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首页> 外文期刊>Journal of arid environments >Dynamics of soil physical and chemical properties and vegetation succession characteristics during grassland desertification under sheep grazing in an agro-pastoral transition zone in Northern China
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Dynamics of soil physical and chemical properties and vegetation succession characteristics during grassland desertification under sheep grazing in an agro-pastoral transition zone in Northern China

机译：中国北方农牧交错带放牧草地放牧草地土壤理化性质及植被演替特征的动态

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摘要

A number of field experiments were conducted from 1986 to 2003 to investigate the dynamics of soil physical and chemical properties as well as vegetation succession characteristics during the grassland desertification process under sheep grazing. Results indicate that fine silt (0.01-0.001 mm) removal and medium sand (0.5-0.25 mm) increase occurred early in the desertification process resulting in coarser surface soil. The fine sand (0.25-0.05 mm) was the major (33.7-68.4%) soil fractions element throughout the process. Changes in soil fractions were associated with a decline in soil fertility as the natural grassland shifted to a desertified landscape. The organic matter concentration decreased significantly by 94%, 89% and 69%, respectively, in the 0-5, 5-10 and 10-30cm soil layers. The desertification effects on total soil N followed the same trend as the organic matter. Total soil P and K concentrations decreased only slightly and were consistent early in the desertification process. Soil bulk density increased companied with the decline of soil porosity and compaction as the desertification process continued. Species diversity declined both in the plant community and the soil seed bank, and species richness decreased by 56%. Three successional stages were identified, with bunchgrass communities being the first, followed by the growth of rhizomous grasses, and then sandy species and annual plant communities. In conclusion, grassland desertification was accompanied by severe soil erosion, soil nutrition decline and species diversity losses.
机译：1986年至2003年进行了许多野外试验，以调查绵羊放牧期间草地荒漠化过程中土壤理化性质的动态以及植被演替特征。结果表明，在沙漠化过程的早期，细泥沙（0.01-0.001毫米）被清除，中砂（0.5-0.25毫米）被增加，导致表层土壤变粗。在整个过程中，细砂（0.25-0.05毫米）是主要的土壤成分（33.7-68.4％）。随着天然草原向荒漠化景观的转移，土壤组分的变化与土壤肥力的下降有关。在0-5、5-10和10-30cm的土壤层中，有机质浓度分别显着下降了94％，89％和69％。沙漠化对土壤总氮的影响趋势与有机质相同。土壤中磷和钾的总含量仅略有下降，并且在荒漠化过程的早期是一致的。随着荒漠化过程的继续，土壤容重增加，而土壤孔隙度和压实度下降。植物群落和土壤种子库中的物种多样性均下降，物种丰富度下降了56％。确定了三个演替阶段，首先是束草群落，然后是根茎草的生长，然后是沙质物种和一年生植物群落。总之，草原荒漠化伴随着严重的土壤侵蚀，土壤营养下降和物种多样性丧失。

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