日本中部不同放牧条件下人工草地地上枯死量的时间变化

日本国立草地研究所位于日本中部的西那须地区,为了提示草地生态系统的能流和碳循环与气象因素与人为干扰之间的关系的规律,在其所辖人工草地的放牧试验场内,自1974a至1994a间,进行了不同放牧条件的长期实验。对该人工草地在21a间的地上枯死量(包括立枯部和地面凋落物)随时间变化规律以及不同放牧处理(不同放牧强度和施肥量)对其影响进行了评价和分析。结果表明,地上立枯部分和凋落物的量随季节和年度变化很大,并与地上部现存生物量有显著的正相关关系;协方差分析结果表明放牧压力、季节和年度等变化因素对地上立枯部分和凋落物的量有着极强的影响(p<0.01),而施肥量的影响则无显著性差异。

Temporal changes in aboveground dead material under different grazing conditions in a snow pasture in central Japan

In order to understand the relation between primary production, energy flow and carbon recycle in grassland ecosystem, climatic factors and artificial disturbance, a grazing experiment with different grazing management treatments (different grazing intensities and nitrogen applications) was carried out in a snow pasture of the National Grassland Research Institute located in Nishinasuno, the central area of Japan from 1974 to 1994. As a part of these studies, the aim of present study was to assess the temporal changes in aboveground dead material (standing dead and litter) over a 21-year period since 1974. The result showed that the amount of aboveground dead material varied greatly seasonally and yearly, and also tended to have a high positive correlation with the aboveground biomass. The result of an analysis of variance (ANOVA) showed aboveground dead material was influenced strongly by grazing intensity, year, month (P<0.01), the temporal changes of aboveground dead material were independent of the nitrogen application levels.