关键词: 洛川旱塬, 苹果园地, 土壤水分, 土壤养分, 深层土壤

Abstract: ased on the field survey data, fecundity schedules of Picea mongolica population on sandy land were established and a series of parameters of population increment was calculated. Stability of the spruce population was analysed according to R.May's stability theory and the parameters of population increments in this paper. The results are as follows: Intrinsic increment rates of the spruce populations in mixed spruce forest, spruce forest with grasses, spruce forest with grasses and mosses are higher, but generation length of above spruce population is shorter. Owing to environmental conditions on sandy land,the spruce population must increase its reproductive rate to gainitself stable existence by large consumption of sapling pool. When it is disturbed, so long as disturbed intensity is not too strong and with suitable protective measures, spruce population will sustainedly exist on sandy land in the Inner Mongolia.

Key words: Luochuan highland, apple orchard, soil moisture, soil nutrient, deep layer soil.