基于不同夏作物-冬小麦种植制度的黄土高原东部农田土壤物理质量研究

黄土高原东部农田土壤物理质量下降是限制该地区农业生产的重要因素之一,合理的种植制度能够改善土壤物理质量。本试验于2016年设置连续夏绿豆-冬小麦(MB-WW,T₁)、2年夏玉米-冬小麦+2年夏绿豆-冬小麦(2 a SC-WW+2 a MB-WW,T₂)及连续夏休闲-冬小麦(SF-WW,T₃) 3种种植制度,分析实施第3和4年的土壤物理质量,以探索潜在的适宜于改善研究区土壤物理质量的种植制度。结果表明：T₁处理下冬小麦收获后0~30 cm各土层毛管孔隙度较T₂和T₃处理分别显著提高了19.20~28.49%和18.86~31.86%。此外T₁处理夏播作物收获后,10~20 cm土层土壤储水量较T₂显著增加了6.37%,20~30 cm土层土壤质量含水量和储水量较T₂处理分别显著增加了7.87%和4.70%。相较于T₃,冬小麦和夏播作物收获后T₁和T₂处理下土壤容重、总孔隙度和土壤固、液、气三相比偏离值没有得到明显的改善。综上所述,绿豆-冬小麦种植制度对土壤物理质量有一定的改善,采用连续夏绿豆-冬小麦种植制度可能是改善黄土高原东部农田土壤物理质量潜在的措施之一。

Assessment of Physical Quality of Farmland Soil on the Eastern Loess Plateau Under Different Summer Crops-Winter Wheat Farming Systems

The degradation of farmland soil physical quality is one of the important factors limiting agricultural production on the eastern Loess Plateau. A reasonable farming system could improve soil physical quality. This experiment was carried out with three different farming systems since 2016, including continuous summer mung bean-winter wheat (MB-WW, T₁), 2 years’ summer maize-winter wheat + 2 years’ summer mung bean-winter wheat (2a SC-WW+2a MB-WW, T₂) and continuous summer fallow-winter wheat (SF-WW, T₃). In the 3^rd and 4^th year of the experiment, soil physical quality was assessed to find a potential farming system for improving soil quality in this region. The results showed that under T₁, the capillary porosity in the 0-30 cm of soil profile after harvest of winter wheat increased significantly by 19.20%-28.49% and 18.86%-31.86% compared with that under T₂ and T₃, respectively. In addition, compared with those of T₂, soil water storage of T₁ significantly increased by 6.37% in the 10-20 cm soil layer after harvest of summer crops, soil mass water content increased by 7.87% and soil water storage increased by 4.70% in the 20-30 cm soil layer. However, compared with T₃, there was no significant improvement of soil bulk density, total porosity, and the deviation values of soil solid-liquid-gas phases of T₁ and T₂ after harvest of winter wheat and summer crops. In conclusion, the farming system of mung bean-winter wheat could improve soil physical quality to a certain extent, and the adoption of continuous summer mung bean-winter wheat cropping system might be one of the potential measures to improve soil physical quality of farmland on the eastern Loess Plateau.