关键词: 植树造林, 土壤水分亏缺, 兰州市南北两山, 黄土高原

Abstract: By position-monitoring and comparatively analyzing, we studied the soil water deficit degree and the spatio-temporal distributions of compensation degree of plant water storage deficit in a plantation site under different water administration measures in the southern and northern mountains of Lanzhou city. The results showed that the deficit degree of plant water storage in irrigative plantation was the smallest, it was less than 20% in most times, the deficit situation in plantation with natural slope water-harvesting was better than that in non-irrigative plantation. Although the deficit degree of soil water of plantations under the three different disposal methods (sprinkling irrigation, natural slope water-harvesting, non-irrigation) was some different, all of them were on the condition of plant waters severe deficit. Besides satisfying with plant's growing, compensatory irrigation could compensate some soil water, the compensation degree was about 70%. The compensation degree of non-irrigative plots was negative, which showed that there was no compensation for soil water in whole rainy season in these plots. The spatial change of plant water deficit degree had relation with the distribution of plant root. In level direction, the deficit degree of plant water decreased along with the increase of distance from the root crown. In vertical direction, the deficit degree of plant water in surface layer was the minimum, along with the increase of depth, the deficit degree increased, in 100~200 cm layer it was the maximal, then it decreased gradually. The compensation degree of plant water was the reflection of rainfall and plant water deficit degree, the higher the deficit degree of plant water was, the bigger the compensation degree was.

Key words: afforestation, soil water deficit, southern and northern mountains in Lanzhou city, the Loess Plateau