Randolph Barker

Water productivity in agriculture: limits and opportunities for improvement

A water productivity framework for understanding and action economics of water productivity in managing water for agriculture the concept of efficiency in water resources management and policy rice production in water-scarce environments managing saline and alkali water for higher productivity opportunities for increasing water productivity of CGIAR crops through plant breeding and molecular biology world water productivity - current situation and future options improving water productivity through deficit irrigation - examples from Syria, North China Plain and Oregon, USA.

Rice and Water

The Comprehensive Assessment of Water Management in Agriculture (CA) seeks answers to the question of how freshwater resources can be developed and managed to feed the worlds population and reduce poverty, while at the same time promoting environmental security. The CA pays particular attention to rice as this crop is the most common staple food of the largest number of people on Earth (about 3 billion people) while receiving an estimated 24–30% of the worlds developed freshwater resources. Rice environments also provide unique—but as yet poorly understood—ecosystem services such as the regulation of water and the preservation of aquatic and terrestrial biodiversity. Rice production under flooded conditions is highly sustainable. In comparison with other field crops, flooded rice fields produce more of the greenhouse gas methane but less nitrous oxide, have no to very little nitrate pollution of the groundwater, and use relatively little to no herbicides. Flooded rice can locally raise groundwater tables with subsequent risk of salinization if the groundwater carries salts, but is also an effective restoration crop to leach accumulated salts from the soil in combination with drainage. The production of rice needs to increase in the coming decades to meet the food demand of growing populations. To meet the dual challenges of producing enough food and alleviating poverty, more rice needs to be produced at a low cost per kilogram grain (ensuring reasonable profits for producers) so that prices can be kept low for poor consumers. This increase in rice production needs to be accomplished under increasing scarcity of water, which threatens the sustainability and capability to provide ecosystem services of current production systems. Water scarcity is expected to shift rice production to more water‐abundant delta areas, and to lead to crop diversification and more aerobic (nonflooded) soil conditions in rice fields in water‐short areas. In these latter areas, investments should target the adoption of water‐saving technologies, the reuse of drainage and percolation water, and the improvement of irrigation supply systems. A suite of water‐saving technologies can help farmers reduce percolation, drainage, and evaporation losses from their fields by 15–20% without a yield decline. However, greater understanding of the adverse effects of increasingly aerobic field conditions on the sustainability of rice production, environment, and ecosystem services is needed. In drought‐, salinity‐, and flood‐prone environments, the combination of improved varieties with specific management packages has the potential to increase on‐farm yields by 50–100% in the coming 10 years, provided that investment in research and extension is intensified.

Water scarcity in the twenty-first century

As we approach the next century, more than a quarter of the worlds population or a third of the population in developing countries live in regions that will experience severe water scarcity. This paper reports on a study to project water supply and demand for 118 countries over the 1990-2025 period. The nature and geographic focus of growing water scarcity are identified. In the semi-arid regions of Asia and the Middle East, which include some of the major breadbaskets of the world, the ground water table is falling at an alarming rate. There is an urgent need to focus the attention of both professionals and policy makers on the problems of ground water depletion, which must be seen as the major threat to food security in the coming century.

Economics of water productivity in managing water for agriculture

In Kijne, J. W.; Barker, R.; Molden. D. (Eds.). Water productivity in agriculture: limits and opportunities for improvement. Wallingford, UK: CABI; Colombo, Sri Lanka: International Water Management Institute (IWMI)Comprehensive Assessment of Water Management in Agriculture Series 1

Adoption Ceilings and Modern Coarse Cereal Cultivars in India

The concept of, and evidence for, regional adoption ceilings is assessed for modern coarse cereal cultivars in India. Adoption is defined as the proportion of total area of a given coarse cereal planted to modern cultivars. Agroclimatic and soil differences are more important than disparities in infrastructure in explaining the variation across regions in estimated adoption ceilings. Qualitatively different modern cultivars from those now released are necessary to change regional adoption behavior. The results support an agricultural research strategy that gives higher priority to more regionally oriented breeding and testing programs in preference to the past emphasis on wide adaptation.

Water transfer from agriculture to urban uses: lessons learned, with policy considerations

This paper sets forth the accomplishments to date of the international collaborative study program on efficient and equitable transfer of water from agriculture to other uses. The research consists of several components. First a bibliographical review was prepared of literature available on the practice of inter-sector water transfer. Second, nine case studies have been prepared that illustrate inter-sector water transfer under a variety of physical and economic and political environments. Third, a framework has been developed for characterizing and comparing water transfer options and compensation among case studies. We discuss the pricing of irrigation water in determining compensation. We develop a decision tree that traces the paths to the various sector water transfer options. Finally, we discuss water transfer policy options with specific reference to Taiwan, though they have more general relevance. Three options are identified which reflect different objectives for government intervention.

Effect of modern rice varieties and irrigation on household income distribution in Nepalese villages

Since high-yielding modern rice varieties (MVs) are adopted only in favorable production environments, significant regional productivity differentials have emerged in Nepal. This study explores the distributional consequences of such differential MV adoption based on an intensive survey of favorable and unfavorable villages. We found that MV adoption increased returns to land but decreased family labor earnings from rice production, as it facilitated the substitution of hired for family labor. As a result, the differential MV adoption did not significantly worsen the household income distribution according to the results of the counterfactual Gini decomposition analysis.

Economic Analysis of Residential, Commercial, and Industrial Uses of Water in Sri Lanka

Abstract The aim of this study is to provide an economic analysis of urban water use with a view to enhance the understanding of the factors influencing urban water demand and to estimate price elasticities of residential, commercial, and industrial water demands in Sri Lanka. Lack of research in the Sri Lanka context of this area and the need for understanding the price elasticity of demand for urban water for effective implementation of the new water-demand management policy formulated by the Government of Sri Lanka in early 2000 were important motivations for this study. Separate water-demand functions for each of the major sectors were estimated, using monthly time series for 60 months from January 1994 to December 1998. In general, the price is found to have a significant effect on water demand, and this effect is much higher for the industrial sector than for the residential and commercial sectors. In addition, real income, number of connections (population), and weather variables are found to be important determinants of urban water demand. Estimated price elasticities are -0.18, -0.17, and -1.34 for the residential, commercial, and industrial water demands, respectively. The study concludes that while the price will be an important tool in influencing demand, other measures such as public education and information/awareness will be necessary to achieve desired reductions in water consumption, especially in the less-responsive residential and commercial sectors.

Estimation and Aggregation of Firm Supply Functions

Five years ago Nerlove and Bachman provided an excellent review of research on agricultural supply and discussed current problems and approaches to solving these problems. Since that time considerable effort has been concentrated on estimating supply functions using linear programming models for representative farms. This article reviews some of the recent research in this approach to estimating supply. The interrelationships among regional linear programming studies, aggregation models, producer panels, and recursive programming models are discussed. Although progress has been made in solving problems relating to the construction and aggregation of firm supply functions and in creating a more dynamic firm model, many additional problems must be solved if this approach is to provide usable estimates of national and regional supply.

The evolution of Taiwanese irrigation: implications for the future.

In the 1960s and 1970s, Taiwans irrigation sector was organized with effective Irrigation Associations characterized by user control, with user payment for operation and maintenance and for a substantial portion of system improvement. At the present time user participation has declined substantially, there is no user fee, and the government exercises much greater control. This study suggests that, as Taiwan developed, the widening differential between rural and urban incomes, the small contribution of agriculture to gross domestic product, and the smaller fraction of labour force in agriculture provided the conditions for the decline in user participation.