SOIL FERTILITY AMENDEMENT USING MOLASSES WASTEWATER AND PIGWASTE AND THEIR INFLUENCE ON SOIL CHARACTERISTICS AND YIELD OF COWPEAS (Vigna unguiculata)

Abstract

Soil fertility is the number-one natural resource in Africa. However, due to high soil acidity and low fertility, food production has declined over the last decade. A case in point is in Uasin Gishu County, where farmers continue to report continued decrease in farm production. This is mainly due to continuous use of soil acidifying inorganic fertilizers that include diammonium phosphate (DAP). Remedy for such reduced soil fertility may be done through soil fertility amendments. Large amounts of pig manure containing high concentrations of nutrients are generated on pig farms while factories generate large quantities of waste water. The aim of the current research was to determine the use of molasses fermentation wastewater and pig waste as an amendment to soil acidity and determine the impacts of such amendments on soil characteristics, plant nutrient characteristics and crop yields. This research was carried out under field and green house conditions in the University of Eldoret Farm. The treatments were pig waste, molasses fermentation wastewater and DAP on cowpea. The molasses fermentation wastewater used in the experiment was obtained from Muhoroni Agro-chemicals and Food Company (ACFC) while the pig waste used was obtained from University of Eldoret Farm. Chemical analysis for molasses fermentation wastewater and soils before and after treatment were carried out and also done on dry cowpea seeds. In the field, complete randomized division blocks each measuring 3 m x 3 m were used. Eight treatments were used and replicated to give a total of 72 plots. The fertilizer treatments were applied based on P requirement of the plant. The experiments were carried out in two seasons. After harvesting, the seeds were dried to 13% moisture content and grain yield (kg/ha), seed quality and economic analysis was done. From the study, Soil characteristics differed significantly between seasons 1 and 2 among all the analyzed parameters (p < 0.05) except in the control plots. In both seasons, the pH value was found to be highest in treatment using wastewater, combination of pig waste and wastewater and then pig waste alone. DAP had the lowest pH. The treatment combining DAP, PW and WW had the highest yield followed by those with PW + WW while treatment with only WW and DAP were lower, which were, however, higher than the control. Other parameters of yield such as, plant height, leaf height, leaf width, and number of pods, number and weight of seeds followed similar trend. The results in this research show that molasses fermentation wastewater and pig waste are suitable to amend soil acidity in the university of Eldoret farm. The results should be replicated outside the University of Eldoret especially in Uasin Gishu County farms. Data was analysed using SPSS.