<正>福建省长汀县河田镇是我国南方红壤区水土流失最严重的地区之一。通过对长汀河田严重侵蚀地采取乔灌木混交治理近 2 0a后林分N、P养分循环的研究 ,结果表明 ,乔灌木混交林乔木层地上各组分的N、P含量大

In this paper the accumulation and cycle of N and P elements in the community of soil and water conservation forest composed of P.massoniana and shrubs in Hetian Town,Changting County of Fujian Province has been studied. P.massoniana in mixed forest,the concentration of N and P in the aboveground fractions was in the order of leaves>stem bark>branches>stem wood and those in the below ground fractions increased with the decrease in root diameter,and those in each fraction were both higher than those of P.massoniana on the control(wasteland).The accumulation of N and P elements in this stand was up to 339.200 kg/hm 2 and 2.088 kg/hm 2 ,respectively,amount 100.6 and 69.6 times higher than that in control,of which 93.0% and 93.6% were accumulated in tree layer.Among the undergrowth,mosses accumulated the highest amount of both N and P.Amount of annual retention,return and uptake of N in mixed forest were 33.6,25.9 and 30.3 times higher,and that of P were 81.4,35.9 and 63.4 times higher than that in control,respectively,and each of return of N and P was 36.3% and 22.3% of uptake.