Applying rice husk biochar to revitalise saline sodic soil in Khorat Plateau area - A case study for food security purposes

Abstract

Salt-affected soils occur in the areas where excess dissolved mineral salts accumulate in the root zone that crop yields are adversely affected from the salts released by weathering of rock or those initially present in the soil-forming materials. In addition, evaporation and transpiration processes, due to high temperatures and droughts, can cause salt movement with capillary action inducing its accumulation in surface soil. Excess amounts of salts cause adverse effects on the physical and chemical properties of soil, microbiological processes and food security. Biochar produced from rice husk (RH) under the pyrolysis condition (400-500 °C) from a retort designed to produce laboratory quality biochar that is easy for farmers to use in order to promote self- sustaining biochar production. This study aimed to explore the use of rice husk biochar as a soil amendment in order to solve the saltaffected soil problems. The study area was Bung O sub- district, Kham Thale So district where the critical of salt-affected soil and drought area in Nakhon Ratchasima, Thailand. The results indicated that adding RH biochar with organic fertilizer into soil can improve both physical and chemical properties in every parameter. Particularly, the soil became less alkalinity. The results also showed an increased ion exchange capacity, higher amount of major and minor soil nutrients and the reduced amount of all sodium in the soil in every parameter. This included the absorption rate of sodium in the soil, the conductance of the soil, all of the amount of sodium in the soil, and the increasing amount of exchangeable magnesium and the amount of exchangeable calcium. The two elements contained positive ions which could replace the sodium ions in the salty soil making the soil less salty.