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研究植被恢复对土壤碳氮动态的影响,对了解陆地生态系统碳氮循环,应对全球温室效应具有重要意义.本研究以黄土丘陵区不同人工恢复植被为对象,以农田为参照,分析了不同人工植被恢复方式对0~100 cm剖面土壤有机碳(SOC)和全氮(TN)含量影响的差异及其影响因素.结果表明:退耕还林还草显著提高了土壤的SOC和TN含量.退耕后,SOC和TN含量均较农田明显提高.0~100 cm土层SOC平均含量人工乔木林为农田的1.43倍,增幅最大;其次是人工灌木,为1.36倍;最后是人工草地,为1.21倍.0~100 cm土层TN平均含量人工乔木林增幅最大,是农田的1.30倍;其次是人工草地,为1.21倍;而人工灌木增幅最小,为1.13倍.与农田相比,人工恢复植被类型间SOC和TN含量及细根密度的差异在土壤剖面深度上表现出不同,人工乔木和灌木最明显,影响深度>100 cm;草地最小,仅为60 cm.恢复植被的细根密度、C∶N和凋落物量显著高于农作物,细根密度与SOC、TN呈显著线性相关(P<0.01).细根的质和量以及凋落物量是不同人工恢复植被下SOC和TN含量差异的重要影响因素.
Studying the influence of vegetation restoration on soil carbon and nitrogen dynamics is of great significance to understand the carbon and nitrogen cycle of terrestrial ecosystems and to cope with the global warming effect.Taking the different artificial restoration vegetation in the loess hilly region as an object and farmland as the reference, Effects of Vegetation Restoration on Soil Organic Carbon (SOC) and Total Nitrogen (TN) in 0 ~ 100 cm Section and Its Affecting Factors The results showed that returning farmland to forest or grass significantly increased soil SOC and TN content. , SOC and TN were significantly higher than farmland.The average SOC content in 0 ~ 100 cm soil layer was 1.43 times that of farmland, the largest increase, followed by artificial shrubs, which was 1.36 times and finally artificial grassland, which was 1.21 times. The TN content in 0 ~ 100 cm soil layer was the largest in artificial tree forest, which was 1.30 times that of farmland, followed by artificial grassland, which was 1.21 times, while the growth of artificial shrub was the lowest, which was 1.13 times. Compared with farmland, The difference of SOC and TN contents and fine root density showed different depth of soil profile, and the artificial trees and shrubs were the most obvious, with the depth of> 100 cm and the smallest grassland of 60 cm. The fine root density, C: N And the amount of litter Higher than crops, fine root density SOC, TN was significant correlation (P <0.01). The quality and quantity of fine roots, and the amount of litter is an important factor in artificial restoration of different content difference and SOC TN under vegetation.