【摘要】 应用对比分析和空间代替时间的方法,以黄土高原丘陵沟壑区罗玉沟流域不同恢复年限的人工草地土壤为研究对象,分析土壤碳氮磷含量及其生态化学计量特征的变化,探讨它们与土壤理化性质之间的关系.结果表明,随着恢复年限的增加,人工草地土壤有机碳、全氮和全磷含量均增加,恢复至8年以后有机碳含量保持平稳.人工草地土壤C/N呈先增后减的趋势,变化范围为10.66-13.62,与全国土壤C/N平均水平持平;土壤C/P和N/P呈先增后减再增的趋势,变化范围分别为9.19-13.18和0.82-1.17,均低于全国水平.土壤有机碳、全氮和全磷与土壤含水率、容重、孔隙度和p H值之间呈显著的相关关系(P <0.01),土壤有机碳、全氮和全磷含量间具有显著的正相关性(P <0.01). C/N与全氮含量存在显著负相关关系,与有机碳含量不存在相关性,说明C/N受氮素影响较大;C/P与有机碳含量呈显著正相关(P <0.01),与全磷含量不相关,则说明C/P主要受碳素限制;而N/P与全氮、全磷含量均达到显著正相关(P <0.01),说明N/P由氮素、磷素共同决定.由此可知,氮和磷是该地区主要的限制营养元素;本研究结果可为当地通过合理利用草地恢复方式改善土壤质量和维护草地健康提供理论参考.更多还原

【Abstract】 Using the methods of comparative analysis and substituting temporal serial with spatial serial, we investigated the artificial grassland soil with different recovery years in Luoyugou watershed in the hilly gully region of loess plateau. In particular, we analyzed the content of carbon, nitrogen, and phosphorus and their ecological stoichiometric characteristics and discussed their relationships with soil physical and chemical properties. The results showed that with the increase of restoration years, the content of organic carbon, total nitrogen, and total phosphorus in artificial grassland increased, and the organic carbon content remained stable after eight years. The soil C/N ratio in artificial grassland first showed an increasing trend and then a decreasing trend, and the variation range was 10.66–13.62, which was equal to the national soil C/N average level.The soil C/P and N/P ratios showed an increasing-decreasing-increasing trend, and the ranges of variation were 9.19–13.18 and 0.82–1.17, respectively, which was lower than the corresponding national level. A significant correlation was observed between soil organic carbon, total nitrogen, total phosphorus and soil moisture content, density, porosity, pH. A significant positive correlation was observed between soil organic carbon, total nitrogen, and total phosphorus(P < 0.01). The C/N ratio had a significant negative correlation with total nitrogen, but not with organic carbon(P < 0.01), indicating that it was significantly affected by the total nitrogen content. The C/P ratio was positively correlated with organic carbon, but not with total phosphorus(P < 0.01), indicating that it was mainly controlled by the organic carbon content. The N/P ratio was positively correlated with total nitrogen and total phosphorus(P < 0.01), indicating that it was significantly affected by total N and P content. Therefore, N and P were found to be the main restricted nutrients in this area. Planting artificial grassland not only changes soil structure and nutrient content, but also plays an active role in maintaining soil and water, regulating climate, and so on. It can be used as one of the effective measures for grassland ecological restoration in the Luoyugou Basin.更多还原