Effects Of Different Stocking Rates Ang Precipitation Gradients On Soil Respiration And Related Factors In Desert Steppe

In order to study the effect of simulated precipitation on soil respiration after grazing at different stocking rates in desert steppe,a simulated precipitation experiment was established on the experimental platform for long-term grazing of Stipa brebiflora desert steppe in Inner Mongolia.The long-term grazing experiment was treated with a completely random block design,divided into 4 treatments and 3 replicates.4 treatments were control,light stocking rate,moderate stocking rate and high stocking rate,respectively.Each stocking rate included four different water control treatments,which were 50%water reduced,natural precipitation,50%water increased and 100%water increased,respectively.During the experiment,root stock biomass,net root biomass,soil moisture,soil temperature,soil total carbon,soil total nitrogen,soil total phosphorus and soil respiration were measured,and the soil nutrient stoichiometry was calculated.The results showed that:(1)In 2018 and 2019,different stocking rates did not have a significant on root stock biomass and net root biomass;50%reduced water treatment significantly reduced the root stock biomass,and net root biomass in natural precipitation was significantly higher than that in water reduced and water increased.(2)Different stocking rates have no significant difference in soil moisture,soil temperature,soil total carbon content,total phosphorus content and stoichiometric ratio,but the soil total nitrogen content in moderate and high stocking rates were significantly lower than that in control and light stocking rate.With the increase of water content,the soil moisture showed a significant increased trend,and soil temperature,total nitrogen and total phosphorous contents showed a significant downward trend.There was no significant difference in soil total carbon content under simulated precipitation treatment,and the ratio of soil nitrogen and phosphorus under 100%water treatment was significantly higher than that in natural precipitation.(3)The simulated precipitation mainly has a significant negative effect on soil total phosphorus content and soil temperature by changing soil moisture,and the increase of soil moisture promotes soil respiration rate.