氮添加对墨西哥柏人工林土壤碳氮磷化学计量特征及酶活性的影响  

Effects of N addition on C,N and P stoichiometry and soil enzyme activities in Cupressus lusitanica Mill. plantation

作　　者：李瑞瑞 卢艺 王益明 万福绪 LI Rui-rui;LU Yi;WANG Yi-ming;WAN Fu-xu(College of Forestry,Nanjing Forestry University,Co-Innovation Centre for Sustainable Forestry in Southern China,Nanjing 210037,China)

机构地区：[1]南京林业大学林学院南方现代林业协同创新中心,南京210037

出　　处：《生态学杂志》2019年第2期384-393,共10页Chinese Journal of Ecology

基　　金：江苏省林业三新工程(LYSX[2015]20);PAPD项目资助

摘　　要：为探讨氮沉降对土壤碳氮磷生态化学计量化学特征及其相关酶活性的影响,在南京林业大学科研教学基地墨西哥柏(Cupressus lusitanica Mill.)人工林设置N0、N1(24 kg·hm^(-2)·a^(-1))、N2(48 kg·hm^(-2)·a^(-1))、N3(72 kg·hm^(-2)·a^(-1))、N4(96 kg·hm^(-2)·a^(-1))和N5(120 kg·hm^(-2)·a^(-1)) 6个不同施N量处理。结果表明:(1)随氮添加量的增加,土壤有机碳(SOC)含量显著增加,并在N4样地达到最大值。土壤可溶性有机碳(DOC)含量在N2、N3样地显著高于对照样地。N2样地土壤全氮(TN)、N/P显著高于对照样地,其余样地之间差异性不显著。N4、N5样地土壤C/N、C/P显著高于对照样地。氮添加对土壤全磷(TP)没有显著影响。(2)在低氮和中氮处理下土壤碳氮磷相关酶活性均出现提高。在高氮处理下,纤维素酶显著低于对照样地,脲酶活性出现降低趋势;而磷酸酶、木质素分解酶及蔗糖酶活性显著提高。(3)聚类分析及因子分析发现,墨西哥柏人工林N添加量最好不超过72 kg·hm^(-2)·a^(-1),这为以后墨西哥柏人工林施肥管理提供数据参考。冗余分析结果可知,土壤TP、SOC、DOC与磷酸酶、脲酶、多酚氧化酶及过氧化氢酶呈显著正相关。(4)因子分析及冗余分析发现,DOC是驱动土壤酶活性的主要环境因子。研究结果可为评估氮沉降增加背景下我国亚热带地区人工林的土壤养分循环提供依据,为进一步预测未来氮输入情景下的区域养分平衡提供参考。We carried out an experiment to understand the effects of nitrogen deposition on soil C ∶ N ∶ P stoichiometry,extracellular enzyme activities associated with C,N and P cycles in a Cupressus lusitanica Mill. plantation in Nanjing,Jiangsu Province,China. There were six levels of nitrogen addition,including 0,24,48,72,96,and 120 kg·hm^-2·a^-1,designated as N0,N1 N2,N3,N4,and N5 respectively. The results showed that:( 1) The concentration of soil organic carbon( SOC) was significantly elevated with increased N and peaked in N4 treatment.The concentration of soil dissolved organic carbon( DOC) was significantly higher in N2 and N3 treatments than that in the control. The soil total nitrogen( TN) concentration and N ∶ P ratio were significantly higher in N2 treatment than those in the control. No significant differences were found in other treatments. Soil C ∶ N and C ∶ P were significantly higher in N4 and N5 treatments than those in the control. Nitrogen addition had no significant effects on soil total phosphorus concentration( TP).( 2) Activities of soil urease,phosphatase( acid phosphatase,alkaline phosphatase,neutral phosphatase),polyphenol oxidase,cellulose,invertase,and catalase in lowand middle-level nitrogen treatments were higher than those in the control. In the high-level N addition treatment,activities of soil urease and cellulose showed a decreasing trend,whereas activities of phosphatase,lignin oxidase and invertase were significantly increased.( 3) Results from both cluster analysis and factor analysis showed that it was reliable to regard the level of 72kg·hm^-2·a^-1( N3) as the optimal rate for the C. lusitanica plantation. This result would provide a reference for fertilization in the C. lusitanica plantation. Results from redundancy analysis showed that concentrations of TP,SOC,and DOC were significantly positively correlated with the activities of soil phosphatase,urease,polyphenol oxidase,and catalase. The results showed that the variation in soil enzyme activities greatly accounted

关 键 词：N添加 墨西哥柏人工林 生态化学计量 土壤酶活性 

分 类 号：S714[农业科学—林学]