密云水库北京集水区油松水源保护林主要养分元素积累与分配研究

Nutrient Distribution and Accumulation Pattern of Pinus tabulea formis Water Resources Protection Forest in Miyun Reservoir Watershed, Beijing

对密云水库北京集水区油松水源保护林主要养分元素积累与分配的研究结果表明:29年生油松林的生物量为92 627 kg/hm2。油松林不同器官中各养分元素的含量差异较大,在叶、枝和干中各养分元素的含量顺序分别为N(K)>K(N、Ca)>Ca(K)>Mg(P)>P(Mg)。根系中的养分元素随着根系直径的增加呈各养分元素的含量降低。油松林生态系统5种养分元素的贮存量为695.17 kg/hm2。若以各养分元素在油松林生态系统中的贮存量来计,则N的贮存量最大,P的最小,不同养分元素贮存量的顺序N>Ca>K>Mg>P。油松林生态系统对N元素的富集能力最强,不同器官中各养分元素的富集系数排序均为N>P>K>Ca>Mg。油松林每积累1 t干物质需N、P、K、Ca和Mg等5种养分元素共计7.51 kg。

Pinus tabulaeformis is the mainly afforested tree in the Huabei district, it mainly distributed in the hilly area. The the Pinus tabulaeformis water resources protection, forest ecosystem, nutrient accumulation and distribution pattern are studied in the upper watershed of Miyun reservoir, north Beijing mountain area. Its results show that the total biomass of the Pinus tabulaeformis forest ecosystem in the stand is 92627 kg/hm^2. The nutrient elements nitrogen （N）, phosphors （P）, potassium （K）, calcium （Ca） and magnesium （Mg） concentration are analyzed in the different organs of Pinus tabulaeformis forest ecosystem. The five kind nutrients content in the leaves show that sequences as follows： N 〉K （Ca）〉Ca （K）〉 Mg〉P, in branches show that the sequence as follows：N〉K〉Ca〉Mg〉P, in truck shows that the sequence as follows： K〉N〉Ca〉Mg〉P, and in the different diameter of the root, the N, P, K, Ca and Mg content show that the concentration become smaller accompanied with the root diameter increased. The total store is 695.17 kg/hm2 of the five kind nutrient elements in the Pinus tabulaeformis forest ecosystem. If sum up the nutrient amount according the different nutrient element, then the nutrient elements N, P, K, Ca and Mg store in the Pinus tabulaeformis forest ecosystem is 270.61 kg/hm^2 , 34.22 kg/hm^2 , 157.24 kg/hm^2,184.32 kg/hm^2 and 48. 77 kg/hm^2 , respectively. The sequence of nutrient storage of five kind nutrient element as follows. N〉 Ca〉K〉Mg〉P. The accumulation coefficient of nutrient element N is higher than others, and order of accumulation coefficient of different elements is： N〉P〉Ca〉K〉Mg. The net production of organic matter per ton needs about 7.51 kg of five elements and the order of demand as follows： N〉Ca〉K〉Mg〉P.