耕作模式对红壤坡耕地典型作物不同生育期土壤入渗特性的影响

The influence of tillage measures on soil infiltration characteristics at different growth stages of typical crops in red soil slopes farmland

以南方红壤区典型作物玉米为试验作物,设置顺坡垄作(Downslope ridge tillage,DT)、横坡垄作(Cross-slope ridge tillage,RT)、传统耕作(Conventional tillage,CT)、覆膜耕作(Plastic mulching tillage,PM)4种耕作模式试验小区,利用环刀法测定土壤入渗速率和累积入渗量,探析了耕作模式对红壤坡耕地作物不同生育期土壤入渗特性的影响,同时还对5种典型入渗模型在红壤坡耕地上的适宜性进行了评价。结果表明:(1)作物不同生育期土壤入渗速率和累积入渗量曲线差异明显,RT、PM的土壤入渗过程变化相对较大,而CT、DT的土壤入渗过程变化相对较小;(2)总体来看,RT、PM初始入渗率较大,且入渗速率变化较大,而DT、CT初始入渗率较小,入渗速率变幅也较小,饱和导水率总体表现为CT>RT>PM>DT;(3)不同耕作模式下的土壤初始入渗率与土壤容重呈负相关,与土壤有机质呈正相关,而稳定入渗率和饱和导水率则与土壤全氮含量呈正相关;(4)5种入渗模型均可较好地对不同耕作模式的红壤坡耕地土壤入渗过程进行拟合,其中Horton模型的拟合效果总体最优。研究结果可为红壤坡耕地降雨径流调控和坡耕地水土流失防治提供理论依据。

In this context,the present study selected maize,a representative crop in the southern red soil region,as the experimental object,and established experimental plots with four different tillage measures treatments:Downslope ridge tillage(DT),Cross-slope ridge tillage(RT),Conventional tillage(CT),and Plastic mulching tillage(PM).The infiltration rate and cumulative infiltration were measured by using the ring knife method to investigate the impact of different tillage measures on the soil infiltration characteristics during different growth stages of crops in the red soil sloping farmland.Moreover,the suitability of five typical infiltration models in the red soil sloping farmland was evaluated.The results indicate:(1)There are significant differences in the soil infiltration rates and cumulative infiltration curves at different growth stages of crops.The soil infiltration process shows greater variations under RT and PM,while it remains relatively stable under CT and DT;(2)Overall,RT and PM exhibit higher initial infiltration rates with greater variations,whereas DT and CT show lower initial infiltration rates with smaller variations.The saturated hydraulic conductivity is ranked as follows CT>RT>PM>DT;(3)The initial infiltration rate under different tillage measures negatively correlates with soil bulk density and positively correlates with soil organic matter content.On the other hand,the steady-state infiltration rate and saturated hydraulic conductivity positively correlate with total nitrogen content in the soil;(4)All five infiltration models can effectively fit the soil infiltration process under different tillage measures in red soil sloping farmland.Among them,the Horton model demonstrates the best overall fitting performance.The findings of this study provide a theoretical basis for rainwater runoff regulation and soil erosion control in red soil sloping farmland.