Strategies for bridging the yield gap in rice: a regional perspective for Asia

R.C. Chaudhary
Chairman, Participatory Rural Development Foundation.

Rice in the Asia and Pacific region, where 90 percent of it is produced and consumed, will remain the lifeline of the people. Demand for rice is expected to grow faster than production in most countries (Swaminathan, 1998), so much so that by 2025, 800 million tonnes of it will be needed annually. How an additional 300 million tonnes per year will be produced (Hossain, 1997) with less land, water, pesticide and labour, is the crucial question for the next millennium. The reduced resource base and the gradually eroding quality of land, water and the environment pose threats of another magnitude. The currency crisis in most Asian countries has an added dimension in importing and exporting countries through its effect on the cost of rice and investment in research or production. The yield deceleration, stagnation and decline observed in high-yielding environments is another danger signal (Papademetriou, 1998). Rice area has already started to decline in China, Malaysia, Bangladesh, the Red River delta in Viet Nam, and elsewhere (Table 1).

TABLE 1
Asia and the Pacific rice production, yield and area (1997) and their growth rates, 1987-1997
Country	Production (P) (`000 tonnes)	Area (A) (`000 ha)	Yield (Y) (kg/ha)	1987-1997 growth rate (%)
				P	A	Y
Australia	1 352	164	8 244	6.2	4.5	1.6
Bangladesh	28 183	10 177	2 769	1.1	-0.4	0.7
Bhutan	50	30	1 667	-0.2	0.1	-0.2
Cambodia	3 390	1 950	1 771	4.4	2.4	2.2
China	198 471	31 348	6 331	1.0	-0.7	1.6
Fiji	18	7	2 246	-5.5	-7.1	0.8
India	123 012	42 200	2 915	2.6	0.5	2.1
Indonesia	50 632	11 100	4 449	2.2	1.2	0.8
Iran, Islamic Rep.	2 600	550	4 240	4.9	1.5	2.8
Japan	12 531	1 953	6 416	-	-0.5	0.5
Korea, Dem. People's Rep.	2 347	611	3 841	-5.1	-1.7	-3.3
Korea, Rep.	7 100	1 049	6 794	-1.8	-2.3	0.5
Lao People's Dem. Rep.	1 414	554	2 902	2.1	-	2.8
Malaysia	1 970	655	3 008	1.6	0.1	1.5
Myanmar	189 000	6 070	3 064	4.0	3.3	0.6
Nepal	3 711	1 511	2 455	1.3	0.5	0.9
Pakistan	6 546	2 316	2 827	3.3	1.2	2.1
Papua New Guinea	1	-	3 023	-	-	0.1
Philippines	11 269	3 840	2 933	2.7	1.8	1.0
Sri Lanka	2 610	660	3 954	1.3	-	1.3
Thailand	21 280	9 932	2 143	1.3	0.2	1.1
Viet Nam	26 397	7 021	3 760	5.5	2.4	3.1
Total	523 784	133 696	3 918	1.8	0.4	1.4
Rest of world	49 479	16 115	3 070	2.0	0.3	1.7
World total	573 263	149 811	3 827	1.8	0.4	1.4
Source: FAO-RAP Publication 1998/21.

Approaches to bridging the gap between projected demand and the current level of production include expanding the rice area (horizontal expansion), increasing the yield (vertical expansion), bridging the yield gap and reducing yield losses. Yield gap bridging, i.e. filling the gap between the best experimental yields and those that farmers can achieve, is promising. But, because of its complexity, there are different views concerning its value as a tool for increasing rice production (Duwary, Tran and Nguyen, 1998). Pingali, Hossain and Gerpacio (1997) argue that, in favourable rice ecologies, yield gaps are not significant for exploitation or increasing rice production.

In such situations, further increase in yield is possible only through the deployment of new technologies, such as hybrid rice. The causes of the large gap between available and adopted technology have also to be understood (Fujisaka, 1994). In the meantime, pre- and post-harvest yield losses of as much as 49 percent continue to be recorded.

MEANS AND MODELS FOR BRIDGING THE YIELD GAP

The narrowing of the yield gap in rice requires integrated and holistic approaches, including appropriate concepts and policy intervention (Cromwell, 1996). If any one of these components is missing or weak, the yield gap in that area cannot be narrowed (Tran, 1996). Narrowing the yield gap (Figure) aims not only at increasing rice yields and production but also at improving the efficiency of land and labour use, thereby reducing the cost of production and increasing sustainability. Exploitable yield gaps of rice are caused by various factors, including physical, biological, socio-economic and institutional constraints, which can be improved effectively through participatory and holistic approaches to action and government intervention (IRRI, 1998b). An integrated programme approach is required. The narrowing of the yield gap is not static but dynamic, adapting to technological developments in rice production. Gaps tend to increase when the yield potential of rice varieties is improved.

Benefits of yield gap bridging

While efforts are made to raise the yield ceiling, there is an even more pressing need to address the yield gap (Duwari, Tran and Nguyen, 1998). A yield gap reduction can be seen as the local solution to a global problem. It can lead to increased production with the additional incentives of cost reduction, poverty alleviation, social justice and equity. While no major breakthrough is expected immediately, reducing the yield gap alone could supply 60 percent of the increased annual rice demand by the year 2025.

Lessons from selected countries

In Indonesia, through various schemes, the national rice yield increased by about 4.9 percent per year during the 1967 to 1977 period and by 4.3 percent between 1977 and 1987. Indonesia's experience illustrates the importance of establishing strong test-transfer centres for technology (Chaudhary, 1998).

Viet Nam became the fourth largest exporter (Le, 1998), highlighting ownership policy reform - from government to family holding. Various methods and models of technology transfer have been tried since the green revolution began in India (Chaudhary et al., 1998; Taimni and Verma, 1998). Compact block frontline demonstration (FLD) was started in 1990 in a focused demonstration. Egyptian rice yield increased from 5.8 tonnes/ha in 1987 to 8.5 tonnes/ha in 1997 (Table 2), owing to the adoption of new technology which reduced yield gaps (Badawi, 1998). In Australia, the Ricecheck concept and use of a very efficient system of technology transfer reversed a yield decline of 2.4 percent per year in 1967, to the current level of 10 tonnes/ha (Lacy, 1998).

In the United States, the yield gap is small (David Mackill, personal communication) while the national yield of Greece, where there is no yield gap, reached 7.6 tonnes/ha in 1996, setting a good example for others to follow.

TABLE 2
Egyptian rice yields in demonstration plots, national averages and yield gaps, 1988-1997 (tonnes/ha)
Year	Demonstration plot yield	National average	Yield gap
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 Mean	9.90 10.50 10.43 10.60 10.64 10.31 10.45 10.51 10.29 1033 10.40	6.07 6.45 7.29 7.57 7.67 7.74 7.93 8.20 8.35 8.56 7.58	2.83 4.05 3.14 3.0. 2.97 2.57 2.52 2.31 1.94 1.77 2.82
Source: Badawi, 1998.

OVERCOMING BIOLOGICAL CONSTRAINTS

Stable performing varieties

Available superior-yielding varieties can take farmers' yield to 8 tonnes/ha if grown properly (Chaudhary, 1996), although their performance is variable owing to a higher proportion of genotype X environment interaction (Gauch, 1992; Chaudhary, 1996). The genetic causes of stable performance may be difficult to understand, and there is a need to identify and release stable- yielding varieties that are appropriate to a specific area, rather than releasing relatively less stable varieties over a wider area. There are strong genotypic differences among varieties for this interaction, and methods are available for selecting the more stable ones (Gauch, 1992; McLaren and Chaudhary, 1998). The new rice plant type (called Super Rice), which has been developed by the International Rice Research Institute (IRRI), may raise the present yield potential by 25 to 30 percent (Khush, 1995). Rice biotechnology has recently made considerable progress and may also provide an opportunity to increase rice yield in a more effective and sustainable manner. Hybrid rice has been adopted in China, India, Viet Nam, Myanmar and the Philippines, and it too may reduce yield gaps.

Weeds

Weeds reduce rice yield by competing for space, nutrients, light and water, by serving as hosts for pests and diseases, and as a result of allelopathy. Under farmers' conditions, yield losses, and thus gaps, are high owing to improper or untimely operations.

Biotic and abiotic stresses

Rice has been cultivated for thousands of years. As a result, it has served as a host for a number of diseases and insect pests: 54 in temperate zones and about 500 in tropical countries. Of the major diseases and pests, 45 are fungal, ten bacterial, 15 viral and 75 are insect pests and nematodes. In view of the economic losses caused by diseases and pests, efforts have been directed to understanding the genetic basis of resistance. Host-plant interaction and other control measures reduce losses in proportion to their use, and this is one way of reducing yield gaps.

Soil problems

Rice is grown from the equator to 45^oS and 50^oN, and from below sea level to 2 500 m above. Rice soils vary from sand to clay, acidity from 5 to 10 pH, organic matter from 1 to 50 percent and salt content from 0.1 to 1 percent. As well as on normal soils, rice is also grown on marginal and problem soils, where plants face nutrient deficiency or even toxicity. Inappropriate varieties and improper management cause heavy yield losses and resultant yield gaps. Technologies are developing fast to ameliorate such situations.

Soil fertility and fertilizer

Soil degradation and quality deterioration limit crop yields on many intensive farms in Asia. Major indicators of deteriorating soil quality include changes in organic matter and capacity to supply nutrients, nutrient imbalance and multinutrient deficiency, waterlogging and iron toxicity, soil salinity and alkalinity, and the development of hard pan at shallow depths. Many yield gaps can be attributed to a lack of knowledge (Balasubramanian et al., 1998). Rice suffers from a mismatch between its nitrogen (N) demand and the N supplied as fertilizer, resulting in a 50 to 70 percent loss of applied N fertilizer. Two basic approaches may be used to solve this problem: regulating the timing of N applications, based on the plant's needs, thus increasing the efficiency of the plant's use of the applied N; and increasing the ability of the rice system to fix its own N through nodulin genes and bacterium genes.

Water and irrigation

Most studies on constraints to high rice yield indicate the availability of water as the main cause of yield gaps and yield variability between experiment stations and farms. A recent study conducted by the International Water Management Institute (IWMI) estimates that, by the year 2020, one-third of the Asian population will face a water shortage. Wars may be fought over water (Gleick, 1993). The growth rate in the development of irrigation has already declined (Barker et al., 1998).

Integrated crop management

Based on extensive and critical testing of rice varieties and crop management technology, it is possible to develop a rice farming prescription for an individual farmer and a specific situation. The concept was tested on a limited scale in Indonesia during 1996/97. Integrated weed management practices and integrated pest management (IPM) increase yields and decrease the cost of pesticides, the cost of production and the risk to health and the environment. Other knowledge-based techniques will also help (Price and Balasubramanian, 1998). Narrowing yield gaps by improving the crop management practices of small farmers in developing countries is often not an easy task. It is therefore essential that practices should not be applied in isolation but within integrated crop management packages (ICMPs) that have flexibility to adjust to prevailing environmental, socio-economic and market factors.

Post-harvest

The introduction of more efficient technologies for handling the drying, storage and milling of rice at the village level is essential for the reduction of post-production losses. The post-production phase is labour-intensive, as the operations involve hand harvesting, sun drying, threshing by trampling, and wind winnowing. Physical losses are higher in wet season harvests, and arise from problems with drying and the use of an-tiquated mills. This results in poor-quality milled rice, with problems that include grain discoloration. People living in communities whose livelihood is affected are expected to motivate themselves to make the changes that will ensure increased benefits. It is also believed that local farmers and entrepreneurs should be given the opportunity to define their own post-production needs and should be consulted during the selection of appropriate technologies.

OVERCOMING THE SOCIO-ECONOMIC CONSTRAINTS

Risk, cost and return

Rice is a very risk-prone crop in ecosystems that are rainfed, upland or flood-prone. Even in irrigated ecosystems, rice is at risk from pests, diseases and flood. These dangers are a problem for farmers, particularly when they are applying costly inputs such as seed and fertilizer. Economists, as well as farmers, advocate diversification and maximization of income from sources that are not closely connected to rice farming. Farmers are confident about using inputs and enthusiastic about reducing yield gaps only when stress-resistant rice varieties are readily available.

Credit

The difficulty in obtaining sufficient, timely credit for the development of infrastructure, capital costs and crop loans is a major constraint. As well as the lack of collateral, the interest rate is a threat to credit availability, and this affects farmers' input-applying capacity and profit margins. Government policy and the institutional framework affect credit availability to farmers (Cromwell, 1996). A policy intervention must be implemented in order to make farmers creditworthy and enable them to acquire enough timely credit to buy annual inputs. Crop insurance is a suitable policy support in India.

Tradition and attitude

The current level of factor productivity, which is still declining, cannot satisfy the food requirements of a growing population. Productivity must be increased in a sustainable manner. The major causes of instability in productivity are weather aberrations, crop management practices and the severity of pest outbreaks. Although varieties that are tolerant to environmental stresses, more stable and more resistant to pests have helped to stabilize production, there is still room for improvement in these aspects. The main issue in establishing stable productivity is to ensure that there is no degradation of the resource base in terms of soil, water and the biodiversity of rice types.

Input availability

Fertilizers, especially N, play an important role in rice production and productivity. Farmers need adequate amounts of fertilizer at the right time if they are to obtain high yields. The supply of fertilizers needs to be decentralized to village markets, and the quality of fertilizers should be assured. Small farmers are usually unable to buy sufficient quantities in time for application; the provision of village credit could greatly help. The Bangladesh Grameen Bank is an interesting example of rural credit provision to landless and resource-poor farmers. Loan proposals are received by the bank on a group basis only (involving at least five persons) and focused on technology loans, housing loans, joint loans and general loans (Dadhich, 1995). The use of quality seed is the most effective way of realizing the yield potential of the recommended technology. High-quality pure seed ensures correct germination, good crop stand and freedom from weeds and seed-borne diseases. In general, it is recognized that the use of high-quality seed ensures yields that are 10 to 15 percent greater than they would have been under the same crop management practices.

Institutions

The adoption rate of knowledge-intensive technology is affected by the availability of agricultural credit, the supply of inputs (seeds, fertilizers, pesticides), the availability and quality of contract services and machinery for different farm operations, and repair and maintenance services in rural areas (Price and Balasubramanian, 1998). The government and private institutions associated with credit, inputs and pricing have a direct influence on the adoption and level of use, and thereby on the yield level.

PREPARING TO BRIDGE THE GAP

Centres of the Consultative Group on International Agricultural Research (CGIAR), such as IRRI, the International Centre for Tropical Agriculture (CIAT) and the West Africa Rice Development Association (WARDA), are starting to listen to farmers (IRRI, 1996) and plan farmer-relevant research with farmers' cooperation. Future projects could involve collaborating institutions, the training of local researchers on the basics of yield gap bridging, strategic planning with local counterparts, the development of operational plans, the introduction of selected technologies, and extension success cases. A model framework for such projects is urgently needed.

As a first step, rapid appraisal studies are undertaken, when such information does not already exist. Projects have the following components:

Survey, analysis and prescription: system perspective and requirements; consideration of all the key factors and players in order to identify appropriate intervention points.
Technology resourcing: existing technologies from international, national and provincial institutions, including modern progressive farmers.
Institutional arrangements: linkages, including the integration of activities with other disciplines and among intergovernmental, government, non-governmental and private organizations.
Communication: communicating the technology and knowledge-based practices that have been developed.
Critical research: new technologies and practices to explore the opportunities for improvement.

Survey, analysis and prescription

Yield gap analysis must take into consideration the uniqueness of the individual situation. Another interesting area of inquiry would be a study of the relative magnitude of yield gaps in different yield-potential groups of rice, say within tolerant varieties (TVs), high-yielding varieties (HYVs), hybrid rice and new plant type (NPT) rice. The current hypothesis is that yield gaps should be lowest with hybrid rice, as the seed cost is high and farmers take relatively better care of crops, including fertilizer application, weeding and irrigation. This is where the methodology proposed by De Datta et al. (1978) needs to be examined critically and modified to satisfy the following criteria:

characterization of the yield gap (by estimating potential yield levels in different production
environments), and stratification of the relative magnitude of yield gaps in various yield potential groups, say within TVs, HYVs, hybrid rice and NPT rice;
breakdown of the total yield gap into individual components according to management, biological and socio-economic groups;
analysis and establishment of a systematic approach to understanding decision-making processes and management practices;
intervention points and measures to improve management efficiency and alleviate the working conditions of farmers, especially women;
development of decision-support and communication systems to bring information-intensive
technologies to farmers, and of guidelines for potential extrapolation to larger groups and other areas.

Technology resourcing

Technology resourcing has to be carried out on an area- and situation-specific basis to support prescription farming and comprises:

Technology resourcing: assessment of requirements, evaluation of available technology, assistance in pilot application.
Information and knowledge: establishment of a database, training.
Development of a decision-support system.

Farmer outreach: models of technology transfer

Communication issues are significant to development agencies when technologies are transferred to farmers. Methods for communicating knowledge-intensive technology to farmers must be found. The aim is to increase the impact of appropriate high-potential rice production and utilization interventions, and promote their adoption through development and the application of improved dissemination strategies. The following are some of the institutional arrangements that have been devised.

Government organizations (GOs). The positive aspects of government extension services lie in early successes with simple seed-based technologies, promotion of State objectives, and the fact that they are relatively well resourced and staffed. Among their negative points are staff's responsibility for non-extension activities, slow bureaucratic responses, weak links with research, a tendency to favour more advantaged farmers, and a top-down focus.

Non-governmental organizations (NGOs). The positive aspects of NGOs are that they are strongly decentralized, less bureaucratic and more flexible, people- and poor-centred, capable of articulating the needs of disadvantaged groups, community-focused, effective in community mobilization and motivation, and active where the State and market are absent. Their negative points are their restricted impact, distance from policy decisions, professional and technical limitations, and limited infrastructure, coordination, accountability and resources.

Private organizations (POs). The positive aspects of private-sector organizations are that they have strong, centralized systems and good resources, management skills and technical competence; they are less bureaucratic, more flexible and innovative; and they have clear objectives. There are, however, also a number of significant negative points which focus on POs' putting profits before development, their manipulation of markets and adoption of questionable technologies, and their tendency to favour large and resource-advantaged farmers.

Participatory (GO-NGO-PO). GOs, NGOs, POs and farmers may collaborate in, for example, the resource-test-demonstrate-adopt model. When there are appropriate roles and decision-making processes, this may be the most effective, broad-based and sustainable solution. Recently, IRRI has implemented a number of such proposals (IRRI 1998a; 1998b). Partnerships among NGOs, POs and GOs are likely to be the agents of change for the future, although the most appropriate combination for a given situation will vary depending on the existing circumstances and technology.

The general trend away from the traditional GO approach towards new agents of change (POs and NGOs) is recognized, but partnership is itself an experiment in development and technology transfer. Several issues arise: Are these new agents of change more effective in promoting technology transfer? In what kind of circumstances and for what kinds of technologies are the new agents most effective? and What are the most appropriate roles, responsibilities and linkage mechanisms?

Another set of questions must be taken into account when comparative advantages and maximization of resources are being assessed in order to achieve common objectives: Is the partnership feasible? What can be done to encourage partnership formation? In what kinds of circumstances and for what kinds of technologies is partnership appropriate? and What are the most appropriate roles, responsibilities and linkage mechanisms within such partnerships?

Next, weaknesses within the system need to be addressed and strengths capitalized on, and the relative strengths of the agencies pulled together, be they GO-NGO-PO partnerships, research-NGO-PO partnerships, hybrid diffusion systems, or unitized new tools.

Farmer-to-farmer. The experiences of successful farmers illustrate the relative importance of biophysical and socio-economic constraints. The hypothesis in this case is that farmers with small yield gaps will have used sets of technologies and knowledge that are adapted to their locations within a dynamic decision-making process that is different from those followed by farmers with high yield gaps. Tapping the knowledge of successful farmers is considered an effective way of resourcing and spreading location-specific, improved technologies. Appropriate national agencies must learn the gamut of successful technologies, knowledge and experience in order to transfer them to other farmers.

Policy support

Government policies provide the environment for research investment, improve productivity, alleviate poverty, ensure the sustainability of systems, protect the environment and provide food security. There is a need for various types of policy interventions that influence investments in research, ensure the availability of inputs and credit, provide crop insurance policy to encourage the use of inputs, and reduce risks. It is therefore imperative that appropriate policies and socio-economic adjustments be affected in terms of input-output pricing, institutional support and addressing the needs of rice farmers so as to complement technological gains. There are examples of success, such as that from Indonesia; when firm and consistent policy support is provided, the impact on bridging yield gaps becomes noticeable. Experience in this area also emphasizes the need for consistency.

Linkages

Linkages within and outside the country are important aspects of the project for which the following list may be considered:

linkages with the efforts of national agricultural research systems (NARS) in Asia and the Pacific;
GO-NGO-PO-farmer linkages;
linkages with IRRI projects - RE4, the Crop and Resource Management Network (CREMNET) and RTDP;
linkages with FAO projects in the area;
linkages with other international agricultural research centres (IARCs) on a case-by-case basis;
linkages with donor consortiums for funding support.