| South-East Asia's Environmental Future: The Search for Sustainability (1993) |
|Part III - Selected issues: Change and the environment|
|Ecological policies for sustaining high production in rice: Observations on rice intensification in Indonesia|
Facing the problems of sustainability
New Genetic Material
The crucial technology of the Green Revolution consisted of important new genetic material: short, stiff-strawed, photoperiod-insensitive rice varieties that tillered profusely and produced heavy panicles of grain. These varieties were highly responsive to nitrogen fertilizers but, unlike taller varieties which tend to fall over as their stalks lengthen, a high proportion of the uptake of nitrogen in the new HYVs went into the production of grain. Because of this capacity to utilize nitrogen, an essential requirement of the technology was increased application of nitrogen fertilizers. Other fertilizers were critical but nitrogen fertilizers were essential.
The 'appropriate' level of application is in fact a complex question and one that has continued to confront farmers, policy makers and scientists alike. The solution varies, depending on whether concern is with affordability, with improved average yields or with maximum yields. Indonesia's national strategy called for maximum yields and thus, from the outset of the programme, it committed itself to a substantial fertilizer subsidy.
Efficiency is a further issue of importance (De Datta, 1987). Since studies have shown that in applying urea on to flooded rice fields, there is an average recovery of only 30 per cent of the fertilizer nitrogen by the rice crop, much research and experimentation has been directed to improving the efficiency of fertilizer management. More generally, the effects of high levels of fertilizer use on the environment are also important. The production of methane from flooded fields, and the more pressing concern with nitrate and phosphorus contamination of rivers, aquifers and surface water are questions to be addressed.
Indonesia's fertilizer subsidy began as a subsidy for nitrogen; but by the end of the 1970s, it had become a general subsidy for all fertilizers used for rice (urea, ammonium sulphate, triple superphosphate and potassium chloride). This subsidy provided rice farmers with all their fertilizer requirements, regardless of their different costs, at a single, relatively low farm-gate price. Generous subsidies, coupled with the government's own high fertilizer recommendations, prompted farmers to adopt application levels that were some of the highest in all of South-East Asia. By the time Indonesia achieved self-sufficiency in the mid-1980s, the cost of this fertilizer subsidy had ballooned to approximately one-third of the entire development budget. This increasing subsidy was itself unsustainable and forced a re-evaluation. In the late 1980s, while still continuing to expand its production, Indonesia began to reduce the levels of its fertilizer subsidy, to create a differential price structure for nitrogen and non-nitrogen fertilizers, and to reduce its official recommendations for the application of fertilizers, especially triple superphosphate. Having urged farmers over the decades to increase their use of fertilizers, the government found it a daunting task to persuade farmers to begin immediately to reduce their application levels.
The third element of the technology of the Green Revolution involved the use of modern pesticides to prevent crop loss and ensure high production. In retrospect, it is possible to see the profound effect of pesticide use on shaping the Green Revolution and development of its essential seed component. Initial introduction and rapid adoption of a small number of closely related HYVs reduced genetic diversity. Genetic uniformity invariably sets the stage for widening crop vulnerability to disease and destruction by insects. The heavy and routine use of pesticides, high applications of nitrogen fertilizers, the closer spacing of plants, and a continuous monocrop culture involving double or triple cropping-all these practices in combination-also increased vulnerability. As the risks of crop loss increased, the use of pesticides escalated. Farmers throughout Indonesia were instructed in the use of pesticides which were often represented as 'medicine' for growing plants. They were advised to conduct spraying at regular intervals during the growing cycle. Pesticides were subsidized by the government at levels that often exceeded that for fertilizers and were included in the various formal packets of the intensification programme. Periodic outbreaks of BPH infestations appeared to confirm for farmers the need for regular pesticide use and, on irrigated rice in particular, this rose steadily.
Indonesia's use of pesticides was in line with that of other countries in Asia. Despite increasing applications, in the late 1960s and through the 1970s, BPH outbreaks occurred not just in Indonesia but throughout South-East Asia, India and China. Why a minor pest of rice that had previously merited no more than a footnote in the standard textbooks should suddenly become the major pest threat to rice in all of Asia became the subject of intensive investigation. Gradually, in the second half of the 1970s and early 1980s, the phenomenon of 'resurgence' began to be understood. The answer lay in understanding the complex balance of predator-prey relationships that had developed and persisted over centuries in the rice-growing environments of Asia. As the evidence began to accumulate, it became clear that the BPH was an extremely vulnerable rice pest. IRRI researchers identified well over 100 predators or parasites that preyed upon the BPH. Its great strength was its ability to breed and spread rapidly. This breeding capacity gave it enormous powers of resurgence, which none of its predators possessed.
The BPH is a fast-breeding invader pest. It has a short generation time, high fertility, enormous tolerance of crowding and tremendous mobility, thanks to its complex development cycle that produces winged progeny every other generation. Lodged in the stalks of rice, the eggs of the BPH survive, sheltered from insecticide spraying; and, as the larvae of these hoppers emerge, they suck the juices of the rice plant. In large numbers, they are capable of sucking a healthy green crop of rice to a withered, 'burnt' brown in the course of a day or two. At severe infestation levels, the spread of the BPH is rapid and relentless, resulting in widespread devastation known as 'hopperburn'.
This pest presents a double danger. It is also the carrier of a virus that causes a disease technically known as 'grassy stunt', which manifests itself in what superficially resembles a normal verdant crop but, in fact, the rice plants do not form grains. The result is an empty harvest. Often, this disease appears in the crop that follows a heavy infestation of the BPH. Another hopper-the green planthopper-is the carrier of a more serious virus known as tungro. Together, the two planthoppers, if not kept in balance, offer formidable threats to rice cultivation.
The introduction and increased use of broad-spectrum insecticides that accompanied the dissemination of high-yielding rice-seed varieties altered predator-prey relationships in sawah environments. Certain insecticides were more damaging to the parasites and predators of the BPH-useful spiders, beetles and dragonflies-than they were to their intended target. In effect, insecticides actually cleared the way for the BPH by destroying its natural enemies, allowing it enormous scope to burst forth, expand and multiply. Sublethal doses of insecticides may even have stimulated female reproduction. Retrospective interpretation of the evidence from the 1970s, based on IRRI research findings, indicates quite clearly that the BPH outbreaks that disrupted Indonesia's intensification programme from 1974 to 1979 were insecticide-induced (Heinrichs and Mochida, 1984: Kenmore et al., 1984). By the mid-1980s, instead of continuing to emphasize the value of pesticides, the IRRI began to insist on the 'judicious' use of such chemicals, to support an increasing variety of research on biological controls, and to recommend the newly rediscovered strategies of integrated pest management (IPM). (4)
By 1979 in Indonesia, with the introduction of reliable resistant varieties such as IR36, the need for insecticides should have receded. Instead, pesticide usage increased dramatically. Subsidies on pesticides, whose real costs were not borne by farmers themselves, tended to promote indiscriminate and injudicious use: and excessive application had the effect of accelerating natural selection by BPH populations to allow them to feed on previously resistant varieties of rice. To a certain extent, it can be said that Indonesia, by its pesticide subsidy, proceeded to finance its subsequent BPH outbreak in the mid-1980s.
Faced with an outbreak situation potentially more threatening than any in the 1970s, President Suharto adopted the advice of his national scientific advisers. On 5 November 1986, he personally issued a presidential decree (INPRES, 3/1986) embodying a series of ecological measures to overcome the spread of the BPH. The most prominent of these measures was a ban-for use on rice-on 57 varieties of insecticides (including the entire spectrum of organo-phosphates) implicated as resurgence-causing agents. Only certain carbamates were allowed to be used in severe outbreak conditions. The decree also recommended the use of a new, highly effective juvenile hormone that prevented the development of the BPH to reproductive maturity. The presidential ban was immediately implemented with remarkable effectiveness for the 1986 7 rainy season.
INTEGRATED PEST MANAGEMENT
More importantly, for the long-term prospects of the Green Revolution, the decree embodied a commitment to a national policy of IPM that replaced regular calendar spraying with a range of biological and cultural controls, plus judicious spraying only after identifiable thresholds of insects were exceeded. With the support of the Food and Agriculture Organization (FAO), Indonesia also committed itself to the training of 2.5 million farmers in the techniques of IPM. Furthermore within two years of the decree, Indonesia reduced and then eliminated all subsidies for pesticides.
From an international ecological standpoint, Suharto's decision in November 1986 is of fundamental importance. Having the previous year been awarded recognition for the success of Indonesia's intensification programme, Suharto took the decision to give priority to biological, as opposed to largely chemical, means of pest management. Indonesia is the first country in the world to take such a major step to protect its primary crop, and its continuing success from 1987 to 1990 in increasing production should have demonstrated to the world that IPM methods are viable and effective.