Study On Enzymatic Distributing Characteristics Of Black Agrarian Soils

The black soil is the main agrarian soil and has high crop-producing power in our country. The fertility is coming down as worse outside conditions, long-term cultivation. Soil enzymes play an important role in evaluating soil nutrients, because soil enzyme activities can reflect the power and direction of biochemical process in soils. Soil nutrients at northeast blackland belt had investigated. Therefore this paper studied distributing characteristics of soil enzyme activities. Vertical and horizontal distributing characteristics, influence of different dark layers and crop stubble, correlations with nutrients of nitrogen, phosphorus, carbon, potassium of catalase, phosphatase, urease, invertase, nitrate reductase activities were researched. Variations of catalase, phosphatase, urease, invertase activity during corn growth were studied too. Metabolic mechanism of soil enzyme activities were discussed. Soil enzyme functions in evaluating nutrients were discoved. The aim offered academic base of improving and utilizing black agrarian soil effectively.Vertical distribution characteristics of catalase, phosphatase, urease, invertase, nitrate reductase activities of nine typical profiles at black belt in Heilongjiang province were studied.The results showed that vertical distribution followed this rule: five enzyme activities reduced in turn from surface layer to 80 cm layer but catalase, invertase, nitrate reductase activity got to stabilization or increased a little, while phosphatase, urease activity reduced sharply even to zero below 80 layer. The results of path analysis showed that there were dierect and indierect correlations between total nitrogen, available nitrogen, total phosphorus, total carbon, C/N and five soil enzyme activities. Principal component analysis revealed that urease and phosphatase activities could be used to valuate vertical distribution of total nitrogen, available nitrogen, total phosphorus and total carbon. However Catalase, invertase and nitrate reductase activities could not.Three typical blackland areas in north, middle and south of Heilongjiang province were investigated and thirty to sixty sampling points were selected in them. Horizontal distribution characteristics of catalase, phosphatase, urease, invertase, nitrate reductase activities in and among three areas were studied too. The results showed that five enzyme activities in area 1 reduced as well as latitude decreasing. In area 2 and 3, phosphatase and nitrate reductase activities decreased along with latitudinal falling, however catalase, urease and invertase activities kept sTab. or increased a little. Among three areas, phosphatase and nitrate reductase activities were area 1>area 2>area3 and have the same trend with the distributing rule of soil nutrients. In opposition, catalase, urease and invertase activities were area3> area2 >area1.The results of path analysis showed that there were dierect and indierect correlations between...