Abstract The annual double cropping of winter wheat and summer maize plays an important role in ensuring the food supply in the North China Plain (NCP). With the intensifying water shortage, a deficit irrigation strategy has been gradually applied to this cropping system. The limited irrigation water supply generally results in a dry root zone soil profile at winter wheat harvesting which further negatively affects the grain production of its following crop, summer maize. Field studies from 2016 to 2019 at a typical site in the NCP (Luancheng Agro-experimental station) were undertaken to examine the effects of different irrigation schedules during the winter wheat season on summer maize production, and water conservation techniques that might benefit maize production under a limited water supply. The results indicated that soil water contents at maize sowing played an important role in deciding the final maize yield. Under the recommended winter wheat deficit irrigation schedule for this region, the yield of maize would be reduced by 22–32% compared to the maize following the full irrigation schedule. Water deficits mainly occurred during the earlier growth stage of maize, before the rainfall season. Reducing water consumption during the earlier growth stages of maize was important for prolonging the soil water availability for crop growth from the irrigation at maize sowing. Due to the smaller canopy cover at the earlier maize growth stages, using straw from the winter wheat to fully cover the soil surface was an active measure to preserve soil moisture, and the maize yield under mulch was increased by 10–25%, while the water use efficiency (WUE) was increased by 5–25%. Under a limited water supply, reducing planting density by 11% over the normal density could reduce crop water use during the vegetative stage and increase crop water use during the reproductive stage, which increased grain production and water productivity. The reduced density also decreased the production cost. These results indicate that measures to preserve soil water during the vegetative growth stages of maize would benefit grain production under limited water supply conditions in the NCP.

中文翻译：

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影响夏玉米产量和水分生产力的播前土壤水分条件及保水措施

摘要 冬小麦、夏玉米一年两季对保障华北平原粮食供应具有重要作用。随着水资源短缺的加剧，亏缺灌溉策略已逐渐应用于这种种植系统。有限的灌溉水供应通常导致冬小麦收获时根区土壤干燥，这进一步对其下一季作物夏玉米的粮食生产产生负面影响。2016 年至 2019 年在 NCP 典型地点（栾城农业试验站）进行了田间研究，以研究冬小麦季节不同灌溉计划对夏玉米生产的影响，以及可能有利于玉米生产的节水技术。有限的供水。结果表明，玉米播种时土壤含水量对玉米的最终产量起着重要的决定作用。在该地区推荐的冬小麦亏缺灌溉计划下，与完全灌溉计划后的玉米相比，玉米的产量将减少 22-32%。水分亏缺主要发生在玉米生长早期，即雨季之前。减少玉米早期生长阶段的耗水量对于延长玉米播种时灌溉对作物生长的土壤水分供应很重要。由于早期玉米生长阶段冠层盖度较小，利用冬小麦秸秆充分覆盖土壤表面是保持土壤水分的积极措施，地膜下玉米产量提高了10-25%，而用水效率 (WUE) 提高了 5-25%。在有限的供水条件下，种植密度比正常密度降低11%，可以减少作物营养阶段的用水量，增加作物生殖阶段的用水量，从而提高粮食产量和水分生产率。降低的密度也降低了生产成本。这些结果表明，在 NCP 有限供水条件下，在玉米营养生长阶段保持土壤水分的措施将有利于粮食生产。降低的密度也降低了生产成本。这些结果表明，在 NCP 有限供水条件下，在玉米营养生长阶段保持土壤水分的措施将有利于粮食生产。降低的密度也降低了生产成本。这些结果表明，在 NCP 有限供水条件下，在玉米营养生长阶段保持土壤水分的措施将有利于粮食生产。