| 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0~10，10~20，20~30 cm土层的土样，研究0~30 cm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0~30 cm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0~30 cm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RP40a＞RP35a＞RP25a＞CL；有机碳密度从高到低依次为CK35a＞CK40a＞CK25a＞CL；全氮密度由大到小依次是CK35a＞CK25a＞CK40a＞CL。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。 |
| 关键词: 黄土丘陵区 退耕年限 退耕林地 环境因子 土壤有机碳 土壤全氮 |
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| 基金项目: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) |
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| Differences in soil carbon and nitrogen and the influencing factors in abandoned cultivated lands for different years in Loess Hilly Area |
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WU Jianping,HAN Xinhui,REN Chengjie,et al
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| Abstract: |
| 【Objective】This study investigated the differences in soil organic carbon and total nitrogen in abandoned cultivated lands after different years and analyzed their relationship with environmental and soil factors to provide reference for ecological restoration and soil quality evaluation in Loess Hilly Area.【Method】Taking crop land (CL) as contrast,soil samples in Caragana korshinskii Lam.(CK) and Robinia pseudoacacia L.(RP) abandoned after 25 to 40 years in the Loess Hilly Area (CK25a,CK35a,CK40a,RP25a,RP35a,and RP40a) were collected.Combined with field investigation and laboratory analysis,the characteristics of organic carbon,total nitrogen,soil organic carbon density,total nitrogen density,microbial biomass carbon,and microbial biomass nitrogen at the depths of 0-10, 10-20 and 20-30 cm were investigated using statistical analysis and redundancy analysis (RDA).Their relationships with environmental and soil factors were also analyzed.【Result】Compared with CL land,organic carbon,total nitrogen,microbial biomass carbon,microbial biomass nitrogen content and carbon and nitrogen density in soil layer of 0-30 cm in CK and RP lands increased significantly.Organic carbon,total nitrogen,microbial biomass carbon,and microbial biomass nitrogen were in the order of RP40a＞RP35a＞RP25a＞CL,organic carbon density was in the order of CK35a＞CK40a＞CK25a＞CL and nitrogen density was in the order of CK35a＞CK25a＞CK40a＞CL.Vegetation coverage,slope,and years of restoration had positive relationship with organic carbon,total nitrogen and soil organic carbon density,while total nitrogen density,slope direction,elevation,bulk density and pH were negatively correlated with them.There were positive correlations between microbial biomass carbon and microbial biomass nitrogen,total hole degree and organic carbon,as well as total nitrogen and carbon and nitrogen density,while bulk density and pH were negatively correlated.【Conclusion】The changes in soil organic carbon and total nitrogen had close relationship with vegetation restoration years,environmental factors and soil factors.The soil quality was greatly improved due to vegetation restoration. |
| Key words: Loess Hilly Area restoration years restoration cultivated lands environmental factors soil organic carbon soil total nitrogen |
