Author(s): Pramod Pandey
Linked Author(s):
Keywords: Rainwater harvesting; Rainfed agriculture; Climate conditions; Crop characteristics
Abstract: More than 94% of the cropland in sub -Saharan Africa, and about 66% of the cropland in Asia is rainfed. Although crop yields of rainfed cropland are relatively poor, rainfed cropland produces about 70% of the world’s food supply. Since rainfed crop production dominates the world’s food supply, improving water availability for rainfed cropping system warrant attention. To improve the water availability in rainfed areas, rainwater harvesting system can be a viable option. Water stored in rain water storage structures during a rainy season can help improving water availability in a dry season i. e., stored water can be used to provide supplemental irrigation (SI) to crops. The benefits of such system, however, will largely depend on rainfall patterns and crop characteristics. To improve understanding of rainwater harvesting system suitability for increasing crop production, here calculations were made for evaluating the impacts of various rainfall patterns and crop characteristics on crop yields of rainfed areas with and without rainwater harvesting system. Two scenarios: 1) rainfall scenario, which simulates the dry and wet conditions; 2) crop characteristic scenario, which simulates the impacts of crop coefficients on crop yield were simulated. In both the scenarios, crop yields and water uses were estimated with SI (i. e., rainwater harvesting system) and without SI (no rainwater harvesting system). Results indicate that the performance of rainwater harvesting system varies considerably with rainfall patterns and crop characteristics. For example, in an average rainfall condition the crop yield of a rainfed land without rainwater harvesting system was 33% of the crop yield of the rainfed land with rainwater harvesting system. During dry season, however, when rainfall was 50% lower than the average precipitation, crop yield in without rainwater harvesting system was only 14% of the crop yield of the rainwater harvesting system. Similarly, when crop coefficients were increased by 50% , the crop yield of without rainwater harvesting system was 21% of the crop yield of rainwater harvesting system. The results and approach presented here will help improving rainwater management in rainfed areas for increasing crop production.
Year: 2013