西鄂尔多斯沙冬青(Ammopiptanthus mongolicus)平茬效应初探

Effectes of Cutting on Ammopiptanthus mongolicus in the Western Ordos Plateau,Mongolia,China

在西鄂尔多斯国家级自然保护区，对天然珍稀濒危植物沙冬青（Ammopiptanthusmongolicus）灌丛进行机械平茬。平茬后，萌芽时间提前了7d左右，经过3年的生长完全恢复到平茬前的生物量，新萌生的一级分枝平均长度可达70．5cm，基部直径15．72mm2同时，分析了平茬沙冬青种群的结构动态和土壤结构的变化。结果表明：依靠人工平茬改善种群结构，对沙冬青衰老株和干枯枝进行及时刈割更新复壮，最后形成了过渡类型结构介于稳定和衰老之间，即幼年植株比例低于稳定型而高于衰老型、壮年植株比例低于稳定型而高于衰老型，形成具有潜在恢复能力的种群结构。并且通过减少死亡植株对水分的消耗，使平茬区O～80cm土层3年平均含水率较未平茬区的高出0．57％。

The western 0rdos Plateau of National Nature Reserve is a distribution center of many endangered shrub species such as Ammopiptanthus mongolcus. The effects of cutting on A. mongolicus were re searched. After the cutting, the germination time was ahead about 7 d than the controlled plants. The bio mass of the stubbles had completely restored in three years. Branch length of coppice shoot is 70.5 cm. Branch diameter of coppice shoot is 15.72 mm. Dynamic variations of the stubble population structure and soil structure revealed that cutting the cradling aging plants and deadwood could reduce the water consump tion. Therefore the population structure between stable type and decline type with potential recovering ca pacity was formed, in which the ratio of young individual was higher than that of the decline type but lower than that of the stable type. It can improve population structure. The soil moisture in cut woodland is 0.57% higher than controlled plot.