黑土肥沃耕层构建效应

东北黑土区粘重的耕地土壤，经多年不合理耕作后产生了较厚的“犁底层”，成为该地区农业生产的主要限制因子.本研究利用田间试验，分析了构建肥沃耕层对作物产量、土壤物理性质、土壤含水量和微生物数量的影响.结果表明：肥沃耕层构建后，土壤形成了一个深厚的耕层，作物产量增加.与常规耕作法相比，向20～35 cm土层施用秸秆和有机肥使土壤容重分别降低了9.88%和6.20%，总孔隙度分别增加了9.58%和6.02%，饱和导水率分别增加了167.99%和73.78%，表明肥沃耕层的构建能够有效地改善土壤的通气透水性，提高大气降水的入渗能力；向“犁底层”施用秸秆和有机肥处理0～100 cm土层土壤含水量和水分利用效率均显著高于常规耕作法，该处理玉米出苗率与0～35 cm土层土壤含水量之间呈显著正相关关系.肥沃耕层的构建由于增加了土壤中的有机碳源和透气性，从而增加了土壤中的微生物数量.

Construction effect of fertile cultivated layer in black soil

The clayey farmland soil in black soil region of Northeast China, due to the existence of thicker plough pan created by unreasonable tillage, is a main limiting factor for local agricultural production. In this paper, a field experiment was conducted to study the construction effect of fertile cultivated layer on crop yield, soil physical properties, soil moisture content, and soil microbial number. After the construction of fertile cultivated layer, the soil had a thicker cultivated layer, and the crop yield was increased. Comparing with traditional tillage, applying straw and organic manure into 20-35 cm soil layer decreased soil bulk density by 9.88% and 6.20%, increased soil porosity by 9.58% and 6.02%, and enhanced soil saturated hydraulic conductivity by 167.99 and 73.78%, respectively, indicating that the construction of fertile cultivated layer could improve soil aeration and water permeability, and enhance the infiltration of rainfall. The soil moisture content and water use efficiency under the application of straw and organic manure into plough pan were higher than those under traditional tillage, and a positive correlation was observed between the moisture content in 0-35 cm soil layer and the emergence of maize seedlings. Due to the increased organic carbon source and aeration in the constructed fertile cultivated layer, soil microbial number was also increased.