Optimal, farm plans for small holder farmers practising irrigation along Yatta canal of Machakos District, Kenya: a linear programming approach

Abstract

The main objective of the study was to develop optimal farm plans for irrigation farmers along the Yatta canal who are permitted to irrigate a maXlmum area of 0.5 hectare per growing season. Other objectives of the study were: 1) to describe the existing farming system in the study area 2) to identify the main constraints faced by the irrigation farmers along the Yatta canal. A random sample of 60 farmers was used in this study. Optimal farm plans were developed using linear programming farm planning technique and are meant to guide the farmers in their farming activities to ensure maximization of farm income. This would mean that maximum benefits are gained from the irrigation water. The study tested the hypothesis that the present level of resource use is sub-optimal and hence higher farm income could be realized by reorganizing the existing crop enterprises. Total gross margin comparisons of the developed optimal farm plans and the existing farming system are used to test the hypothesis. When the comparisons considered the existing farming system which is based on an average farm, net increments in total gross margin resulting from the optimal farm plans were found to range between 27.6 percent and 120.6 percent. Similar comparisons made under the assumption that the available irrigable land is fully utilized in the existing farming system had net increments ranging between 7.5 percent and 30.8 percent. Based on this findings the hypothesis was accepted. Working capital was found to be a limiting resource in all the farm models considered . Results of the study showed that the marginal value product for capital ranged between Kshs. 1.483 and Kshs. 12.70. Such findings imply that the increment s to every additional Kenya shilling of working capital invested in the optimal farm plans are higher than the current lendingg rate of 14% charged by lending institutions for agricultiral loans. Assuming other factors constant, it is therefore economically feasible to obtain credit from the lending institutions. Both irrigated and unirrigated land were found to be limiting resources in most of the farm plans. Comparatively irrigated land had higher shadow prices than the unirrigated Land most of the cases. In most of the developed farm models the irrigated land shadow price values are more than Kshs. 25,000, with the highest observed value being Kshs. 32,606. For the unirrigated land, only two of the developed f arm models have shadow price values above Kshs. 5,000, with the highest observed value being Kshs. 5652. These findings mean irrigated land could be increased at the expense of unirrigated land if conditions allowed.