耕作深度及秸秆还田对农田黑土土壤供水能力及作物产量的影响
The Impact of Tillage Depth and Straw Incorporation on Crop Yield and Soil Water Supply in Arable Black Soil
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摘要: 黑土是我国重要的农田土壤,耕作深度和秸秆还田是影响黑土生产力的重要因素。此研究利用一个三年的田间试验,分析了耕作深度和秸秆还田深度对玉米和大豆产量的影响,并探讨了其影响机制。试验采用裂区设计,主处理包括浅耕0~15 cm(D15),中浅耕0~20 cm(D20),深耕0~35 cm(D35)和深耕0~50 cm(D50),副处理对照和秸秆还田(+S)。结果表明增加耕作深度能够增加玉米和大豆的产量,并在D35处理达到了最大值,分别为8 999 kg·hm-2和2 424 kg·hm-2,说明耕作深度是影响作物产量的一个重要因子。每个耕作深度又裂区为是否秸秆还田,即增加了D15+S,D20+S,D35+S,D50+S处理,与非秸秆还田处理相比,当秸秆还田深度≤ 20 cm时,作物产量降低了10.62%~16.81%,而当还田深度≥ 35 cm时,作物产量提高了2.25%~7.29%,说明秸秆还田深度是影响秸秆还田效果的重要因素,D35+S处理作物的产量达到了最大值。与D15+S相比,D20+S,D35+S,D50+S,0~15 cm土层土壤含水量增加了7.81%~12.63%,作物的出苗率增加了11.42%~16.94%,土壤的供水量增加6.71%~10.43%,其中D35+S的效果最佳,说明上述因素是能够调控秸秆还田效果;虽然D50+S也能够增加作物产量,但是增加了作业成本,同时不利于保水。因此,在典型黑土区为了提高粮食产量,提高大气降水的利用效率,推荐的耕作深度是0~35 cm配以全层秸秆深混还田。Abstract: Black soil is one of important arable soil in China, tillage depth and straw incorporation both impacted the agricultural production of black soil. The impact of tillage depth and straw incorporation depths on maize and soybean yield were considered based on a three-year field experiment which is a split block design. The main treatments included shallow cultivation within 0~15 cm (D15), medium-shallow cultivation within 0~20 cm (D20), deep cultivation within 0~35 cm (D35)and 0~50 cm (D50),secondary treatments included contrast and straw incorporation (+S). Yields of maize and soybean were increased along with the increase in cultivation depth, and obtained the greatest values of 8 999 kg·hm-2 and 2 424 kg·hm-2, respectively, suggesting that the cultivation depth was an important factor impacting crop yield. Straw incorporation within 0~15 cm (D15+S),0~20 cm (D20+S),0~35 cm(D35+S),0~50 cm(D50+S)were added after each cultivation depth treatment was split. Comparison with corresponding no straw incorporation treatments, maize and soybean yields were decreased when cultivation depth was ≤ 20 cm, but were increased when cultivation depth was ≥ 35 cm, and obtained the greatest yield in D35+S treatments, which suggested that the depth of straw incorporation was key factor impacting the role of straw incorporation. Comparison with D15+S, soil water content in 0~15 cm soil layer, crop emergence rate and soil water supply under D20+S, D35+S and D50+S treatments were increased by 7.8%~12.6%, 11.4%~16.9% and 6.7%~10.4%, respectively, suggesting that above factors could regulate the role of straw incorporation. D50 and D50+S treatments increased maize and soybean yields, but increased also mechanical operation cost and was not in favor of soil water conservation. Therefore, combination of 0~35 cm cultivation depth and straw incorporation was recommended with the objectives of increasing crop yield and rainfall use efficiency in study site.