土壤水分和养分是影响作物生长的关键因素,合理的水肥搭配不仅能够改善土壤养分供给状况,还能使作物高产稳产。为进一步研究水氮调控对春小麦土壤、叶片养分含量及化学计量比和产量的影响,以陇中黄土高原旱地春小麦为研究对象,采用野外采样与室内实验相结合的方法,分析了不同灌水量（W₁：50 mm、W₂：100 mm、W₃：150 mm、W₄：200 mm）和不同施氮量（N₁：62.5 kg·hm^-2、N₂：102.5 kg·hm^-2、N₃：152.5 kg·hm^-2）下土壤、叶片有机碳（OC）、全氮（TN）、全磷（TP）含量的变化特征及土壤、叶片养分含量和产量间相关关系。结果表明：（1） 土壤OC、TN、TP含量均随土层深度增加逐层降低。土壤OC、TN含量均随灌水量和施氮量增加呈先增后降的趋势,在W₃N₂处理下达到最大值;而土壤TP含量变化不大。C:N、C:P、N:P变化范围分别为5.81~8.24、8.35~13.75、1.23~1.95,均小于全国平均值。（2） 春小麦成熟期叶片TN含量随灌水量增加呈先增后降的趋势,随施氮量增加呈逐渐增加的趋势,在W₃N₂处理下达到最大值;而OC、TP含量变化不大。（3） 春小麦穗数、穗粒数均随灌水增加呈先增后降的趋势,随施氮量增加呈逐渐增加的趋势;千粒重、产量均随灌水量和施氮量增加呈先增后降的趋势,且在W₃N₂处理下达到最大值,说明W₃N₂是最优于春小麦生长发育的水氮耦合模式。（4） 相关性分析表明,春小麦产量与土壤、叶片养分含量之间有显著相关关系,可通过改变水肥供应状况进而提升产量。综上所述,灌水量和施氮量控制在W₃（150 mm）、N₂（102.5 kg·hm^-2）水平下可满足春小麦生长过程中对养分含量的需求,进而提高产量,是符合当地生产条件的较优水氮组合。

Soil moisture and nutrients are deemed as key factors affecting crop growth. A reasonable combination of water and fertilizer can improve the soil nutrient status and lead to high and stable crop yield. In this study, spring wheat in the dryland of the Loess Plateau in Central Gansu Province was examined by combining field sampling with an indoor experiment to further clarify the response mechanism of water and nitrogen regulation in soil, leaf nutrient content, stoichiometry ratio, and yield of spring wheat. Various characteristics of soil and leaf carbon (OC), nitrogen (TN), and phosphorus (TP) contents under different irrigation rates (W₁: 50 mm; W₂: 100 mm; W₃: 150 mm; W₄: 200 mm) and nitrogen application rates (N₁: 62.5 kg·hm^-2; N₂: 102.5 kg·hm^-2; N₃: 152.5 kg·hm^-2) were analyzed, and the correlation between soil and leaf nutrient contents and yield was examined. Results show that (1) the OC, TN, and TP contents decreased as soil depth increased. The OC and TN contents in soil initially increased and subsequently decreased as the amounts of irrigation and nitrogen application increased. Their maximum values were obtained under the W₃N₂ treatment. By comparison, the TP content of soil did not change remarkably. The ranges of C:N, C:P, and N:P were 5.81-8.24, 8.35-13.75, and 1.23-1.95, respectively, which were less than the national average. (2) The TN content of spring wheat leaves at the mature stage increased first and then decreased as the amount of irrigation increased. It gradually increased as the nitrogen application rate increased, reaching the maximum under the W₃N₂ treatment. Conversely, the OC and TP contents did not vary considerably. (3) The number of spikes and the number of grains per spike of spring wheat increased initially and decreased subsequently as the amount of irrigation increased. They gradually increased as the nitrogen application rate increased. Similarly, the 1000-grain weight and yield increased first and then decreased as the amounts of irrigation and nitrogen application increased. Their maximum values were observed in the W₃N₂ treatment, suggesting that W₃N₂ was the best water nitrogen coupling model for the growth and development of spring wheat. (4) Correlation analysis showed that spring wheat yield was significantly correlated with soil and leaf nutrient contents, which could be improved by changing the water and fertilizer supply. In conclusion, the amounts of irrigation and nitrogen application controlled at W₃ (150 mm) and N₂ (102.5 kg·hm^-2) levels, which were a better combination of water and nitrogen in line with local production conditions, could satisfy the demand for the nutrient content of spring wheat during growth. Thus, its yield could be improved.