Effects of N, P, and K Fertilizer Application on Cotton Growing in Saline Soil in Yellow River Delta

This study aimed at guiding fertilizer management for Bt cotton cultivar SCRC28 growing in coastal saline soil in the Yellow River Delta area in Shandong Province, China. SCRC28 was planted in the soils with high, middle, and low salinity under 3 fertilizer treatments, namely control (no fertilizers), NPK, NP, and NK. The effects of different fertilization treatments on nutrient assimilation, Na+ assimilation, net photosynthetic rate (Pn), dry matter accumulation, and lint yield of Bt cotton were investigated. Compared to the corresponding controls, the NP and NPK treatments had significantly higher nutrient uptake levels in plants in the 3 types of saline soils, and significantly lower levels of Na+ uptake, especially the NPK treatment. The nutrient use efficiencies in agronomy of cotton in the NPK treatment were the highest among treatments regardless the salinity level. The N use efficiencies in agronomy were 0.20, 1.95, and 2.07 kg lint kg−1 under the low, middle, and high salinity level, respectively; the P use efficiencies in agronomy were 0.87, 8.35, and 8.71 kg lint kg−1, respectively; and the K use efficiencies in agronomy were 0.26, 2.89, and 3.77 kg lint kg−1, respectively. The NPK treatment also maintained the highest levels of leaf area, chlorophyll content, and Pn among fertilization treatments in the 3 types of saline soils. The NPK treatment obtained the highest biomass and lint yield among the treatments, and the link yields were enhanced, compared to the corresponding controls, by 2.53%, 28.67%, and 30.47% in the low, middle, and high salinity soils, respectively. The effect of fertilization was obviously in the middle or high salinity fields. In this study, the fertilization quantities were based on the salinity level of soil. The NPK treatments were applied with N 165 kg ha−1 plus P2O5 38.57 kg ha−1 plus K2O 111.5 kg ha−1 in the middle salinity soil and N 135 kg ha−1 plus P2O5 32.14 kg ha−1 plus K2O 74.35 kg ha−1 in the high salinity soil. Therefore, rational fertilization schemes are recommended according to the salinity level of soil in order to alleviate nutrition obstacles and improve cotton nutrition, which ultimately result in the increases of nutrient use efficiencies in agronomy and cotton yield.

摘 要为探讨盐渍土抗虫棉施用氮(N)、磷(P)、钾(K)肥的效应及其营养生理机制, 指导滨海盐渍土抗虫棉合理施肥, 在黄河三角洲盐渍土低、中、高盐棉田种植转Bt基因抗虫棉鲁棉研28, 研究N、P、K肥配合施用对其养分吸收利用、Na+吸收积累、光合速率、干物质积累和产量的影响。结果表明, N、P肥配合, 尤其是N、P、K肥配合施用显著增加了低、中、高盐田棉花的N、P、K养分吸收量, 减少了Na+吸收积累量。低、中、高盐田棉花的N、P、K养分农学利用效率均以N、P、K配施的处理较高, 氮养分农学利用效率分别为0.20、1.95和2.07 kg皮棉 kg–1 N, 磷养分农学利用效率分别为0.87、8.35和8.71 kg皮棉 kg–1 P, 钾养分农学利用效率分别为0.26、2.89和3.77 kg皮棉 kg–1 K。N、P、K肥配合施用还维持了较高的棉株叶面积、叶绿素含量和净光合速率。低、中、高盐田棉花的生物产量和皮棉产量也均以N、P、K配施的处理较高, 皮棉产量分别增产2.53%、28.67%和30.47%。中、高盐棉田的施肥效应明显好于低盐棉田。表明根据盐碱程度分类合理施肥是减轻盐渍土营养障碍、改善棉花营养、提高养分农学利用效率和棉花产量的有效途径。