Effect of field covering with plastic and straw on agricultural ecology of apple orchard in arid desert area

The effects of different saving water measures on soil water content(SWC)，temperature and fertility，as well as growing and fruiting were studied including mulching with straw，plastic and both of them in apple orchard of arid area．The results show that SWC of root-room from 0 tO 60cm depth is increased with water saving measures．Its highest increase occurs in May and June when apple tree is in the course of water-demanding and the contradiction between water supply and demand is eased up．The so“temperature increases obviously at the depth from 0 to 45cm with mulching either plastic or plastic and straw in the growing season．But the soil temperature is lower in the early season only under strawm ulching，however，higher than CK in the later season．The budding and blooming will be delayed because of lower ternperature with straw mulching in spring in comparison with CK，thus the frosly injury can be avoided or at least lightened Also，the contenls of soil organic matter，N，P and K available are increased，and the bulk density is decreased forln 0．019 to 0．133g／cm³．As a result．the mean length of annual shoot and the single leaf area increase by 16．4％～39．4％and 2．7～3．86cm²．respectively．The yield and quality of apple are enhanced．increasing the soluble solids form 0．9％ to 1．2％ and the yields from 1710 to 2460kg／hm² ．