切根和施氮对退化羊草草地土壤理化性质的影响

Effects of Cutting Root and Nitrogen Application on Soil Physical and Chemical Properties of Degraded Leymus chinensis Grassland

通过切根施氮在松嫩退化羊草草地开展连续2年的二裂式裂区试验。结果表明,井字型切根(Q40)较条形切根方式(Q20)显著降低了土壤容重。切根条件下,施氮处理显著提高土壤全氮和有机质。在所有切根施氮组合中,组合Q40N4(井字型切根宽度40cm方式下施氮4kg·亩^(-1))产量为310.91±10.623g·m^(-2),显著高于对照及其他处理,其中Q40N2处理的产量最少,为208.10±14.326g·m^(-2)。相关性分析和典范对应分析(CCA)表明,土壤理化因子对草地生物量的实际贡献仅为34.23%。经蒙特卡罗置换检验表明,这种解释是可信的,且磷(P)元素是显著影响该区域草地全年产量的主要土壤限制因子。因此,在提高该区域羊草草地生物量方面,建议加大对磷肥的使用量,解除该区域草地土壤存在的长期磷限制,以获得较高的草地生物量。

A two-year splitting plot test was conducted in the Songnen degraded Leymus chinensis grassland by cutting roots and applying nitrogen.The results showed that T-shaped root cutting(Q40)significantly reduced soil bulk density compared to the strip-shaped cutting method(Q20).Under the condition of root cutting,nitrogen application significantly increased soil total nitrogen and organic matter.The yield of Q40N4 was 310.91+10.623 g·m-2,which was significantly higher than that of the control and other treatments.The yield of Q40N2 was 208.10+14.326 g·m-2.Correlation and canonical correspondence analysis(CCA)showed that the actual contribution of soil physical and chemical factors to grassland biomass was only 34.23%.Monte Carlo substitution test showed that this explanation was credible,and P was the main soil limiting factor significantly affecting the annual yield of grassland in the region.Therefore,it is suggested to increase the use of phosphate fertilizer and remove the long-term P limitation of grassland soil in this region to obtain higher grassland biomass.