Effect Of Different Grazing Intensities On Community Characteristics And Soil Physicaland Chemical Character Of Deyeuxia Angustifolia

This study was a grazing trial in the Calamagrostis angustifolia meadow of Dongshengwetland in Baoqing county, The Experiment take the local cattle as the test animal(Simmental♂+Local cattle♀), We set three grazing intensities: lightly grazed (0.99AU/hm2/month,LG), moderately grazed (1.65AU/hm2/month, MG), heavily grazed (2.30AU/hm2/month, HG),With no grazing as controls. Observation and analysis the feature and nutrition of plantcommunities, soil characteristics under different grazing intensities,grazing in the second year, toexplore the variation above. To provide a theoretical basis in order to sustainable use theCalamagrostis angustifolia meadow of Sanjiang plain. Results as follows:1. Grazing changes the composition and proportion of plant species of Calamagrostisangustifolia community, the number of species in light grazing, moderate grazing and heavygrazing was respectively increased41.95%,42.45%and38.07%compared with no grazing.2. Grazing has significant impact on height, coverage and density of Calamagrostisangustifolia community. Compared with no grazing the vegetation height in light grazing,moderate grazing and heavy grazing was respectively reduced39.49%,49.33%and45.61%, whilecoverage was respectively reduced7.86%,11.24%and19.10%, adversely, density wasrespectively increased81.51%,96.87%and74.22%.3. Grazing has significant impact on standing croup and underground biomass. Comparedwith no grazing, the standing croup in light grazing, moderate grazing and heavy grazing wasrespectively reduced32.79%,45.17%and50.15%; while underground biomass in heavy grazingincreased15.69%, but in light grazing, moderate grazing was respectively reduced4.07%and21.06%.4. Grazing made changes in the standing crop plant structure in Calamagrostis angustifoliacommunity. Compared with no grazing, the Gramineae in light grazing, moderate grazing andheavy grazing was respectively reduced12.45%,16.36%and11.41%; Leguminosae wasrespectively reduced98.14%,99.33%and97.10%; Cyperaceae was respectively increased194.04%,7.12%and166.14%; Chenopodiaceae was respectively increased0%,0.01%and0.02%,while Other plants was respectively increased20.78%,93.20%and85.01%. 5. Compared with no grazing, crude protein content in light grazing, moderate grazing andheavy grazing was respectively increased42.58%,28.55%and25.36%, but crude fat content wasrespectively reduced16.02%,0.30%and11.83%; The content of NDF in heavy grazing has themin-value; the content of crude ash, ADF, Ca and P in different districts had no significantdifferences.6. Grazing mainly influence the content of water and bulk density in0-10cm soil layer. Withthe increasing of grazing intensity, the content of water was reduced but the bulk density wasincreased.7. With the increasing of grazing intensity, in0-10cm soil layer, available potassium wasincreased, but the content of organic matter, total nitrogen, total phosphorus, total potassium,nitrogen and available phosphorus were decreased; in10-20cm soil layer, The content of totalnitrogen, total phosphorus, total potassium and available phosphorus were not significantlychanged, but nitrogen, available K and organic matter were decreased; in20-30cm soil layer, Thecontent of total phosphorus was increased, but the content of organic matter, total nitrogen, total Kand available nitrogen were reduced, the content of rapid available phosphorus and potassium hasno significant change.