载畜率对荒漠草原生长季近地面土壤风沙及其养分通量的影响

Effect of different stocking rates on dust flux and nutrient flux in desert steppe in growing season

家畜放牧可使土壤表面更易受强风吹蚀,并带走大量养分,导致土壤贫瘠化。文中以内蒙古乌兰察布市四子王旗短花针茅荒漠草原为研究对象,在长期梯度放牧试验和风蚀监测实验平台上,通过对2020年5~10月生长季风沙通量及其养分含量、通量的测定计算,探讨荒漠草原不同载畜率下近地表高度的风沙通量与风蚀物养分通量的变化特征及风沙通量与风蚀物养分通量的关系。结果表明:在荒漠草原生长季,1)增加载畜率会加剧土壤风蚀,集沙高度10cm、30cm处的风沙通量均显著增加。集沙高度50cm下的总风沙通量随载畜率增加表现为对照区(CK)<轻度放牧区(LG)<中度放牧区(MG)<重度放牧区(HG),轻度、中度和重度放牧区总风沙通量分别是对照区的1.13倍、1.71倍和2.45倍。2)随着载畜率的增加,10cm集沙高度处,风蚀物全碳、全氮、全硫含量平均分别降低38.9%、36.1%、51.5%,近地面高度下全硫含量流失最严重。3)风蚀物各养分通量均随载畜率增加而增多。集沙高度50cm下的全碳、全氮、全硫总通量的重度放牧区分别是对照区的1.33倍、1.41倍、1.45倍,不同载畜率下的风沙通量对全硫养分通量影响最大。综上所述,随着载畜率的增加,土壤风蚀逐渐加强,导致草原土壤养分发生流失,适度放牧可缓解草地侵蚀现象的发生,实现草地资源的可持续利用。

The soil surface erosion caused by livestock grazing can take away a lot of nutrients, and lead to soil infertility. Based on the long-term gradient grazing experiment and wind erosion monitoring on the experimental platform in Stipa breviflora desert steppe in Siziwang Banner, Ulanchabu City, Inner Mongolia, dusts were collected from April to October 2020, and the nutrients were analyzed, in order to explore the relationship between the dust flux and the nutrient flux that caused by wind erosion at the near surface under different stocking rates. The results shown that: in the growth season, with the stocking rate increases, the soil wind erosion is aggravated, the dust fluxes of 10 cm and 30 cm increase significantly. The total dust flux under 50 cm shows the control(CK) <light stocking grazing treatment(LG) <moderate grazing treatment(MG) <high grazing treatment(HG). The total dust fluxes of the LG, MG and HG area are 1.13 times, 1.71 times, and 2.45 times more than control, respectively. The total carbon, total nitrogen, and total sulfur contents of aeolian dust at the height of 10 cm reduce 38.9%, 36.1% and 51.5%, respectively. The loss of total sulfur is the most serious at near ground level. The nutrient fluxes of dust increase with the stocking rate increase. The total carbon, total nitrogen, and total sulfur fluxes of HG are 1.33 times, 1.41 times, and 1.45 times of CK, LG and MG, respectively. The dust fluxes under different stocking rates have the greatest impact on total sulfur nutrient flux. The study results show that with the stocking rate increasing, more and more soil nutrients will be blown away;Moderate grazing can alleviate the occurrence of grassland erosion and realize the sustainable use of grassland resources.