Improved crop production under water constraints

摘要

Different technologies are available to increase crop production where water is a major constraint, but they are not universally applicable; rather each is suitable for a particular water environment/crop combination. This paper reviews recent developments in our understanding of the crop-water environment and crop responses to water constraints, and provides several examples of technologies that have improved or could improve crop production under water limitations. In semi-arid areas crop yield can be increased by fallowing to increase stored soil water, and by increasing the row spacing to use soil water slowly. These technologies ensure that water is available until crop maturity. Under more favourable humid environments, the total amount of water is commonly sufficient, but there are often periods of water shortage that affect crop yield. A small amount of supplementary irrigation available at the critical stage could markedly stabilise production. The current rainfed lowland system uses water inefficiently, and there is an opportunity to develop an aerobic system which uses limited water more efficiently. A few examples of genetic improvements to increase crop production under water limiting conditions are also given. Water environment characterisation is important for determining which promising technologies are likely to be successful for a particular location/crop combination. Many experiments are often needed to cover the temporal and spatial water environment variations. The technology development can be achieved by an interdisciplinary team of scientists: without the consolidated efforts of a critical mass of scientists, new technologies will be slow to develop.