东北风沙土是一种障碍性土壤,明确风沙土区低产田障碍因子是改良低产田,提高其玉米产量的关键。以位于东北风沙土区的杜尔伯特蒙古族自治县域内6对低产田与同一微区域内高产田为研究对象,对比分析剖面(表土层、稳定层、犁底层和心土层)土壤的10项物理指标(层厚度、容重、孔隙度、硬度、三相比结构距、田间持水量、团聚体平均重量直径(MWD)、砂粒、粉粒和黏粒)和10项化学指标(pH、有机质、碱解氮、速效磷、速效钾、全氮、全磷、全钾、阳离子交换量、C/N)。结果表明,高低产田土壤的差异主要表现为表土层土壤的容重、MWD、砂粒、粉粒、粘粒、有机质、碱解氮、速效钾、全氮、全磷和阳离子交换量显著不同；稳定层土壤的三相结构距、MWD、砂粒、粘粒、有机质、碱解氮、速效磷、速效钾、全氮、全磷和阳离子交换量差异显著；犁底层的差异表现在MWD、粘粒、有机质和全氮; 心土层土壤主要是三相结构距、田间持水量、MWD和粘粒。利用主成分分析方法确定低产田风沙土障碍层主要表现在耕层和犁底层；土壤有机质、全氮、全磷、速效钾、粘粒五项因子含量低是风沙土低产田土壤主要障碍因子。
英文摘要:
The Aeolian sand soil of northeast China is a kind of obstructive soil. It is the key point to clear the barrier factor for improving maize yield in the Aeolian sand soil zone. Six pairs of high- and low-productivity Aeolian sand soils were studied, which located in Dulbert Mongolian Autonomous County, Heilongjiang Province, Daqing. Ten physical (layer depth, bulk density, porosity, hardness and three-phase Ratio Structure Distance, field capacity, mean weight diameter, sandy, silt and clay) and ten chemical (pH, organic matter, available nitrogen, phosphorus and potassium, total nitrogen, phosphorus and potassium, exchanged cation and C/N) parameters were determined from four soil profiles (surface, stable, plough pan and core soil layers). Results showed that the difference in high- and low-productivity field might be attributed to four reasons. First, the differ in bulk density, mean weight diameter, sand, silt, clay, organic matter, available nitrogen and phosphorus, total nitrogen and phosphorus, exchange cation in surface soil. Second, there are significant variation in three-phase Ratio Structure Distance, mean weight diameter, silt, clay, organic matter, available nitrogen, phosphorus and potassium, total nitrogen and phosphorus, exchange cation. Third, significant difference was observed in mean weight diameter, clay, organic matter and total nitrogen in plough pan layer. Fourth, higher three-phase ratio structure distance, and lower field capacity, mean weight diameter and clay in low- than high-productivity field at core soil layer. The result of principal analysis showed that the major obstructive layer was surface and plough pan layers, where organic matter, total nitrogen and phosphorus, available potassium and clay were the main obstacle factors.
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