Abstract Nitrogen (N) and sulfur (S) critical dilution curves and the N:S stoichiometry are useful tools for evaluating nutrient status in maize (Zea mays L.). Nutrient supply for both N and S impact plant nutrient uptake, consequently influencing the overall performance of fertilization diagnostic tools. Interaction between these nutrients has not been studied relative to their nutrient use efficiencies (NUE and SUE), agronomic efficiencies (NAE and SAE), and components of these. The aim of this study was to analyze the effect of N and S fertilization on: i) N and S uptake (NU and SU) dynamics, ii) N and S dilution curves, iii) N:S stoichiometry, and iv) NUE, SUE, NAE, SAE, and their components in maize. Five maize field trials were conducted evaluating the effect of N and S fertilization with two levels for each nutrient (unfertilized and fertilized). Maize shoot biomass and its N and S concentrations were measured from six-leaf to physiological maturity. The main outcomes of this study were: i) averaged across sites, N fertilization increased yield by 41% and S fertilization by 10%; ii) SU was delayed relative to NU; iii) S fertilization increased shoot S concentration when N was not limiting; iv) N dilution curve was not affected by S supply; v) N:S ratio decreased with increasing shoot biomass and varied with N and S supply; vi) N fertilization improved SUE and SAE via greater S recovery, with a similar S fertilization effect on NUE and NAE. This study demonstrated that both the critical S dilution curve and N:S stoichiometry are useful tools to characterize S status when N is not deficient. Simultaneous N and S management is critical for increasing their use efficiencies, improving crop productivity, and reducing environmental footprint.

中文翻译：

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氮和硫相互作用对玉米养分利用效率和诊断工具的影响

摘要 氮 (N) 和硫 (S) 临界稀释曲线以及 N:S 化学计量是评估玉米 (Zea mays L.) 营养状况的有用工具。N 和 S 的养分供应影响植物养分吸收，从而影响施肥诊断工具的整体性能。这些养分之间的相互作用尚未研究过它们的养分利用效率（NUE 和 SUE）、农艺效率（NAE 和 SAE）及其组成部分。本研究的目的是分析 N 和 S 施肥对以下方面的影响：i) N 和 S 吸收（NU 和 SU）动力学，ii) N 和 S 稀释曲线，iii) N:S 化学计量，以及 iv) NUE， SUE、NAE、SAE 及其在玉米中的成分。进行了五次玉米田间试验，以每种养分（未施肥和已施肥）的两个水平评估 N 和 S 施肥的效果。测量了从六叶到生理成熟期的玉米芽生物量及其 N 和 S 浓度。本研究的主要结果是：i) 平均而言，施氮使产量增加 41%，施硫增加 10%；ii) SU 相对于 NU 延迟；iii) 当氮不受限制时，施硫增加了芽中的硫浓度；iv) N 稀释曲线不受 S 供应的影响；v) N:S 比率随着地上部生物量的增加而降低，并随着 N 和 S 的供应而变化；vi) 施氮通过更大的硫回收改善了 SUE 和 SAE，施肥对 NUE 和 NAE 的影响相似。该研究表明，临界 S 稀释曲线和 N：当 N 不缺乏时，S 化学计量学是表征 S 状态的有用工具。同时进行氮和硫管理对于提高其使用效率、提高作物生产力和减少环境足迹至关重要。