2种典型耕作方式影响下的蔗田土壤孔隙结构及其水分运动特性

为了明确农业生产过程中耕作方式对田间土壤孔隙结构及土壤水分运动特性的影响,以广西农地蔗田为研究对象,基于土壤切片技术分析研究免耕和垄耕2种典型耕作方式蔗田的田间土壤孔隙结构特征,并结合土柱模拟入渗试验,探究土壤孔隙结构对土壤水分运动的影响,进一步揭示孔隙结构与土壤水分运动特性之间的相互作用关系。结果表明：随着土层深度的增加,免耕蔗田孔隙形态以聚集的团块状分布为主,垄耕蔗田孔隙形态以条状分布为主。与免耕蔗田相比,垄耕蔗田的土壤总孔隙度和>2.5 mm孔径的孔隙度分别增加32.5%和21.9%。垄耕蔗田在局部土层深度范围内显著增加上下土层孔隙的变异度(p<0.05),显著降低土壤孔隙的连通性(平均邻近指数为0.448)(p<0.05),土壤孔隙形态相对规则(平均成圆率为0.335)。对于土壤水分运动特性,免耕蔗田总体的土壤饱和导水率和质量流率显著高于垄耕蔗田(p<0.05),初始含水率显著低于垄耕蔗田(p<0.05),质量流率随时间变化强度相对较大,提高水流入渗能力。垄耕降低土壤孔隙结构连通性,使水分蓄存在表层土壤中,一定程度上可降低土壤水分的入渗现象,改变蔗...

Soil Pore Structure and Water Movement Characteristics of Sugarcane Field Under the Influence of Two Typical Tillage Methods

In order to clarify the effects of tillage methods on soil pore structure and soil water movement characteristics during agricultural production,sugarcane field in Guangxi was taken as the research object,soil pore structure characteristics of sugarcane field under two typical tillage methods of no-tillage and ridge tillage were studied based on soil slicing technique,combined with simulated infiltration test of soil column,the influence of soil pore structure on soil water movement was explored,and the interaction between pore structure and soil water movement characteristics was further revealed.The results showed that with the increase of soil layer depth,the pore morphology of no-till sugarcane field was dominated by aggregated clumps,while the pore morphology of ridge tillage sugarcane field was dominated by strip distribution.Compared with no-till sugarcane field,the total porosity and porosity of the soil with > 2.5 mm pore size increased by 32.5% and 21.9%,respectively,in ridge tillage sugarcane field.In the range of local soil depth,the ridge cultivated land significantly increased the porosity variation of the upper and lower soil layers (p<0.05),and significantly decreased the connectivity of soil pores (average proximity index was 0.448)(p<0.05),the soil pore morphology was relatively regular (average pore roundness was 0.335).As for the soil water movement characteristics,compared with the ridge tillage sugarcane field,the overall soil saturated hydraulic conductivity and mass flow rate in no-till sugarcane field were significantly higher (p<0.05),while the initial water content was significantly lower (p<0.05).The change intensity of mass flow rate over time was relatively large,which improved the water infiltration capacity.Compared with no-tillage,the ridge tillage of sugarcane field reduced the connectivity of soil pore structure and resulted in water separation and storage in the surface soil,thus could reduce the infiltration of soil water to a certain extent,which was helpful to improve the soil water condition of sugarcane field.