Increasing soybean seed production and obtaining more vegetable oil and vegetable protein are important measures to ensure global food security. The Huang-Huai-Hai region is the main production area of high-quality and high-protein soybeans in China. No-tillage with straw mulching seeding technology is a new soybean planting mode in this area, which can significantly improve seed yield. However, the yield increasing mechanism is still unclear. A split-plot experimental design was adopted, which includes the main plot of seeding practice and the subplot of fertilizer treatment. The soil bulk density, soil water content, soil temperature, soybean root morphology, leaf area index, photosynthetic characteristics, canopy light transmittance, dry matter accumulation, and their relationship with seed yield were investigated. With the increase of experimental years, soil bulk density in topsoil decreased gradually (down 8.63 %) under straw mulching seeding treatment. Straw mulching stabilized the surface soil temperature, especially avoiding excessive surface soil temperature (down 1.11 ℃), which was beneficial to soil moisture retention (up 11.53 %). Straw mulching seeding practice created a suitable soil environment and promoted root growth (i.e. root length, root surface area, and root volume), especially when combined with fertilizer application. Both straw mulching and fertilizer application improved the leaf area index (up 16.55 %) of soybean. Furthermore, the leaf area index of soybean under fertilization was significantly increased in the R3-R5 stage, while it was increased during the period of R5-R7 under straw mulching treatment. In addition, the highest net photosynthetic duration was found under straw mulching (107 d), followed by straw crushing (104 d), and straw removing (102 d). The average soybean yield under straw mulching treatment was 4589.9 kg ha, which was increased by 15.2 % and 10.3 % compared to straw removing and straw crushing, respectively. Compared with no fertilizer treatment, the average soybean yield with fertilization was 4580.2 kg ha, which was increased by 17.2 %. In conclusion, under semi-arid conditions, straw mulching seeding practice with fertilization application created a suitable soil environment beneficial in promoting the growth of soybean underground and above ground, ultimately improving the seed yield.

中文翻译：

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全田秸秆覆盖施肥优化根冠结构提高大豆种子产量——以黄淮海地区为例


提高大豆种子产量、获取更多植物油和植物蛋白是保障全球粮食安全的重要举措。黄淮海地区是我国优质高蛋白大豆的主产区。免耕秸秆覆盖播种技术是该地区大豆种植的新模式，可显着提高种子产量。然而，增产机制仍不清楚。采用裂区试验设计，包括播种实践主区和施肥处理子区。研究了土壤容重、土壤含水量、土壤温度、大豆根系形态、叶面积指数、光合特性、冠层透光率、干物质积累及其与种子产量的关系。随着试验年限的增加，秸秆覆盖播种处理表土容重逐渐下降（下降8.63%）。秸秆覆盖稳定了表层土壤温度，特别是避免了表层土壤温度过高（下降1.11℃），有利于土壤保墒（上升11.53%）。秸秆覆盖播种创造了合适的土壤环境，促进了根系生长（即根长、根表面积和根体积），特别是与施肥结合时。秸秆覆盖和施肥均提高了大豆叶面积指数（提高了16.55%）。此外，施肥下大豆叶面积指数在R3-R5时期显着增加，而秸秆覆盖处理在R5-R7时期叶面积指数显着增加。 此外，秸秆覆盖下的净光合持续时间最高（107 d），其次是秸秆粉碎（104 d）和秸秆清除（102 d）。秸秆覆盖处理大豆平均产量为4589.9公斤·公顷，比秸秆清除和秸秆粉碎处理分别增产15.2%和10.3%。与不施肥处理相比，施肥大豆平均产量为4580.2公斤·公顷，增产17.2%。综上所述，在半干旱条件下，秸秆覆盖播种施肥创造了适宜的土壤环境，有利于促进大豆地下和地上生长，最终提高种子产量。