EFFECT OF IRRIGATION WITH TREATED WASTEWATER ON SOIL CHARACTERISTICS AND BEAN YIELD: A CASE STUDY OF UNIVERSITY OF ELDORET FARM

Abstract

It is proposed that treated wastewater reuse with the correct regulations can be used to supplement the available amount of water for agricultural use. The research determines the effect of using this water on soil and crop yield. An experimental set up was done on 18 (1.5 m x 3 m) plots, where each plot received a different treatment. Experimental field treatments were set up at the University of Eldoret farm that is next to the waste water (WW) treatment plant. The farm is located in Uasin Gishu County, Kenya. The field experiments were carried out between June and October 2018. The research is directed at solving the problem of waste water reuse and disposal into rivers and lakes without strategic measures. Hence, the key objective of the study was to evaluate the effect of treated waste water irrigation on soil physical and chemical characteristics, and bean crop yield. The approach took a randomised complete block design (RCBD) where the treatments were replicated twice. For the treatments, treated waste water at 0 %, 25 %, 50 %, and 75 % NPK and fresh water at 0%, 25%, 50%, 75%, and 100 % NPK was applied to the plots. The fresh water at 100% NPK was considered as the control experiment. For all the plots, supplemental irrigation was carried out for the rainy season based on crop water requirement and growth stages for the crop. Treated waste water samples were collected from the tertiary pond and tested in the chemistry laboratory. Also, soil samples were collected for different plots after the planting period, and tested in the soil science laboratory. The bean yield was measured and recorded after the growth period. Results showed that plots irrigated with treated waste water and under 25% NPK yielded 1.55 Tonnes/ha and 50% NPK yielded 0.71 Tonnes/ha, which is more compared to fresh water irrigated treatments. Based on the statistical analysis, F critical is greater than F observed, that is 10.13 > 0.0164 and 9.28 > 0.0438, to accept the alternative hypothesis. Soils irrigated with waste water had better physical characteristics, more nutrients, and organic matter. Also, by comparing soil characteristics from waste water and fresh water plots, it is evident that soils irrigated with waste water showed prevalent and higher mineral and nutrient content. It is concluded that the simulated irrigation schedule for the two irrigation treatments can be used as a recommendation strategy for the farmers to adopt treated waste water recycling for irrigation. Also, the nutrients in the waste water can be used as an alternative to the inorganic fertilisers that are expensive.