The Characteristic Of "Fertile Islands" Of Tamarix L. In Xinjiang

The desertification is the global significant environment problem,the desertification area in Xinjiang is the biggest in China. Under the arid wilderness severe habitat, there are large area Tamarix in north and south xinjiang. Studied on characteristic of"fertile island"Tamarix has a great reality means in protecting and restructing ecological environment of arid-area, and also has theoretical value in soil-plant interaction mechanism,Restoration Ecology,pedology,desertification land manual prevention facts. The research was based on Geo-statistics and GIS technology, studied soil characteristic of"fertile islands"Tamarix shrubs in.FUKANG of north XINJIANG and Tarim River of south XINJIANG. The results indicated:1,In two study-areas, soil nutrients under Tamarix were canopy center higher than canopy edge and canopy outside, canopy edge and canopy outside have not remarkable difference, the difference of withered Tamarix in Tarim river was not remarkable. The same sampling pot was silt percentage>Sand percentage> clay percentage. Namely the silt occupied the dominant position, sand and clay next best. The sand of canopy center was bigger than that of canopy edge and canopy outside; silt and clay of canopy center were smaller than that of canopy edge and canopy outside. There were mainly KCl and NaCl in soil salinity of Tarim River, and KSO4,NaSO4 in Fukang. The total salt content of Tarim River crown inside and outside overall was not obvious rule; the total salt content of Fukang canopy center was smaller than canopy edge and canopy outside. pH value in Tarim River and Fukang presented the opposite tendency, pH value was decreasing from"inside island"toward"outside island"progressively in Tarim River, whereas it was increasing in Fukang.2,The soil nutrients enrichment ratio were all over 1, it meaned soil nutrients in Tamarix were enriched. Withered-Tamarix in Tarim river was also over 1, it showed that the process of formation and dissipation of"fertile islands"needed a long term.Soil nutrients enrichment ratio in different growth stages had not extremely remarkable difference in two areas except the available phosphorus of big Tamarix. This indicated that growth stages of tamarix has little influence to the"fertile islands"intensity. Soil texture in two research area was silt-sand context, the sand was enriched, the silt and the clay were not concentrated nearly. Root concentration rate of Mg²⁺,K⁺+Na⁺,SO₄^2-,HCO₃^- in Tarim River was higher than crown edge, presented the salinity"the ion island"effect. Root enrichment rate of Ca²⁺,Mg²⁺,HCO₃^- and Cl^- was higher than crown edge in Fukang, and the enrichment ratio was over 1. Total salt and pH value enrichment ratio in Tarim River was that the root's was overall higher or equal to a crown edge, however, in Fukang the root's was lower than crown edge's. This indicated that some soil chemistry spatial pattern under and between the brush had relationship with the research area's concrete environment.3,Tamarix soil nutritions"fertile island"sphere of action in Tarim River was 6.2-10.1 m scopes, 4.1-14.8 m in Fukang. In Tarim River and Fukang sampling range were 4.4m and 8.5m, respectively. Fukang Tamarix canopy was 2.61m, Tarim River Tamarix canopy was 3.82m. This indicated the Tamarix effective range was outside canopy. Tarim River and Fukang's soil nutritions nuggets and sill ratio value (C0/C0+C) were less than 25% except Tarim River's available potassium and this assumed it had intense spatial relevance, and its variation was mainly caused by the structure factor. Tarim River particle size range overall was higher than that of Fukang, it was also Consistent with Tamarix canopy. Effective ranges were all canopy outside. Tarim River salinity ion range were among 7.4-71.0m, Fukang 0.7-7.6m, the effective range far exceeded canopy outside.4,Tarim River and Fukang Tamarix soil profile's nutrients range except Tarim River alkaline hydrolysis nitrogen and the Fukang available potassium≥1m, others were less than 1m. The soil profile sampling depth was 0.8m, it showed the sampling depth was reasonable. Tarim River and Fukang's total salt and pH had intense spatial relevance, and the range is less than 1m. Tarim River soil nutrient's sphere of action only had remarkable difference in surface layer 0-20cm and 20-80cm, Fukang 0-40cm and 40-80cm. It was the difference of climatic conditions between two research areas that caused the soil development degree different. soil development degree in Fukang is better than Tarim River. Salinity ion totally was remarkable different in surface layer 0-20cm and 20-80 cm in Tarim River and Fukang. This indicated that the salinity ion drenched melts and moved downward from the surface layer weakly. It was consistent with the rainfall amount and the transpiration rate intensity in two research areas.