Field Irrigation Practice and the Performance of Smallholder Irrigation in Zimbabwe: Case Studies from Chakohwa and Mpudzi Irrigation Schemes

Abstract

Developing economies have often regarded smallholder irrigation as a means to ensure food security, create employment and promote agro-based industries in rural areas. However, of late smallholder irrigation has come under scrutiny as its performance has fallen short of expectations. This has prompted the need for an understanding of irrigation practices and their impact on performance so that remedial measures can be implemented. An analysis of smallholder irrigation practices and the subsequent impact on performance for two irrigation schemes located in the drier parts of Zimbabwe are presented. One is a surface irrigated scheme (Chakohwa scheme) measuring 90 ha while the other is drag hose sprinkler irrigated scheme (Mpudzi scheme) measuring 48 ha. Farmer practices were assessed through observation and use of structured interviews. Technical performance measures relating to the efficiency, adequacy and uniformity of irrigation events were assessed using standard field evaluation methods. To a large extent, the farmers\' practices were determined by their perceptions and understanding of irrigation events. An assortment of irrigation scheduling methods was practised, water application approaches were not as per system design and there was a general tendency to over irrigate. The performance of both schemes was generally poor as the technical performance measures did not match the expected irrigation standards. At Chakohwa irrigation scheme, application efficiency averaged a low 24.7%, deep percolation losses a high 75%, and requirement efficiency a high of 87.3%. At Mpudzi drag hose irrigation scheme, the distribution uniformity was 44.9%, application efficiency of the lower quarter was low at 26.4%, and Christiansen\'s uniformity coefficient averaged 62.6%. These results indicated that the effectiveness of irrigation was low to medium implying an inefficient utilisation of resources, especially water, in irrigation. This has implications on sustainability of smallholder irrigation. Despite these technical performance shortcomings the irrigation schemes contributed significantly to the livelihoods of the irrigators.


J. agric. sci. technol. Vol.5(1) 2003: 1-21