Innovative use of Rice Husk Biochar for Rice Cultivation in Salt-affected Soils with Alternated Wetting and Drying Irrigation

Abstract

Nakhon Ratchasima, Thailand, is the most severely salt-affected area in the country’s Northeast region caused by the underlying geology and human activities. In this condition, evaporation of groundwater with salt to the soil surface is an important issue that affects the use of the area primarily for agricultural purposes. This research aimed to improve saline soil quality using rice husk biochar (RHB) to enable rice cultivation. The experiment was designed to limit the evaporation of salty groundwater by cultivating rice in the cement pond. A mixture of different amounts of RHB with four replicates at 0%, 1%, 1.5%, and 2.0% by weight (wt.%) and 500 g dried cow manure were used for rice cultivation. Jasmine rice variety KDML 105 was planted in cement ponds filled with saline sodic soil at pH 10.6, with a total sodium content of 0.83%, electrical conductivity of 68.6 dS/m, and SAR of 11,707. The results indicated that RHB could significantly reduce the soil salinity, EC, Na⁺ content, and SAR value while elevating the levels of available macronutrients within just one crop of rice cultivation (120 days). In addition, salt evaporation from groundwater to the soil surface can be limited. The study demonstrated that mixing RHB at 1.5% wt into the saline soil can improve the salted soil and yield the highest rice production. Applying RHB in saline sodic soil for rice cultivated in cement pond is an alternative way for salt-affected areas to reach food security and long-term salted soil revitalization.