不同N素形态对落叶松苗木根/土界面pH值及养分有效性的影响  

Effect of Different Nitrogen Sources on pH and Nutrient Availability in the Root/Soil Interface of Larix gmelinii Seedlings

作　　者：陈永亮[1] 周晓燕[1] 韩士杰[2] 

机构地区：[1]临沂师范学院生命科学学院,临沂276005 [2]中国科学院沈阳应用生态研究所,沈阳110016

出　　处：《林业科学》2006年第9期134-139,共6页Scientia Silvae Sinicae

基　　金：国家自然科学基金(30070129);中国科学院"百人计划A"项目-"森林界面生态学"资助

摘　　要：The effect of different nitrogen and phosphorus sources on pH and the availability of mineral nutrients in the root/soil interface of Larix gmelinii seedlings were studied by means of root-mat method. The results showed that the addition of NH+4-N decreased the pH in the root/soil interface, while the addition of NO-3-N increased the pH in contrast with the control treatment. The sort of the P sources and the distance from the root plane remarkably influenced the changes of pH in the root/soil interface induced by the addition of the nitrogen sources. Compared with the addition of only NH+4-N, the extent to which the pH in the root/soil interface decreased was obviously smaller when treated by NH+4-N and rock P. When treated with different P sources, the contents of available P in the root/soil interface were affected by the sort of the N sources. When treated with soluble P, the contents of the available P in the root/soil interface obviously increased for the addition of both NH+4-N and NO-3-N. When treated with rock P, the contents of the available P increased only in the area 0～3 mm from the root plane for NH+4-N, whereas the contents of available P in the root/soil interface changed little for NO-3-N. The results above showed that the protons excreted by the roots were the main driving force for the solution of the rock P in the root/soil interface. The availability of Fe in the root/soil interface increased as a result of acidity induced by the NH+4-N, whereas the availability of Fe in the root/soil interface decreased because of the pH increase induced by the NO3-N. The effect of different N sources on the availability of Fe in the root/soil interface was also affected by the sort of P sources. The concentrations of P、Fe in the leaves remarkably differed when treated by different N、P sources and concentrations of the P、Fe in the root/soil interface were correlated to those in the leaves of the seedlings.The effect of different nitrogen and phosphorus sources on pH and the availability of mineral nutrients in the root/soil interface of Larix gmelinii seedlings were studied by means of root-mat method. The results showed that the addition of NH4^＋ -N decreased the pH in the root/soil interface, while the addition of NO3^- -N increased the pH in contrast with the control treatment. The sort of the P sources and the distance from the root plane remarkably influenced the changes of pH in the root/soil interface induced by the addition of the nitrogen sources. Compared with the addition of only NH4^＋ -N, the extent to which the pH in the root/soil interface decreased was obviously smaller when treated by NH4^＋ -N and rock P. When treated with different P sources, the contents of available P in the root/soil interface were affected by the sort of the N sources. When treated with soluble P, the contents of the available P in the root/soil interface obviously increased for the addition of both NH4^＋ -N and NO3^- -N. When treated with rock P, the contents of the available P increased only in the area 0 ~ 3 mm from the root plane for NH4^＋ -N, whereas the contents of available P in the root/soil interface changed little for NO3^- -N. The results above showed that the protons excreted by the roots were the main driving force for the solution of the rock P in the root/soil interface. The availability of Fe in the root/ soil interface increased as a result of acidity induced by the NH4^＋ -N, whereas the availability of Fe in the root/soil interface decreased because of the pH increase induced by the NO3^ - -N. The effect of different N sources on the availability of Fe in the root/soil interface was also affected by the sort of P sources. The concentrations of P,Fe in the leaves remarkably differed when treated by different N,P sources and concentrations of the P,Fe in the root/soil interface were correlated to those in the leaves of the seedlings.

关 键 词：落叶松苗木 根/土界面 N素形态 PH值 养分有效性 

分 类 号：S718.43[农业科学—林学] S723.7