杉木桤木混交林生长量与土壤肥力的研究

在福建省南平市峡阳镇18地位指数的第1代杉木林采伐迹地上营造杉木纯林和杉木桤木混交林(混交比例2∶1).造林后10 a,对立地条件一致的2种人工林的生长量和土壤肥力进行了比较研究.结果表明,杉木桤木混交林林分蓄积量大于杉木纯林,但差异未达显著水平(P>0.05);杉木桤木混交林中的杉木平均胸径、树高和单株材积生长量均显著大于纯林杉木(P<0.05),但混交林中桤木生长比杉木差,其胸径和单株材积生长量均显著小于混交林中的杉木(P<0.01).10年生杉木桤木混交林的土壤性质(主要是0-10 cm和10-20 cm层次的速效性养分、全N和有机质)比杉木纯林有所改善,但只有水解性N在0-10 cm和10-20 cm层次显著(P<0.05)高于杉木纯林.

Growth and soil fertility of a mixed plantation of Chinese fir with Alnus cremastogyne

Pure Chinese fir plantation and mixed plantation of Chinese fir with Alnus cremastogyne were established in the cutover area of a first-rotation Chinese fir plantation with site index class 18 in Xiayang,Nanping City,Fujian Province,China.Ten years after planting,growth and soil properties of the 2 types of plantations at the sites with the same site conditions were studied.The results showed that stand volume of the mixed plantation was higher than that of the pure Chinese fir plantation,but the difference is not significant(P>0.05).Mean diameter at breast height(DBH),height and single-tree volume of the Chinese fir in the mixed plantation were significantly (P<0.05) higher than those in the pure plantation.But A.cremastogyne grew poorer than the Chinese fir in the mixed plantation,with DBH and single-tree volume significantly(P<0.01) lower than those of the Chinese fir.Soil properties(mainly available nutrients,total N and organic matter at 0-10 cm and 10-20 cm soil layers) of the 10-year-old mixed plantation of Chinese for with A.cremastogyne were improved compared with the pure Chinese fir plantation.But only hydrolytic N at both 0-10 and 10-20 cm layers significantly(P<0.05) higher than those in the pure Chinese fir plantation.