Two-year experiments were conducted to assess the responses of yield and nutrient use efficiency of sorghum to nitrogen and phosphorus under saline soils. Three nitrogen rates (0, 180, and 360 N kg ha−1) and three phosphorus rates (0, 60, and 120 P2O5 kg ha−1) were used in this study. Our results showed that nitrogen and phosphorus supply increased SPAD (leaf greenness, 5.0–29.1%), NSC (non-structural carbohydrates, 14.0–41.2%), nutrient accumulation (nitrogen: 14.1–50.0%, phosphorus: 11.8–41.5%, potassium: 13.7–28.2%), biomass (fresh: 10.8–29.3%, dry: 5.0–22.8%), yield (16.6–30.7%), and harvest index (2.0–9.8%) of sorghum at the maturity stage grown in saline soils but significantly decreased nutrient use efficiency. Combined application showed better performance on these attributes than sole nitrogen and sole phosphorus. The highest seed yield (5919 kg ha−1) was recorded at 180 N kg ha−1 and 60 P2O5 kg ha−1 treatment, while the largest value of dry biomass (18,401 kg ha−1) was obtained at 360 N kg ha−1 and 120 P2O5 kg ha−1 treatment. The Pearson analysis showed that seed yield had the highest correlation with aerial potassium accumulation, while dry biomass had the highest correlation with NSC as well as aerial nitrogen accumulation. A treatment of 180 N kg ha−1 and 60 P2O5 kg ha−1 was recommended to be used in sorghum production in saline soils based on harvest index and nutrient use efficiency.
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机译：进行了为期两年的试验，以评估盐渍土壤下高粱产量和养分利用效率对氮和磷的响应。本研究使用了三种氮用量（0、180 和 360 N kg ha-1）和三种磷用量（0、60 和 120 P2O5 kg ha-1）。我们的结果表明，氮和磷供应增加了盐渍土壤中生长的高粱成熟阶段的 SPAD（叶绿度，5.0-29.1%）、NSC（非结构性碳水化合物，14.0-41.2%）、养分积累（氮：14.1-50.0%、磷：11.8-41.5%、钾：13.7-28.2%）、生物量（新鲜：10.8-29.3%，干燥：5.0-22.8%）、产量（16.6-30.7%）和收获指数（2.0-9.8%），但显著降低了养分利用效率。联合施用在这些属性上显示出比单独氮和单独磷更好的性能。在 180 N kg ha-1 和 60 P2O5 kg ha-1 处理下记录了最高的种子产量（5919 kg ha-1），而在 360 N kg ha-1 和 120 P2O5 kg ha-1 处理下获得了最大的干生物量值（18,401 kg ha-1）。Pearson 分析显示，种子产量与空气中钾积累的相关性最高，而干生物量与 NSC 和空气氮积累的相关性最高。根据收获指数和养分利用效率，建议将 180 N kg ha-1 和 60 P2O5 kg ha-1 的处理用于盐碱土壤中的高粱生产。
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