Paddy and water management with the System of Rice Intensification (SRI) – A special issue of the journal "Paddy and Water Environment"

PAWEThis  brings together the results of formal research on SRI in a number of countries (Part I) and also reports on initiatives by government agencies, NGOs, universities, or the private sector, bringing knowledge of SRI to farmers in a wide range of agroecological circumstances (Part II). It has six articles and nine technical reports from Afghanistan, China, the Gambia, Kenya, India, Indonesia, Iraq, Mali,  Pakistan, Panama, and Thailand as well as several review articles.

The System of Rice Intensification (SRI), developed in Madagascar almost 30 years ago, modifies certain practices for managing plants, soil, water, and nutrients with the effect of raising the productivity of the land, labor, and capital devoted to rice production. Certain production inputs are reduced—seeds, inorganic fertilizer, water, and fuel where water is pumped—with increased yield as a result.

SRI is gaining interest and application in over 40 countries around the world. Its practices make soil conditions more aerobic and promote greater root growth, as well as larger, more diverse communities of beneficial soil biota. These below-ground changes support more productive phenotypes above-ground for practically all rice genotypes (cultivars) tested so far, with supportive evidence accumulating both from scientific institutions and field applications. SRI methodology remains controversial in some circles, however, because of the transformational change it introduces into traditional lowland rice production systems. A summary of the lead article by Uphoff et al and articles, reviews and technical reports relevant to India have been provided below –

SRI as a methodology for raising crop and water productivity: productive adaptations in rice agronomy and irrigation water management by Norman Uphoff, Amir Kassam and Richard Harwood

This paper introduces the subject of SRI, which is then addressed variously in the articles that follow. The introduction presents the basic principles that underlie SRI and discusses the nature of this innovation as well as considers some of the issues in contention. SRI continues to evolve and expand, being a work in progress. Its concepts and methods are being extended also to upland (rainfed) rice production, as well to other crops. Accordingly, SRI should not be regarded or evaluated in conventional terms as if it were a typical component technology. It is understood more appropriately in terms of a paradigm shift for rice production. In particular, it calls into question the long-standing belief that rice is best produced under continuously flooded conditions.

Effects on rice plant morphology and physiology of water and associated management practices of the system of rice intensification and their implications for crop performance by Amod K Thakur, Sreelata Rath, D U Patil and Ashwani Kumar

This article presents the findings of field experiments conducted in Bhubaneswar, Orissa, India, during the dry season (January–May) in 2008 and 2009 to investigate whether practices of the System of Rice Intensification (SRI), including alternate wetting and drying (AWD) during the vegetative stage of plant growth, could improve rice plants’ morphology and physiology and what would be their impact on resulting crop performance, compared with currently recommended scientific management practices (SMP), including continuous flooding (CF) of paddies.

With SRI practices, grain yield was increased by 48 per cent in these trials. At the same time, there was an average water saving of 22 per cent compared with inundated SMP rice. Water productivity with AWD-SRI management practices was almost doubled. It concludes that SRI practices with AWD improve rice plants’ morphology, and this benefits physiological processes that result in higher grain yield and water productivity.

Rice root growth and physiological responses to SRI water management and implications for crop productivity by Abha Mishra and Vilas M Salokhe

This paper reports on several research findings on rice root responses, in terms of growth and physiology, manifested when applying System of Rice Intensification water management principles under semi-field and field conditions, in conjunction with variations in plant density and microbial density in the soil. The research aimed to learn about causal relationships, if any, between rice root and shoot growth at different growth stages of the rice plant’s development and their cumulative effect on yield, which is affected by both biotic and abiotic influences.

It was seen that greater root length density and a higher rate of root activity affected the yield-contributing parameters in all of the trials, whether conducted under semi-field or field conditions. At the same time, both root parameters were significantly affected by the water regime, soil microbial density, and planting pattern, the three main factors considered.

The most important finding observed under semi-field conditions was that enhanced microbial density in the soil improved the sink capacity of the rice plants under all water regimes evaluated. To realize the highest crop yield per hectare, both planting pattern and spacing are factors that need to be optimized. This paper in its conclusion considers the relevance of exploiting roots’ potential for plasticity to enhance crop productivity in the context of impending water constraints and climate-change effects.

A review of studies on SRI effects on beneficial organisms in rice soil rhizospheres by Iswandi Anas, O P Rupela, T M Thiyagarajan and Norman Uphoff 

This communication reports on separate research efforts in India and Indonesia to evaluate the effects that modifying methods of plant, soil, water and nutrient management could have on populations of soil organisms, particularly on those that can have beneficial consequences for crop growth and yield. Comparison of these parallel studies draws attention to the impacts that management can have on the soil biota, given that certain organisms are known to have positive implications for plants’ nutrition, health, and productivity. This review was written to encourage more studies to assess these kinds of soil biotic relationships and dynamics.

Potential of the system of rice intensification for systemic improvement in rice production and water use: the case of Andhra Pradesh, India by Ravindra Adusumilli and S Bhagya Laxmi

This study, based on an analysis of experience from the state of Andhra Pradesh, addresses the potential of the System of Rice Intensification (SRI) to contribute to systemic corrections in present paddy cultivation, both with regard to agronomic productivity and irrigation water use efficiency. It points to the considerable increase in rice productivity and farmer incomes, which is being achieved in Andhra Pradesh with substantial reduction in irrigation water application, labor, and seed costs through utilization of SRI methods. Potential public savings on water and power costs could be drawn upon not only for promoting SRI but also to effect systemic corrections in the irrigation sector, to mutual advantage.

Review of SRI modifications in rice crop and water management and research issues for making further improvements in agricultural and water productivity by Amir Kassam, Willem Stoop and Norman Uphoff

The System of Rice Intensification (SRI) developed in Madagascar has been showing that, by modifying crop, soil, water and nutrient management, it can under most of the circumstances evaluated thus far raise of the productivity of land, water, seeds, capital, and labor used for irrigated rice production. This article summarizes and reflects on the evidence provided in the preceding articles in this special issue. It draws on the scientific evaluations and field experience from Asia, Africa, and Latin America to offer some conclusions about the methodology known as SRI. Since this methodology is still evolving, no final assessment is possible.

Much more research and evaluation remain to be done, and there will be further modifications and refinements since making adaptations to local conditions is regarded as intrinsic to the methodology. Further improvements in SRI will come from both researchers and farmers, with the latter considered as partners rather than simply adopters. This is consistent with SRI’s representing a paradigm shift more than a fixed technology. The article identifies a number of areas for additional research that can probably improve factor productivity still further.

The issue can be downloaded at Springerlink here (access to this content is restricted)

Post By: Amita Bhaduri