|Author:||Rocksröm, J. ; Barron, J.|
|Book Group Author:||NA|
Addressing the Millennium Development Goals on food and poverty over the coming decade puts enormous pressure on the world's finite freshwater resources. Without water productivity (WP) gains, the additional freshwater in agriculture will amount to 5,600 km3 year-1 in 2050. This is three times the current global irrigation use. This paper focuses on the underlying processes and future opportunities of WP gains in water scarcity prone and poverty stricken savannah regions of the world. The paper studies the consumptive (green) WP dynamics rainfed farming systems, and shows that the often assumed linear relationship between evapotranspiration (ET) and yield (Y) does not translate into constant WP over a wide range of yields. Similarly, crop transpiration (T) and Y show non-linearity under on-farm and low yield conditions. This non-linearity is validated against several on-farm research experiments in semi-arid rainfed farming systems. With integrated soil and water management, focusing in dry spell mitigation and soil fertility can potentially more than double on-farm yields, while simultaneously improve green (ET) WP and productive green (T) WP. Through the adoption of appropriate soil and water management in semi-arid smallholder farming systems, crop yields improve and result in improved livelihoods and WP gains.
|Pages:||299 - 311|
crop yield, evapotranspiration, grasslands, irrigation,irrigation systems, irrigation water, plant water relations, poverty,productivity, savannas, semiarid zones, soil management, wateravailability, water management, water supply, water use, water useefficiency, rainfed farming, water resource management, water shortages,water supplies, watering, Income and Poverty (EE950), Plant WaterRelations (FF062), Plant Production (FF100), Plant Cropping Systems(FF150), Soil Water Management (Irrigation and Drainage) (JJ800)(Revised June 2002) [formerly Soil Water Management], Soil Management(JJ900), Erosion; Soil and Water Conservation (PP400)