水分养分协同对冬小麦干物质运转和氮吸收利用的影响

【目的】 研究水分养分协同对冬小麦光合产物运转和氮素吸收利用的调控效应，旨在寻求提高冬小麦水肥利用效率的途径。 【方法】 采用防雨棚下测坑试验方法，于2015和2016年在黄淮海平原河南新乡连续进行了2 年田间试验。试验采用二因子 (土壤水分调亏度和施肥水平) 随机区组设计。3个土壤水分调亏度为轻度调亏、中度调亏和重度调亏，相对含水量分别为田间持水量的60%～65%、50%～55%和40%～45%；3个施肥水平为高施肥水平 (N 240 kg/hm2、P₂O₅ 240 kg/hm2、K₂O 240 kg/hm2)，中等施肥水平 (N 180 kg/hm2、P₂O₅ 180 kg/hm2、K₂O 180 kg/hm2) 和低施肥水平 (N 120 kg/hm2、P₂O₅ 120 kg/hm2、K₂O 120 kg/hm2)。共9个水肥组合，三次重复。利用氮同位素示踪技术研究不同水肥组合对植株氮吸收、分配与利用的影响。 【结果】 在高施肥水平下，中度水分调亏 (50%～55%) 可促进小麦营养器官花前贮藏物质向籽粒再运转；在中等施肥水平下，叶片花前贮藏同化物再运转量以轻度水分调亏为最高；在低施肥水平下，各营养器官花前贮藏同化物再运转量和再运转率随水分调亏度加重呈提高趋势。不同施肥水平下营养器官花前贮藏同化物总运转量对籽粒产量的贡献率随水分调亏度加重呈提高趋势。 【结论】 水分调亏提高了籽粒中来自花前营养器官贮藏物质转运的比例。水分调亏与养分调节相结合可有效调控小麦植株对肥料氮的吸收、积累和利用。低施肥水平 (N 120、P₂O₅ 120、K₂O 120 kg/hm2) 和轻度水分调亏 (60%～65%田间持水量) 组合是本试验条件下节水减肥高产高效方案。

Interactive effects of water and fertilization on biomass translocation and nitrogen uptake and utilization of winter wheat

【Objectives】 In order to improve water and nitrogen use efficiencies of winter wheat, a research was conducted to examine photosynthetic partitioning and translocation in plant organs as well as the nitrogen uptake under different water–nitrogen levels. 【Methods】 A field experiment was conducted for two years in Xinxiang City, Henan Province. Water supply was regulated as light, moderate and severe deficit levels, with corresponding water contents of 60%–65%, 50%–55%, and 40%–45% of the field capacity. Nutrient input levels were setup as high (N 240 kg/hm2, P₂O₅ 240 kg/hm2, K₂O 240 kg/hm2), middle (N 180 kg/hm2, P₂O₅ 180 kg/hm2, K₂O 180 kg/hm2) and low (N 120 kg/hm2, P₂O₅ 120 kg/hm2, K₂O 120 kg/hm2), respectively. Labeled 15N method was used to analyze the uptake, utilization and distribution of nitrogen in wheat plants as affected by water and fertilizer treatments. 【Results】 A moderate level of water deficit could increase the remobilization of nitrogen from pre-anthesis reserves in vegetative organs to the grains under high fertilizer rate. The transfer amount of the pre-anthesis reserves for the light water deficit was the largest under middle nutrient input level. Under low fertilization level, the transfer rate and amount of pre-anthesis reserves in vegetative organs increased with the increase of the water deficit. Under all the three levels of fertilization, the contribution rates of the transfer amount from pre-anthesis reserves to grain yield increased with the increase of water deficit. 【Conclusions】 The deficit irrigation could improve the redistribution of nitrogen and dry matter stored in vegetative organs before anthesis. The coupling of the deficit irrigation and fertilization could effectively control the nitrogen uptake and accumulation of winter wheat. The low N–P₂O₅–K₂O rate (120–120–120 kg/hm2) and light water deficit (60%–65% of field water capacity) is the optimum scheme for saving water and fertilizer, and achieving high yield and high efficiency under the experimental condition.