' knowledge of their own areas' ecosystems - plants, soils and ecological processes - hence the term agro-ecology. The resulting agricultural approximation to the peasant production process is radically different from that of the Green Revolution or other high-input approaches (see Table). It also tends to be more socio-culturally acceptable, since it builds on local tradition. Techniques are ecologically sound because they don't radically modify or transform the peasant system, instead identifying traditional and/or new management elements that, once incorporated, lead to optimal production.
By emphasizing the use of locally-available resources, rather than expensive or hard-to-obtain imported inputs, these technologies are also more economically viable.
In practical terms, NGO programs emphasize six key points:
(1) Improving production of basic foods, including traditional food crops (Amaranthus, quinoa, lupine, etc.), and conservation of native crop germplasm.
(2) Recovering and re-evaluating peasants' knowledge and technologies.
(3) Promoting efficient use of local resources (land, labor, agricultural byproducts, etc.).
(4) Increasing crop and animal diversity in the form of polycultures, agroforestry systems, integrated crop/livestock systems, etc., to minimize risks.
(5) Improving the natural resource base through soil and water conservation and regeneration practices.
(6) Reducing the use of external chemical inputs, through developing, testing and implementing organic farming and other low-input techniques.
Despite insufficient and in some cases unreliable data, preliminary qualitative evaluations of some NGO programs show agro-ecological schemes have resulted in such tangible benefits for local populations as higher food production, regeneration and improved quality of natural resources, and higher use-efficiency of local resources. These successes are commendable, given the diverse socio-economic and biophysieal handicaps - from lack of access to land and low peasant family incomes to drought, frost and marginal soil - under which NGOs operate.
As already noted, appropriate means for evaluating the impact of such programs, and a satisfactory set of indicators to judge their viability, adaptability and durability, are in short supply. However, some progress has been made using two relatively new procedures: rapid rural appraisal (RRA) and natural resource accounting (NRA). RRA techniques emphasize the informal gathering and presentation of information, to foster a participatory process between local people and researchers. Technologies are evaluated through very general criteria, addressing environmental, economic and social concerns expressed by residents. NRA techniques incorporate environmental factors in conventional cost-benefit analyses, and can be used to measure the real profitability of alternative systems, including their effects on the natural resource base.
Despite the availability of these analytical tools - which may not be perfect but at least provide a starting point - and the obvious promise of the systems in question, little has been done by academic research institutions in the region to try to quantify the impacts of agro-ecological strategies.
The NGOs themselves, meanwhile, are action-, rather than research-oriented and must operate with minimal funds. Nevertheless, several have engaged in modest research efforts, yielding important information, as the following brief survey shows:
Conserving soil on slopes
A major challenge in Latin America is designing hillside cropping systems that maintain yields while reducing erosion. Several NGOs have taken on the challenge, and Loma Linda, in Honduras, has developed a simple, no-till system for steep slopes. Initially, weeds in a fallow area are simply cut with a machete or other tool, and no soil is removed. Using a hoe or small plow, small furrows are made every 50 to 60 centimetres, following the contour. Seeds and compost and/or chicken manure are placed in the furrow and covered with soil. As the crop grows, weeds are kept mowed to avoid excessive competition, with the cut weed biomass left between rows as a mulch cover and source of organic nutrients. Excellent yields can be obtained this way without using chemical fertilizers and - more importantly - without significant soil loss.
In a similar project in Guinope, Honduras, the private voluntary organization World Neighbors began a development and training program to control erosion and restore soil fertility. It introduced such soil conservation practices as drainage and contour ditches, grass barriers and rock walls, and emphasized such organic fertilization methods as using chicken manure and intercropping with leguminous plants. In the first year, yields tripled or quadrupled from 400 kilograms per hectare to 1 200 to 1 600 kilos. This jump in per-hectare grain production has assured the 1 200 families participating in the program ample grain supplies for the ensuing year. In the past five years, 40 other villages have requested training in the soil conservation practices.
Increased per-hectare productivity means most farmers are now farming less land than before, allowing more territory to grow back to pine forest or be used for planted pasture, fruit or coffee trees. The net result is that hundreds of hectares formerly used for erosive agriculture are now covered by trees, while production has not suffered.
In Peru, several NGOs as well as government agencies have programs to restore abandoned terraces and build new ones. In the Colca Valley of southern Peru, the Programa de Acondicionamiento Territorial y Vivienda Rural (PRAVTIR) sponsors terrace construction by offering peasant communities low-interest loans or seeds and other inputs to restore abandoned terraces, up to 30 ha at a time. The advantages of terraces are that they minimize crop loss risk in times of frost or drought, improve crop yields, reduce soil losses, and amplify cropping options because of the microclimatic and hydraulic advantages they provide. First year data from new bench terraces showed a 43 to 65 per cent increase in yield in potatoes, maize and barley, compared to yields grown on non-terraced slopes. A drawback of this technology is that it is labor-intensive. An estimated 2 000 worker-days would be needed to reconstruct one hectare in the Colca Valley region, although in other areas of Peru terrace reconstruction has proven less labor-intensive, requiring only 350 to 500 worker days/ha.
In the Central Cordillera of the Dominican Republic, most residents are resource-poor farmers devoted to subsistence agriculture, which combined with other social phenomena results in soil erosion. The short-fallow, shifting cultivation conuco itinerante cropping system dominates, but rarely permits forest regrowth. Rather, with land concentration and population pressure, it is converted to pasture, or simply becomes unproductive due to soil degradation and loss of fertility caused by the short fallow periods.
About 10 years ago, Plan Sierra, an ecodevelopment project, decided to break the link between rural poverty and environmental degradation. Its strategy involved developing less erosive production systems than the conucos used by local farmers. Controlling runoff would not only stop erosion, but could also make use of hydroelectric potential and make possible the irrigation of up to 50 000 ha of land in the downstream Cibao Valley.
The specific objectives were to allow farmers to make more efficient use of soil moisture and nutrients, crop and animal residues, natural vegetation and genetic diversity, as well as family labor, in order to satisfy their need for food, firewood, construction materials, medicinals and cash income. From a management viewpoint, the strategy consisted of a series of farming methods integrated in several ways:
soil conservation practices such as terracing, minimum tillage, alley cropping, use of
living barriers, mulch, etc.;
use of leguminous trees such as Gliricidia, Calliandra, Cajanus and Acacia spp., planted
in alleys, for nitrogen fixation, biomass production, green manure, forage production,
and sediment capture;
use of organic fertilizers based on optimal employment of plant and animal residues;
adequate combination and management of polycultures and/or rotations planted along
the contour and at optimal crop densities and planting dates;
conservation and storage of water through mulching and water harvest techniques.
Animals, crops, trees and shrubs are integrated, to produce multiple benefits, including soil protection, diversified food production, firewood, and improved soil fertility.
Since more than 2 000 farmers adopted at least some of the improved practices, an important task of Plan Sierra was to determine the erosion reduction potential of proposed systems. This was difficult because most methods of estimating erosion aren't applicable to farming systems managed by resource-poor farmers under marginal conditions. Given the project's lack of funds and research infrastructure, a simple method using measuring stakes had to be devised, for employment on both traditionally-managed and improved conucos.
Figure (a) depicts the cumulative erosion rates of three traditional and one improved system, based on 1988-89 field data. Although rates were unacceptably high in all systems, the alternative system recommended by Plan Sierra (Conuco PMA) exhibited substantially less soil loss than the traditional shifting cultivation, cassava and guandul monocultures. The Conuco PMA's positive performance seems related to the continuous soil cover provided by intercropping, mulching and rotations, as well as the shortening of the slope and sediment capture produced by alley cropping and living barriers.
Plan Sierra's simple but effective methods of estimating soil loss are providing useful data. In most cases, measured erosion rates obeyed the determinants of slope, rainfall and soil cover. Given the ecological variety of the area, however, it is difficult to generalize across systems.
Re-creating Incan agriculture
In Peru, a new enthusiasm for ancient technologies extended to rescuing an ingenious system of raised fields that evolved on the high plains of the Peruvian Andes about 3 000 years ago. These waru-warus, consisting of platforms of soil surrounded by ditches filled with water, were able to produce bumper crops in the face of floods, droughts and the killing frosts common at altitudes close to 4 000 metres. Around Lake Titicaca, remnants of more than 80 000 ha of such platforms can still be seen.
In 1984, several NGOs and state agencies created the Proyocto Interinstitutional de Rehabilitation de Waru-Waru en el Altiplano (PIWA) to assist local farmers in reconstructing the ancient farms. The combination of raised beds and canals has proven to have remarkably sophisticated environmental effects. During droughts, moisture from the canals slowly ascends to the roots via capillary action, and during floods, the furrows drain away excess runoff. Waruwarus also reduce the impact of temperature extremes. Water in the canals absorbs the sun's heat by day and radiates it back at night, helping to protect crops from frost. On the raised beds, night temperatures can be several degrees higher than elsewhere. The system also maintains soil fertility. In the canals, silt, sediment, algae and plant and animal remains decay into a nutrient-rich muck which can be dug out seasonally and added to the raised beds. Soil analysis of samples from reconstructed waru-warus showed increased levels of nitrate nitrogen, phosphorus and potassium, as well as a pH ranging from 4.8 to 6.5, optimal for potato growth.
These environmental effects determined the high productivity of the waruwarus, compared to that of chemically fertilized pampas soils. In Huatta District, waru-waru fields exhibited a sustained potato yield of eight to 14 tons per hectare per year, comparing favorably with the average Puno potato yields of one to four t/ha/yr. In Camjata, potato yields reached 13 t/ha/yr and quinoa yields reached two t/ha/yr in a 12-hectare waru-waru area built by local farmers with the assistance of an NGO, the Centro de Investigacion, Educacion y Desarrollo (CIED).
This ancient Incan technology is proving so productive and inexpensive that it is being actively promoted throughout the Altiplano in preference to modern agriculture. It requires no modern tools or fertilizers. The main expense is for labor - requirements vary from 200 to 1 000 worker days/ha - to dig canals and build up the platforms.
In situ conservation in Chile
The archipelago of Chiloe, a group of islands in southern Chile, is one of the centres of the potato Solanum tuberosum L., and collecting expeditions by researchers over the years found a great diversity of native potato varieties. In 1975, Chilean botanists collected 146 different samples of native varieties, the most prevalent being so-called michunes coloradas y moradas and the clavelas. These varieties are highly adapted to the region's range of ecological conditions and are crucial to subsistence production.
Starting in the early 1940s the Chilean government introduced several European and North American varieties (some originally bred from Chilotan material). In areas close to urban and market centres, farmers have abandoned most native varieties and adapted such introductions as Desiree, Industrie, Condor or Ginecke, which have greater commercial demand. Not only have these introductions contributed to the extinction of native varieties, but they brought diseases with them (Ceres No. 130). Around 1950, Phytophthora infestans devastated most potato fields, especially damaging native varieties that had never been exposed to the exotic pathogen and hence lacked resistance.
To slow genetic erosion and recover some of the native potato germplasm, the Centro de Educacion y Tecnologia (CET) initiated an in situ conservation program at its peasant training centre in Notuco, near Chonchi, as well as in several neighboring communities. In 1988, CET technicians surveyed several farm areas of Chiloe and collected hundreds of samples of native potatoes still grown by small farmers. A live collection (garden seed bank) of 96 native varieties was established at Notuco, with varieties planted in rows of five to 10 plants in a 0.5 ha plot. Varieties are grown every year, and subjected to selection and seed enhancement.
In 1990, CET initiated an in situ program involving 21 farmers in five rural communities (Dicham, Petanes, Huitauque, Notue and Huicha). Each farmer is given samples of five varieties to grow in his potato fields. After harvest, farmers return part of the seed production to CET for its garden bank, exchange seeds with other farmers, or plant the seeds again. As more farmers are involved in the project, CET will be able to select varieties based on farmers' actual needs and locally desirable characteristics. Selected varieties will be propagated and distributed among the farmers. Excess seeds could also be sold or exchanged for seeds of traditional varieties not yet in CET's collection. This will allow a continuous supply of valuable seeds to resource-poor farmers for subsistence, as well as create a repository of genetic diversity for future regional crop improvement programs.
Designing integrated systems
Since 1980, CET has engaged in a rural development program aimed at helping peasants reach year-round food self-sufficiency while rebuilding the capacity of their small landholdings. The approach has been to set up several 0.5 ha model farms where most food requirements for a family with little capital can be met. The critical factor is diversity. Thus crops, animals and other farm resources are assembled in mixed and rotational designs to optimize production efficiency, nutrient cycling and crop protection.
The model farm is a combination of forage and row crops, vegetables, forest and fruit trees, and animals. Components are chosen according to crop or animal nutritional contributions, their adaptation to local agroclimatic conditions, local peasant consumption patterns and, finally, market opportunities. Most vegetables are grown in heavily composted raised beds (five by one metre each) located in the garden section, each of which can yield up to 83 kg of fresh vegetables per month. The rest of the 200-square-metre area surrounding the house is used as an orchard, and for animals (a jersey and holstein cow, a sow, 10 laying hens, three meat rabbits and two Langstroth beehives). The rest of the vegetables, cereals, legumes and forage plants are produced in a six-year rotational system within a 4 200 m2 area adjacent to the garden. Relatively constant production is achieved (about six tons per year of useful biomass from 13 different crop species) by dividing the land into as many small fields of fairly equal productive capacity as there are years in the rotation. The rotation was designed to produce the maximum variety of basic crops in six plots, taking advantage of the soil-restoring properties and built-in biological control features of the rotation. Thus each plot receives the treatments described in Figure (b) throughout the six-year period.
CET personnel have monitored these systems' performances closely. Throughout the years, soil fertility has improved (P205 levels, which were initially limiting, increasing from five to 15 parts per million) and no serious pest or disease problems have been noticed. Fruit trees in the orchard and around rotational plots produce about 843 kg of fruit per year (grapes, quince, pears, plums). Forage production reaches about 18 tons per 0.21 ha per year. Milk production averages 3 200 litres per year, and egg production reaches a level of 2.531 units. A nutritional analysis of the system based on its production components (milk, eggs, meat, fruit, vegetables, honey) shows that it produces a 250 per cent surplus of protein, 80 and 550 per cent surpluses of vitamins A and C, respectively, and a 330 per cent surplus of calcium. A household economic analysis indicates that, given a list of preferences, the balance between selling surpluses and buying preferred items is a net income of US$790. If all of the farm output is sold at wholesale prices, the family could generate a net monthly income 1.5 times greater than the monthly legal minimum wage in Chile.
Farmer groups from local and distant areas live on CET's farms
for variable periods of time, learning by participation in planning, management
and evaluation of the organic production systems. After training, they are given
a packet of the seeds needed to set up a similar system of their own, and return
to their communities to teach their neighbors the new methods. Follow-up
evaluations in rural communities reveal that many peasants adopt a portion or
all of the CET design, in many cases modifying the technologies according to
their own lore and resources.
Two crucial dimensions
The challenges of Latin American agriculture are socio-economic and environmental, as well as technical. In this decade, they include two crucial dimensions: the ecological management of peasant agricultural resources, and the transformation of peasant communities into actors in their own development. Many NGOs have already adapted to these imperatives.
Examination of NGO projects applying agro-ecological concepts indicates that many of their proposed technologies and designs are highly productive and sustainable, as well as socio-economically and culturally compatible. In marginal environments, especially, they appear to be capable of greatly improving the resource base, along with the wellbeing of farm communities.
In contrast, development projects emphasizing such capital-intensive, high-input technologies as mechanization, agrochemicals, or imported seeds are proving ecologically unsound, as well as socially inequitable due to their tendency to benefit only a small portion of local populations. In terms of hectares planted, eucalypts - including more than 600 species of the genus Eucalyptus - may be the world's most popular trees.
Yet they may also be the most hated: Portuguese peasants brand them "fascist trees" or "capitalist trees", charging they bring profits to landowners and industrialists at the expense of the environment and the livelihoods of smallholders. In Iberia, they are seen as the deadly foe of the venerable cork oak (Ceres No. 127). Villagers in India, Thailand, Spain and Portugal have uprooted seedlings by the thousands, battled police and chained themselves to tractors to stop land from being cleared for eucalyptus plantings. Throughout much of Asia, the trees have such a reputation for being "detrimental to development" that donors shy at the very mention of their name. Planting eucalypts has been banned altogether in Kenya and parts of Burma (Myanmar).
That such hostility has developed toward such seemingly inoffensive things as plants can be traced to the real virtues of the trees themselves and the too-frequent vices - shortsightedness, silvicultural and environmental ignorance, sometimes outright greed - of growers.
Most maligned of trees
The eucalypts' defenders insist they are the most maligned of trees, not bad in themselves, only badly used. As Dr Y.S. Rao, senior forestry officer in the Bangkok Regional Office of the UN Food and Agriculture Organization (FAO), recently told Depthnews Science Service: "If you plant the wrong species in the wrong place for the wrong reasons, you are going to be disappointed, possibly dismayed, at the tree's performance". Eucalypt specialist and FAO consultant Chris Davis agrees. "How can you write off an entire genus, which has hundreds of species?" he asks. "What is important is to know how and where and when to plant. Whether you use eucalyptus or not depends on your needs".
Native to the islands east of the so-called Wallace's Line from Australia, where it is called the gum tree, south to Tasmania and north to the Celebes, Papua New Guinea, Indonesia, Borneo and Java, the eucalyptus genus takes its name from the Greek eu, meaning well, and kaluptos, meaning covered, the latter referring to the trees' covered flowers. Generally fast-growing and highly adaptable, eucalypts can produce large quantities of wood in poor soil, with little labor. They are cultivated in more than 100 countries, and new species are still being discovered. These may range from towering giants of 90 metres to dwarfs known as "mallees", which have large underground stems that enable them to grow in scrub where there is little rain. Some species form dense foliage and big crowns, making them useful for ground cover, as well as timber, poles, etc.
Probably first grown outside their natural habitat in Portugal
about 400 years ago, their first major plantings were in South Africa and Brazil
around 1904. Brazil's research and hybridizing programs, dedicated largely to
industrial needs, have given it the highest mean annual growth rate per hectare
in the world. The country has well over one million hectares of eucalypt
plantations, providing 60 per cent of its wood for industrial purposes. Brazil
may, in fact, be too enthusiastic a patron: in 1990, the government announced -
in the face of vociferous protests from ecologists and indigenous people - that
it would reforest one million ha of recently logged land in Amazonia, not with
threatened indigenous species, but with more eucalypts for timber and pulp
Thrive in extremes
Eucalypts thrive in extremes of latitude and altitude. Eucalyptus globulus, which occurs naturally between latitudes of 38.5 to 43.5 degrees S and under 1000 m altitude, grows equally well in Ethiopia at a latitude of 12 degrees N and altitude of 2 500 m, in the Nilgiri Hills of India at a latitude of 17 degrees N and altitude of I 000 m, and in the Andes Mountains of Peru at latitudes of five to 10 degrees S and an altitude of 3 000 m. In 1955, there were an estimated 700 000 ha of eucalypts throughout the world; 25 years later there were almost four million ha, with plantings increasing by more than 175 000 ha a year.
Clearly, if it's being planted this widely, the genus has its pros as well as its cons. The pros: The outstanding traits of eucalypts are the variety of their uses and the speed and ease with which they grow. They can mature and reach a height of 10 m in as little as five years, and can be harvested every four to eight years. For at least three or four harvests they don't have to be replanted because of their "coppice vigor" - they resprout from the original stump.
The trees provide fuelwood, poles and posts, pulp, paper, raw material for reconstituted wood products, nectar for honeybees and oils and tannins for perfumes and medicines. They also serve as shelterbelts and create rapid tree cover. Eucalpyt branches with their decorative blue-green leaves are also a staple of florist shops, and the trees are widely grown as decorative landscape species.
The cons: Planted as exotics, eucalyptus trees generally do not provide fodder, fruit, food or a habitat for wildlife. They tend not to enrich the soil, and if planted on the wrong site may sometimes even affect it adversely. Commonly grown varieties with sparse canopies do not give shade or protect the soil against erosion as well as some other species. Monocultural plantations invite pests and can threaten the environment. Many eucalypts compete with agricultural crops, absorbing large quantities of water and the often scarce supplies of micro-nutrients needed to sustain rapid growth.
Worse still, eucalypt plantations offer few local jobs (though some may open up in distant sawmills) and may upset local, communal traditions, such as grazing agreements.
But there is more to the eucalypt dilemma than balancing the pros against the cons. Some of the cons have their pro aspects, and others have more gray than black marks against them.
Trees are like goats
Davis compares eucalypts to goats. "They are the perfect design. Like goats, they can live anywhere, eat anything. And like goats, they also eat things you don't want them to", he says. The trick is to manage them in such a way that they eat only what you want them to.
The large amount of water eucalypts consume is a drawback, but their consumption is extremely efficient by unit of biomass produced, and they need less water than pines do. This thirst can be turned into a virtue by using it to drain swampy areas, or to fight salinity (Ceres No. 127). Digging narrow trenches along the edges of a eucalypt plantation will stop tree roots growing out sideways to compete for water with nearby crops.
Because the trees usually don't provide fodder - except for Australia's koala bears, which feed on eucalyptus leaves - they can be grown to form fences without having to protect the seed-rings and young trees from grazing cattle. While the shoots and branches are not tempting, the Chinese have extracted oils from eucalypts on which livestock will feed and fatten.
Whether eucalypts help or harm the soil depends on which species are planted and how they are managed. Recent studies in India and the Mediterranean show that eucalypts had a beneficial effect on soil structure, comparing favorably with pine and, in India, Shorea rohusta (sal). Planted on formerly treeless sites, their decayed leaves and litter improved soil fertility. Cropping the trees young, as often happens in plantations of eucalypts grown for industrial uses, and removing the biomass, removes some nutrients that otherwise would be cycled between trees and soil. Eucalypts do not fix nitrogen in the soil but, according to Davis, "Nitrogen-fixing is not necessarily a panacea. You have to have reasonable soil containing the nitrogen first". And one of the virtues of eucalypts is that they can grow in less-than-reasonable soil. Davis says foresters are now experimenting with growing eucalypts in combination with nitrogen-fixing acacias, which are native to almost every part of the world.
When eucalypts are planted as an exotic monoculture. replacing natural forest, the indigenous forest ecosystem is destroyed, depriving local wildlife of habitat. But, Davis points out that Australia's natural eucalypt forests are full of wildlife. Again it is a case of which eucalypts are planted, where and how. A mixture of exotic species grown in multipurpose plantations to provide fuel and timber can also attract animals and birds that used to live in natural forests if there are occasional open spaces and undergrowth is left untouched here and there. The FAO reports that in India's Karnataka State, scene of violent anti-eucalypt demonstrations, the progressive reforesting of grassland in the Rannibennur Blackbuck Sanctuary with Eucalyptus tereticornis, which grows well in very dry climates, has led to an increase of wildlife species that had almost disappeared, like the blackbuck (antilope cervicapra), great Indian bustard (Choriotis nigriceps) and wolf (Cants lupus). Strips of exotic trees planted along roadsides in India have attracted large numbers of partridges.
The dangers of competition between eucalypts and other plants can also be minimized by better management. Farmers in India have planted eucalypts with elongated crowns and vertical roots along farm boundaries. The eucalypts do not noticeably reduce field crop yields, and the farmers can sell the produce of the trees. In Colombia, single trees are grown along field boundaries for pulpwood. Eucalypts can have a decidedly beneficial effect on agriculture when planted as a shelterbelt, protecting crops from strong winds in hot, dry climates. Because they are hardy and do not tempt the palates of grazing herds, eucalypts establish themselves easily and quickly. They can serve to start a shelterbelt, after which other trees can be added to yield fruit, fodder and firewood.
Social considerations, however, are crucial and, in the eyes of many critics, too often completely ignored. When eucalypt plantations intrude on land that rural people need for crops or grazing, and provide no alternate employment for them in return, upheavals are inevitable.
Theodore Panayotou, a fellow of the Harvard Institute for International Development working at the Thailand Development Research Institute, told the Thai magazine Manager that Thailand's severe problem of forest encroachment grows out of land-use conflicts. "There is little sustainable about eucalyptus plantations on encroached forest lands unless the problem of land rights is solved first". In extreme cases, he said, rural people occupying forest reserves are termed illegal occupants and driven out with no compensation, even though they were taxed for the lands and settled on them before they became forest reserves. "No one yet is facing the real issue head-on. The two critical problems are the natural forest and the rural poor. We are losing sight of both for the eucalyptus", Panayoutou warned.
Five key questions
Y.S. Rao poses five questions that should be asked before planting eucalypts:
(1) Is the purpose to put the land under the best use, in terms of economics, and obtain the maximum return on investment?
(2) Is the purpose to generate wood at the fastest possible rate to meet needs within the country and, if possible, earn export revenues?
(3) Is the purpose to provide tree cover for denuded or degraded sites using the species that has the best chance of surviving and growing?
(4) Would eucalypts be planted in agricultural areas where they would compete with crops for water and nutrients?
(5) Would eucalypts be planted in areas where local people need grazing land for their cattle?
Rao's advice is that it probably would be a good idea to plant eucalypts in the first two cases, and definitely in the third. It is a more efficient producer of wood and biomass than most other trees - always keeping in mind its high water and nutrient requirements - and can be ideal for reclaiming wastelands. In the last two cases, however, planting eucalypts would likely lead to trouble, because they would deprive agricultural crops and grasses of water, while their leaves are not palatable to cattle.
Really, such rules of thumb are only common sense. There is no such thing as a "bad plant", much less a fascist one. There are only poor land-use planners - who fail to see the forest for the eucalyptus trees-or, worse, no planning at all.