Effect of Biochar Application Rates on Soil Properties, Growth and Yield of Maize under Greenhouse Conditions

A greenhouse experiment was conducted two consecutive times to assess the effects of biochar from different sources on the growth of maize (Zea mays) with a view to determining the biochar rate that would give optimum growth performance of the test crop. The experiment consisted of six different biochar as treatments [cocoa pod husk (CPH), maize stovers (MAS) and maize cobs (MAC) applied singly and in equal combination (CPH MAS , CPH MAC and MAS MAC )]. All the 50 50 50 50 50 50-1 treatments were applied at different rates (0, 5, 10, 15, 20, 25 t ha ), each replicated thrice and arranged in completely randomized design. Highest stem girth of 4.2 ± 0.21 cm was obtained with 5 t ha of MAS biochar application. Similar results were obtained with the plant height and number of leaves. However, highest grain yield of 21.37 g 10 kg of soil -1-1 (4.27 t ha ) at 15 t ha , which was not significantly (F-1-1 70, 107 -1 = 1.88; p > 0.05) -1 different from 16.16 g 10 kg of soil (3.23 t ha ) at 10 t ha of MAS application was obtained during the first cultivation. The repeat experiment without further biochar additions gave lower and comparable values. Soil pH, organic carbon, nitrogen and available phosphorus increased + with biochar addition to soil. Also, except for Na , concentrations of Ca , Mg and K increased with biochar addition, and with high concentrations of these cations at high levels of biochar application. It was concluded that addition of biochar to sandy loam soil increased soil chemical properties, growth and yield of maize.