Research On Ecological Stoichiometry Of Degraded Grassland

Being influenced by natural and human factors, the grassland in western Jilin hasdegraded significantly, which lead to the outflow of C, N, P in soil and interfere the plantgrowth. Moreover, this phenomenon has critical impacts on the development of grazieryand the stability of ecosystem. Many scholars have done many researches on the currentsituation, reasons, succession, restoration of grassland degradation, but the research on micro-element perspective is still relatively weak.Therefore, this arcticle reaearchsgrassland degradation from the elements perspective,draws the key elements affectinggrassland degradation.This can provide scientific guidance to ease the grasslanddegradation, recovery and reconstruct the harmonious ecological environment ofgrassland.Based on the the ecological stoichiometry stability theory and the theory of relativegrowth rate, this article studies the degraded grassland in western Jilin Province,analysises the ecological stoichiometry characteristics of C, N, P elements and theirratios in “soil-root-stem–leaf” system, respectively, and then explores Leymuschinensis ecological stoichiometry stability characteristics in the grassland degradationprocess. Besides, we also study the differences of L. chinensis plant growth rate atdifferent degradation stages, discuss the rate between plant growth rate and C: N: P. Theconclusions of this paper prove:1. The content of C, N, P element in the soil and sheep grass root is much lower thanthe average of the soil in China, the content of P element belongs to a very poor level. In the grassland degradation process, both the content of N, P element in the sheep grassroot, stem, leaf show the trends of first reducing and then increasing.2. C: N, C: P and N: P in the soil is much lower than the average of the soil in China,the order is, C: P> C: N> N: P. In the “soil-root-stem-leaf”system, C: P and N: P islowest is in the soil, while the highest rate is in the root. L. chinensis is limited by Nelements in the non-degraded stage, limited by the P element at lightly degraded stage,the moderately degraded stage and severe degradation stage, limited by the N, P elementat extremely serious degradation stage.3. According to the inner stability index, the N、P element in the roots and leavesexhibit stability stems, the C、N element in the stems exhibit stability stems in grasslanddegradation process, the C: N, C: P and N: P in roots, stems and leaves has shownstability. According to different organs, the stability index of C: N, C: P and N: P in stemsis higher than the roots. According to elemental ratios, the stability index of C: P ishigher than C: N、N: P.4. Different organs have different stability, different elements or elements have thedifferent the inner stability index5. The growth rate of L. chinensis is different in different grassland degradationstages. Along with the growth rate of grassland degradation, underground part (root),aerial parts (stems and leaves) showed M-type changes.There is significant positivecorrelations between the growth rate of underground part and the C:P of root, andbetween the growth rate of aerial part and the N:P of stem, which is in the limitation of N,P nutrient.