Litter Decomposition Characteristics In Different Habitats In Extreme Arid Area

In the deep continent of the Tarim Basin,the ecological environment is fragile and highly heterogeneous.Different habitat types are formed under the influence of local topography,light conditions,water conditions,and salt conditions.Litter decomposition is the main way of material circulation and energy flow in the ecosystem.Understanding and understanding the law of desert vegetation decomposition in arid regions is of great significance to the desert ecosystem material circulation.Using the litter bag method,720 d decomposition tests were carried out on the litter of Populus euphratica,Tamarix Ramosissima,and Glycyrrhiza inflata in desert arid areas,arid habitats,and seasonal flood overflow habitats.By analyzing the decomposition characteristics of litter,the release dynamics of each major element composition,and the restriction factors of litter decomposition in various habitats,the nutrient release process of plant communities in various habitat is revealed,which provides data support for the study on litter decomposition of plant communities in arid desert areas.The following main conclusions are drawn:?1?During the observation period,there are differences between the quality residual rate values of the three dominant desert litter species in various habitat,which are as follows:P.euphratica litter mass residual rate values,halo habitat?73.73%?>arid habitat?66.75%?>Seasonal flood overflow habitat?26.27%?;Tamarix litter mass residual rate values,salt habitat?86.66%?>arid habitat?70.69%?>seasonal flood overflow habitat?16.23%?;G.inflata litter mass residual rate values,arid habitat?58.76%?>salt habitat?46.63%?.Affected by the environmental differences between different habitats,the same plant species have different rates of litter decomposition in different typical habitats.?2?During the observation period,the decomposition coefficients of the three dominant litter species in various habitat differed in the typical habitats,as follows:the decomposition coefficient values of the three dominant litter species in the saline habitats were K_0.99a>K_1.97a,the litter decomposition coefficient value of the three dominant desert species in arid habitats and seasonal flood overflow habitats is K_0.99a<K _1.97a,the larger the decomposition coefficient K value is,the smaller the t_0.5 and t_0.95 values are.The shorter the time required,the total amount of soil salt is the main factor affecting the decomposition rate of litter 0-360 d and 360-720 d.?3?Decomposition of the three desert dominant species litter in various habitat during the observation period,and the difference between the residual rate of each element in the typical habitat.The performance is as follows:3 kinds of litter C elements between the salt habitat and the arid habitat There is a very significant difference between them;There is a very significant difference between the two types of litter lignin between the salt habitat and the seasonal flood overflow habitat;The C,N and P elements of the two types of litter between the arid habitat and the seasonal flood overflow are both There are very significant differences.?4?Different treatments?inner forest and forest gap?of P.euphratica,Tamarix,and G.inflata litter residue rate difference,the performance is:H₂P₁?66.36%?<H₂P₂?67.15%?,H₁T₁?85.77%?<H₁T₂?87.64%?,H₂T₁?88.09%?<H₂T₂?88.16%?,H₂G₁?86.43%?>H₂G₂?79.22%?;After 720 d decomposition of P.euphratica and Tamarix litter residue rate value forest gap>forest,The residual rate of litter of G.inflata litter was within forest>gap.The loss of C element caused by strong light radiation under different treatments is an important factor affecting the decomposition of litter.?5?There are significant differences in soil water content,total soil salt content,soil K⁺,Na⁺,Ca²⁺,CO₃^2-,SO₄^2-,Cl^-between the salt habitat,arid habitat and seasonal flood overflow habitat.Differences between micro-environments and climates will also have extremely significant or significant differences between soil physical and chemical properties under long-term influence.?6?The main factor affecting the K value of the litter decomposition coefficient in the saline habitat is the cellulose residual rate,and there is a very significant positive correlation between the cellulose residual rate and the decomposition coefficient K value.The K value of the decomposition coefficient of P.euphratica litter showed a very significant linear relationship with the residual rate of cellulose,residual rate of mass and cellulase;The decomposition coefficient K value of Tamarix litter had a very significant linear relationship with the residual rate of polyphenol oxidase,cellulose,and residual mass;The decomposition coefficient K value of the litter of G.inflata litter showed a linear relationship with the residual rate of cellulose.?7?The main factor influencing the decomposition coefficient K value in arid habitat is the mass residual rate,and there is a very significant negative correlation between the mass residual rate and the decomposition coefficient K value.The decomposition coefficient K value of P.euphratica litter showed a very significant linear relationship with the residual rate of mass,catalase and total C;The decomposition coefficient K value of Tamarix litter had a very significant linear relationship with the mass residual rate and total N;The K value of the litter decomposition coefficient of G.inflata litter showed a very significant linear relationship with the residual rate of mass and the residual rate of cellulose.?8?The main factors affecting the decomposition coefficient K of litter in seasonal flood overflow habitats are the mass residual rate and soil moisture.There is a significant negative correlation or a very significant negative correlation between the mass residual rate and soil moisture and the decomposition coefficient K,respectively.Related.The decomposition coefficient K value of P.euphratica litter showed a very significant linear relationship with the residual rate of mass and total salt content,and a significant linear relationship with soil moisture;The decomposition value K of Tamarix litter showed a significant linear relationship with the residual rate of mass and soil moisture.The litter decomposition of dominant species in three various habitats under arid and climatic conditions is as follows:the litter decomposition characteristics of the same species in different various habitats are significantly or very significantly different,the habitat conditions are different,and the factors affecting the litter decomposition are also different.Due to the differences in habitat conditions between the various habitats,the main influencing factors are also different.The factors affecting the decomposition of different litters in the same habitat are basically the same.