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close this book Resource management for upland areas in Southeast Asia - An information kit
close this folder 2. Integrated upland systems management
View the document General systems overview
View the document Overview of agroforestry systems in Southeast Asia
View the document Design and management considerations for agroforestry systems
View the document Integrating local tree species into family farms
View the document Agroforestry systems in China
View the document Agroforestry systems in Indonesia
View the document Agroforestry systems in the Philippines
View the document Agroforestry systems in Thailand
View the document Agroforestry systems in Vietnam

2. Integrated upland systems management

 

General systems overview

Prescriptive models and packages of technology are seldom transferable from site to site. (See also Upland development issues and approaches.) Conditions within Southeast Asia, within particular countries, within watersheds, and even within communities are generally too diverse for top-down models to be applied at the farm level. Apart from agroecological diversity, there is a diversity of clients to address— large and smallholder farmers, marginal farmers, the landless, rural industry workers, shopkeepers, townspeople and urban dwellers—all with different socioeconomic and cultural characteristics and needs.

This chapter brings together lessons about prominent agroforestry systems in the region. The next chapter describes important soil and water conservation practices that are being applied in these systems. To understand what makes these systems and practices work, it is important to identify factors or considerations that influence farmers in deciding how to manage their natural resources.

The broad framework for this discussion incorporates socioeconomic, biophysical, conservation and agriculture production issues, which interrelate with the farm household. Many factors influence a farmer's choice of production enterprise or conservation effort.

An example of a checklist of considerations which influence the management of upland systems can be found on the next page. The objectives of this checklist are to:

· Equip extension workers with a framework for understanding the multiple factors that influence how and why farmers make production and resource allocation decisions.

· Serve as a tool for conducting diagnostic activities and helping farmers and extension workers improve their decision-making process.

The checklist may be used at the diagnostic phase for guiding semistructured interviews and group discussions with farmers. (See also chapter on Diagnostic methods and tools ) It may also help to probe for underlying biophysical and socioeconomic factors that explain how and why farmers make specific choices regarding management of their farming systems. Finally, the checklist can be used in monitoring and evaluating field activities.


Considerations that influence the management of upland agriculture and natural resource systems


Upland resource management: A checklist of influences

 

Overview of agroforestry systems in Southeast Asia

What is agroforestry?

Agroforestry is the deliberate growth and management of trees along with agricultural crops and/or livestock in systems that are ecologically, socially and economically sustainable.

or, more simply:

Agroforestry is the use of trees in farming systems.


What is agroforestry?

 

How is agroforestry relevant in Southeast Asia?

In agroforestry research and development, both farmers and scientists should test and validate the aims, potential and positive interactions among both socioeconomic and ecological components. Some important aims of agroforestry are:

· Increased productivity/income

· Improved equity in benefit-sharing

· Sustainable upland management.

To work effectively with farmers, researchers and development workers must be able to approach agroforestry from a farming systems perspective. (See also Farming systems development.)

Ways to classify agroforestry systems

By components

(What combinations of trees, crops, pasture and other components?)


By components

By function of trees

(Are the trees used primarily for production or conservation?)


By function of trees

 

By temporal association

(Is the system only temporary or more permanent?)


By temporal association

 

By pattern of trees

(Are trees managed in a regular pattern or irregularly spread?)


By pattern of trees

 

By tenure

Agroforestry practices are influenced by the land and tree tenure system (private or state-controlled) that farmers operate in.

Tenure affects the decision farmers make about the kind of agroforestry system they can use.

Farm-based

Forest-based

Biased toward crops and

Biased toward trees

livestock.

Emphasizes forest and

Emphasizes fruit trees and

timber tree species

multipurpose tree species.

Generally on government

Generally on private farm lands.

controlled forest lands

 

Other important factors

· Agroecological and environmental adaptability.

· Socioeconomic characteristics.

· Culture and traditions.

· Management practices.

Tenure and land-use rights

Agroforestry technologies are only a partial solution to upland problems. Fundamental issues of land tenure and long-term use rights need to be resolved in the uplands. Secure tenure is an essential but not sufficient conditions. Other required support services must be mobilized; otherwise agroforestry efforts will not truly benefit resource-poor farmers.

Examples of tenurial policy changes that favor farming households

· Renewable 25-year certificates of land stewardship granted within the Philippines, Integrated Social Forestry Program.

· Renewable long-term production contracts (20 years on agricultural land and 50 or more years on forest land) provided to Vietnamese farmers on over 5 million hectares of lands formerly controlled by state agriculture and forest enterprises.

Evolution of agroforestry

Agroforestry systems in Southeast Asia have evolved over centuries and are very diverse and complex. Today, as conditions change, farmers continue to innovate, experiment and improve these systems.

To meet their needs of food, fodder and fuelwood, fiber and cash, farmers integrate agriculture crops, trees and livestock in their farming systems. This integration has resulted in a wide diversity of traditional agroforestry systems. Most of these systems are well-suited to the local agroecological conditions, the specific subsistence and cash needs of farmers, their social and cultural context and the environmental conservation needs.

In areas where the people are still living in forest areas or still surrounded by abundant forests (e.g., parts of Laos and Indonesia), they practice shifting cultivation and harvest or collect many nonwood forest products for their own use or for markets.

In settled agriculture, trees are extensively integrated with the farming systems. In densely populated areas, trees may be more valued and more valuable than in low-population areas where forests are still abundant. Agroforestry systems, particularly in high-population and fuelwood-deficit areas, can serve as buffer zones to mitigate the degradation of natural and plantation forests.

Trees in and around farms are planted judiciously, carefully and selectively. This is the most widely practiced agroforestry system. Very specific tree and crop combinations are developed for all agroecological zones. If the farming system is based on a tree that takes long time to produce yields (e.g., coconut, areca nut, horticultural trees, rubber), farmers intercrop and/or integrate livestock to generate some early economic returns.

Farmers living near the forests in densely populated areas have developed practices to integrate their farming systems with the adjoining forests to graze their cattle (or collect fodder) in the forest, or have develop forest gardens to meet their subsistence and cash needs.

Indigenous vs Introduced technologies

An agroforestry system may use:

· Indigenous (existing) technologies that farmers are familiar with.

· Practices that have been modified or improved by farmers or outsiders.

· Practices introduced by outside researchers or extension agents.

Indigenous or existing practices and knowledge should be the basis for designing agroforestry interventions. But many projects have relied (largely unsuccessfully) on introducing agroforestry models and technologies using exotic tree species and technologies.

Introducing technologies from outside has two risks:

· Introduced technologies may not be socially or economically acceptable to farmers.

· Introduced technologies or species may not be ecologically sound (e.g., introduction of Leucaena on acid soils).

Small-scale, on-farm experiments to test new technologies must be properly conducted and evaluated before these technologies can be promoted.


Current priorities in agroforestry development


Examples of agroforestry systems in Southeast Asia


Examples of agroforestry systems in Southeast Asia - continue 1


Examples of agroforestry systems in Southeast Asia -continue 2


Trees, crops and livestock combined (Agrosilvipastoral)


Trees, crops and livestock combined (Agrosilvipastoral) - continue


Other systems

 

 

Design and management considerations for agroforestry systems

Agroforestry is an approach to sustainable land-use which is very relevant for the management of upland areas with severe physical and chemical soil constraints.

Agroforestry systems can improve and maintain soil fertility by:

· Increasing nutrient input. The incorporation of trees and shrubs into the farming system can increase the organic matter of the soil and the fixation of nitrogen.

· Recycling nutrients from deep soil layers. Soil nutrients are taken up by tree/shrub roots from deeper soil layers and recycled to the topsoil through litter or lopping (including root residues), forming an almost closed cycle of nutrients.

· Synchronizing nutrient inputs with plant growth. Trees or shrubs can help synchronize nutrient release with crop requirements by controlling the quality, timing and manner of addition of plant residues like prunings and cuttings.

· Preventing erosion. In sloping areas, trees or shrubs act as a physical barrier to reduce nutrient loss from erosion.

The soil-nutrient cycle in the agroforestry system consists of nutrient pools, nutrient flows within the system and nutrient gains and losses.

The most common problems of upland soils

· Acidity.

· Low nutrient content, particularly deficiencies of nitrogen and phosphorous.

· Nutrient losses through soil erosion, leaching and volatilization.


Potential nutrient pools

 

Key technical considerations for design and maintenance of agroforestry systems

1 Use nitrogen-fixing trees or shrubs to increase gains from symbiotic fixation. Examples of nitrogen-fixing trees are Gliricidia septum, Desmanthus virgatus, Flemingia macrophylla, Leucaena leucocephala, Cajanus cajan, Paraserianthes falcataria, Erythrina spp., Albizzia spp. and Calliandra calothyrsus

2 Select fast-growing and deep-rooted trees or shrubs that can be pruned or lopped more frequently to provide organic matter. Deep-rooted trees can enhance nutrient uptake and act as "nutrient pumps.,, They can store nutrients from below the surface in above-ground biomass. Examples: Acacia spp., Cassia siamea, Gliricidia septum, Desmanthus virgatus, Albizzia lebbek.

3 Plant trees or shrubs (and crops also) along the contour as a barrier to control soil erosion. The most common design is contour planting or hedgerows. Place crop residues, twigs, barks and other materials on the upward side of the hedgerows or spread along the contours to serve as mulch to control surface run -off further.

4 In hedgerow intercropping, the hedgerows can be pruned to a height of 75 cm to 100 cm (I m). Incorporate all cuttings and other available organic materials (e.g., twigs, barks, leaves, fruit residues, etc.) into the soil.

5 Synchronize the timing of tree pruning or lopping with the required nutrients needed by a crop. The potential contribution of plant residues is important, as the nutrients can be supplied to the crops when the nutrients are most needed. The decomposition rate for all organic material is directly proportional to the availability of soil moisture. For example, lopping should be done before the intercrop is planted to allow the residues to be converted from the organic materials to available nutrients.


Growing period

 

6 Practice crop rotation for the intercrops. Plant leguminous nitrogen-fixing crops after grain crops to replenish losses from grain harvest. Some legume crops improve nitrogen gains through symbiotic fixation. Example of a crop sequence: mungbeancorn/rice-cowpea.


Practice crop rotation for the intercrops

 

7 Develop and maintain the upper slopes of farmlands as forested plots. These areas then protect the watershed and serve as a source of fuelwood and other wood products. The overall area planted to trees or shrubs should be about 60 percent.

8 Plant cover crops or green manure crops in fallow areas. Cover crops improve soil fertility through the addition of significant amounts of nutrients such as nitrogen (as much as 200 kg/ha). They also help suppress weeds that might use stored nutrients in the soil. Some recommended cover and green manure crops are: Desmanthus virgatus, Clitoria ternatea (butterfly pea), Centrocema pubescens (centrocema), Phaseolus antropurpureus, Vigna radiata (mungbean), Vigna sinensis (cowpea), Sesbania rostrata (sesbania).

 

Integrating local tree species into family farms

An experience from Sumba, Nusa Tenggara Timur, Indonesia

Swidden cultivators have traditionally relied upon both their gardens and the local forest to provide for their basic needs. Due to a variety of factors, many shifting cultivators are gradually turning to more sedentary forms of farming. Farmers making this transition often begin planting perennial cash crops in addition to their annual staple crops. However, these tree crops incorporated into their farming system cannot totally supplant the functions of the slowly disappearing natural forests.

In the province of Nusa Tenggara Timur (NTT) in Indonesia, many of the transition farmers working with Yayasan Tananua, a local farmers' organization, have been gradually planting trees to create "forests,, on sections of their own farms. These "family forests,,, or hutan keluarga, are planted with exotic trees and a variety of local forest species that traditionally provided the farm families with food, timber, fuelwood, herbal medicines and other useful products. These hutan keluarga have evolved into highly varied systems in terms of species composition and planting distances resulting from individual preferences and selection of each household.


Family forest

 

Examples of local tree species integrated in family forests (NTT, Indonesia)

 

Names

Scientific name

Use (parts used)

Sumbanese

Indonesia

   

Ha Moi Hua

_

_

traditional medicine (bark)

_

Melinjo

Gnetum gnemon

vegetables (leaves), snacks

     

(processed seed), rope material(bark)

Hureni

Suren

Toona sureni

timber/construction material(trunk)

Kaduru

Kayu Merah

Pterocarpus indicus

timber/construction material(trunk)

Kajiu

Cemara

Casuarina junghuhniana

timber/construction material(trunk)

Kajiu Omang

Cemara Hutan

Podocarpus imbricatus

timber/construction material(trunk)

Kaninggu

Kayu Manis

Cinnamomum zeylanicum

spice (bark), traditional medicine

Kayu Loba

_

_

cloth dye (bark)

Kiru

_

Dyxoxylum caulostachyum

timber/construction material(trunk)

Kombu

Mengkudu

Morinda citrifolia

cloth dye (bark)

Lamua

Mindi

Melia azedrach

timber/construction material(trunk)

Langira

_

Nauclea orientalis

timber/construction material (trunk)

Lobung

_

Decaspermium sp.

vegetable (leaves), food

     

ingredient (seed), timber/

     

construction material (trunk)

Mangata

_

_

timber/construction material (trunk)

Mangawa

Jabon

Anthocephalus cadambu

timber/construction material(trunk)

Mbaku Hau

Melur

Podocarpus amarus

timber/construction material(trunk)

Pau Omang

Mangga, kedipir

Mangifera indica, Mangifera gedebe

timber/construction material(trunk)

Tumbu Ndaba

Tumbaran

Neonauclea exelsa

timber/construction material(trunk)

Wihi Kaloki

_

Calophyllum soulattri

timber/construction material(trunk)

Wora

Bayur

Pterospermum diversifolium

cloth dye (bark)

 

Factors influencing adoption

When the hutan keluarga became popular in the island of Sumba during the late 1980s, it was expected that farmers would plant many of the local species from the natural forest on their own farms. This way, the original role of the forest in the traditional shifting farming system could be maintained. This, however, did not happen, most of the hutan keluarga that currently exist have only a few species endemic to the natural Sumbanese forest.

Reasons for not cultivating local species

· Planting materials of preferred local species are difficult to find and collect. On the other hand, planting materials of exotic or naturalized species are easily accessible from the market, the government or nongovernment organizations in the area.

· Some local species are hard to propagate.

· Farmers are not convinced that forest species can grow outside the natural forest.

· The perception that exotic species are "modern,, made some farmers prefer them over local species.

· Some farmers perceive that local species are not as valuable as exotics.

 

Difficulties encountered by farmers planting local species

· Collecting and transporting planting materials (saplings are most commonly used) from the forest to their farm is difficult and timeconsuming.

· Saplings from the forest need special care (watering, shading, wind protection, etc.) compared to naturalized or exotic species commonly grown in the locality.

· Local forest species have generally lower survival rates, despite the special care given to them.

· Most of the preferred local species have long growing cycles, e.g., first grade construction wood normally takes 10-1 5 years before it can be harvested.

Most transition farmers do want to plant more species from the natural forest to their hutan keluarga. However, incorporating local species, even among the more experienced and enthusiastic farmers, is still a matter of trial and error. Thus, the practice has spread only to a limited area. If incorporating the local forest species into the hutan keluarga is to be encouraged, the more problematic issues of access to planting materials and proper care and management practices need to be addressed.

 

Agroforestry systems in China

China is a vast country, with mountains (including hills and plateaus) covering 6.3 billion ha, or approximately 66% of the total area. About onethird of the total population, two-fifths of the cultivated land and 90% of the forest are located in this mountainous area.

The practice of agroforestry in China has a long history, though use of the term "agroforestry" is new. Given that there are so many types and patterns of agroforestry systems, only some of the more important examples are presented below.


China

 

Farm-based agroforestry systems

Crop-based agroforestry

Crop-based agroforestry systems are composed of herbaceous agricultural crops (the major component) and woody trees. They are oriented towards food production focusing on grains, cash crops and vegetables.

The trees are usually planted in rows. Tree density depends on the production purpose and the area to be covered. In some areas, fish ponds are included.

 

"Agroforestry in Chinese"

While there is no single equivalent Chinese term for agroforestry, several parallel terms can be used. These include:

hun nong lin xi tong

Mixed agriculture and forestry system

Iin nong fu he xi tong

Forestry and agriculture complex system

nong lin fu he xi tong

Agriculture and forestry complex system

nong lin xi tong

Agriculture and forestry system

nong lin mu yu fu he xi tong

Agriculture-forestry-animal-fish sideline complex system

nong yong lin ye

Forestry for agricultural purposes

Different agroforestry systems are most commonly named according to their major components, for example, the "Paulownia-wheat" system.

 

Advantages

· Crop-based agroforestry can produce both woody and agricultural products, improve the physical environment and increase farm productivity. For example, during winter and early spring the trees have no leaves and, therefore, do not affect the growth of the crop. However, during late spring and summer, the trees can reduce wind speed (by as much as 30%), reduce soil evaporation (by 10%) and increase air humidity (by about 5%), all of which enhance grain yields

· Firewood collected from the trees provides cooking materials, reducing the pressure on forests and saving straw and animal manure for use as organic fertilizers

Fruit tree-based agrotorestry

Intercropping fruit trees with herbaceous crops is an age-old practice by Chinese farmers. However, the system has been improved as more technology and management options have become available. In central and northern China, deciduous fruit species are dominant, while in central and southern China, evergreen species dominate. There are numerous planting patterns that are adapted to local situations in China.

Many herbaceous crops are grown in association with the fruit trees In many places, animals and fishes are also major components of the system.

Variations of crop-based agroforestry systems

Although crop-based agroforestry systems are most widely practiced in Henan province, some neighboring provinces also have similar systems. A variation involves the use of tree species as forest windbreaks. This is widely practiced throughout the northern area of Dongbei, Huabe and Xibei and covers about 46% of the total land in that area.

Another variation is the development of bamboo-based systems, now rapidly expanding in Zhejiang, Fujian, Guangdong and other provinces. Bamboo is planted on sloping or flat farmland. Vegetables, grains, legumes and other crops are intercropped in the initial years. After a few years, the bamboo becomes dense and is the single most important crop in the system. Because of the high price for edible bamboo shoots, small bamboo plantations can generate very high economic returns—up to US$20,000/ha in some places. Most of the bamboo shoots are sold as fresh shoots, but some amount of post-harvest processing is done, including drying, preservation in solution and some canning for local, national and international markets.

Advantages

· Intercropping with fruit trees can fully utilize land and labor resources, give better vegetative cover for soil and water conservation and provide products for humans, fodder for animals and green manure to improve soil fertility.

· Intercropping can also increase soil temperature, promote root and microorganism activity in winter reduce labor and minimize competition for nutrients and light.

Limitations

· Fruit tree production can be a profitable enterprise. However, risks of overproduction of fruits do exist. For example, in some parts of China, yellow peach trees were replaced with other fruit trees because of low market prices. Ecological risks also exist. For example, in recent years citrus trees have been planted on land where other crops have not performed well due to low temperatures.

Homegardens

Homegardens are an ancient agricultural system in China and are commonly found throughout the country. Researchers and Chinese practitioners of ecological agriculture have helped to improve and intensify these systems significantly in recent years.

Every garden is a unique creation, with a complex set of tree and crop species and animals. Mushrooms are often grown as well. Fishponds are used to raise fish or high-value species such as eels or soft turtles. Biogas digesters supplied with animal dung are common.

Fruit tree-based agroforestry

Common fruit trees

Apple

Orange

Chestnut

Peach

Citrus

Pear

Grape

Persimmon

Jujube

Plum

Longan

Pomelo

Lychee

Walnut

Common crops

Beans

Sweet potato

Grains

Vegetables

Green manure

Legume and

Peanut

grass fodder

Strawberry

crops

 

Homegardens

Common crops and trees

Bamboo

Flowers

Fruits

Herbs

Medicinal plants

Ornamental trees

Vegetables

Other cash crops

Animals

Pigs

Chicken

Ducks

Mushrooms

Pasania

Oyster-cap

Straw mushrooms

Aquatic species

Fish

Eels

Soft turtles

Advantages

· The system is usually small in scale. However, the potential to generate income is generally very high.

· Homegardens are very flexible and can allow adjustments in production as prices change. In addition to providing income, homegardens contribute to the nutritional improvement of a household, as well as improving the beauty of the homestead.

Limitation

Operating and managing an intensive homegarden requires a high level of skills.

Tea-based agroforestry

Tea-based agroforestry systems are common in the provinces along the Yangtze river valley. Tea is usually intercropped with fruit or timber trees and crops. Many different herbaceous crops, especially legumes, are intercropped into the rows of trees and tea. In certain circumstances, grain or vegetable crops are intercropped. This is especially common in newly established tea plantations. The system often includes animals and fish: usually, there are more animal and fish species in this system than in the crop-based system.

Advantages

· Intercropping of woody or fruit trees can improve the local microclimate (temperature, humidity, light scattering, etc.), enhancing tea yield and improving tea quality.

· As well as producing tea, the system yields other products such as fruits, firewood, fodder and green manure.

· Intercropping of trees in a tea plantation can reduce runoff, lessen soil erosion and moderate high summer temperatures.

Tea-based agroforestry

Tea

Common trees

Jujube, peach, pear, persimmon, plum and other deciduous fruit trees

Masson pine, slash pine, loblolly pine, Chinese fir, Chinese tallowtree, tung oil tree, paulownia, poplar and sassafras

Common crops

Alfalfa

Barley

Chinese milky vetch

Common vetch

Corn

Horse bean

Pea

Soybean

Wheat

Animals and fish

Chicken

Duck

Pig

Eel


Deciduous trees

 

 

Limitations

· Crops such as sesame that share common pests with tea should not be used as an intercrop.

· The proper selection of pesticides and timing of application on the intercrop are important to avoid pesticide residues on the tea.

Rubber-based agroforestry

An agroforestry system which incorporates tree species and herbaceous crops into the rubber plantation is widely practiced.

Rubber, commonly grown in large-scale plantations, is widely grown in the tropical areas of Hainan, Yunnan, Guangxi and Guangdong provinces. The system contributes greatly to the dried rubber production of China. Although it is varied both in terms of species combination and density, the rubber-based system is not as diversified as the tea-based agroforestry system.

Rubber-based agroforestry

Rubber

Other common woody perennials

Coffee

Tea

Windbreak trees

Common crops

Legumes

Medicinal crops

Pepper

Sugar cane

Advantages

· The system enhances resource use efficiency (light, heat, water, etc.), increases biomass productivity, fully utilizes the land and improves soil and water conservation.

· It absorbs labor and enhances economic efficiency.

· It is more tolerant to natural disasters than are monocropped rubber plantations.

Limitation

· Rubber-based agroforestry requires an intensive use of technology and material inputs. Technical aspects to be considered include the selection and proper arrangement of the species

(more tea should be planted on the upper part of a slope, with more rubber on the lower part to avoid wind injury), proper pruning of the rubber trees and proper application of fertilizers and pesticides.

Forest-based agroforestry systems

Timber tree-based agroforestry

Timber tree-based agroforestry includes large-scale, industrial tree plantations for production of timber. One example is the Chinese fir system, located mainly in the provinces along the Yangtze River valley. Crops are often intercropped into the newly established tree plantations by planting in between the young seedlings. Chinese fir, pine and other fast-growing species often dominate these plantations. The tree density is high and intercropping with herbaceous crops can only be practical during the initial years. Animals are also raised in the system.

Advantages

· Intercropping between timber trees can effectively balance short-term and long-term benefits. Better vegetation cover can reduce soil and water erosion. Cultivation and fertilization can promote the growth of both crops and trees.

Limitations

· Land preparation is laborintensive.

· Land preparation for tree planting and intercropping can destroy the natural vegetation. Serious soil and water erosion can occur after heavy rains and before the intercrop is well-established. This affects overall soil degradation, as well as reducing the yields of the crop and tree species.

· For these reasons (and others), this system is not welladapted to the conditions of individual farm households.

Timber tree-based agroforestry

Common trees

Chinese fir, pine

Common crops

Beans

Grains

Green manure

Legume and grass fodder crops

Peanut

Sweet potato

Vegetables

Watermelon

Animals

Chicken

Duck

Pig

Timber and medicinal plants agroforestry

Herbaceous and woody plants have long been used in Chinese medicine. Using timber tree plantations to produce medicinal plants is a recent variation to this age-old practice. This agroforestry system can be found in hilly and mountainous regions of China.

High-value medicinal plants (woody or herbaceous) are often intercropped into established timber plantations 4-5 years after first pruning.

Advantages

· This agroforestry system can help balance the conflict between the long-term economic benefits of timber production and mediumterm livelihood opportunities. It can also meet the increasing demand for high value medicinal plants like ginseng.

Limitations

· Susceptible to fluctuations in market prices for medicinal plants.

 

Timber and medicinal plants agroforestry

Medicinal plant species

Amur corktree

Eucommia

Ginseng

Magnolia

Nackberry lily

White aster

Villous amomum

Other promising agroforestry systems in China

Intercropping agricultural crops with Paulownia sp.

This system has become important in the flatland areas of north China. Paulownia is a fast-growing tree with a deep root system (minimizing root competition with annual crops). It seems to enhance the suitability of the microclimate for agricultural crops and also produces timber within a short period (about 10 years).

Intercropping agricultural crops with Ziziphus jujuba (Chinese date)

In an intercropping system, the mixed planting of the Chinese date with an annual crop such as wheat can increase the yield of both crops. The vitamin-rich Chinese date is very popular in China and is found from temperate to subtropical areas, with the Yellow River—Huaihe River plain as the center of distribution.

Multiple-layer artificial population

Several variations of multiple-layer agroforestry systems have been found to perform well in the tropical regions of southern Yunnan. Rubber-tea and rubber-camphor-tea combinations have been the most productive. Traditional Chinese medicine species (e.g., Cinchona ledgeriana) have also been used successfully.

 

Agroforestry systems in Indonesia

Traditional agroforestry systems are found throughout Indonesia, including the kebun-talun and pekarangan systems in Java, and the multistoried agroforestry gardens in Sumatra. Introduced agroforestry systems also are common in many parts and are integrated into forest development programs on forest lands, as well as being widely practiced on private farm lands.


Indonesia

 

Farm-based agroforestry systems

Pekarangan system

The pekarangan (homegarden) is a mixture of annual crops, perennial crops and animals (including livestock) in the area surrounding a house. It is an integrated system with definite boundaries that serves a variety of economic, biophysical and sociocultural functions. The homegarden system originated in Central Java and spread to East and West Java in the middle of the eighteenth century.

Kebun-talun and homegardens in West Java generate relatively good income and are good sources of calcium, vitamin A and vitamin C.


A typical homegarden in West Java

 

A typical homegarden has a similar structure from year to year, though there may be some seasonal variations. The lowest two layers (up to 2 m in height) are dominated by starchy food plants, vegetables and spices. Cassava and ganyong (Canna edulis) are the most common plants found in the homegarden. The next layer (two to five meters) is dominated by bananas, papayas and other fruit trees. The five to ten meters layer is also dominated by fruit trees or other cash crops, such as cloves. The top layer, higher than 10 meters, is dominated by coconut and other trees, e.g., Albizia, for building materials and firewood.

Kebun-talun system

The kebun-talun system usually consists of three stages: kebun (garden), kebun campuran (mixed garden) and talun (mixed tree garden). The first stage, kebun, involves clearing the forest and cultivating annual crops. These crops are generally consumed by the farm household, with part of the produce sold as cash crops.

In the kebun stage, three vertical layers of annual crops predominate: the lowest layer consists of creeping plants that occupy the ground below a height of 30 cm. The layer from 50 cm to 1 m is occupied by vegetables, and the upper layer includes maize, tobacco, cassava or leguminous vines supported by bamboo sticks.

 

Pekarangan (homegarden)

Top layer (>10 m)

Coconut, Albizia, other trees

5-10 m layer

Fruit trees: Soursop, jackfruit, duku (Lansium domesticum), guava, mountain apple, cloves

2-5 m layer

Bananas, papaya, other fruit trees

1-2 m layer

Ganyong (Canna edulis), Xanthosoma, beans, spinach, cassava, gembili (Dioscorea esculenta)

Lowest layer (< 1 m)

Taro, Xanthosoma, chili pepper, eggplant


Development from garden to mixed garden to mixed tree garden

 

After two years, tree seedlings start to grow, leaving increasingly less space for the annual crops. The kehun gradually evolves into the kebun campuran, in which the annuals are mixed among half-grown perennials. The economic value of the mixed garden is less than that of the garden, but the biophysical value becomes higher. The diversified nature of the kebun campuran also enhances soil and water conservation. Erosion in the talun system is minimal, because undergrowth and litter are abundant. When the undergrowth and litter are removed, erosion may increase substantially.

In the kebun campuran, shade-tolerant plants such as taro occupy the space below one meter. Cassava forms the second layer from one to two meters height and the third layer is occupied by bananas and trees.

After harvesting the annual crops in the kebun campuran, the field may be abandoned for two to three years to become dominated by perennials. This stage is known as talun and is the climax stage of the kebun-talun system.

The talun is dominated by a mixture of perennial trees and bamboos, forming three vertical layers. The talun stage can take a variety of forms such as woodlots (for firewood and building materials), bamboos and mixed perennials.


The three-strata system in Bali

 

The three-strata system

The three-strata system is a method of planting and harvesting grasses, legumes, shrubs and trees in such a way that animal fodder will be available throughout the year. The practice was developed by households in the island of Bali. The first layer, consisting of grasses and legumes is intended to supply fodder at the beginning of the wet season. The second layer, consisting of shrubs, is to supply fodder in the middle and the end of the wet season. The third layer, comprised of trees, is to supply fodder during the dry season.

The three-strata system divides a piece of land into three parts:

· nucleus

· blanket

· boundary.

The nucleus is maintained for food production. The blanket is divided into a number of compartments, with each compartment cultivated with various grasses and legumes.

Fodder tree species are planted around the boundary at a spacing of 2 trees every 5 m. Between these trees Gliricidia or Leucaena shrubs are planted at a 10 cm distance between the shrubs.

Animal stocking rates can vary from low (0. 5 ha per cow) to high (0.25 ha per cow) due to improved fodder availability. Cattle raised in the system grow rapidly and are ready for market at an early age.

Alley cropping in the semi-arid provinces of East Indonesia

This technology has been developed in dryland farming programs in the semi-arid provinces of Nusa Tenggara since the early 1980s. The technology consists of hedgerow planting on contour lines with legume species. Before 1986, the hedgerow mainly consisted of lamtoro gung (Leucaena leucocephala); but after the psyllid (Heteropsylla cubana) infestation, Gliricidia septum and Calliandra calothyrsus were used. The hedgerows are intended for enhancing soil and water conservation. Between the hedgerows, annuals, perennial crops and grasses are planted.

In Sumbawa and other islands, live fences and rock walls are constructed to protect the crops against grazing livestock and wild animals.


Hedgerow planting in South Lombok

 

Forest-based agroforestry systems

Shifting cultivation

Shifting cultivation (also called swidden or bush fallow agriculture) is widely practiced in most Indonesian islands, except Java. Shifting cultivation includes a variety of practices occurring in a diversity of environments under many specific circumstances.

In Apo Kayan (East Kalimantan), almost all the forests cleared for agriculture are secondary forests and the fallow period is between 10 to 30 years. The farmers believe that the fallow period should be long enough to reduce weeds and to prevent the short-term degradation of the forest into scrub. Occasionally, sites may be left unused for even longer periods (40 to 50 years) to prevent gradual declines in fertility and an increase in weedy species. The farmers recognize the merits of long-term swidden management.

In Long Segar (also in East Kalimantan) shifting cultivators clear more primary forest than secondary forest for swiddens. People in Long Segar grow rice, easily selling the surplus through trade boats or to local markets. For this reason and because of the availability of chainsaws and fuel for motor boats, the area cleared and cultivated by Long Segar farmers is about 0.4 ha per capita per year, or about 33% larger than in Apo Kayan. The total area cultivated in 1979-1980 was about 400 ha, of which 82% was primary forest. Because of market, technology and population pressure, the rotation is becoming shorter. The recovery of such fields to forest is slow and, consequently, there is danger of land degradation.


Brunei

 

Improved fallow

Improved fallow technology is one of the alternatives to control destructive shifting cultivation practices and to develop more sustainable dryland agricultural systems. Abandoned fields are planted to the fast-growing cover crop, Pueraria javanica, to rehabilitate soil fertility and as a perennial cash crop. Food crops can again be planted after 3-4 years—a much shorter fallow period than traditionally followed

This revised cropping pattern will produce rice and cassava within a short period; pineapple, ginger and peanut in the near term and melinjo (Gnetum gnemon) in the long-run.

Multistoried agroforestry garden system in West Sumatra

The system is characterized by an intensive integration of forest species and commercial crops, forming a multilayer, forest-like system. The intimate association of different species provides both subsistence and commercial products which supplement rice production.

Tumpangsari (Taungya)

Various tumpangsari methods exist. They are introduced agroforestry systems designed to meet the subsistence needs of households with limited access to cultivable lands.

The implementation of tumpangsari in Java's teak forests includes four main activities: (1) site preparation, (2) seed preparation; (3) planting and (4) maintenance. The spacing of the main crop (teak) is generally I x 3 m; Leucaena is planted as a dense row in the middle between the teak rows. Additional crops can be planted in the I . 5 m-wide space between the teak and the Leucaena rows.

Similar activities can also be carried out in the establishment of plantations of other timber species, such as Pinus, Agathis, Altingia and Swietenia. Tumpangsari can also be found in rubber (Hevea) plantations, especially among smallholders. Due to the psyllid infestation problem with Leucaena, other species for interplanting need to be tested: Acacia villosa, Calliandra calothyrsus and Gliricidia.

Inmas or intensified tumpangsari

Intensified tumpangsari includes the following technologies:

· high-yielding crop varieties

· improved soil conservation and tillage methods

· fertilizers

· insecticides (if necessary)

· correct timing for planting and fertilizing with respect to rainfall.

Since the 1970s, the intensified tumpangsari approach in teak forests has given satisfactory results and is increasingly being applied over larger areas. With the use of selected superior crop varieties and crop fertilization (in the range of 90-100 kg urea and 60-150 kg triple super phosphate per ha), together with the use of insecticides, yields of dryland rice may increase from 700 kg to 2,000-3,000 kg per ha.

Another example of intensified tumpangsari is vegetable tumpangsari in the Lembang area. Farmers in Lembang cultivate high-value vegetables between pine and other tree species on forest as well as on private lands. The vegetables include tomato (Lycopersicum Iycopersicon), potato (Solanum tuberosum), cabbage (Brassica oleracea), Chinese cabbage (Brassica pekinensis), white beans (Visum sp.), chili pepper (Capsicum anuum), kidney bean (Phaseolus vulgaris). Dryland rice (Oryza sativa) is also grown.

 

West Sumatra multistorey system

Cultivated annual crops

Chili (Capsicum anuum), eggplant (Solanum melongena), maize (Zea mays), beans ( Vigna spp., Phaseolus spp.), cucumber (Cucumis sativus)

Trees

Durio zibethinus, Pterospermum javanicum, Toona sinensis, Cinnamomum burmani, Myristica fragrans, Coffea canephora

Damar mata kucing agroforestry in Krui

Damar mate kucing is a resin of Shorea javanica produced in artificial forests in Krui, Lampung, in Sumatra. The resin is a cash crop sold throughout the year. The damar trees dominate the ecosystem. Other products are fruits, vegetables and other horticultural products, including langsat (Aglaia domestika), duku (Aglaia dookoo), jackfruit (Artocarpus heterophyllus), menteng (Baccaurea racemosa), durian (Durio zibethinus), aren (Arenga pinata), coffee (Coffea spp.), doves (Syzygium aromaticum), bamboo and rattan.

 

Whole rotation, or integrated tumpangsari

A more recent variation of tumpangsari is the integration of the approach into social forestry programs which include formation of farmer's groups, longer-terra tenurial arrangements and more flexibility of farm households to plant food crops.

In traditional tumpangsari, farmers are entitled to plant food crops between the young forest trees for only about two years. In the integrated tumpangsari, they are also allowed to grow fruit trees, grasses and other kinds of plants between the timber trees during the whole rotation period of the forest crop. The various planting materials for the forest, as well as the non-forest trees, are provided by the Forestry Service. The farmers may harvest the fruits, fuelwood, grasses, medicinal and other plants during the rotation period of the forest crops.


Pattern of whole rotation tumpangsari

 

Agroforestry systems in the Philippines

Agroforestry has been traditionally practiced by different tribal groups in the Philippines for generations. This land-use system is now recognized by the government as one of the alternatives to address the twin problems of meeting the needs of upland farmers and maintaining the integrity of the environment. It is one of the major components of the community-based forestry programs of the government, such as the Integrated Social Forestry Program and the Community Forestry Program. Many nongovernment organizations also develop and promote different forms of agroforestry as approaches for sustainable upland development.


Philippines

 

Farm-based agroforestry systems

Alley cropping

Alley cropping is also known as hedgerow intercropping system. Hedgerows of trees or shrubs (usually double hedgerows) are grown at intervals (usually 4-6 m) along the contours. The strips or alleys between the hedgerows are planted with agricultural crops (annuals and/or perennials).

A good example of this system is the Sloping Agricultural Land Technology (SALT).

One or two rows of woody perennials are grown as hedgerows, either from seeds or cuttings, along the contours. Contour lines are located using an Aframe tool. The recommended horizontal distance between contour hedgerows is 46 m or about 1.5 m vertical distance. At an average of 5 m interval (horizontal distance) and l m width of hedgerows, about 20% of the total area is occupied by the hedgerows. For the alleys, the recommended cropping pattern is to plant perennial crops (e.g., coffee, fruit trees, etc.) in every third alley while the other two alleys can be devoted to annual crops. This makes a spatial ratio of about 20% hedgerows, 25% perennials and 55% annuals.

Philippine upland situation (1990)

· Uplands constitute 17.5 million ha, or 59% of the total land area.

· About 12.2 million ha are marginal upland areas.

Cultivated/open areas

0.30 million ha

Grasslands

1.80 million ha

Cultivated mixed grasslands

10.11 million ha

Eroded and other barren areas

0.01 million ha

Total

12.22 million ha

· Upland population is estimated to be about 18 million, or more than 3 million households.

—8.5 million forest dwellers

—6.0 million tribal Filipinos

—3.3 million migrants from lowland areas

· At a population growth rate of 2.6% per year, an additional 5.25 million ha of forest lands will be cleared by the year 2025.

 

 

The hedgerows are regularly pruned to a height of about 0. 5 m to minimize shading of agricultural crops in the alleys. The pruning frequency depends on the coppicing ability of the species. Biomass from the prunings can be used as green manure or mulch to the alley crops or as fodder fed to livestock. Through time, natural terraces can form at the base of the hedgerows, thereby minimizing soil erosion and surface run-off.

Advantages

· Conserves soil and water.

· Can increase crop yield and farm income (e.g., 4-5 fold increase in maize yield when compared to maize yield of upland fields without hedgerows.

· Flexible since different cropping systems can be integrated (e.g., annual and perennial crops can be mixed in different ratios along the alleys; livestock can also be integrated.)

· Reduces dependence on inorganic fertilizers. (Prunings can be used as organic fertilizer.)

Limitations

· Can decrease overall farm yield due to: (1) loss of cropland resulting from hedgerow establishment; (2) improper pruning and too-close hedgerow interval can reduce light penetration, and (3) some hedgerows may have allelopathic properties which can adversely affect crop growth.

· Laborious to establish and maintain.


Double hedgerows

 

Alley cropping with improved pasture grasses and/or fodder trees or shrubs

Hedgerows of fodder trees or shrubs (e.g., Desmodium rensonii, Leucaena leucocephala, Gliricidia septum, Flemingia congesta) are planted along contours at intervals. The alleys between the hedgerows are planted with improved pasture grasses and/or fodder trees or shrubs. Pruning from the hedgerows grasses and fodder trees/shrubs are fed to animals in a cut-and-carry method.

Ideal characteristics of hedgerow species

· easy to establish (from seed or cutting)

· fast-growing

· good coppicing ability

· nitrogen-fixing

· deep-rooted has multiple uses (i.e., food, fuel, fodder, etc.)

Some recommended hedgerow species

· Gliricidía septum

· Flemingia congesta

· Leucaena leucocephala

· Desmodium rensonni Cassia spectabilis Calliandra calothyrsus

· Desmanthus sp.

· Some grasses such as napier (Pennisetum purpureum), vetiver ( Vetiveria zizanoides), guinea grass (Panicum maximum) and Setaria sp.

 

Multistorey system

In this agroforestry system, mixed species occupy different canopy levels, with the upper layers occupied by trees or other woody perennials that provide partial shade to agricultural crops in the lower layers. This system is similar to the structure (multilayer) and composition (diverse species) of a tropical rainforest. Examples are coconut-coffee-pineapple-banana mix (commonly found in Cavite province); Albizia-coffee/cacao mix (commonly found in provinces of Mindanao); Gliricidia-coffee mix (found in many areas); and homegardens (found throughout the country).

This system can be adapted by interplanting shade-tolerant species under established tree and coconut plantations.

Advantages

· Promotes optimum utilization of light and soil resources.

· Promotes efficient nutrient cycling.

· Series of canopy layers minimizes rainfall impact, thus reducing soil erosion and runoff.

· Promotes greater diversity; hence, crops become less prone to pests and diseases.

· Diversified cropping helps to ensure a year-round source of food and income.

· Promotes maximum utilization of labor and time.

Limitation

Possibility of too much competition among crops for light and nutrients.

Desirable characteristics of upper canopy trees

· small crown or sparse foliage to allow some light to pass through to lower canopies

· nitrogen-fixing

· deep-rooted

Some common nursery trees for coffee and cacao plantations

· Gliricidia septum

· Alnus japonica

· Leucaena leucocephala

· Erythrina orientalis

· Paraseriantes falcataria

· Pterocarpus indicus

· Samanea saman


Narra - coffee - gabi

 

Multistorey system + animals

This system is similar to the multistorey system except that freerange grazing animals are added as a component. An example is the coconut-lanzones mixture, with horses or cattle, found in Laguna and Quezon provinces.

Trees along farm boundaries

Trees are planted along farm boundaries as: boundary marker, live fence, live-fence post for tying barbed wire or bamboo slats, or as shelterbelts/windbreaks.

When mature, some of these trees can be harvested and used as posts or as light construction materials. Pruning can also provide fuelwood, fodder or green manure.

Live fences (or living fences) can be established by planting rows of trees or shrubs around a grassland area to enclose the grazing animals. Aside from the tree's role as a fence, it can be managed (e.g., by regular top-pruning to encourage more lateral branching) so that the enclosed animals can browse on the low-lying branches, which serve as fodder supplement.

Advantages

· Trees serve as windbreak or live fence.

· Trees serve as source of post, fuelwood, fodder, green manure and live trellis.

Limitations

· Possible shading of crops by tree.

· Can be difficult to establish if animals are allowed to graze, as they may browse the trees before they are well-established as a fence

Species used as live fence

· Leucaena leucocephala

· Gliricidia septum

· Sesbania grandiflora

Species used as windbreak/shelterb elt

· Eucalyptus camaldulensis

· Casuarina equisettifolia

· Acacia auriculiformis

· Bamboo

Trees as live trellis

Trees are top-pruned (pollarded) to serve as live trellis for climbing crops, especially vegetables like beans, peppers, yams and cucumbers. The most commonly used trees as live trellis are Gliricidia septum and Leucaena leucocephala.


Rope of wire

 

Tree-crop grazing system

Animals (e.g., cattle, carabao, goats, sheep) are allowed to graze freely underneath relatively mature tree plantations. A good example is the silviculture scheme of the Nasipit Lumber Company in Agusan province.

The cattle are allowed to graze freely under lumbang (Aleurites moluccana) trees where improved forage grasses have been planted. This system has proven to be practical and economical because the land is fully utilized while being maintained and protected. The grazing animals keep the grass down, allowing for easier collection of the lumbang nuts.

Protein or fodder bank

Leguminous fodder trees or shrubs (e.g., Leucaena, Gliricidia, Flemingia) may be established in intensively planted small stands on the farm. These are usually fenced off and serve as a supplementary source of protein for livestock. The top and branch prunings are fed to animals through a "cutand-carry" system. A good example is the intensive feed garden.

Advantage

· Ideal for coconut plantations commonly found throughout the Philippines

Limitation

· Grazing animals may eat the tree bark if it is palatable.


Leucaena

 

Forest-based agroforestry systems

Taungya system

Taungya is an agroforestry system in which newly established reforestation areas are interplanted with agricultural crops. As soon as the tree canopies close making the light intensity critically low for crop production, the farmers move to another reforestation area and the same process is repeated. An example of this is the Family Approach to Reforestation piloted by the Bureau of Forest Development (now the Department of Environment and Natural Resources).

Advantage

· Proven to be a cost-effective reforestation strategy.

Limitations

· Farmers cannot grow permanent crops since they have to leave the area as soon as the tree canopies start to close (after 3-5 years).

· Can be discouraging to farmers as the more they care for the area (e.g., weeding and fertilizing their crops which also favor the trees), the faster the trees grow and the sooner they will lose access to the land.

· Provides only a temporary, supplementary source of food and income for the first 3-5 years after the establishment of the reforestation area.

· Family resettlement after the tree canopy closes can be very difficult.


Forest trees

 

Alley cropping—tree plantation integrated production system

In this system, the upper 60% of the hillside is devoted to small-scale tree plantation, devoting one or more forest tree species for various uses (e.g., timber, polewood and/or fuelwood). These tree plantations may be established at close spacing to ensure that poles and posts are produced. When the trees are already tall enough, rattan or other shadetolerant crops can be interplanted. The lower 40% of the hillside is devoted to food production where the alley cropping system is practiced.

Advantages

· Effectively conserves soil.

· Provides abundant food, wood and income for upland farmers.

 

Improved fallow system

In the uplands, cultivated areas are planted with agricultural crops and then allowed to fallow for some time to allow the soil to rejuvenate. To shorten the fallow period, the area can be seeded with leguminous trees. Once the soil has been rejuvenated, these areas are again cleared for crops. This can be considered as an improved version of the traditional shifting cultivation practice.

An example is the Naalad-style farming system, practiced in Naalad, Naga, Cebu. In this system, the native Leucaena is used as the species to shorten the fallow period; the trees are cut and the branches are piled along the contours to form a barrier structure known locally as balabag, which traps the eroding soil. Through time, natural terraces are gradually formed, thus stabilizing the steep slopes.

Advantages

(improved fallow system vs. traditional shifting cultivation)

· Introduction of nitrogen-fixing trees as fallow species shortens the fallow period required for soil rejuvenation.

· Terraces are gradually formed, thus stabilizing slopes.

· Promotes efficient nutrient cycling (no burn).

Limitations

· Laborious because of the construction and maintenance of the balabag.

· Wood from the fallow species (Leucaena) is used for construction of the balabag rather than for fuel.


Improved fallow system

 

Rice terraces—forest agroforestry system

This indigenous agroforestry system can be considered sustainable as it has existed for more than 2000 years, as pioneered by the Ifugao tribe in northern Philippines. A series of bench terraces is constructed along steep mountainsides and rice is planted throughout the year. Irrigation is provided through a network of canals along dikes which originate from natural springs emanating from small forest stands celled pinugo. These are managed and protected by Ifugaos based on a set of tribal laws.

Advantages

· Sustainable.

· Steep slopes are put to productive use.

Limitations

· Laborious to establish and maintain.

· Limited to areas where there are natural springs.


Rice terraces

 

Agroforestry systems in Thailand

Agroforestry has long been practiced by farmers in Thailand. Shifting (rotational) cultivation, for example, has been used by some ethnic groups in the upland areas of northern Thailand for centuries. In the Lab Lae district of Uttaradit province, homegardens have been cultivated for more than 200 years. Similarly, multistorey fruit orchards have been cultivated in many parts of the country for more than 100 years.

Traditional agroforestry, characterized by a simultaneous combination of trees and crops, low-input techniques and indigenous knowledge, are harmonized with local culture and traditions.

Newly developed agroforestry systems, with a systematic combination of trees, crops and livestock and usually driven by market forces, emerged in areas where cultivated land is limited, beginning during the mid-1950s. These systems were first introduced in Prae province, where teak plantations were intercropped with upland rice (in a taungya system). They have since evolved, however, into improved taungya systems, with crops, fruit trees and rubber trees grown in various combinations with timber trees.

Thailand's a total land area of 51,311,500 hectares, consists of 76 provinces with a population of 56.5 million and an average population density of 1.1 person per hectare. In 1988, 48.9 percent of the country was officially categorized as forest land, consisting of 1,215 national reserved forest areas 120 million hectares), 58 national parks (2.5 million hectares) and 30 wildlife sanctuaries (2.2 million hectares).


Thailand

 

Farm-based agroforestry

Homegardens

Homegardens are multitiered systems found in family compounds surrounding the home. Permanently settled communities in upland areas throughout the country have cultivated homegardens for centuries. Most notable are the Karen and the Lua ethnic groups. In the north, homegardens are mostly located in communities in the foothills. Owing to small landholdings in the central region of the country, homegardens here tend to be small.

Most homegardens have three to five layers. Erythrina dadap and banana are common tree species providing shade for crops and vegetables. Moringa oleifera and Sesbania grandiflora are commonly planted as multipurpose trees. In the south, big trees such as wild durian (Durio spp.), yang trees (Dipterocarp spp. ), Parkia speciosa and Artocarpus integer dominate the top storey of the gardens. Eugenia caryophyllus is commonly mixed with fruit trees to provide cash income.

 

Limitation

· Homegardens require considerable indigenous knowledge and labor to establish and maintain.

Live fences on farm land

Live fences of bamboo and fast-growing trees are common in the central and eastern regions of Thailand (Prachinburi, Nakornnayok, Srakhew and Chanthaburi provinces) where they serve as windbreaks and shelterbelts for crops and fruit orchards and as boundary markers. Commonly planted species are Thysostrycus siamensis, Bambusa nana, Bambusa flexuosa and Acacia spp. In the south, Azadiractha excelsa is commonly planted in and around farm fields.

Advantages

· Trees supply poles and wood for farms.

· Fences protect crops in the field and reduce wind damage.

Limitation

· Some productive land must be sacrificed to establish the windbreaks.

Natural trees and shrubs left on agricultural land

Diverse trees and shrubs are deliberately left on farmland to serve as shade and provide green manure for crops such as rice and beans. The trees and shrubs also recycle minerals in the soil and control the development of problem soils, particularly saline soils in the northeastern region.

Forest-based agroforestry

Small-scale block planting on abandoned agricultural land

Due to migration of rural people to cities, large marginal upland areas which used to be cultivated are being abandoned. This has presented an opportunity for small-scale commercial tree farming.

People from urban centers are investing in land in rural areas and planting high-value trees such as teak (Tectona grandis), eucalyptus and Azadirachta excelsa These species are longterm alternatives to large plantations for both economic and ecological reasons.

Shifting (rotational) cultivation

This system involves the cultivation of several areas of sloping land on a rotational basis (short cultivation, long fallow). It has long been sustainably practiced in upland and highland areas by several ethnic groups, most notably the Karen and the Lua. Rice and various other crops are planted simultaneously to produce food and fodder.

Advantage

· This system helps conserve the biodiversity of indigenous plant genetic resources such as rice, other crops and medicinal plants.

Limitations

· This system is rather fragile. It may collapse due to inappropriate interventions and population increases.

· The system requires several pieces of land for adequate rotation and to allow the land to recover, thus it is inappropriate where land is scarce or population density is high.

Forest gardens

Forest gardens include various indigenous forest and fruit trees, located away from but within walking distance of the family house. In forest gardens in central Thailand (Khao Sol Doa, Chanthaburi), Amomum xantitioides has been cultivated under moist evergreen forest for centuries. However, forest gardens are mostly found in the mountainous area of Uttaradit province in the north and Nakornsrithammarat, Trang and Phattalung provinces in the south.

In the northern forest gardens, Cammellia sinensis is cultivated under evergreen forests without having to cut trees in the forest.

In the south, wild durian (Durio sp.), duriannok (Durio sp.) takiens and yangs (Dipterocarp spp.) are the most dominant species of the top storey.

Advantages

· In the forest garden systems, trees and crops are simultaneously cultivated, thus requiring few inputs.

· Because of their diversity, forest gardens are ecologically sound.

Limitation

· Because they are located away from the village, forest gardens are difficult to manage and are subject to loss from theft, fire, or livestock.

Forest plantation and livestock

This system incorporates cattle grazing under tree plantations. It is commonly practiced in old plantations where grasslands for livestock are scarce.

Forest species planted in this system are Tectona grandis, Dipterocarpus spp., Hevea brasiliensis and other fast-growing species, such as Eucalyptus spp. and Azadirachta indica.

Advantage

· This system reduces dry matter in the forest plantation, thus reducing the risk of fires.

Limitations

· Fruit trees, crops and other plants cannot be cultivated.

· Without appropriate management of livestock numbers, season of grazing, etc., the soil can be seriously compacted by livestock.

Improved taungya

This system, combining trees and livestock, was first developed under the government reforestation program, with an aim toward establishing teak plantations. It has since been expanded to include other species and to increase crop production. It is currently being practiced in both government and private forest plantations.

Forest tree species commonly planted include Tectona grandis, Pinus kesiya and Pterocarpus marcrocarpus. However, in some areas, fruit and rubber are also planted as the major trees. Normally, cash crops are intercropped with the trees in the early years of establishment. Livestock are usually allowed to graze in the plantation when the trees are more than three years old.

Advantage

· This system benefits the government and private companies by expanding forest plantations. It can benefit local people by providing land for fruit trees, crop and livestock production on a temporary or long-term basis.

Limitations

· Taungya systems have traditionally not been beneficial to local people over the long term. From the perspective of timber production, risks also exist that people will damage the trees in order to continue crop and fruit tree production and grazing beyond the limited number of years permitted by the system regulations.

 

Agroforestry systems in Vietnam

In the uplands of Vietnam, agroforestry in various forms is widely used by farmers and forest enterprises. Of the total land area, 70% is upland and almost 30% of the population lives in upland areas. Almost all of the 54 ethnic minority communities are found in the upland areas.


Vietnam

 

System

Region

Farm-based agroforestry

 

· Homegardens and von ao ca chuong

all regions

· Fruit orchards, including coconut-based gardens

all regions

· Forest/crop/irrigated rice

hilly and mountainous areas

· Woodlot

mostly midland areas

· Commercial crops under multipurpose tree species

 

—tea

midlands and uplands

—coffee

central and southern

 

midlands and uplands

—black pepper

central and southern

 

midlands and uplands

—other agricultural crops

 

· Agricultural crops under commercial trees

 

—rubber

central and southern

 

midlands and uplands

—cashew nut

coastal and midland areas

—fruit trees

all regions

—cinnamon

central and northern regions

· Hedgerow and contour planting

central and northern regions

 

(SALT)

Forest-based agroforestry

 

· Shifting cultivation/fallow upland areas

 

· Taungya

 

—timber production

northern midlands and

 

uplands

—paper pulp production

central and northern

 

midlands and uplands

· Accelerated pioneer climax series

all regions

Upland use

Total upland area

24.5 million ha

· Arable land

5.4 million ha

Cultivated

3.5

—Perennials

0.6

—Rice

1.4

—Annual crops

1.5

Pasture

0.3

Others

1.6

· Forest land

19.1 million ha

Forested

9.3

—Natural forest

8.7

Planted forest

0.6

Deforested

9.8

Upland population

19 million

Ethnic minorities practicing shifting cultivation

2 million

Average household size

7 persons

 

 

Farm-based agroforestry systems

Homegardens

The homegarden is a traditional agroforestry system found throughout Vietnam from the lowlands to the highlands. On a relatively small piece of land around the house (usually only about 0.5 ha, but occasionally up to 5 ha), the land is used as efficiently as possible to produce a wide variety of products. Fruit, vegetables, root crops, fish, livestock, fodder, fiber, medicine, small timber fuelwood and various minor products are grown in a multilayered structure. Seed and seedlings for propagation are often obtained from the family or neighbor's gardens. One kind of tree or crop may be dominant and the homegarden may be named accordingly, e.g., coconut garden. Although the size of individual homegardens is small, their cumulative effect can be very important in watershed and natural resource management on a community or regional scale.

One very common type of homegarden is the so-called von ao ca chuong or rung von ao ca chuong (RVAC) system, combining forest trees, fruit trees, fishpond and livestock in an integrated farming system.

Factors influencing species composition

· soil conditions.

· available labor.

· local climate.

· household needs.

· household economy.

· farmer skills and preferences.

 

· Iocal markets.


RVAC system in Tuyen Quang

 

Species found in Vietnamese homegardens

Fruit trees

Root crops

jacktruit

cassava

banana

sweet potato

orange

taro

lemon

canna

pomelo

yam

grapefruit

 

papaya

Vegetables

sapote

squash

longan

soybean

litchi

pumpkin

starfruit

Chinese

coconut

cabbage

cashew nut

squash

durian

spinach

rambutan

black pepper

avocado

carrot

guava

mungbean

water apple

 

custard

Others

apple

peanut

cumquat

sugarcane

mangosteen

pineapple

langsat

ginger

jujube

medicinal

 

plants

Others

 

coffee

Animals

cacao

fish

bamboo

pigs

rattan

goats

mulberry

chickens

tea

ducks

cinnamon

cattle

Melia spp.

deer

forest trees

silkworms

 

bees

 

 

Advantages

· ecologically/economically stable.

· Iow labor requirements.

· Iow level of pests and diseases.

· familiar to farmers (traditional).

Limitations

· Quality and availability of seedlings are not yet fully established.

 

Forest/crop/irrigated rice

Forest/crop/irrigated rice systems are often established in hilly and mountainous areas. A natural forest or plantation crowns the site and is usually managed by state. forest enterprises or community groups. In some places, the upper part of the system includes a water reservoir which is to irrigate the lower areas and to generate electricity. Vegetables or cash crops are grown on terraces or along contour lines and the irrigation system allows farmers in the valley to grow paddy rice.

Advantages

· The spatial arrangement of the components enables their positive interaction, thereby optimizing the overall production of the area.

· Even distribution of work and income throughout the year.

· Diversity of locally available products.

Limitation

· The system requires good relations and cooperation between farmers, farmers' cooperatives and the forestry agency or group managing the forest This can be difficult in newly established communities.

Woodlot

Woodlots have been successfully established on underutilized or degraded land, using fast-growing trees, especially nitrogen-fixing multipurpose species.

Along with the rehabilitation of wastelands, these woodlots supply fuelwood, small timber and other minor products for local consumption. Beekeeping and livestock grazing are often practiced in the woodlot. Agricultural crops can be intercropped during the establishment of the woodlot tree species. State lands, as well as financial and technical support, have been allocated to individual farmers for plantations.

Advantages

· Simple management (monoculture, regular arrangement).

· Can provide windbreak and soil protection.

· Aesthetic improvement to the landscape.

· Intercropping is possible during woodlot establishment.

Limitations

· Sufficient planting material not available.

· Requires extension support.

· Pests and diseases.

· Uncertain distribution of work responsibilities and income on state lands.

Commonly used woodlot tree species

Acacia auriculiformis

A. mangium

Cassia siamea

C. fistula

Erythrina spp.

Eucalyptus tereticornis

E. camaldulensis

Gliricidia septum

Melia azedirachta

 

Cash crops under multipurpose tree species

Cash crops, such as coffee, tea and black pepper, can be grown under trees which provide shade and other forms of support to the crops. Tree species commonly used in these systems are Pinus kesya, P. merkusii, Cassia siamea, Leucaena leucocephala, Gliricidia sepium, Pterocarpus indicus, Moringa oleifera, Manglieta glauca, Aleurites fordii, T. candida and cinnamon. Although the trees do not provide the major income from these systems, their contribution to farm income can still be important. They also serve various other purposes.

Advantages

· Protection and support of agricultural crops through windbreaks, shade and possible nitrogen fixation provided by trees.

· Improved soil protection through contour planting.

· Increased soil cover by tree litterfall.

· Diversification, which improves food security.

Limitations

· Crops such as coffee or tea are dependent on international market fluctuations.

· Practice requires much skill and technical expertise.

· Trees may affect cash crop productivity.


An agroforestry system from Lao Cai province (northern Vietnam)

 

 

Agricultural crops under commercial trees

Several agroforestry systems use the space between commercial tree crops to intercrop agricultural crops (annuals). This intercropping is usually limited to the first few years of plantation establishment (e.g., rubber plantations, or fruit orchards of cashew nut, mango or jackfruit) until the tree canopy closes. This is usually done by a farm family who manages the plantation for another landowner (usually a state enterprise).

Advantages

· Potentially high income.

· Tree cover improves soil protection.

Limitations

· Labor intensive

· Allows for cultivation of agricultural crops only during establishment.

· High investment costs.

Intercropping during the establishment of cinnamon plantations

A common practice of the ethnic Zao people is to intercrop during the establishment of a cinnamon plantation. The plantation is often established on steep slopes (>25 degrees) under natural forest with a crown cover varying from 50-70 %. Cinnamon requires 2000mm of evenly distributed annual rainfall, generally warm and humid conditions and good soils. Usually, the eastern side of a slope is used for this practice.

· Initially 2000-3000 cinnamon seedlings per hectare are planted under the shade of the forest trees after clearing shrubs.

· In the first 3 years, upland rice and cassava may be intercropped.

· After 2-4 years, the trees of the natural forest are thinned to provide more light.

· When the cinnamon is 6-7 years old, a second thinning of the natural forest trees is carried out.

· At the age of 8-10 years, most forest trees are cut and the cinnamon becomes the dominating tree in the system.

· When the cinnamon trees are 20-25 years old, they then reach their mature harvest age.


Cutting of most forest trees

 

Hedgerow and contour planting

Various combinations of techniques have evolved to allow cultivation on steep, sloping terrain without causing serious soil erosion. In Vietnam, within the last decade, farmers have adapted the SALT (Sloping Agricultural Land Technology) technique, originally developed in the Philippines. Locally suited species, like Tephrosia shrubs and Indigofera trees, have been incorporated. By the use of a very simple A-frame, farmers are able to mark out the contour lines of the slope. Along these contour lines, physical measures may be applied to enable cultivation, including construction of terraced fields and stone embankments. On the edge of the terraces, rows of woody perennials are grown. In Central Vietnam, trees are also planted on the contour lines, together with grasses and other crops. Natural terraces will gradually form as the tree rows form a barrier which prevents soil and plant material from washing down the slope.

Advantages

· Soil and water control.

· Diversified production.

· Income throughout the year.

· Increased yields.

· Green manure can improve soil fertility.

Limitations

· Labor intensive.

· High investment for seed/seedlings required.

· Training of farmers required.

· Difficulties in marketing newly introduced products or crops.

· Farmer reluctance to adopt the new system.

Sequence of SALT practice in Lang Son province

· Initially, forest trees are planted at the top of the slope (generally 15-25 degrees) and cash crops such as pineapple and hill rice are planted. At the foot of the hill, forest trees (such as Manglieta) are inter-planted with rattan.

· After 2 years, barrier crops such as Tephrosia spp. and pineapple are planted along the edges and waterdiverting ditches are constructed, creating natural terraces over time.

· Depending on water availability, fruit trees, tea, staple food crops or other crops can be planted on the terraces.


Food crops

 

 

Forest-based agroforestry systems

Shifting cultivation

Shifting cultivation, or slash and burn, is practiced extensively by more than two million people from more than 50 different ethnic groups in the hilly and mountainous areas of Vietnam. On a patch of upland forest, farmers slash shrubs and other low vegetation and then burn it. Hill rice is then grown for two to three years. The field is then abandoned and the farmer moves to another site to repeat the process. In the past, the farmer returned to a site only after 10 to 20 years, depending on the recovery rate of the fallowed fields. Rice yields were reported from 2000 kg/ha in the first year to 900 kg/ha the third year in central and northern Vietnam. However, today this fallow period is often reduced to 5-7 years, resulting in much lower yields. In some places, cassava is cultivated for 1-2 years after the first two years of rice cultivation. But this practice leaves the soil without any cover for 34 months following each harvest, causing severe erosion. Besides these two crops, farmers may also cultivate corn, bamboo and various tree species, such as Manglieta or Melia.

Traditionally, shifting systems were sustainable because population pressure was low and enough time was allowed for the forest to regenerate. However, with today's rapidly growing population, this system has been cited as a major cause of deforestation in Vietnam.

Advantages

Limitations

· Low cost.

· Large land area needed.

· System is familiar to farmers.

· Soil erosion after burning.

 

· Leads to deforestation.

· Simple technology.

· Low yields.

· Integrated part of local culture.

· Extensive weeding initially needed.


Agricultural farming cycles on the hillslope

 

 

Taungya

The taungya system allows venous intercrops to be grown (until the tree canopy closes) between newly established tree rows in forest plantations. This system has been used for many contract reforestation projects throughout Vietnam as a means to rehabilitate degraded natural forest lands. These contracts between state forestry enterprises and rural households often include technical support, such as the introduction of new species, supply of seedlings and fertilizers, training in planting and intercropping techniques, as well as financial support. The contracts also specify land tenure and duration and percentage of benefits to the farmer from the clearing, thinning and harvesting operations to be undertaken. The forest trees may be grown for either timber or paper pulp production.

Advantages

· Reduced management costs for plantation owner.

· Provides additional cropland to farmers (in the initial stages).

· Ecological benefits of reforestation.

Limitations

· Short agricultural cropping period.

· Farmers must have other land.

· Requires some management skill.

· Requires a guarantee for the sale of the forest product.

 

Taungya system for timber production

· Fast-growing trees Acacia auriculiformis, A. mangium or Cassia siamea are planted at a density of 1250 trees/ha (2m x 4m spacing) for fuel wood and small timber production in a 10-year rotation.

· Timber species Hopea odorata and Dipterocarpus alatus are planted with a density of 312 trees/ha (4m x 8m spacing).

· Cash crops are interplanted in the alleys between rows of forest trees during establishment.

Taungya is also practiced by several state forestry enterprises to produce pulp for paper production. In these systems, each family plot is divided into 20 parts that are gradually planted with EucaIyptus and Acacia species in an 8- to 10year cycle and intercropped with annual cash crops.

Degraded land restoration by sequential planting accelerated pioneer climax series system

Reforestation has been proposed as the most promising stategy to rehabilitate degraded upland soils and make them more productive and ecologically balanced. The accelerated pioneer climax series (APCS) system has been applied in reforestation of marginal lands in the midhills and uplands of central and southern Vietnam. Experiments with APCS were carried out in Vietnam as early as the 1920s. Although reforestation is the major aim, intercropping of agricultural crops is possible during certain phases.

APCS is based on the ecological principle of natural succession, which relies on pioneer species that have the ability to adapt to adverse conditions. These species will improve the microclimate and soil conditions of a particular site, making it favorable for the establishment of less-sturdy climax species. Natural succession is a slow process, but it can be accelerated considerably through planting pioneer species and interplanting climax species. Variations of this practice focus on different species and planting distances. There are two main phases:

Phase 1. The establishment of dense stands of fast-growing species to eliminate "cogon grass" (Imperata cylindrica) and to produce short-cycle fuelwood and roundwood. This involves high tree densities (2000-3300 trees per ha) to eliminate light-demanding grasses within two years after planting. Species commonly used are Acacia auriculiformis, A. mangium, Indigofera teysmanii and Gliricidia septum. Four years after establishment, the trees are thinned to remove one out of every four rows for fuelwood and small-pole production. Crops and dipterocarp species are then planted in the alleys between the double rows of pioneer trees. At years 8 and 12, the pioneer species will be gradually cut and removed, providing more light for the climax species and space for growing crops.

Phase 2. The establishment of mixed plantation with pioneer, intermediate and climax tree species. Pioneer species may be Indigofera teysmanii, intermediate species are Acacia auriculiformis, or Cassia siamea; and climax species include Dipterocarp species, like Dipterocarpus alatus, D. dyerii and Hopea odorata. Planting densities follow these guidelines: pioneer species—1666 trees/ha, intermediate species—833 trees/ha and climax species—278 trees/ha.

Objectives of APCS

· To quickly rehabilitate wasteland and denuded hills

· To produce fuelwood and small timber for local consumption

· To make the site favorable for the climax forest species


Objectives of APCS

 

 

The three species planted are:

· The pioneer species (Indigofera teysmanii) which is cut every two years for fuelwood production. This species grows fast and coppices well.

· The intermediate species (Acacia auriculiformis) which is gradually thinned every six years, providing fuelwood, poles and small timber.

· The climax species (Dipterocarpus alatus or Hopea odorata) which is expected to develop for 60 years before harvest for timber.

Advantages

Environmental

· Follows the principle of natural succession.

· Promotes tree diversity (at least two species are planted).

· Recovers grassland areas, which were formerly dipterocarp forests.

· Improves the microclimate and provides immediate cover.

· Protects upland soils from erosion.

· The pioneer trees improve soil conditions, particularly the soil's biological and physical properties.

· The growth performances of the intermediate and climax species are improved and are much better than in pure stands.

· Strengthens the nutrient cycling process, thereby restoring the productivity of the upland tropical forest ecosystem.

Socioecono mic

· Thinnings from the pioneer and intermediate species can be good sources of fuelwood, roundwood, fodder, mulch, organic fertilizer and small timber for local consumption.

· Acceptable to local people since the practice allows participating farmers to get different products shortly after establishment until the end of the climax species rotation.

· Cost-effective, especially on open grasslands, since the pioneer and intermediate trees quickly suppress light-demanding grass.

Limitation

· Willingness of farmers to accept this system to rehabilitate degraded lands or on commununal lands.