INFLUENCE OF BIOCHAR AMENDMENTS ON SOYBEAN AND TOMATO YIELD IN A SANDY LOAM SOIL

Abstract

The benefits of biochar to soils for agricultural purposes are numerous. Application of biochar to soils may improve the soil, displace an amount of conventional fossil fuel based fertilizers, and sequester carbon. This study was conducted to investigate the effect of biochar amendment on the growths and yields of soybean and tomato. In addition, carbon sequestration potential of biochar was evaluated. A replicated randomized complete block design with treatments consisting of BC20 (1.16 kg/plot at 20%), BC10 (0.58 kg/plot at 10%) and BC0 (0 kg/plot at 0%), biochar application rates was established on the experimental Farm at Ipere- Ekiti, Ilejemeje Local Government Area of Ekiti State, Nigeria. The research comprised three treatments with three replicates in a completely randomized design. The total numbers of plots cultivated in this experiment were 18 plots for both soybean and tomato plots. The surface soils (0–15 cm) were analysed for chemical and physical properties before and after the experiments. The total seasonal amount of rainfall was 685 mm. Under the soybean plot, BC10 retained the highest amount of Organic Carbon (OC), Organic Matter (OM), available Phosphorus (P), exchangeable potassium and calcium Magnesium compared with other biochar application levels while BC20 produced the smallest decrease in total nitrogen, Zinc (Zn), and cation exchange capacity. In the Tomato plot site, BC20 produced the largest amount of organic carbon, organic matter, total nitrogen, exchangeable potassium, Zn and Fe. There was 5% increase in Soil Organic Carbon (SOC) contents from 20% biochar-amended soil while 10% biochar treatment level maintained the original value of 1.70%. In the control group where the addition of biochar was 0kg/kg, there was 6.5% decrease in the value of SOC in the soybean plot. Under Tomato plot, there was 11.8%, 12.4% and 13.5% decrease in the BC20, BC10 and BC0 respectively. The pattern of the agronomic parameters (plant height, stem width and number of leaf) of Soybean and Tomato showed an increasing trend with time. The highest average plant heights measured were 87, 70 and 56 cm for soybean and 173, 171 and 157 cm for tomato for the treatments BC0, BC10 and BC20 respectively. Difference in plant parameters (plant height, stem with and number of leaves) among BC20, BC10 and BC0 biochar application were statistically significant (p ≤ 0.001). The number of soybean pods, number of seeds per pod, total number of seeds per pod and 100 seeds dry weight were significantly different among treatments (p < 0.05). Number of fruits per plant, fruit yield per plant, fruit yield per plot and tomato yield were significantly (p < 0.05) affected by use of biochar. Wood biochar increased the chemical characteristics and nutrients of the soil. Application of wood biochar to sandy loam soil increased soybean and tomato growth compared to the control group (BC0 biochar). The application of biochar also led to increase in soil fertility thereby increasing the growth and yield of soybean and tomato compared to the control group (BC0). Soil management has a major impact on agricultural productivity and ecosystem sustainability as soils differ in their response to different management