Effects of biochar, composted biochar, or inorganic NPK fertiliser application on soil properties and yield of amaranth (Amaranthus cruentus)
Emmanuel Abban-Baidoo1, Kwame Agyei Frimpong1, Delphine Manka'abusi2, Bernd Marschner2
1University of Cape Coast, College of Agriculture and Natural Sciences, Dept. of Soil Science, Ghana
In this study, we conducted a pot experiment with soils collected from the coastal savannah (CSZ), Guinea savannah (GSZ), and the semi-deciduous forest (SDFZ) agroecological zone of Ghana to assess the direct and residual effects of rice husk biochar (RHB) or corn cob biochar (CCB) applied singly, composted rice husk or corn cob biochars, and inorganic fertiliser (IF) on soil properties, and yield of amaranth in amaranth – cowpea rotation trial. The composted biochars comprised of 60.6% domestic bio-waste, 21.2% poultry litter, 18.2% rice straw and either 0%, 5%, or 10% RHB or CCB mixes. The effect of biochar, composted biochar, and inorganic fertiliser application on soil properties and amaranth yield varied significantly with soil type. The result showed that all the amendments, except the IF increased soil pH compared to the control. Soil pH was increased by 0.04 - 0.8 units in the CSZ, 0.7 - 1.6 units in GSZ, and 0.08 - 0.9 units in SDFZ soils. The pH of the pure biochars (RHB and CCB) were similar but among the composted biochars, pH increased with increasing biochar content. CEC in the pure biochars and the composted biochars were higher than in the IF and control treatment. Soil total nitrogen (TN) was similar in the CSZ soil, while in the GSZ and SDFZ soils, additions of composted biochars increased TN with increasing biochar content. Pure biochar addition increased soil total carbon (TC) than in their corresponding composted biochars. Sole compost addition increased soil available P by 5076%, 2679%, and 31%, respectively in the CSZ, GSZ, and SDFZ soils. The uptakes of N, P, K, and Mg as well as the aboveground biomass yield of amaranth were greater in all amended soils than in the control. We concluded that the application of inorganic fertiliser, biochar, and composted biochar improved soil quality and increased nutrient uptakes, leading to higher yields of amaranth.
Keywords: Biochar, compost, composted biochar, inorganic fertiliser, nutrient uptake, soil quality
Contact Address: Emmanuel Abban-Baidoo, University of Cape Coast, College of Agriculture and Natural Sciences, Dept. of Soil Science, Plot no. 4 4th Street North Ola, Cape Coast, Ghana, e-mail: eatoabban69gmail.com