Study On Activities Of Soil Enzyme In Rhizosphere Of Psammonphyte In Minqin Oasis-Gobi Ecotone

The impact of change of water supplies and underground water depth on the pH, the activities of cellulase, catalase and urease of rhizspheric soil of hedysarum scoparium, Haloxylon ammodendron and Calligonum mongolicum were studied at the Plant Transpiration Consume Water Observation Station in Minqin Desert botanical Garden, Gansu province. In the experiment, the depths of groundwater(DGW)were set at three levels as 1.4m, 2.4m and 3.4m. Water supply were treated at Okg, 15kg and30kg/month-m2 artificially .The results show that:1) the three different DGW treatments resulted in a marked changes of soil moisture, pH, activities of cellulase, urease and catalase of hedysarum scoparium and Haloxylon ammodendron. In same DGW,activities of cellulase,catalase and urease of Haloxylon ammodendron and Hedysarum scoparium decrease with increment of depths of soil layers The activities of celluase and catalase of hedysarum scoparium is lower than Haloxylon ammodendron 's,the same trends were observed with increment of DGW,activities of urease of Haloxylon ammodendron is higher than hedysarum scoparium's at 1.4m,and lower than hedysarum scoparium's at 3.4m.At same soil layer,water content of hedysarum scoparium and Haloxylon ammodendron.decrease, pH increase with increment of DGW; activities of cellulase and catalase of Hedysarum scoparium and activitie of catalase of Haloxylon ammodendron is highest at 1.4m,lowest at 3.4m, activities of urease of Hedysarum scoparium and activities of cellulase and urease of Haloxylon ammodendron are highest at 2.4m.lowest at 3.4m2) Different water supplies significantly affected water content, pH, activities of cellulase, urease and catalase of Hedysarum scoparium and Calligonum mongolicum. Content and pH increase with increasing water supplies.The activities of catalase of Hedysarum scoparium and activities of cellualse of Calligonum are highest in the same soil layer in 0kg/month water supplies,lowest in 30kg/month water supplies Activities of cellulase and urease of Hedysarum scoparium , activities of catalase and urease of Calligonum mongolicum are highest in the 15kg/month water supplies,lowest in the 30kg/month water supplies.In the oasis-Gobi ecotone,the depths of groundwater increase, quantity of irrigation water overaboundance ,could depress activities of soil enzyme in therhizosphere of hedysarum scoparium, Haloxylon ammodendron and Caliigonum mongolicum,and eliminated C, N cycle of interfacial between soil and plant in the rhizosphere...