黄土丘陵区不同恢复年限退耕林地土壤碳氮差异及其影响因素

发布时间：2018-07-05 15:55

本文选题：黄土丘陵区 + 退耕年限　；参考：《西北农林科技大学学报(自然科学版)》2017年06期

【摘要】：【目的】研究黄土丘陵区不同退耕年限林地有机碳及全氮的差异性,分析全氮及有机碳与环境和土壤因子的关系,为该区域生态恢复与土壤质量评价提供科学参考。【方法】结合野外调查和室内分析,运用统计分析及冗余分析方法(RDA),以耕地(CL)为对照,对黄土丘陵区退耕种植25,35,40年的柠条(Caragana korshinskii Lam.,CK)、刺槐(Robinia pseudoacacia L.,RP)林地(以下分别用CK25a、CK35a、CK40a、RP25a、RP35a、RP40a表示)为研究对象,分别采集各样地0~10,10~20,20~30cm土层的土样,研究0~30cm土层有机碳、全氮含量及有机碳密度、全氮密度、微生物生物量碳、微生物生物量氮随退耕年限的变化特征,最后分析了土壤有机碳、全氮含量及有机碳密度、全氮密度与环境因子、土壤因子的关系。【结果】与耕地相比,不同退耕年限刺槐、柠条林地0~30cm土层土壤有机碳、全氮、微生物生物量碳、微生物生物量氮含量及有机碳密度、全氮密度显著增加,在0~30cm土层,有机碳、全氮、微生物生物量碳和微生物生物量氮含量由大到小依次为RP40aRP35aRP25aCL;有机碳密度从高到低依次为CK35aCK40aCK25aCL;全氮密度由大到小依次是CK35aCK25aCK40aCL。对于不同退耕年限的刺槐和柠条林地,环境因子中的植被盖度、退耕年限、坡度均与土壤有机碳、全氮及有机碳密度、全氮密度呈正相关,坡向、海拔、土壤体积质量、pH均与其呈负相关。而土壤因子中的微生物生物量碳、微生物生物量氮、总孔隙度均与有机碳、全氮及有机碳密度、全氮密度呈正相关,土壤体积质量、pH均与其呈负相关。【结论】土壤有机碳及全氮含量变化与退耕年限、植被盖度、坡度及土壤因子存在密切关系,且植被恢复使土壤质量得到了极大改良。
[Abstract]:[Objective] to study the difference of organic carbon and total nitrogen in forest land in the loess hilly area, analyze the relationship between total nitrogen and organic carbon with environment and soil factors, and provide scientific reference for the ecological restoration and soil quality evaluation in this region. [method] combined with field investigation and indoor analysis, the method of statistical analysis and redundancy analysis (RDA Taking cultivated land (CL) as the control, the cultivated land (Caragana korshinskii Lam., CK) and Robinia pseudoacacia (Robinia pseudoacacia L., RP) for 25,35,40 years were planted in the Loess Hilly Region for the study of the soil samples of the soil layer, respectively. Carbon, total nitrogen and organic carbon density, total nitrogen density, microbial biomass carbon, microbial biomass nitrogen with the change of the years of tillage, and finally analyzed soil organic carbon, total nitrogen content and organic carbon density, total nitrogen density and environmental factors, soil factors. Compared with cultivated land, different years of cultivated locust, Caragana woodland 0~30cm soil layer soil organic carbon, total nitrogen, microbial biomass carbon, microbial biomass nitrogen content and organic carbon density, total nitrogen density significantly increased, in the 0~30cm soil layer, organic carbon, total nitrogen, microbial biomass carbon and microbial biomass nitrogen content from large to small in turn is RP40aRP35aRP25aCL, organic carbon density from high to low to CK35aCK40aCK in turn to be CK35aCK40aCK 25aCL, the total nitrogen density from large to small is CK35aCK25aCK40aCL. for Robinia pseudoacacia and Caragana woodland with different years of cultivated land, the vegetation coverage in the environmental factors, the years of cultivation, the slope are all positively correlated with soil organic carbon, total nitrogen and organic carbon density, total nitrogen density, slope direction, sea pull, soil volume quality, and pH are negatively correlated. Microbial biomass carbon, microbial biomass nitrogen and total porosity were positively correlated with organic carbon, total nitrogen and organic carbon density, total nitrogen density, soil volume quality and pH. [Conclusion] the change of soil organic carbon and total nitrogen content is closely related to the years of tillage, vegetation coverage, slope and soil factors. The restoration of the soil has greatly improved the quality of the soil.
【作者单位】：西北农林科技大学农学院;陕西省循环农业工程技术研究中心;
【基金】：国家自然科学基金项目(41301601) 国家林业公益性行业科研专项(201304312)
【分类号】：S714

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