N添加对油松幼苗土壤酶活性和微生物生物量的影响  

Effects of N addition on soil enzyme activities and microbial biomass beneath Pinus tabuliformis seedlings

作　　者：吕凤莲[1] 薛萐[2,3] 王国梁[2,3] 景航[2] 

机构地区：[1]西北农林科技大学资源与环境学院,陕西杨凌712100 [2]西北农林科技大学水土保持研究所,陕西杨凌712100 [3]中国科学院水土保持与生态环境研究中心,陕西杨凌712100

出　　处：《生态学杂志》2016年第2期338-345,共8页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(41371508);西北农林科技大学重大项目培育专项(ZD2013021);陕西省自然科学基础研究计划重点项目(2013JZ006)资助

摘　　要：通过连续6年对盆栽油松(Pinus tabuliformis)幼苗进行不同水平N添加(0、2.8、5.6、11.2、22.4和44.8 g N·m^(-2)·a^(-1)),研究了N添加对土壤酶活性(蔗糖酶、脲酶和碱性磷酸酶)和微生物生物量碳、氮的影响。结果表明:N添加水平低于11.2 g N·m^(-2)·a^(-1)时,对油松幼苗土壤蔗糖酶和脲酶活性均有促进作用,但过量N添加,尤其超过22.4 g N·m^(-2)·a^(-1)时,蔗糖酶、脲酶和碱性磷酸酶活性均不再提高,甚至表现为抑制作用;N添加为5.6 g N·m^(-2)·a^(-1),微生物生物量碳显著增加,微生物生物量氮无显著变化,而当N添加达到11.2 g N·m^(-2)·a^(-1)时,微生物生物量氮呈显著增加的趋势;土壤蔗糖酶、脲酶活性与微生物生物量碳和微生物生物量氮间均有显著相关关系,而3种酶活性间、微生物生物量碳、氮间均无显著相关性;土壤酶活性和微生物生物量与地上生物量、土壤有机碳和全氮含量显著相关。油松在5.6~11.2 g N·m^(-2)·a^(-1)水平下生长达到最佳。目前黄土高原地区N沉降水平(2.06 g N·m^(-2)·a^(-1))有利于该地区油松林生长;可以通过适当增施N肥的方式提高油松生长。With a pot experiment, we compared the effects of N addition （0, 2.8, 5.6, 11.2, 22.4 and 44.8 g N·m^-2·a^-1 ） on soil enzyme activities （ invertase, urease and alkaline phosphatase） and microbial biomass beneath Pinus tabuliformis seedlings after 6 years consecutive treatment. The results showed that soil invertase and urease activities were improved when the N -1 addition was below 11.2 g N·m^-2·a^-1, while soil invcrtase, urease and alkaline phosphatase activities did not increase, even declined with a higher rate of N addition, especially more than 22.4 g N ·m^-2·a^-1 The microbial biomass C significantly increased at N addition 1〉 5.6 g N·m^-2·a^-1, while microbial biomass N significantly increased at N addition ≥ 11.2 g N ·m^-2·a^-1 , compared with the control. Significant correlations were found between soil invertase and urease activities and microbial biomass C and microbial biomass N. No significant correlations, however, were found among the three enzyme activities, or between the microbial biomass C and N. Soil enzyme activities and microbial biomass were significantly correlated with above,round biomass, soil organic carbon and total nitrogen content. Additionally, the growth of P. tabuliformis seedlings reached the maximum at the N addition levels of 5.6-11.2 g N ·m^-2·a^-1. The current N deposition level of 2.06 g N ·m^-2·a^-1 on the Loess Plateau can be favorable to P. tabuliformis growth, and the growth of P. tabuliformis would be improved through appropriately enhanced N fertilization.

关 键 词：N添加 油松幼苗 土壤酶活性 微生物生物量碳 微生物生物量氮 

分 类 号：S714.3[农业科学—林学] S791.254