不同干扰条件下荒漠区土壤种子库

在内蒙古阿拉善荒漠区选择开垦、轮牧、过牧和禁牧4种不同干扰条件的样区,于2005年4月(春)、7月(夏)和10月(秋)分别对土壤种子库取样,并在实验室条件下进行发芽试验,得出如下结果:(1)4种不同干扰区在春、夏、秋三个季节土壤种子库可萌发种子平均数量分别为,开垦干扰:688粒/m2;轮牧干扰:1328粒/m2;过牧干扰:1488粒/m2;禁牧干扰:944粒/m2;(2)开垦区与禁牧区在4月份(春)、7月份(夏)、10月份(秋)土壤种子库可萌发种子数量呈连续上升趋势,而轮牧区与过牧区则呈先上升后下降趋势;(3)4种不同干扰条件下,开垦区、过牧区和禁牧区在不同深度土层中水分含量均无显著差异;而轮牧区0-5cm与其它三个土层中水分含量出现显著差异,而且0-5cm土壤层的水分含量与种子的萌发数量呈显著正相关。

The Soil Seed Bank in Desert Region Under Different Disturbance

The farmland,rotational grazing,over grazing and fenced grazing areas were selected as four kinds of disturbances areas in which the soil seed banks were sampled in the Spring,Summer and Autumn respectively in 2005 in Alashan Desert of Inner Mongolia.All of the seeds were conducted for germination test in the laboratory.The results showed that(1) in three seasons,the numbers of germinated seeds under four different disturbances were as follows: farmland area 668 grains/m2;rotational grazing area 1328 grains/m2;over grazing area 1488 grains/m2;fenced area 944 grains/m2.(2) The numbers of germinated seeds of soil seed banks in farmland and fenced areas in three seasons showed trends of continued raising,but these in rotational grazing and over grazing areas showed trends of raising and then declining.(3) Under four different disturbances,the water contents in different soil depths in farmland,over grazing and fenced areas were not significantly different.But the water contents in soil depths between 0-5cm and other three depths in rotational grazing area showed significant difference and the water content in soil depths in 0-5cm in rotational grazing area was positive related to the numbers of germinated seeds.