Saving irrigation water through application of organic fertilizer.

Abstract

The objective of this study was to assess the saving of irrigation water through optimum organic fertilizer application. Water-saving technology is of great interest and concern to crop producers in both humid and semi-arid regions of the tropics. The amount of irrigation water used could be substantially reduced by the application of organic fertilizer. Results show that in both tropical humid and semi-arid regions, organic fertilizer application on some of the ”thirstiest” cash crops can save irrigation water needed. The net irrigation depth in organic fertilizer-amended soil was substantially raised, thus reducing the number of irrigation applications required. The reduction in number of irrigation applications ranged from 1 to 2 and 1 to 5 in tropical humid and semi-arid regions, respectively. With rainfall, supplementary irrigation was necessary only for rice and cabbage in tropical humid regions, while in semi-arid regions, irrigation constitutes the main source of crop water supply. Without rainfall, the quantity of water saved was estimated to be 15.4% and 14.5% of the total water required in tropical humid and semi-arid regions respectively; while with rainfall, it was 54.7% and 34.9%, respectively. In Chad (a semi-arid region), this accounted for about 1.6% the total Lake Chad annual inflow.