砒砂岩区沙棘人工林雌雄分异规律

雌雄分异规律的研究对于晋陕蒙砒砂岩区沙棘生态工程的建设具有十分重要的意义。通过对36块沙棘人工林标准地的调查统计发现：这一地区沙棘人工林雌雄比例平均为1：2．6;低龄时雄株比例很高,其数量甚至可达雌株的10倍;而在5～8年生时,雌雄比例变化渐趋平缓,基本上在1：2左右波动;冲积土、风沙土（盖沙黄土）、黄土基质上生长的沙棘人工林,其雌雄比例约为1：2．2～2．4,而砒砂岩上的沙棘雌雄比例为1：3．4。严酷的自然生态环境条件,是当地人工林中雄株比例明显居多的主要原因。以采果为主要经营目标的“经济型”或“生态经济型”沙棘林,应当建立在生态条件相对较好的沟谷川滩地段,适度追求经济效益;条件严酷立地应当建设“生态型”沙棘林,采取切实措施加以保护,充分发挥其水土保持、涵养水源和防风固沙等效益。

Female and male proportions of artificial Hippophae rhamnoedes ssp.sinensis forest in soft sandstone area

Hippophae rhamnoedes ssp.sinensis is a very suitable shrub for afforestation in the northern China especially in the Loess Plateau,which has been planted for more than twenty years in China under the careful design and strong management.The ecologic and economic benefits of which have been achieved,and play a key role to increase farmer and enterprises' incomes.The sex ratio rule of dioecious species is very important for the rehabilitation with seabuckthorn in the soft sandstone area of the adjacent area of Shanxi,Shaanxi,and Inner Mongolia of China.Survey and statistics for 36 kinds of artificial sea-buckthorn stands show that the female ratio to male is 1∶2.6 as a whole,while the male quotient of young stand is very high with the highest of 10 times as high as that of female,and the female ratio to male is about 1∶2 or so for 5 to 8 year's old stands.The female ratio to male for alluvium,sand soil,and loess is 1∶2.2-2.4 whereas the ratio is 1∶3.4 for the forest in the soft sandstone site condition.Rigorous site conditions in the research area cause the more proportions of male plants.Economic or eco-economic types of Hippophae rhamnoedes ssp.sinensis forest or cash forest should be set up in good site conditions like the bottomland in wide valley for more economic benefits,while the ecological type of Hippophae rhamnoedes ssp.sinensis forest in bad site conditions for ecological benefits consideration.