Effect Of Fertilization On The Soil Fertility And Physiological Activity In Larch Plantations

The study is the content of Harbin'fund project (project number:0071007014) for reserved person who will take the lead in special subject in the future.Research on the soil fertility,soil enzyme activity,soil microbiological quantity,forestnutrient and forest physiological activity before and after fertilization was conducted throughthe method of contrast experiment with the different developing phase of larch plantations.,that is young forest land,young stands and near mature forest as research objects in this paper.The results indicate that the soil fertility of larch plantations is decreasing all along with theaddition of forest age and the soil potential has the trend of recession under long managementof larch plantations. Several better schemes of fertilization were gained,that is treatment 2(N120) .treatment 6 (P90) and treatment 9 (N200P120K80M) for young forest land,treatment2 (N120) .treatments (P90) and treatment 9 (N200P120K80M) for young stands,treatment 1(N60) .treatments (P90) and treatment 9 (N200P120K80M) for near mature forest.Soil physical character was improved in forest land of larch plantations,after fertilization. The soil was loose and the ability of water sluice and fertility conservation was enhanced. The contents of organic matter,Total N,Total P,hydrolyzed N,rapidly available P and etc. were increased a little in soil,especially the availability of P was obviously enhanced. The content of organic matter was added in soil after fertilization,so the soil microbiological quantity was added,especially the quantity of bacteria was obviously added. The soil enzyme activity was strengthened. Full N and full P of leaves and roots and the content of chlorophyll and the net photosynthesis velocity of leaves were added in larch plantations,after fertilization,but the velocity of respiration and the ratio of a and b were decreased. In addition,an experiment of fertilization treatment on Larch-Manchurian ash mixed forest and Larch- Mongolia mixed forest was conducted.The soil physical and chemical properties,microbiological quantity,enzyme activity,plant nutrient and physiological characters were improved and advanced in some extents after fertilization and the fertilization effect of Larch- Mongolia_walnut mixed forest was better than Larch-Manchurian ash mixed forest.