Charateristics Of Ecological Stoichiometry Of Oasis Farmland Ecosystem In The Northern Marigin Of Tarim Basin

The ecosystem is the functional unit of the interaction between the biological and the external environment.The change of the nutrient elements such as carbon,nitrogen and phosphorus in the ecosystem will strongly affect the nutrient cycling process of the ecosystem.Farmland ecosystem is an important part of oasis ecosystem,which is a relatively stable whole,which is the energy exchange,material circulation and information transfer between the crop population and the soil.C,N and P are important elements of plant growth and development,and also a key indicator of soil fertility.The relationship between crop and soil C,N,P and its stoichiometric ratio can be studied in depth,and the relationship between crop and environment can be deeply understood by the relationship between crop and environment.Eco-chemistry metrology provides a new idea and theoretical basis for exploring the dynamic changes of C,N and P chemical elements in the process of crop growth.In this paper,the ecological and chemical characteristics of C,N and P in the three crops and their soils were analyzed by using wheat,maize and cotton in the Oasis farmland of Tarim Basin.The relationship between the three crops and soil ecological chemical characteristics was also explored.The main conclusions are as follows:(1)There are some differences in the ecological and chemical characteristics of C,N and P in wheat,maize and cotton crops in the oasis of the northern Tarim Basin,and there are some differences with the growth period.The content of C,N and P in maize were the highest among the leaves,and the contents of C,N and P in maize were the highest among bracts,leaves and spores.The C content in cotton was the highest among the leaves,N and P were the highest in the buds.The three crops are limited by the N and P elements.In the early stage of growth,the elements absorbed by the three crops were used to meet the growth of vegetative organs.Wheat heading date,maize tassel stage,cotton flower bloom period were the strong growth period of each crop,and also the vegetative growth and reproductive development The same stage of occurrence;maize ripening period and cotton boll opening period are their growth end.Crops at different times can adapt to environmental changes by adjusting the nutrient changes in different organs and their stoichiometric ratios.(2)Soil chemical metering is an important indicator of the character and condition of soil nutrient elements.The contents of C,N,P in the three crops was lower than the national level(1112,1.06,0.65 mg.g-1);C / N,C / P and N / P of the three crop soils were also lower than the national level(12.01,25.77,2.15).The C,N,P chemical metrological characteristics of the three crop soils also showed some differences with the growth period.The content of C,N and P in wheat soil decreased gradually from seedling stage to mature stage,and the content of C,N and P in maize soil decreased first and then increased from seedling stage to maturity stage.The content of C,N and P in cotton soil decreased from the seedling stage to the baking stage,and the content of N and P decreased first and then increased.This difference is mainly related to the fertilization of farmers,the use of fertilizer and the amount of different formulations.Therefore,soil nutrient characteristics and change.(3)There is a large difference in the internal stability between different crops,organs and elements.In this study,the contents of C,N and P in the wheat,maize and cotton organs showed a constant trend with the seasonal stability index.From the seedling stage to the mature stage,the internal stability index of C and N elements in wheat was the largest in the leaves,and the P element was the largest in the root.From the seedling stage to the mature stage,the internal stability index of the C element And the N and P elements are the largest in the stem.From the seedling stage to the boll opening stage,the C and N elements of the cotton have the largest internal stability index,while the P element is the largest in the leaves.(4)In addition,the ecological and chemical characteristics of C,N and P in wheat,maize and cotton were different in the growth period and the single factor of organ and the interaction of two factors.The effect of the growth period on the ecological and chemical characteristics of the crop is related to the physiological characteristics of the crop phenology.The influence of the organ on the ecological and chemical characteristics of each crop is related to their own structural and genetic characteristics,so the growth period and season are different The extent of the crop is different.(5)There is a certain correlation between different crops and soil C,N,P ecological chemical measurement characteristics.There was a significant positive correlation between C and N contents in soil and P content in soil,and P content was only negatively correlated with soil C: P.There was a significant positive correlation between P content and P content in soil.The content of N in cotton was higher than that in soil C,N and P content,P content and soil C content showed a very significant positive correlation.This indicated that the nutrient content of each crop was affected by crop species and soil nutrient characteristics,which also explained to some extent that the correlation between some nutrient elements and the soil was not significant.