南平溪后杉木林取代杂木林后土壤肥力变化的研究

 本文对福建省南平溪后70年生杉木丰产林与杂木林的土壤肥力进行对比研究。结果表明：与前茬杂木林相比，70年生杉木林下土体较紧实，土壤有机质和营养元素含量降低，土壤酶活性和氧化代谢能力减弱。目前70年生杉木丰产林之所以仍保持较高的土壤肥力水平，主要是杉木林林冠疏开后林下植物多样性提高及生物量增加的缘故。

STUDY ON CHANGES OF SOIL FERTILITY AS AFFECTED BY THE REPLACEMENT OF BROADLEAVED STAND BY CHINESE FIR STAND IN NANPING

The changes of soil fertility in a 70 year old fast-growing,highyield Chi-nese fir stand,which was originally occupied by a broadleaved stand,were studied for 2 consecutive years in Anchaoxia,Qihou,Nanping The results show-ed that the soil fertility of the 70-year-old fast-growing high-yield-Chinese fir stand had declined obviously. In comparison with the original broad-leafed forest stand,the Chinese fir site showed increased soil bulk density, decreas-ed soil organic matter content and nutrient element concentrations, and dimi-nishing soil enzyme and other biological activities.The reason that the 70-year-old Chinese fir stand still maintains relatively high fertility is that the increased undercanopy space facilitates the maintenance of high species dive-rsityand biomass production.