耕作深度对蔗地土壤物理性状及甘蔗产量的影响

探讨蔗地机械化耕作深度对耕层土壤物理性状及甘蔗产量构成因子的影响,阐明深松作业的针对性土壤区位和障碍因子,可为甘蔗良好耕层的构建和土壤改良策略的制定提供科学依据.本研究设置3种深松作业深度(35、40和45 cm),以不深松为对照,对蔗地土壤物理性状(紧实度、容重、含水率、孔隙度、三相容积率)和甘蔗产量构成因素及蔗茎产量等指标进行研究.结果表明: 耕作作业深度与蔗地土壤结构特性及甘蔗产量的改善提升效应呈显著正相关.深松能够打破犁底层,显著降低土壤紧实度和容重,减小机械作业相应的贯入阻力和抗剪强度,尤其对20～30 cm土层的上述因子具有显著改善效应,对甘蔗高产意义重大.深松显著提高了30 cm以内土层的液相容积率,增大了土壤水分库容,使10～30 cm土层的水分指标显著改善.10～30 cm土层是深松对耕层土壤固相容积率改善效应最显著的区位.耕作深度的增加对甘蔗有效茎数、株高、蔗茎产量及蔗糖含量具有显著的促进效应.鉴于蔗区当前较普遍的机具装备水平,我国适宜蔗区实施机械化深松的作业深度标准应不小于40 cm.

Effect of subsoiling depths on soil physical characters and sugarcane yield.

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.