施氮量对柳枝稷生物质产量和水肥利用特性的影响

在黄土高原半干旱地区,以能源作物柳枝稷为材料,通过田间试验,研究不同施氮量(0、60、120和240kg/hm2)对柳枝稷生物质生产和水氮利用效率的影响。结果表明:施氮显著提高柳枝稷生物质产量,当施氮量为120kg/hm2时柳枝稷生物质产量最高;施氮显著增加柳枝稷耗水量,在一定程度上降低土壤含水量,但显著提高水分利用效率;施氮显著提高柳枝稷生物质中氮质量分数和吸氮量,但施氮量超过120kg/hm2后,继续增加施氮量则不能显著增加植株对氮素的吸收积累;柳枝稷氮肥利用效率随氮肥用量增加而降低。可见,施氮量60~120kg/hm2既能保证柳枝稷较高的生物质产量,又能保证较高的水分利用效率和氮肥利用效率。

Effect of Nitrogen Rate on Biomass Yield, Water and Fertilizer Utilization Characteristics of Switchgrass

The field trials were conducted to investigate the influence of nitrogen application rate on biomass production and water and nitrogen use efficiency of energy crop switchgrass in semi-arid areas of the Loess Plateau. The treatments included four nitrogen fertilizer rates, respectively: N0 (0 kg/hm), N60 (60 kg/hm), N120 (120 kg/hm) and N240 (240 kg/hm). The results showed that nitrogen application significantly improved the biomass yield of switchgrass, and the highest biomass yield were observed in N application treatment of 120 kg/hm. Nitrogen application significantly increased switchgrass evapotranspiration, and reduced soil moisture to some extent, but significantly improved water use efficiency. Within the range of 0-120 kg/hm N fertilizer level, nitrogen concentration and N uptake of switchgrass plant significantly increased, but no significant increase in nitrogen absorption and accumulation were found with more N application. Nitrogen use efficiency of switchgrass reduced with the increase of nitrogen application rate. Under the experimental condition, the nitrogen application rate between 60 kg/hm and 120 kg/hm could maintain higher biomass yield, higher water use efficiency and higher nitrogen use efficiency.