黄土区油松人工林生态系统营养元素分配格局和积累的研究

在陕北黄土区 3块油松人工林样地中 ,对油松人工林生态系统各组分中N ,P ,K ,Ca ,Mg等 5种营养元素的含量、分配格局和积累规律进行了研究 .结果表明 ,油松人工林不同器官中营养元素含量排序为树叶 >树枝 >树根 >树皮 >干材 ;在油松人工林现存量中N ,P ,K ,Ca ,Mg总量分别为 319.5 2 ,32 .5 3,2 5 0 .0 2 ,2 19.11,4 3.5 4kg hm2 ;乔木层、灌木层、草本层和死地被物层养分贮量分别为 6 6 8.75 ,0 .6 7,0 .2 4 ,195 .0 6kg hm2 ;油松人工林N ,P ,K ,Ca ,Mg的富集系数分别为 3.81,5 .19,18.78,1.0 7,4 .81;每生产 1t有机物质需要这 5种元素约 9.4 1～ 12 .19kg (hm2 ·a) ;乔木层中营养元素积累量为 4 71.2 7～ 6 6 8.75kg hm2 ,其中干材营养元素积累量约占乔木层的 14 .9%～ 16 .7% .

Nutrient distribution and accumulation pattern of Chinese pine plantation ecosystems in the loess region.

The contents, accumulation and distribution of 5 nutrient elements (N, P, K, Ca, Mg) were studied in 3 sample plots of Chinese pine plantation in the loess region in Shaanxi Province. The results show that the nutrient content in various organs was in the order of needle > branch > root > bark > stem. The stand had a N storage of 319.52?kg/hm 2, P 32.53?kg/hm 2, K 250.02?kg/hm 2, Ca 219.11?kg/hm 2 and Mg 43.54?kg/hm 2. The total accumulation of the elements in the tree layer was 668.75?kg/hm 2, in the shrub layer 0.67?kg/hm\+2, in the herb layer 0.24?kg/hm 2 and in the dead soil covering layer 195.06?kg/hm 2. The enrichment ratios of N, P, K, Ca and Mg in Chinese pine plantation were 3.81, 5.19, 18.78, 1.07 and 4.81 respectively. The net organic production per ton needs these five elements of 9.41～12.19?kg/(hm 2·a).The total nutrient element accumulation in tree layer was 471.27～668.75?kg/hm 2, of which stem occupied about 14.9%～16.7%.