Effects of Different Rates of Biochar for Soil Nitrogen and Water Dynamics and Teff Production in Highland of Ethiopia

Abstract

Water and nutrient availability are the most important factors which affect crop production. However inconsistent rainfall and high prices of fertilizers have been pushing down crop productivity. The use of biochar (BC) is one of the alternatives to minimize those effects. However, few studies have been conducted under field conditions, especially using BC applied on clayey soil for crop production in a highland of Ethiopian. The objective of this study was to evaluate the effects of BC application on soil water and nutrient dynamics and production of teff. The experimental was laid out in randomized complete block design (RCBD) with 3 levels of BC application rate (0, 5 and 20 t ha–1; 0ACB, 5ACB, and 20ACB) with five replications. Soil pH was increased with BC application throughout cultivation period. There were no apparent effects of BC application on soil NH4+-N and NO3–-N during cultivation period. Soil water contents at field capacity and permanent wilting point were increased and decreased, respectively, leading to increase in plant available water with BC compared to without BC. BC applied on clayey soils could change soil structure and contribute to adequate drainage water during the rainy period and retention of water during the dry period, which collaborate with proper aeration in soil for health plant growth. Our results showed significantly increased plant height, dry biomass, and grain yields of teff for soil treated with biochar. Soil treatment with 5ACB and 20ACB increased plant height by 17.0% and 40.5%, respectively, dry biomass by 172% and 256%, respectively, and grain yields by 146% and 173%, respectively. Our results showed that BC application improved and regulated water availability for clayey soil during the period of the growing season, which resulted in improved biomass and grain production of teff. Amendment of the soil with acacia biochar can be recommended to increase crop production for clayey soil in highland of Ethiopia in sustainable ways.