Effects Of Stand Transformation Of Eucalyptus Forest On Soil Nutrient And Nutrient Loss Via Surface Runoff

Soil nutrients to maintain the current our country are facing an important ecological environment problems, the south China precipitation period is long, precipitation intensity is big, the resulting serious soil and water and nutrient loss. Eucalyptus(Eucalyptus SPP.) is China's southern camp hill afforestation, one of the important hill afforestation tree species, but the growth of Eucalyptus forest, the forest, such as simple structure, less undergrowth problem increasingly highlight, lead to soil nutrient loss is more serious. So understand different transformation patterns of eucalyptus plantation soil nutrients to maintain performance on scientific stand transformation, reduce the nutrients such as nitrogen and phosphorus loss is of great importance.2 kind of transformation model in this paper, we study the eucalyptus forest thinning 30% + y native hardwood species(remember mode ?), thinning 60% + y native hardwood species(remember to model ?) and the original forest thinning, interplanting(referred to as controlled CK) forests soil nutrient, surface runoff and nutrient loss characteristics of nitrogen and phosphorus. Transformation to implement the eucalyptus forest plantation age of 15 years(2008), to monitor the quality of transformation forest in 2015. The main results were as follows:Through the stand transformation of patterns ?, ? and control the influence of soil nutrient analysis of CK, the following conclusions:(1) 0-20, 20- 40, 40-60 cm soil layer, soil total nitrogen content were mode ?> pattern ?> CK. 0-20 and 40- 60 cm soil layer, soil available nitrogen content are mode ??> control > CK mode; 20-40 cm soil layer, soil available nitrogen content for the pattern ?> pattern ?> CK.(2) 0-20 cm soil layer, soil total phosphorus content for patterns ??> control > CK mode; 20-40 and 40- 60 cm soil layer, soil total phosphorus content are controlled CK > pattern ??> mode. 0-20 cm soil layer, soil available p content for patterns ?> pattern ?> contrast CK; 20-40 and 40- 60 cm soil layer, soil available nitrogen content are mode ?> pattern ?> CK.(3) 0-20, 20-40, 40-60 cm soil layer, soil total potassium and available potassium content are mode ?> CK > mode ?.(4) 0-20, 20-40, 40-60 cm soil layer, soil organic matter content were mode ?> pattern ?> CK. 0-20, 20-40, and 40-60 cm soil layer, the model ? soil p H values are higher than ? and CK.Based on pattern ?, ? and contrast CK in September 4-9 the analysis of the runoff and the loss of nitrogen and phosphorus runoff, the following conclusions:(1) the transformation model, the runoff by comparing CK > pattern ??> mode. Comparing CK the maximum runoff coefficient, its value is 3.32%, pattern ? times, its value is 1.95%, minimum model ? runoff coefficient, the value of 1.54%.(2) the total nitrogen runoff erosion control CK(17.68 g·hm-2) > pattern ?(11.18 g·hm-2) > pattern ?(8.92 g·hm-2); Ammonium nitrogen runoff erosion control CK(2.05 g·hm-2) > pattern ?(0.89 g·hm-2) > pattern ?(0.70 g·hm-2). Ammonium nitrogen runoff loss of total nitrogen runoff erosion case-control ? CK(11.59%) > pattern(7.90%) > pattern ?(7.85%). Nitrate nitrogen runoff erosion control CK(2.06 g.hm-2) > pattern ?(0.97 g.hm-2) > pattern ?(0.72 g.hm-2). Nitrate nitrogen runoff loss of the percentage of total nitrogen runoff loss by comparing CK(11.67%) > pattern ??(8.68%) > pattern(8.07%).(3) the total phosphorus runoff erosion control CK(4.35 g·hm-2) > pattern ?(2.84 g·hm-2) > pattern ?(1.62 g·hm-2). Soluble phosphorus runoff erosion control CK(0.30 g·hm-2) > pattern ?(0.22 g·hm-2) > pattern ?(0.09 g·hm-2).(4) of soluble phosphorus runoff loss of total phosphorus runoff loss ratio for the pattern(7.75%) > control(6.90%) > CK model(5.12%).? ?(5) in contrast to CK, the relationship of runoff and nitrogen loss curve for y=-1.137+0.645x-0.022x2+0.001x3(R2=0.860), the relationship of runoff and phosphorus loss curve for y=-0.048+0.114x-0.003x2+0.002x3(R2=0.900). In model ?, runoff and nitrogen loss curve for y=-0.139+0.410x-0.011x2+0.001x3(R2=0.912), the relationship of runoff and phosphorus loss curve for y=1.017-3.023/x(R2=0.873). In model ?, runoff and nitrogen loss curve for y=2.532- 4.560/x(R2=0.863), the relationship of runoff and phosphorus loss curve for y=0.041·(1.465)x(R2=0.857).After implementing stand transformation, as model relative to reduce surface runoff,? runoff of the nitrogen and phosphorus in runoff loss is reduced, that in the process of the whole stand transformation, pattern with good nutrient conservation effect.