| The grassland accounts for 40% of the Earth's area.It is thought that land use has a significant impact on grassland ecosystems and plays an important role in climate and climate regulation.China's total land area of about 41% of the area for the grass,including more than half of the area(55.9%)of the 12 provinces of the northwest semi-agricultural and pastoral areas and pastoral grassland.As an important ecological barrier in the north and in the country,as well as China's major livestock production base,its role plays a major role in maintaining the balance of global and regional ecosystems.Due to the unreasonable use of land in the region,the Loess Plateau has become one of the most serious areas such as serious soil and water loss and severe ecological and environmental problems.The diversity of land use methods under the disturbance of man-made land is typical of the Loess Plateau.Different land use measures such as returning farmland to forest,returning farmland to grassland,cropping and vegetation restoration have been used by domestic scholars to study the soil Research on the Influence of Quality and Quality.In particular,the area of soil erosion in the Loess Plateau,led by Gansu Province,is more serious,which is 92.2% of the total land area.In this study,we studied the effects of different types of cultivated grassland(mowing)and harvested hay(high-order grass,alfalfa,oat,pepper,rye and different combinations)in the cultivated land of the Loess Plateau in Gansu Province.The effects of different land use types on soil physical and chemical properties,such as soil response,were explored to provide theoretical basis and technical support for the rational utilization and protection of land and plants in the region.The main results are as follows:1.There were no significant differences in soil water content,total nitrogen,nitrate nitrogen and ammonium nitrogen in 0-100 cm soils of different types of typical forage grasses.The carbon storage of high-Dan grass was lower than that of alfalfa and control.2.There was no significant difference in soil water content between the simulated mowing group and the 0-30 cm soil layer in the harvested hay group.The changes of soil water content in the grass species varied with time,and the soil layer at 0-10 cm Water content changes susceptible to weather conditions,and 10-30 cm out of the soil water content is relatively stable;cutting treatment of water content is higher than the control group.3.There was no significant difference in the annual storage and annual carbon storage and carbon storage of 0-30 cm soil under different land use patterns,but the carbon storage in the control group was significantly higher than that in the mowing group,and the control group might be more favorable for the increase of carbon storage;Alfalfa and arrows were significantly higher than those of other forage species,which may be more favorable for carbon storage.4.The annual average nitrogen content and total nitrogen content of 0-30 cm soils under different land use patterns were significantly higher than those of wild peas and oats in 2014(p<0.05).The total nitrogen content in the mowing group was significantly higher than that in the control group,and the mowing group might be more favorable for the increase of total nitrogen content.5.The content of NO3-N in the harvesting period of 0-30 cm soil under different use patterns was significantly higher than that of arrow pea in 2015(p<0.05).There was no significant difference in the average nitrate nitrogen content between the cutting and the control treatments,but the average nitrate nitrogen content in the mowing group was higher than that in the control group,and the mowing group might be more favorable for the nitrate increase.6.The results showed that the harvesting period,annual average ammonium content and ammonium nitrogen content in the 0-30 cm soil under different land use patterns were significantly higher than those of the peanut in the year of planting 30% alfalfa in 2014,And significantly increased the content of ammonium nitrogen in soil(p<0.05).There was no significant difference between the cutting treatment and the control treatment,but the content of ammonium nitrogen in the control group was higher than that in the mowing group. |
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