|CERES No. 058 (FAO Ceres, 1977, 50 p.)|
What is the place of traditional intercropping systems in modern agricultural practice? There are increasing indications that such systems should not be rejected wholesale as primitive and uneconomical. In fact, it appears that past research aimed at improving cropping systems has not paid enough attention to some of the techniques developed by small farmers, and that a scientific approach to such systems can sometimes give better results than the use of technology primarily developed for single-crop systems.
More than 80 researchers have met recently at the Faculty of Agriculture, University of Dar Es Salaam, in Morogoro, Tanzania. They have reviewed many of the aspects of intercropping systems traditionally used in several African countries, and have concluded that the study of crop interaction, soil management, pest and disease control, as well as plant breeding, is likely to help achieve better yields.
A number of significant examples were given. For instance in Zaire, maize is often grown on raised beds separated by furrows. After the harvest, the maize stalks and leaves, together with weeds and other crop residues, are put into the furrows, which become the following year's beds. Researchers of the National Maize Programme have shown that this practice does increase the following year's yields, but that a further increment can be achieved by planting cowpeas with the maize.
In Nigeria, there is a traditional three-year mixed cropping cycle in the area surrounding Zaria; here, researchers have shown that yields can be increased if maize is added to the usual millet-sorghum intercrop. Trials have also shown that during the third year, when cotton is grown between cereals, cotton yields could be improved if it were planted earlier than was the custom among farmers.
In Uganda, where maize and beans are traditionally intercropped, the beans are usually planted two to three weeks after the maize. Research has shown that this delay reduces the yields of both crops: better results are achieved when both maize and beans are sown simultaneously.
These and other examples have shown that, in the study of multiple-cropping systems, research must focus on the whole system, rather than its individual components. The social environment-the farmer himself-is part of the total system, and this aspect should not be neglected. Thus traditional intercropping systems, already adapted to the farmer's environment, can be improved without the substantial alterations often required by the introduction of single-crop technology. Such a scientific approach can help integrate traditional practices with modern agriculture.
· Preventing shigellosis
Most scientists believe that shigellosis, a particularly severe form of dysentery, is not a waterborne infection. But recent research, carried out in Bangladesh, has shown that water may be a more important factor than person-to-person contact, and that the improvement of water, nutrition and basic hygiene may be a key to preventing outbreaks of shigellosis.
Epidemics of shigellosis broke out in 1972 and 1973 in Teknaf, a peninsula at the southernmost point of Bangladesh. This infection had been an insignificant cause of dysentery before the 1971 war of independence. But, after the Cholera Research Laboratory in Dacca identified the infectious agent as the Shigella dysenteriae bacillus, a dysentery project was established in Teknaf. In the first 18 months, 1 700 cases were treated, and 700 cases were shown to be infected with the deadly type I bacillus (40 percent of children under the age of six did not survive the disease).
According to Dr. M. Mujibir Rahaman, director of the project, an important finding was that families taking water from the tanks or ponds where people also bathe and wash their clothes had a higher rate of shigellosis than those using community wells.
Now participants in the Teknaf project have adopted as a priority the prevention of disease through a programme of health and hygiene education, and the improvement of sanitation and water supplies. The effectiveness of these measures will be seen only if and when there is another major outbreak.
Dr. Rahaman points out that it was the same shigella organism that caused a major pandemic, affecting several million people, in Central America in 1969/70. The disease disappeared as mysteriously as it had come.
· World trade flutters
World trade increased by 3 percent in 1975 over the preceding year. Actually these findings, published in The Yearbook of International Trade Statistics, 1975 of the United Nations just issued, only seem positive. While true in value terms ($870 thousand million compared with $842 thousand million the preceding year), it is not so in volume: taking price increases into account, the 1975 exports of the market economy countries actually decreased by 7 percent. This is the largest drop registered since the Second World War.
As regards the developing countries, the exports of the OPEC countries decreased during 1975 while their imports continued to grow, reducing their surplus from $86 thousand million in 1974 to $58.5 thousand million. The exports of other developing countries remained, in 1975, at a level similar to that of the preceding year, while their imports increased by 6 percent. Their balance of payments, therefore, showed an imbalance even greater than in 1974, the deficit increasing from $28 thousand to $36 thousand million. This increase of the deficit was aggravated by the rise in import prices (12 percent on the average), whereas the export prices have, on the contrary, decreased slightly.
On the other hand, the developed countries in 1975 saw their trade imbalance almost halved - from $68 thousand million to $35.7 thousand million. Inversely to what took place in the developing countries, the exports of the developed countries increased by 6 percent, while their imports remained at the same level as in 1974.
· New experimental station
The Turkish Ministry of Agriculture is developing an agricultural experiment station that may become one of the most important ones in the region. Four hundred hectares of land will be devoted to research on a number of crops, the major one being wheat, of which Turkey is the world's seventh producer (with 14.7 million tons in 1975).
· A new arrival in the financial world: the Arab Monetary Fund
The Arab Monetary Fund (AMF), another expression of Arab solidarity, is now under way. At a meeting in Abu Dhabi from 18 to 21 April, the finance ministers (or the governors of the central banks) of the twenty countries of the Arab League, as well as a Palestinian delegate, appointed Gawas Hachem, former minister of planning in Iraq, Director-General of the organization. They also designated as members of the governing board the following countries: Algeria, Saudi Arabia, Bahrain, Egypt, United Arab Emirates, Jordan, Mauritania and Somalia. The first meeting of the governing board was on 20 May in Abu Dhabi, headquarters of the Fund, to study the first files.
One year after the adoption of its statutes, AMF-an idea launched in February 1974- is now operational. What is its mission? Like the International Monetary Fund (IMF), of which it is a replica, AMF will grant loans to countries suffering from payment difficulties. To do this, it has been endowed by its founders with a capital of 250 million diners (about $900 million). The biggest subscribers are Algeria and Saudi Arabia (38 million diners each), followed by Iraq, Kuwait and Egypt (25 million each). As with IMF, the loans will be proportionate to the subscriptions of the member c,ountries (at most, four times the subscription), and subject to certain conditions.
As well as this very classic schema of credits opened in favour of temporarily impoverished countries, AMF has a more ambitious aim: that of promoting Arab monetary unity. This aim is certainly not proclaimed in its statutes but the means of achieving it are set out: definition of an accounting currency - the diner (equivalent to 3 SDRs); defence of the stability of Arab currencies; convergence of financial policies; attempts to define a common investment policy for Arab capital outside the Arab zone; and promotion of an Arab financial market. Finally, AMF should be a useful forum for establishing a common position on problems discussed in international monetary circles. Now that their economic and financial power is incontestably established, the Arab countries intend, far more than in the past, to make their voice heard in monetary discussions. And the international community has recognized their right to it by doubling their quota, and thus their voting rights, in IMF on the occasion of the last increase in quotas, which is now being ratified.
· A new source of rubber
A shrub of the sunflower family, growing in poor desert soils, is a potential competitor of Hevea a source of rubber. It is the guayole (Parthenium argentatum Gray, fem. Compositae), which grows in arid regions of north-central Mexico and the southwestern United States.
The latex is contained in cells throughout the plants, particularly in the roots and stems. The whole plant must be harvested, and then sliced into small fragments; the tissues are macerated, and the lighter rubber floats over the vegetal residues.
Research on the guayule plant was conducted in the United States during the Second World War, when Hevea rubber was in short supply, and some 1 300 tons of guayule rubber were produced. After the War, research as well as production were discontinued, and there is no commercial production to day, although attempts at growing the shrub have been made in Turkey and Spain.
A pilot operation was recently established in Mexico. There have been some problems, notably in getting rid of residual resin impurities, but many of these are being overcome.
The potential of guayule now appears to be very important indeed. Hevea rubber supplies about one third of the world's market, the rest being made from synthetic elastomers.
These are superior to natural rubber for some uses, but inferior for others (and they are based on petroleum).
Wild plants can yield as much as 12 percent latex (dry weight) and improved varieties up to 20 percent. The shrubs can live as long as 50 years, which represents a considerable advantage, as the rubber can thus be stockpiled until a good market is available.
New methods of extracting latex are now being teed, and it is expected that the major problems will be solved within a few years. The guayule could then become an important cash crop in arid and semiarid regions.
E. Campos. Director
Centro de Investigaciones en Quimica Aplicanda,
Aldama Ote. No 371, Saltillo. Coahuila, Mexico
Fernandex Aguirre, Director General
Comision Nacional de las Zonas Aridas
Tonala N° 30 Mexico 7, DF
National Academy of Sciences National Research Council 2101 Constitution Avenue Washington, D.C. 20418, U.S.A.