间伐与施肥对柳杉近熟林土壤养分及林木生长的影响

通过设置间伐施肥、间伐未施肥、未间伐未施肥3种处理，研究广西六万林场柳杉人工纯林间伐与施肥措施对土壤养分及林木生长的影响，测定土壤N、P、K 有效性与林分平均树高、胸径。结果表明，在0~20 cm 土层中，间伐施肥林地的速效钾含量与未间伐未施肥林地间差异显著，但有效磷和水解氮含量变化不明显；20~40 cm 土层中，土壤养分含量变化不规律，差异均不显著。间伐施肥处理下的林分比其他两种处理条件下林分的林木树高及胸径生长量要高，间伐施肥条件的林木胸径生长与未间伐未施肥林分间存在极显著差异。水解性氮与柳杉林木胸径生长有显著相关性，上层土壤速效钾含量与上、下层土壤有效磷含量存在极显著相关性。间伐、施肥的同步实施可改善林地养分环境，提高柳杉近熟林林分生长水平。

Effects of thinning and fertilization on soil nutrient andtree growth in near mature Cryptonmeria fortunei plantation

The impacts of thinning and fertilization on soil nutrient and tree growth in near-mature plantation of Cryptonmeria fortunei were studied by setting up three treatments, including thinning plus fertilization, thinning withoutfertilization and no-tending measures, respectively. The nutrition N, P, K in soil and the height and DBH of plantation wereinvestigated and analyzed. The results showed that at the 020 cm layer, the content of available K showed significantdifferences between the treatments of thinning with fertilization and no-tending measures, while the contents of available Pand hydrolysable N didnt significantly change with different treatments. The content of soil nutrients changed irregularlyand not significantly at 20 40 cm layer. The growth increments of height and DBH in the thinned and fertilized plantationwere higher than those in the other treatments, particularly, the growth of DBH had very significant differences between thethinned and fertilized stand and no-tending measures stand. The significant correlation was observed between the contentof hydrolysable N and the growth of DBH. In addition, the highly significant correlation exited between the content ofavailable K at upper layer and the content of available P at both layers. The thinning and fertilization improves the nutrientenvironment and increases the growth level of near mature C. fortunei plantation simultaneously.