毛竹林土壤酶活性变化的海拔效应

Soil enzyme activities in Moso bamboo forests along an altitude gradient

在毛竹分布南缘的中亚热带与南亚热带气候过渡区,选择土壤类型、坡度、坡向、经营水平等一致的3个海拔高度(低海拔90～120m、中海拔360～400m、高海拔700～780m)毛竹林,对其土壤酶活性和物理、化学性质进行了测定。磷酸酶、蔗糖酶和脲酶活性分别为0.031～0.042、0.104～0.146和0.017～0.039mg·g-1.h-1,中海拔是3种酶活性显著变化的转折点。蛋白酶活性为0.248～0.259mg·g-1.h-1,随海拔的升高酶活性缓慢提高。过氧化氢酶活性为0.097～0.143mg·g-1.h-1,随海拔的升高酶活性显著上升。不同海拔高度毛竹林土壤物理性质对土壤酶活性无显著影响。土壤有机质、全氮、碱解氮含量与土壤酶活性呈显著或极显著正相关,pH值对土壤酶活性具正效应,海拔梯度上的土壤全磷、全钾、速磷、速钾含量对土壤酶活性影响不显著。不同种类土壤酶活性间呈显著或极显著相关,酶促反应具专一性和共同性特点。

Soil samples were collected from the Moso bamboo forests with same soil type,slope gradient,slope orientation,and management level at three altitudes（90-120 m,360-400 m,and 700-780 m）in the mid and south subtropical transitional zone,the southern edge of Moso bamboo distribution,with their physical and chemical properties and enzyme activities determined.In the forests,the activities of soil alkaline phosphatase,invertase,and urease were in the ranges of 0.031-0.042,0.104-0.146,and 0.017-0.039 mg·g^-1·h^-1,respectively,with the turning points appeared at altitude 360-400 m.The proteinase activity was in the range of 0.248-0.259 mg·g^-1·h^-1,and increased slowly with increasing altitude;whereas the catalase activity was in the range of 0.097-0.143 mg·g^-1·h^-1,and increased significantly with increasing altitude.The enzyme activities at the all three altitudes were less affected by soil physical properties and soil total and available phosphorus and potassium,but had significant positive correlations with soil organic matter,total nitrogen,and available nitrogen.Soil pH had positive effects on the enzyme activities.There existed significant correlations among the test enzyme activities,suggesting that soil enzymatic reactions were both specific and concomitant.