Abstract: We investigated the physical properties of the plough soil and the components of sugarcane yield in the depth of mechanized subsoiling of sugarcane field, along with the clarification on the specific soil location and obstacle factors of subsoiling, with the aim to provide scientific basis for the construction of a good sugarcane cultivation layer and the development of soil improvement strategies. Three depths of subsoiling operation (35, 40 and 45 cm) were set up, with nosubsoiling as control. Soil physical properties, including compactness, bulk density, water content, porosity, three-phase volume ratio, and yield components and cane yield of sugarcane in the fields were investigated. The results showed that subsoiling depth was significantly correlated with the soil structure characteristics and the improvement of sugarcane yield in sugarcane field. Subsoiling broke down the plow bottom, significantly reduced soil compaction, bulk density, and the corresponding penetration resistance and shear strength during mechanical operation, especially for the above factors in 20-30 cm soil layer, with positive consequences for sugarcane yield. Moreover, subsoiling significantly increased the liquid volume rate of the soil layer within 30 cm and soil moisture storage capacity, and thus significantly improved the water index of the 10-30 cm soil layer. The 10-30 cm soil layer was the location for the most significant effect of subsoiling on the improvement of solid volume rate in the plough soil. The effective stem number, plant height, cane yield and sucrose content of sugarcane were significantly promoted by subsoiling. In view of the common equipment level in the sugarcane planting area, we suggested that the operating depth standard of mechanized subsoiling should not be less than 40 cm.

Key words: sugarcane, subsoiling, yield, sugarcane field, soil physical property