Effects Of Biochar And Compost On Soil Physicochemical Properties And Maize Yield In Acidic Ferralsol In Kamiti Sub-Catchment, Kiambu County, Kenya

ABSTRACT

The rapidly increasing global population, climate change and dwindling resources have made it very difficult to meet global food demand. To address the issue of food insecurity, sustainable intensification of agriculture (SIA) has been proposed. However, the consequences of poorly managed agricultural intensification can negatively affect the ecosystem. Biochar and compost application has been widely recommended as a highly promising soil fertility replenishment option to promote sustainable agriculture. In Kenya, only relatively recent few studies have been done to assess the effect of biochar applications on the quality of poor soils. This research is therefore, intended to investigate how biochar, applied alone or with compost could improve soil quality and increase maize yield in an acidic Ferralsol in Kamiti sub-catchment, Kiambu County of Kenya. Specifically, the study sort to 1) assess the effect of biochar, compost and their combined application on soil physical properties, 2) assess the effect of biochar, compost and their combined application on soil chemical properties and 3) determine the effect of biochar, compost and their combined application on maize growth and yield. To achieve the objectives, 6-month field trial was carried out on an acidic Ferralsol with high Al and Fe contents at the Kenyatta University Research Farm using the Randomized Complete Block Design (RCBD) comprising six treatments which included; control with no amendment (C), 20 t ha-1 Biochar (20B), 40 t ha-1 Biochar (40B), 20 t ha-1 Compost (20C), 40 t ha-1 Compost (40C) and 20 ha-1 Biochar + 20 ha-1 Compost (BC). During the study, data on plant height, stem diameter and leaf area were taken after every 2 weeks. Plant samples taken at the tasseling stage and soil samples taken at physical maturity stage of the maize, respectively, were dried, ground and sieves (< 2 mm) before being sent to the Soil Science laboratory of the Department of Soil Science / Soil Ecology, Ruhr University Bochum for analysis. Statistical analysis of data was done using SPSS (version 25) statistical software. The study showed that single or combined application of biochar and compost reduced soil bulk density. The reduction in bulk density followed the decreasing order BC