坡向坡位和撂荒地对云雾山草地土壤酶活性的影响

对封育21年的云雾山典型草坡不同坡位土壤酶活性进行了研究。结果表明,表层土壤4种酶活性在坡顶和坡底分布均为阴坡>阳坡>撂荒地。蔗糖酶和碱性磷酸酶活性在坡面任何坡位均表现为阴坡>阳坡>撂荒地;过氧化氢酶活性在坡面则表现为阴坡>撂荒地>阳坡。不同坡向、不同坡位剖面土壤4种酶活性随剖面层次的增加而降低;在坡顶和坡中部土壤剖面脲酶活性波动较大,在坡底为阳坡>阴坡>撂荒地。封育增加了土壤蔗糖酶和碱性磷酸酶活性,其影响深度从坡顶向下而增加;长期封育增加了深层土壤水分和有机碳含量,从而降低了相应土层土壤过氧化氢酶活性。不同坡向、不同坡位剖面土壤4种酶的活性与对应土层土壤有机碳呈极显著正相关关系,土壤酶活性敏感地揭示了植被恢复对土壤肥力提高的积极作用。

Influence of slope direction, position and fallow measurement of soil enzymatic activities in grassland at Yunwu Mountain

As a sensitive indicator of soil quality,soil enzymes play an important role in the soil ecosystem.To find the soil biological response to re-vegetation,we analyzed the spatial distribution of soil enzymatic activities at different positions in grass slopes which had been re-vegetated for 21 years on Yunwu Mountain.In both top and bottom of slopes,the activities of four enzymes in the surface layers of soils followed the order of lunar slope > solar slope > bare land.The distribution of invertase and phosphatase activities were in the order of lunar slope > solar slope > fallow land,while catalase activity was in the order solar slope > lunar slope > fallow land.The activities of the four enzymes were all reduced at lower soil depths in all the soil profiles studied.The activities of soil urease fluctuated with soil depth in both top and middle slope positions,but increased in the pattern of solar slope > lunar slope > fallow land at the slope bottom.Re-vegetation exerted obvious increasing effects on soil invertase and phosphatase activities,and its effect at depth increased from top to bottom of slopes.Catalase activity showed an inverse distribution trend in the three slope positions,which may be caused by the increased soil water content and organic matter content after 21 years re-vegetation. In addition,soil enzymatic activities very significantly correlated with soil organic carbon contents.Soil enzymatic activities have thus indicated that vegetation rehabilitation played a positive role in the improvement of soil fertility.