罗望子人工林凋落量及养分归还特征

Characteristics of litter production and nutrient return in Tamarindus indica Linn plantation

通过对金沙江干热河谷元谋县境内2种不同林分的罗望子人工林的年凋落量和养分归还进行分析和研究,结果表明:罗望子人工林成林和嫁接林年凋落量分别为9.61和3.44t·hm-2,落叶比例分别是41.75%和73.79%。成林凋落量月变化表现为不规则的三峰类型,凋落最高峰出现在3月份,其余2个弱峰出现在5月份和11月份。嫁接林凋落量月变化表现为双峰类型,凋落最高峰出现在3月份,另一个弱峰出现在11月份。罗望子自身的生物学特性是影响林地凋落量年动态的内在主导因子,3种气候因子对凋落量的年动态影响较小。凋落物养分归还与林分和凋落物的组分有明显的相关性,且均以N、K、Ca归还最多,Cu归还最少。成林中,落叶、落花和落果是N、P、K、Cu归还的主要来源,落叶是Ca、Mg、Fe归还的主要来源。嫁接林中,落叶是所有养分归还的主要来源。与其他亚热带人工林相比,罗望子人工林凋落量大,养分归还量高,有较好的自养能力,是金沙江干热河谷和类似区域植被恢复与生态系统修复的优势林地,同时,也是促进区域经济发展的一种较佳林地类型。

This study was carried out to investigate the litter yield and its dynamics, as well as the litter＇s nutrient returning into soil for the two different artificial forests of Tamarindus indica Linn in Jinsha river dry-hot valley of Yuanmou, Yunnan Province of China, including a mature forest （A） and an inoculated forest （B）. The results showed that annual litter yield is 9.61 t · hm^-2 and 3.44 t · hm^-2, and leaf litter accounts for 41.75% and 73.79% of total litter in the forest A and in the forest B, respectively. Litter yield in the forest A showed irregular dynamics with three peaks in March, May and November, while in the forest B with two peaks in March and November in a year. This dynamic characteristic is more affected by the inherent biological characteristics of T. indica than by climatic factors. Nutrient return of litter significantly correlated with litter components and stand. Returns of N, K and Ca are the most from litter, and that of Cu is the least. Litter leaves, litter flowers and litter fruits axe main sources of N, P, K and Cu returnning in the forest A, and litter leaves are main sources of Ca, Mg, and Fe returnning. Litter leaves are main sources of all nutrients returnning in the forest B. The results of this study suggested that T. indica plantation had a greater capability of maintaining soil productivity than other sub-tropical plantations, due to its higher litter yield coupled with more nutrient returns, therefore T. indica plantation will be favorable for vegetation, restoration and promoting regional economic development in Jinsha River dry-hot valley and similar regions.