Characteristics and Influencing Factors of Soil Infiltration in Different Agroforestry Types in Purple Soil Area

Abstract

[Objective] To investigate the soil infiltration characteristics of different agroforestry composite modes and their influencing factors types in the purple soil area. [Methods] We analyzed the changes in the soil physical properties and infiltration processes under four agroforestry types in the purple soil area, namely, no crop (CK), peanut (HS), pepper (HJ), and peanut + pepper (HS + HJ), through field surveys and laboratory experiments, and evaluated the applicability of three soil infiltration models including Kostiakov, Horton, and Philip. [Results] (1) The total soil porosity in HJ was not significantly different from that in CK and HS + HJ, but was considerably higher than that in HS (p<0.05); the soil shear strength in CK was similar to that in HS, but were both significantly higher than that of HJ and HS+HJ (p<0.05); the soil bulk density, water content, temperature, water repellency, compactness, and soil hardness were also significantly different among the four agroforestry types (p<0.05). (2) The soil water infiltration process varied significantly among the four types, showing the steady infiltration stage around 20 min under CK and HS, while around 70 and 80 min under HJ and HS + HJ, respectively. The steady infiltration in the HS + HJ was 162%, 140% and 82% higher than that in CK, HS, and HJ, respectively (p<0.05). (3) Compared with the Horton and Philip models, the Kostiakov model was the most effective in fitting the infiltration process (coefficient of determination R2=0.933~0.991), while the Horton model fitted relatively poorly (R2=0.849~0.979). (4) The correlation and multiple linear regression analyses found that the total soil porosity and soil shear strength were the key factors affecting soil infiltration. [Conclusion] The results of the study provide scientific basis for the optimal selection of agroforestry types in the purple soil area.

Keywords

• purple soil
• soil moisture
• agroforestry
• soil infiltration model