麦秸处理和播种方式对夏大豆农艺性状及土壤物理性状的影响

Effects of Straw Management and Sowing Methods on Soybean Agronomic Traits and Soil Physical Properties

【目的】在黄淮海麦豆两熟制条件下,比较不同麦秸处理和播种方式对大豆生长发育、产量及土壤物理性状的影响,探讨麦茬夏大豆免耕播种的技术关键,评估免耕覆秸精量播种技术的利用价值,以期改进黄淮海地区夏大豆生产技术。【方法】定位试验于2012—2014年在江苏徐州进行,采用裂区设计,以播种方式为主因素,秸秆还田量为副因素。播种方式有免耕覆秸精量播种、常规免耕机械条播和浅旋人工撒播3种,秸秆还田量设全量和半量2个水平,共6个处理,比较不同麦秸处理和播种方式对大豆播种和出苗质量、生育进程、产量、土壤物理性状及麦秸腐解率的影响。【结果】免耕覆秸精量播种较常规免耕机械条播出苗早1 d,较浅旋人工撒播早1—3 d,同时田间出苗率最高;免耕覆秸精量播种初花期早0.1—2.3 d,差异显著(P<0.05)。相比之下,秸秆还田量则对出苗速度和生育进程的影响不显著。免耕覆秸精量播种处理较常规免耕机械条播增产4.12%—12.40%,较浅旋人工撒播增产1.96%—5.50%;秸秆半量还田处理的产量高于全量还田处理,但差异不显著。免耕覆秸精量播种和常规免耕机械条播与浅旋人工撒播相比,播种至出苗期土壤温度较低,土壤湿度较高,差异显著(P<0.05)。秸秆全量还田处理土壤温度低于半量还田处理,而全量还田处理土壤湿度仅在干旱年份高于半量还田处理。浅旋人工撒播麦秸腐解率较免耕覆秸精量播种和常规免耕机械条播高,但免耕覆秸精量播种处理的麦秸不会影响下茬小麦的播种和生长。【结论】秸秆覆盖可保蓄土壤水分,降低土壤温度,防止土壤板结,提高大豆出苗率,为下茬小麦提供优良的有机肥料,是麦豆两熟制条件下良好的秸秆还田方式。免耕覆秸精量播种技术同步解决麦秸还田、大豆保苗和土壤培肥难题,适合在黄淮海及同类地区推广应用。

【Objective】 This study is to evaluate the effects of wheat straw management and sowing methods on soybean growth and development and soil physical properties in the wheat-soybean double-cropping system of Yellow-Huai-Hai Rivers Valley, to illustrate the key points of no-till sowing technologies, and to assess the utilization value of a new method of no-tillage plus straw mulching and precise sowing（NTSMPS）, in order to provide the technical solution for improving summer soybean productivity in this region.【Method】The split-plot field experiment, in which the main-plot factor was the sowing method while the sub-plot factor was straw-returning amount, was performed in Xuzhou, Jiangsu Province, China, in 2012-2014. The sowing method factor had three levels： NTSMPS, conventional no-tillage plus-mechanical drilling（CNSD）, and rotary-tillage plus artificial broadcasting（RTAB）, and the straw returning amount had two levels： Total-amount and half-amount straw returning. With six treatments, we compared the effects of straw management and sowing methods on soybean sowing and emergence quality, growing process, yield, soil physical properties and wheat straw decomposition rate. 【Result】 The emergence date of NTSMPS was 1 day and 1-3 days earlier than that of CSND and RTAB, respectively. Meanwhile, the emergence rate of NTSMPS was the highest among the three treatments. Furthermore, the date of beginning bloom（R1 stage） of NTSMPS was 0.1-2.3 days earlier than that of the other two sowing methods, and this difference was significant（P〈0.05）. However, straw returning amount had no effect on emergence speed and growth rate. The yield in the NTSMPS was 4.12%-12.40% and 1.96%-5.50% higher in a comparison with that of CSND and RTAB, respectively. In contrary, there was insignificant difference of yield among two straw returning amount levels. Compared with RTAB, NTSMPS and CSND resulted in an obvious reduction in soil temperature and increase in soil moisture during sowing and seedling emergence（P〈0.05）. Soil humidity was higher in treatment with total-amount straw application than in treatment with half-amount straw returning, while soil temperature was lower only in the dry year（2012）. Wheat residue decomposition ratio of RTAB was lower as compared to NTSMPS and CSND. However, wheat straw of NTSMPS exerted no hazardous influence on the sowing and growth of the next season crop（winter wheat）.【Conclusion】Straw mulching is a good way for wheat residue management in wheat-soybean double cropping system because of its functions in soil moisture remaining, temperature adjustment, soil sealing prevention, soybean emerging enhancement, and organic matter and mineral supply for the next-season wheat. NTSMPS technology is powerful to synchronously resolve the sticky questions of wheat residue management, and soil fertility improvement and can be widely used in the Yellow-Huai-Hai River Valley and similar areas.