Effects of straw mulching on the change of soil moisture and structure in sugarcane field in Guangxi

【Objective】 The effects of straw mulching on the properties of soil pore structure, pore quantity and connectivity of sugarcane field in Guangxi were investigated to analyze the characteristics of soil pore structure and water transport channel, which provided theoretical basis for scientificand rational planting of sugarcane in Guangxi.【Method】 Two treatments including straw mulching(SM) and no straw mulching(CK) were set up to obtain soil pore structure data by CT scanning imaging technology and ImageJ software. Meanwhile the soil organic matter and soil water content at 5, 20 and 40 cm depth in-situ were measured. These data were used to analyze the pore structure characteristics and soil water movement channels in different treatments.【Result】 The organic matter content of 0-10 cm soil layer in SM was significantly greater than that of CK(P<0.05, the same below). The soil water content under SM treatment was significantly higher than that of CK at the same depth. In 0-40 cm soil layer, the soil pore surface density of SM was significantly greater than that of CK, while the soil pore complexity of CK was significantly higher than that of SM treatment. The quantity of pores(19190) and pores with diameter ≥1 mm(952), porosity(0.07%) and specific surface area(1.64 mm^-1) treated by SM were all significantly higher than those treated by CK(9415, 690, 0.06%, 1.43 mm^-1), respectively. The three-dimensional structure of soil pores showed that the relative few pores were mostly dispersed in the 0-20 cm soil layer within obvious stratification in spatial distribution in CK. However, However, the soil pore number treated with SM were large and evenly distributed throughout the space, the obvious stratification of pore distribution was not observed in SM. The relative more pores were distributed in the whole space which induced the well-developed connectivity.【Conclusion】 Straw mulching can effectively increase soil water content and quantity of soil pores, results in the better soil pore connectivity, which can improve the soil structure, finally promote the development of root system for sugarcane.