In order to investigate the effect of biochar addition on soil water infiltration and water holding capacity in the arid regions of central Ningxia, the methods of one-dimensional vertical infiltration and tensionmeter in lab were used to analyze the infiltration rate, wetting front process, cumulative infiltration and water holding capacity. The biochar was added into soil at five ratios of 0% (CK), 1% (B1), 2% (B2), 3% (B3) and 4% (B4), respectively. The initial infiltration rate, average infiltration rate and steady infiltration rate gradually decreased with the amounts of biochar addition. When the infiltration time was 120 min, the wetting front was decreased by 15%, 21%, 24% and 26%, and the cumulative infiltration was reduced by 5.32%, 10.95%, 13.47% and 19.11% in B1, B2, B3 and B4 compared with CK, respectively. With the increasing amounts of biochar addition, the wetting front slowed down and cumulative infiltration decreased. The Kostiakov model was more suitable than Philip model, empirical model and Horton model to simulate the infiltration process of soil water after the biochar addition into soil. The van Genuchten model was suitable for simulating the soil-water characteristic curve under the biochar addition. Under the 25% of soil water content, the soil water suction in B1, B2, B3 and B4 increased by 42%, 75%, 100% and 163% compared with CK, respectively. The addition of biochar could significantly increase soil water holding capacity, and have positive effects on the development of dry farming in arid regions.
Chinese Journal of Soil Science
Water holding capacity
Sandy loam soil