宁夏六盘山落叶森林凋落与枯落物分布及持水特性的研究

本文通过对宁夏六盘山不同森林类型的凋落动态与林下枯落物层的厚度、贮量及其持水特性的研究,揭示了该区不同森林类型林下枯落物层在不同时期的水文生态功能。结果表明:不同森林类型在生长季末期的凋落都具有明显的周期性规律,凋落比率随时间变化的规律一致,凋落从8月下旬开始,红桦与椴树混交林的凋落在10月中旬结束,华北落叶松纯林和白桦与糙皮桦混交林的凋落在10月下旬结束,而辽东栎纯林的凋落会持续到次年;林下枯落物层的厚度在2.0 cm~6.0 cm之间,贮量在10.72 t/hm2~28.73 t/hm2之间;除华北落叶松林林地枯落物在浸泡6h时达到最大持水量外,其余3种落叶阔叶林林地的枯落物各层次均在浸泡3h时就达到最大持水量;枯落物未分解层的最大持水率在2.81~4.47之间,半分解层的最大持水率在3.80~4.32之间。经分析拟合,得到枯落物未分解层与半分解层持水量、持水速率与浸泡时间之间的关系分别为Q=ktn和S=ktn。

THE RESEARCH OF LITTERFALL AND LITTERE DISTRIBUTION AND ITS CHARACTERISTICS OF THE HOLDING WATER OF DIFFERENT DEFOLIATED FOREST IN LIUPAN MOUNTAINS OF NINGXIA

In order to study the hydro-ecological effects of defoliated forests in Liupan Mountains of Ningxia in different periods.Studies on dynamic process of litterfall and thickness,amount and characteristics of contained water of defoliated forests litter showed that litterfall obeys an obvious seasonal rules and the change of the litterfall rates were consistent.The litterfall begins at the last days of August.Fixed Betula albosinensis-Tilia paucicostata forest litterfall is over at the middle the days of October,Larix principis-rupprechtii Mayr pure forest,Fixed Betula platyphlla-Betula utilis forest were at the last days of October,but Quercus liaotungensis pure forest will last to the next year.Thickness of the litters above the forest ground ranges from 2 to 6 cm,amount of the litters ranges from 10.72 to 28.73 t/hm2.The litters on the defoliated broad leaved forests ground became saturated after 3 hours dripping in the water and the defoliated coniferous forest is 6 hours.The maximum specific retention of the non-composed litters ranges from 2.81 to 4.47 and the semi-composed litter ranges from 3.80 to 4.32.The equations of water-holding capacity,specific retention of litter with immersing time are Q=kt~n and S=kt~n respectively.