施磷量对盐碱地柳枝稷生长及土壤养分的影响

Effects of phosphorus application rate on switchgrass growth and soil nutrients in saline-alkali soil

【目的】研究施磷量对盐碱地柳枝稷生长及土壤养分的影响,以期确定适宜的施磷量,为宁夏银北盐碱地区盐碱土壤改良和柳枝稷高产高效栽培提供理论依据。【方法】在宁夏银北地区,以能源作物柳枝稷为材料,通过田间试验,设置0、30、90 kg/hm^(2) 3个磷肥施用量(分别用P0、P30、P90表示),研究不同处理对柳枝稷生长、土壤盐碱含量及养分吸收利用的影响。【结果】在柳枝稷成熟期,各处理0~100 cm土层土壤盐碱含量均表现为P0>P30>P90,土壤有机质、有效磷和碱解氮含量均为P90>P30>P0,与P0相比,P90处理显著降低了土壤盐碱含量、提高了养分含量。施磷有助于柳枝稷生长,促进植株对氮素及磷素的吸收利用,提高地上部干物质积累。3种施磷水平下,土壤氮素收支平衡均为亏缺状态,土壤磷素收支平衡仅在P90处理下表现为盈余。【结论】在本试验条件下,施磷量为90 kg/hm^(2)既能保证柳枝稷生长良好、获得较高的生物质产量,又能缓解盐碱压力,改善土壤养分状况并维持合理的氮、磷素收支平衡。

【Objective】The present paper aimed to the effects of phosphorus application rate on switchgrass growth and soil nutrients in saline-alkali soil, in order to determine the appropriate amount of phosphorus, which provided a theoretical basis for saline-alkali soil improvement and high yield and high efficiency cultivation of switchgrass in Yinbei area of Ningxia.【Method】In Yinbei area of Ningxia, switchgrass, an energy crop, was used as material to study the effects of different treatments on the growth, soil saline-alkali content and nutrient absorption and utilization of switchgrass by setting 0,30 and 90 kg/hmof phosphorus fertilizer(expressed as P0, P30 and P90, respectively) through field experiments.【Result】At the mature stage of switchgrass, the soil salinity and alkali content in 0-100 cm soil layer of each treatment were all P0>P30>P90, and the soil organic matter, available phosphorus and alkali-hydrolyzable nitrogen contents were all P90>P30>P0. Compared with P0, P90 treatment significantly reduced the soil salinity and alkali content and increased the nutrient content. Phosphorus application contributes to the growth of switchgrass, which promoted the absorption and utilization of nitrogen and phosphorus, and improved the accumulation of aboveground dry matter. Under three phosphorus levels, soil nitrogen balance of payments were deficit, and soil phosphorus balance was surplus only under P90 treatment.【Conclusion】The comprehensive results showed that under the conditions of this experiment, 90 kg/hm^(2) P application rate could not only ensure the good growth of switchgrass and obtain high biomass yield, but also alleviate the saline-alkali pressure, improve the soil nutrient status and maintain a reasonable balance of nitrogen and phosphorus.