Vegetos

Abstract

In arid land, water is a limiting factor, the distribution and species of vegetation are greatly affected by water supply. Moss crust is the main components of biological soil crusts (BSCs), it plays an important role in water retention than crusted lichen and algae and generally, moss crust remain distributed in patches. This paper focuses on further explaining the reason that moss crust distribute in the form of different sizes patches from the point of water using. In this study, sizes of moss crust was calculated by Photoshop CS 5.0, dew deposition and water evaporation were measured by micro-lysimeters, soil water content was analyzed by drying oven. The results showed size effect of moss crust on water evaporation which was not consistent, smaller patch evaporated slowly but later, they evaporated fast and large patch evaporated slowly; the medium-size patch showed the greatest deposition ability, and the smallest exhibited the least; there was heterogeneity of soil water content of moss crusts patches, the waterisland of moss crust was a little smaller than patch size; usually, water content of moss crusts patch decreased from center to edge. In whole, medium size patches showed high water using efficiency, it was one of the reasons why there were few large moss crusts patches in the Gurbantunggut Desert. We inferred preliminarily it was a tactic to raise water using efficiency for moss crusts to distribute in patches.