马尾松的生产力和营养元素生物循环

THE PRODUCTIVITY AND THE BIOCYCLING OF NUTRIENT ELEMENTS OF MASSON PINE

广西宜山县庆远林场25年生马尾松的年平均净生产量为7.55 t/ha,各器官占的百分数是:干材72.16,树皮5.77,树根13.63,枝条6.83,叶子1.61。 25～31年生马尾松对N,P,K,Ca,Mg 5种营养元素的年平均总吸收量为116.02 kg/ha,其中36.1%存留在立木上,45.4%通过凋落物、18.5%通过降水淋溶归还土壤。元素的归还比是:N 0.64,P 0.64,K 0.72,Ca 0.59,Mg 0.64。降水淋溶是K归还的主要途径;N,Ca,Mg的归还主要通过凋落物;P的两种归还途径相当。 25～31龄期的马尾松对营养元素的存留量和利用效率都有较高水平,元素生物循环强度较大,生物积累量也较大。

Mean net production of 25 years old masson pine in Guangxi Yishancounty Qingyuan forestry centre was 7.55t/ha.a, in which stems containing 72.16o%, barks 5.77%, roots 13.83%, branches 6.83%and leaves 1.61%. Total uptakes of N,P, K, Ca, Mg nutrient elements of 25～31 years old masson pine were 116.02 kg/ha.a, of which 36.1% was retained in the standing tree, 45.4% and 18.5% were returned to the soil through litterfall or rain leaching. The ratios of annual return to uptake of N, P, K, Ca,Mg were 0.64, 0.64, 0.72, 0.59, 0.64 respectively. The main way ofreturn for N, Ca, Mg was through litterfall, and that for K was throughrain leaching, two ways for P returned were similar. Both its retaining and utilizing efficiencies of nutrient elements of 25～31 years old masson pine were at higher level, the bioeycling strength was greater, the biomass accumulalion was also in large amount.