节水减氮对太行山山前平原优质小麦产量品质的影响

The synergistic effects of water-saving and nitrogen reduction on the yield and quality of high-quality wheat in the piedmont plain of the taihang mountains

  • 摘要: 农业集约化下水氮是限制作物产能提升的重要原因, 但大量灌溉使得太行山山前平原区地下水超采严重, 同时氮肥投入过多造成土壤和水体环境承载能力下降, 因此, 优化氮肥和灌溉应用对于提高干旱地区作物产量和品质, 维持生态可持续性具有重要意义。本研究以太行山山前平原区普栽优质强筋冬小麦“藁优2018”为供试品种, 通过设置4个水分处理W0 (无灌溉)、W1 (拔节期)、W2 (拔节期+抽穗期)、W3 (拔节期+抽穗期+灌浆期, 常规灌溉)和3种施氮水平N250 (农民普遍施肥量, N 250 kg ha–1)、N200 (N 200 kg ha–1)、N150 (N 150 kg ha–1)。研究了节水减氮对冬小麦氮素转运、水氮利用效率及品质的影响, 并综合评价各节水减氮措施效果。结果表明: 与常规灌溉相比, 节水处理显著减少产量16.9%~60.7%, 主要是因为穗粒数和千粒重的减少。减氮处理显著增加不同节水处理的平均地上部生物量(2.5%~21.6%)和收获指数(3.0%~16.0%), 节水处理显著增加营养器官氮素转移率(10.1%~51.2%)和氮素转移量对籽粒的贡献率(9.6%~131.8%), 最终增加了籽粒粗蛋白含量(10.9%~36.3%), 但显著减少总蛋白含量(7.6%~46.5%)。减少灌溉量越多, 籽粒粗蛋白含量增加越多, 但总蛋白含量减少越多。与N250相比, N150和N200减少籽粒粗蛋白含量(0.6%和2.5%), 但显著增加总蛋白含量(6.2%和8.3%)。与W3相比, 节水处理显著减少氮利用效率(18.8%~61.0%)和氮肥偏生产力(16.7%~60.3%), 但显著增加产量(3.1%~38.2%)和生物量水分利用效率(41.85%~93.4%)。产量与氮利用效率、总蛋白含量、千粒重、氮肥偏生产力呈显著正相关。氮转运量对籽粒的贡献率与籽粒粗蛋白含量, WUEy和WUEbm呈显著正相关。综合分析得出W3N150得分最高(2.94), 且各灌溉处理平均得分差异显著, 施氮处理差异不显著。因此, 节水处理可视为该地区主要限制因素, 减氮处理可作为主要的减量措施, 对该地区“双减”策略有重要指导意义。

     

    Abstract: Under agricultural intensification, excessive inputs of water and nitrogen fertilizers have led to severe over-extraction of groundwater in the piedmont plain of the taihang mountains, resulting in a decline in the environmental carrying capacity of soil and other resources. Identifying the primary limiting factors of water and nitrogen in this region and optimizing the application of nitrogen fertilizers and irrigation are key strategies for improving crop yield and quality, as well as enhancing resource use efficiency in arid areas. This study focused on the widely cultivated high-quality strong-gluten winter wheat variety ‘Gaoyou 2018’ in the piedmont plain of the taihang mountains. Four water treatments (W0, W1, W2, W3, with each increment adding 75 mm of water at the jointing, heading, and filling stages) and three nitrogen treatments (N250: conventional farmer practice, 250 kg N ha-1; N200: 20% reduction; N150: 40% reduction) were established to investigate the effects of water-saving and nitrogen reduction on nitrogen translocation, water and nitrogen use efficiency, and grain quality in winter wheat. The results showed that compared to conventional irrigation, water-saving treatments significantly reduced yield by 16.9%~60.7%, primarily due to decreases in grain number per spike and thousand grain weight. Nitrogen reduction treatments significantly increased the average aboveground biomass (2.5%-21.6%) and harvest index (3.0%~16.0%) across different water-saving treatments. Water-saving treatments significantly enhanced nitrogen transfer rate in vegetative organs (10.1%-51.2%) and the contribution rate of nitrogen transfer amount to grain nitrogen (9.6%-131.8%), ultimately increasing grain protein content (10.9%-36.3%) but significantly reducing total protein content (7.6%-46.5%). Greater reductions in irrigation led to higher grain protein content but lower total protein content. Compared to N250, N150 and N200 reduced grain protein content (0.6% and 2.5%) but significantly increased total protein content (6.2% and 8.3%). Compared to W3, water-saving treatments significantly reduced nitrogen use efficiency (18.8%-61.0%) and nitrogen partial factor productivity (16.7%-60.3%) but significantly increased yield (3.1%-38.2%) and water productivity at the biomass level (41.85%-93.4%). Yield was significantly positively correlated with nitrogen use efficiency, total protein content, thousand grain weight, and nitrogen partial factor productivity. The contribution rate of nitrogen transfer amount to grain nitrogen was significantly positively correlated with grain protein content, water use efficiency at yield level (WUEy), and water use efficiency at the biomass level (WUEbm). Comprehensive analysis revealed that the W3N150 treatment scored the highest (2.94), with significant differences among irrigation treatments but no significant differences among nitrogen treatments. Therefore, water-saving treatments can be considered the primary limiting factor in this region, while nitrogen reduction treatments serve as a key strategy for reducing inputs, providing important guidance for dual-reduction strategies in the area.

     

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