The objectives of this meeting are the following.

In opening the Expert Consultation, on behalf of the FAO Regional Representative, who was on mission, Mr. Dong Qingsong, Deputy Regional Representative, expressed his pleasure and privilege to welcome all the participants. He then addressed concerns on land degradation, soil fertility decline, high chemical input uses, pest insect and disease outbreaks and environmental pollution, as well as yield stagnation and the decline in total factor-productivity in intensive-rice farming systems in the region. He also spoke about resource-constraint farmers, generation of off-farm employment and "value addition", at farm or village level, for enhancing income and diversifying options for women. Finally he wished the Consultation's participants a fruitful meeting and an enjoyable stay in Bangkok.

Thereafter, Dr. R. B. Singh, Director, IARI, as a resource person, spoke about "Sustainable Rice Production in Asia and the Pacific, New Research and Technology Development Paradigms". He analysed the trend of rice production, productivity and security during the past 35 years, examined the post-Green Revolution stagnation, or even decline in productivity growth, and the sustainability concerns. He also described the short-and-long-term prospects of meeting rice demands, through the development, transfer and adoption of appropriate technologies. Lastly, he mentioned policy options for rice research and technological development for enhanced and sustainable production of rice under different environments.

Dr. S. S. Virmani, Senior Plant Breeder, IRRI, in place of Dr. G. S. Khush who had other commitments relating to his World Food Prize, addressed the topic "Advances in Rice Varietal Improvement for Increased and Sustainable Rice Production in Asia and the Pacific Region". He stressed that the challenge for rice scientists is how to meet the future global rice demand with less land, less water, less labour and fewer pesticides. IRRI has worked on hybrid rice and new plant types to increase the yield potential of rice. By combining the two approaches - hybrid rice and new plant types - the present yield potential, from 11 t/ha to 15 t/ha, will increase by the year 2000. If apomixis for rice is adopted, it will benefit resource-poor farmers in implementing hybrid rice technology. New strategies, which have been deployed in research on rainfed lowland rice, would make a significant contribution to the increased rice production in the future. The incorporation of resistance/tolerance to biotic/abiotic stresses will increase yield stability of rice varieties, and effective seed industries will contribute to the sustainable rice production as well.

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Dr. D. V. Tran, FAO Senior Rice Agronomist, presented a paper entitled "Evolution of Rice Yield in Asia and the Pacific". He reported that the pattern of yield evolution in a particular country varies with various agro-ecological systems. In Asia, rice yield has increased rapidly in the period from 1970 to 1985, moderately from 1985 to 1990, and slowly, even stagnantly, from 1991 to present day. In rainfed lowland, the improvement of rice yield has been slow and its yield often fluctuates from year to year. The yield of upland rice has been low (1 t/ha) and stagnant in the last two decades. It is noted that more than two-thirds of the Asian countries still have low yields (less than 4 t/ha).

Based on 1995 yield information, the Asian countries can be grouped into 3 categories. In Group I: <3 t/ha (Afghanistan, Bangladesh, Bhutan, Brunei, Cambodia, India, Iraq, Laos, Nepal, Pakistan, Philippines, and Thailand), rainfed rice is still dominant causing low yield. The improvement of water control could rapidly increase their rice yield, particularly in Bangladesh, Cambodia, India, Philippines and Thailand. In Group II: 3-<4 t/ha (Korea D. P. RP, Malaysia, Myanmar, Sri Lanka and Viet Nam), rice yield increased fast from 1975 to 85 then slowly to present, except Viet Nam. The use of improved crop management, particularly with adequate fertilizers and improved water control, could increase further yield in these countries. In Group III: 4t/ha and above (China, Indonesia, Iran, Japan, Korea Rep., Syria and Turkey), yield has recently increased slowly, even stagnantly. In these countries, the closing of yield gaps between the current level and the potential yield requires high-level technologies and upstream research.

It is worthwhile noting that the 18th Session of the International Rice Commission, which took place in Rome from 5-9 September 1994, addressed the alleged phenomenon of yield decline of HYV in intensive rice cropping systems, and it recommended that FAO should work with the relevant NARCs to obtain adequate information on the geographic extent and intensity of yield decline under farmers' conditions. In early 1995, AGPC initiated preliminary studies, including searching for documents, reports, unpublished/published documentation and field survey on alleged yield decline, in collaboration with five selected major rice-producing countries in Asia (Bangladesh, China, India, Indonesia and Viet Nam). The outcome of this preliminary study, among others, was discussed for future actions at this Expert Consultation.

The following are summaries of the five case studies on yield trends of HYV in intensive-rice cropping systems, which have been implemented by selected NARCs and which were presented at the Consultation by national senior rice experts:

Bangladesh (Dr. M. Nasiruddin, Bangladesh Rice Research Institute- BRRI):

The decrease of modern rice (MV) rice yield in Bangladesh can be attributed to several factors such as:

- range of varieties released over the years having different yield potentialscompared to one or two varieties at the initial stage,

- expansion of MV rice area from the favourable to less favourable areas,

- decrease of management intensity,

- increase of biotic pressures from insect pest and disease, and

- degradation of soil resources causing micro-nutrient and hidden deficiencies.

In the long-term yield trials, with MV rices, micro-nutrient deficiencies, like S and Zn, were identified as being widespread in the country. About 4 million ha of S deficient and 2 million ha of Zn deficient areas were reported.

China (Professor Ying Cunshan, China National Rice Research Institute- CNRRI):

At Longyou and Xiaoshan counties in Zehejiang province, the studies showed the following:

- The average grain yield decreased by 1.3-20% from 1989-1992 to 1993-95 (except late crop in Xiaoshan);

- The average annual ratio of output to input price decreased by 1.0-12.4% from 1989-92 to 1993-95,

- The average annual grain yield of rice per kg N fertilizer input decreased by 3.1-17.3% from 1989-92 to 1993-95.

These results partly support a decline in grain yield and productivity growth of rice in intensive irrigated rice cropping systems at farmers' fields in the central China. This is possibly caused by the decrease in the price of rice, a decrease in the use of organic matters, a decrease in the use of less resistant varieties and other socio-economic problems.

India (Dr. K. Krishnaiah, Directorate of Rice Research):

Productivity trends of rice in India at national, state, district, experimental farm and farmers' field levels have been examined in the last decade. In general, rice productivity growth was higher during the dry season than in the wet season at all levels.

- Growth rate of the rice yield during the wet season in Andhra Pradesh dropped from 2.92% per annum during 1972-82 to 2.42% per annum during 1983-94, although fertilizer use increased steadily from 60 to 117 kg/ha/crop.

- In Karnataka, the yield of rice during the wet season increased steadily beyond 1982, but the growth rate started declining since 1987.

- Likewise, growth rate of rice yield in Tamil Nadu started falling retroactive to 1990.

- In the northern states of Punjab and Haryana, where rice is grown under intensive rice-wheat cropping systems, rice yield grew at 130 to 150 kg/ha/annum during 1970-82, but declined at 40 to 60 kg/ha/annum through 1983-94.

- Productivity growth of rice in the eastern states, Orissa and West Bengal, was virtually nil during 1972-82, but it accelerated at 3.0-3.5 % per annum through 1983-94.

- At the research farms located in southern and northern states where HYV are grown with high levels of fertilizers, yields remained stagnant since 1982 and the growth rate started declining at 1.0 to 1.75 per annum after 1986.

- Farmers field data on rice yields for the period from 1971 to 1992 summarises that the productivity growth is either stagnant or declining in southern states, while significantly decelerating in northern states since 1982. However, rice productivity growth is significantly accelerated under farmers fields in eastern states after 1982.

- Total factor productivity is either stagnant or decelerating in the intensive rice growing belts of southern states, while significantly decelerating in northern states since 1982.

Indonesia ( Dr. Soetjipto Partohardjono, Central Research Institute for Food Crops- CRIFC):

Long-term fertilizer experiments were initiated in Muara, Bogor in 1971 and in Sukamandi, West Java in 1981. The long-term growth rate of rice yields in these two sites showed different trends. It was reported that the decline of growth rate in rice yields was expected to occur in the wet season in Muara and in the dry season in Sukamandi.

Preliminary surveys indicated differences in rice yield trends. The common phenomenon is that the increase of yield growth occurred up to a certain period, followed by a levelling-off of yield growth. The total factor productivity (TFP) fluctuated only very slightly; in only one case there was a declining trend on the TFP (TFP is the ratio of output/input price in agriculture).

Data collected from 1971-91 showed an increase of aggregate input as well as rice yield over time. However, an increase of TFP occurred only until about 1977, followed by a declining trend of TFP until 1991. This situation may be viewed as "over-intensified", a symptom of inefficiency in rice farming leading to the decrease of farm income.

Viet Nam (Dr. Vo Tong Xuan, University of Can Tho):

There are 7 agro-ecological zones in the country, including the Mekong Delta. A preliminary investigation on a key rice farming area - Mekong Delta - was carried out. Of all the farmers interviewed, the rice yield is almost stable for some while itwith some and is increasing forin the others, due to the annual alluvial soil deposit and traditional fallow practices (flood/dry fallow), upland crops rotation and crop-livestock systems. Generally, the following trends were observed:

• Grain yields of the dry season crops are higher than those of the rainy season.
• The yields of rice grown in An Giang and Dong Thap provinces are highest owing to the Mekong flood deposits (as the flood enters Vietnamese territory).
• The record yield of 9.70 t/ha was achieved in An Giang province during the dry season crop in 1996.
• Yield potential of rice in the Mekong Delta can be further increased by appropriate fertilization.

However, some yield decreases were observed during the last two years, but they were attributed to the high flood during the ripening stage. No other studies on the alleged yield decline of MV were attempted in other agro-ecological zones, especially in central Viet Nam, where soil fertility is poor, but two or three rice crops per annum have been extensively practised by resource-poor farmers.

Based on the case studies presented, and other reports and studies, there are indications of yield deceleration growth rates, stagnant and declining yields occurring on farmers' fields in intensive rice systems in certain rice ecosystems in some Asian countries. In some cases, yield decreases are confused with yield declines. Realising the very serious consequences of this trend and implications on future research and technology development priorities and policies, the Consultation recommended that the different countries undertake systematic studies on actual and potential yield declines and deceleration and quantify these processes as accurately as possible.

Noting that the various terms were not being used with uniformity and applied correctly with regard to yield trends, the Consultation suggested the following definitions:

• New Crop Diversification Systems for Sustainable Increased Rice production in Asia - The Thai Experience, by Dr. Jinda Jan-orn.
• Adaptation of Small-Scale Rice Mechanisation in Asia - The Thai Experience, by Mr. Chak Chakkaphak.
• Farmers' Evaluation of Knowledge in Intensive Management Technologies to Sustain Rice Yields Under Irrigated Conditions in Asia, by Dr. V. Balasubramanian, IRRI.
• Integrated Nutrient Management Systems for Sustainable Rice Production in Asia and the Pacific, by Dr. F. J. Dent (FAO).
• Integrated Pest Management Systems for Sustainable Rice Production in Asia and the Pacific, by Dr. P. E. Kenmore (FAO).
• Seed Use in relation to Increased and Sustainable Productivity of Rice, by Dr. Noel G. Mamicpic (APSA).

The following major recommendations, were made by the Consultation:

• The Consultation expressed concern that the growth rates, in aggregate rice output and rice yields, had declined from 2.6% in the 1960s and 1970s to 1.5% in the last decade, which is below the desired level. It stressed the importance of reversing the decreasing trend of the past decade. Rice production in the Region should increase annually by 2.5% against the current rate of less than 1.5%.
• The government policy on the national intensive-rice farming systems should be well-defined, coordinated, and implemented to improve rice productivity and farmers' income, ensure system sustainability and food security, and minimise rice cultivation-related to the pollution of the environment.
• Based on the definition of different downward yield trends, there is a need to identify and characterise areas affected by such problems for future action.
• It is necessary to develop and define criteria for deciding the intensity of intensive rice systems: cropping intensity, crop combinations, level of input and energy (mechanisation) use, level of water management, etc. By assigning suitable weights to the selected criteria from the above-mentioned lists, it needs to develop an 'intensification index' that could quantitatively express the level of intensification.
• Technologies for achieving and maintaining the desired yield and productivity growth rates are generally available for most rice production systems and areas in the Region, especially where the average yields are below 6 t/ha. The gaps, in desired yield levels or stagnation or decline or deceleration, are mostly due to the gaps in technology assessment, refinement, transfer and adoption. Therefore, the Consultation recommended that, while maintenance research should continue to receive due attention, much higher priorities should be assigned by the national programmes to transfer and adopt the recommended technologies.
• Recognising the seriousness of the yield decline/deceleration process, the associated problems of food security, environmental and ecological security, as well as economic security, the Consultation recommended that FAO, in close collaboration with IRRI and NARS, should prepare a regional programme on enhanced and sustained rice production for durable food security and environmental protection in Asia and the Pacific for submission to potential donor (s), possibly UNDP.

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