【摘要】 对不同刈割制度(围封、割一年休一年、割两年休一年、一年割一次及一年割两次)处理下内蒙古典型草原长期割草样地0～10cm、10～20cm和20～30cm土壤深度的团聚体分布特征、稳定性和土壤抗侵蚀能力进行了研究。结果表明:在长期不同刈割制度下,典型草原0～10cm土层主要以>0.25mm团聚体为主。10～20cm土层中,一年割一次和一年割两次则以<0.25mm团聚体为主。刈割显著降低了>0.25mm团聚体的含量和团聚体稳定性,并减弱了草地土壤的抗侵蚀能力(P<0.05)。各土层的大团聚体含量、团聚体稳定性和土壤含水量以及其他养分均随刈割干扰强度的增加,呈显著下降的趋势。大团聚体含量及其稳定性在围封处理下最高,刈割处理中,两年割一次最高,一年割两次最低。长期刈割处理对0～10cm表土层大团聚体含量和团聚体稳定性影响较小,而对10～30cm土层大团聚体含量及其稳定性影响较大。随着草地土层深度的增加,>0.25mm团聚体的稳定性逐级降低,深土层的团聚体更加敏感,易受环境干扰。土壤大团聚体含量及其稳定性与土壤含水量、有机碳、速效氮和速效磷含量呈极显著正相关关系(P<0.01)。综上所述,割一年休一年处理下的土壤大团聚体含量较高及其稳定性较好,抗侵蚀能力强,更有利于典型草原长期可持续利用。更多还原

【Abstract】 The distribution characteristics, stability and erosion resistance of soil aggregates at 0～10 cm, 10～20 cm and 20～30 cm soil depths in typical grassland of Inner Mongolia were explored under different mowing treatments(mowing once every two years, mowing twice every three years, mowing once every year, and mowing twice every year) with no mowing as the control. The results showed that soil aggregates > 0.25 mm were mainly distributed in 0～10 cm soil layer of typical grassland under long-term different mowing treatments. In the 10～20 cm soil layer, aggregates <0.25 mm were the main aggregates under mowing once every year and mowing twice every year treatments. Mowing significantly reduced the content and stability of aggregates > 0.25 mm and weakened the erosion resistance of grassland soil(P<0.05). The macroaggregates content, aggregate stability, soil water content and other nutrients in different soil layers decreased significantly with the increase of mowing intensity. In general, the macroaggregates content and their stability were the highest under the enclosure treatments. In mowing treatments, the macroaggregates content and their stability were the highest and lowest under mowing once every two years and mowing twice every year, respectively. Long-term mowing treatment had little effect on macroaggregates and their stability in 0～10 cm soil layer, but had a greater effect on aggregates content and their stability in 10 ～ 30 cm soil layer. With the increase of grassland soil depth, the stability of aggregates >0.25 mm gradually decreased, and the aggregates in deep soil layer were more sensitive and vulnerable to environmental interference. Soil macroaggregates content and aggregate stability were positively correlated with soil water content, organic carbon, available nitrogen, and available phosphorous contents(P<0.01). In conclusion, the soil macroaggregates and aggregates under mowing once every two years had good stability and strong erosion resistance, which was more conducive to the long-term sustainable utilization of steppe grassland.更多还原