The Study On Fertilization And Nutrient Diagnosis Of Poplar ZL-46 Plantation For Plywood

The growth respons to fertilization of zhonglin-46 poplar, which is the dominant tree species of plantation in Langfang area of HeBei province, were determined, and its leaf nutrition diagnosis and soil fertility were measured in regular period as well. Also, for direct fertilization on poplar, its growth response to the different ratio of N, P, K mineral elements and the relationship between the leaf nutrition content and soil fertility were studied. The results were shown as follows:(1) From growth amount, the fertilizer that applied in soil was better than that of multiple-fetilizer.(2) For 4-years-old poplar stand, different mineral elements of N, P, Kthat applied in soil as fertilizer has different efficiency,of which it is N>P>K from the higher to the lower. Through two years measurement on poplar growth, the best fertilizer combination was urea: 0.2-0.3Kg;superphosphate: 0.3Kg;potassiumsulphide: 0.05-0.1 Kg per tree. For 5-years-old poplar stand, the efficiency of mineral element of N, P, K was as the same as 4-years-old poplar stand. The best fertileizer combination was urea: 0.3Kg;superphosphate: 0.3Kg;potassiumsulphide: 0.05-0.2Kg per tree. Either 4-years-old or 5-years-old poplar stand, the best ration of fertilizer for tree hight growth and diameter growth were some slight different.(3) It is demenstrate that the leaf nutrition content were increasing with fertileizer applied in terms of leaf nutrient diagnosis and the growth of poplar is inverse proportion with its content. Measurment leaf mineral elements content variety all year, the N, P, K decreased gradually from late April to late September. The Ca element, however, was increasing at all time . The Mg content in leaf was increasing from late April to middle August,but decreased smoothly in the rest months.(4) By vector analysis, it suggested that the appropriate leaf nutrition content were that of N 2.0- 2.07%, P 0.18-0.19%, K was aboutl.26-1.29%, Ca was 0.82-0.86, and Mg 0.14-0.15%;and the ratio of N/P was 11.05-11.19, N/K was 1.61-1.64, N/Ca was about 2.4-2.5, N/Mg was 14.34-14.66, P/K was 0.14-0.15.(5) The regression equations of poplar growth index with soil fertility and leaf nutrientcontent were established respectively, which could be a guider for poplar plantation fertilization.