施肥草地群落生物量结构的研究

Biomass Structure of Fertilized Grassland Communities

宁南黄土丘陵区干草原地带，由于频繁垦植，形成了大面积的草地退化，许多空间呈现出次生类群和裸地。针对这一现象，于１９９１～１９９４年在该区进行了草地施肥试验，结果表明：该草地类型区通过不同施肥处理，促进了植物的繁殖更新与群落的种间结构变化。而随着时间的延续，长芒草群落和百里香群落生物量的结构层次明显，优良牧草占的比重大，生物产量高。同时，影响该区草地生物量增长速度的限制因子除肥而外，更重要的还有水热条件。只有充足的肥力和适宜的水热条件相互配合，才能获得较高的生物产量，次生裸地的植被即能在２～４ａ内迅速恢复，可为草地建设及畜牧业的发展提供依据。

Due to frequent cultivation, serious degradation in native vegetation has taken place on the dry grassland in the hilly loess region of southern Ningxia. In many places the land has been occupied by secondary communities or has become bare. In order to re-establish the vegetation, a trial of fertilizer application on the grassland was carried out during 1991～1994. It was shown that fertilizer application positively affected plant reproduction, vegetation renewal and the composition of plant species within communities. With the elapse of time after fertilizer application, the biomass composition was becoming clearly stratified in both of Thymus mongolicus and Stipa bungeana communities, with an increased percentage and biomass yield of quality forage species. Native vegetation could be re-established on the degraded bare land within 2～4 years through fertilizer application under adequate moisture and temperature conditions.