间伐对马尾松人工林土壤脲酶活性的影响

Effects of Thinning on the Soil Urease Activity in the Pinus massoniana Lamb Plantation

为了探讨间伐对土壤脲酶活性的影响,以南京溧水林场25年生马尾松(Pinus massoniana Lamb)林为对象,对6a前实施了弱度(25%)、中度(45%)、强度(65%)间伐的各处理样地土壤脲酶活性进行研究。结果表明:间伐对土壤脲酶活性有显著影响,中度间伐在5月和7月显著提升0<h≤10cm土层脲酶活性,差异性达到显著水平(P<0.05)。中度间伐在5、7、10、12月份,强度间伐在7、10、12月份均提高10 cm<h≤20 cm土层脲酶活性,与对照相比,差异性显著(P<0.05)。不同间伐强度对土壤脲酶活性的影响效果不同,土壤脲酶活性在5、7、10月份表现为中度间伐>强度间伐>弱度间伐,在5、7月份前者与后两者差异性显著(P<0.05);12月份的土壤脲酶活性则表现为强度间伐>中度间伐>弱度间伐,前者与后两者的差异性达到显著水平(P<0.05)。4种处理样地土壤脲酶活性平均值在5月达到最高,12月最低。土壤脲酶活性与土壤温度呈显著正相关,与土壤含水量及土壤有机质质量分数相关性不显著。

An experiment was conducted to discuss the effects of thinning on soil urease activity in the soil of 25-year-old Pinus massoniana plantation which was thinned by light （25%）, moderate （45%） and high （65%） intensity six years ago in Lishui, Nanjing. Result shows that： The activity of urease changes greatly with thinning intensity. Surface soil （0-10 cm） urease activity increases obviously in May and July under moderate intensity thinning, and the differences are significant in the comparison with the controls （P〈0.05）. Subsurface soil （10-20 cm） urease activity increases obviously in May, July, October and December under moderate intensity thinning and in later three months under high intensity thinning, and the differences are significant in the comparison with the controls （P〈0.05）. The influences on soil urease activity vary with the different thinning intensity. In May, July and October, the soil urease activity is ranked as： moderate intensity thinning〉high intensity thinning〉light intensity thinning, and the differences between the former and the latter are signifi- cant in May and July （P〈0.05）. In December, the order is high intensity thinning〉moderate intensity thinning〉light intensity thinning, and the differences between the former and the latter two are significant （P〈0.05）. The average activity of soil urease reaches the peak in May and falls to the lowest point in December. Soil urease activity is positively correlated with soil temperature, and is not significantly correlated with the soil moisture content and the soil organic matter.