夏闲期轮耕对小麦田土壤水分及产量的影响

Effects of rotational tillage during summer fallow on wheat field soil water regime and grain yield

2007—2010年在宁南旱区研究了夏闲期免耕/深松/免耕(T1)、深松/免耕/深松(T2)、连年翻耕(CT)3种耕作方式对麦田土壤水分及产量的影响.结果表明:经过3年夏闲期T1和T2处理后,农田土壤蓄水效率平均分别较连年翻耕处理提高15.2%和26.5%;T1和T2处理的降水潜在利用率较高,分别达到37.8%和38.5%,降水生产效率平均分别较连年翻耕处理提高9.9%和10.7%.夏闲期轮耕能显著降低休闲期的土壤无效蒸发,有效保蓄小麦生长期的土壤水分.在冬小麦生长前期,T1和T2处理0～200cm土层土壤水分平均分别较连年翻耕处理增加6.8%和9.4%;在拔节-抽穗-灌浆期,与连年翻耕处理相比,两处理可显著提高0～200cm土层土壤蓄水量,对作物产量的贡献率较高.不同轮耕模式在增加作物耗水量的同时也提高了作物产量及水分利用效率,与CT处理相比,3年T1和T2处理作物耗水量平均分别提高5.2%和6.1%,产量分别增加9.9%和10.6%,作物水分生产效率分别提高4.5%和4.3%.相关分析表明,在干旱缺水的宁南地区,冬小麦播种期、拔节-抽穗-灌浆期的土壤蓄水量可显著影响产量,尤其抽穗期的土壤蓄水量对产量的影响更大.

In 2007-2010, a field experiment was conducted to study the effects of different rotational tillage practices during summer follow on the soil water regime and grain yield in a winter wheat field in Southern Ningxia arid area. Three treatments were installed, i.e., T1 （no-tillage in first year, subsoiling in second year, and no-tillage in third year）, T2 （subsoiling in first year, no-tillage in second year, and subsoiling in third year）, and CT （conventional tillage in the 3 years）. Through the three years of the tillage practices, the soil water storage efficiency in treatments T1 and T2 was increased averagely by 15.2% and 26.5%, respectively, as compared to CT. In treatments T1 and T2, the potential rainfall use rate was higher, being 37.8% and 38.5%, respectively, and the rainfall use efficiency was increased averagely by 9.9% and 10.7%, respectively, as compared to CT. Rotational tillage during summer fallow could decrease the soil ineffective evaporation significantly, and save the soil water effectively in wheat growth season. At early growth stage, the water storage in 0-200 cm soil layer in treatments T1 and T2 was increased averagely by 6.8% and 9.4%, as compared to CT; at jointing, heading, and filling stages, the water storage in 0-200 cm soil layer in treatments T1 and T2 had a significant increase, giving greater contribution to the wheat yield than the control. Different rotational tillage practices increased the water consumption by wheat, but in the meantime, increased the grain yield and water use efficiency. In treatments T1 and T2, the water consumption by wheat through the three years was increased averagely by 5.2% and 6.1%, whereas the grain yield and the water use efficiency were increased averagely by 9.9% and 10.6%, and by 4.5% and 4.3%, respectively, as compared to CT. Correlation analysis showed that in Southern Ningxia arid area, the soil water storage at sowing, jointing, heading, and filling stages, especially at heading stage, could have significant effects on the winter wheat grain yield.