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 show...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.展开更多
In order to investigate the differences of macropores vertical distribution under different surface plants, and to assess the influences of root systems, organic matter and texture on macropore flow paths, two dye tra...In order to investigate the differences of macropores vertical distribution under different surface plants, and to assess the influences of root systems, organic matter and texture on macropore flow paths, two dye tracer infiltration experiments were performed in slopes under two different plants(Campylotropis polyantha(Franch.) Schindl vs. Cynodon dactylon(Linn.) Pers). Dye tracer infiltration experiments with field observations and measurements of soil properties were combined. Results show that the discrepancy in macropores distribution between two slopes under different plants is significant. Root systems have significant effects on macropore flow paths distribution and the effect become more pronounced as the diameter of roots become larger. Organic matter and stone are important factors to affect macropores distribution. Root-soil interface, inter-aggregate macropore and stone-soil interface are important macropore flow paths in well vegetated slopes.展开更多
文摘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.
基金Project(U1502232)supported by the National Natural Science Foundation of China-Yunan Joint FundProject(KKSY201406009)supported by the Natural Science Foundation of Kunming University of Science and Technology,ChinaProject(2014FD007)supported by the Natural Science Foundation of Yunnan Province,China
文摘In order to investigate the differences of macropores vertical distribution under different surface plants, and to assess the influences of root systems, organic matter and texture on macropore flow paths, two dye tracer infiltration experiments were performed in slopes under two different plants(Campylotropis polyantha(Franch.) Schindl vs. Cynodon dactylon(Linn.) Pers). Dye tracer infiltration experiments with field observations and measurements of soil properties were combined. Results show that the discrepancy in macropores distribution between two slopes under different plants is significant. Root systems have significant effects on macropore flow paths distribution and the effect become more pronounced as the diameter of roots become larger. Organic matter and stone are important factors to affect macropores distribution. Root-soil interface, inter-aggregate macropore and stone-soil interface are important macropore flow paths in well vegetated slopes.
