Effects Of Litterfall On Soil Respiration In Typical Stands Of Helan Mountains

Studying the effects of litter on soil respiration in forest ecosystems can provide a scientific basis for accurate assessment of forest CO2 emissions in the context of climate change.This study took Picea crassifolia forest,Pinus tabuliformis forest and mixed forest of P.tabuliformis and Populus davidiana which are dominant tree species in the Helan Mountain National Nature Reserve in Ningxia,as the research objects.Under three treatments were set to remove litter(NL),control(CK)and double litter(DL),and LI-8100A was used to measure the soil respiration,soil temperature and humidity of different treatments.The main conclusions are as follows:(1)The soil temperature of the three stands in summer was higher than that in spring and autumn,and the soil temperature in the forest was lower than that of the gap.There were significant monthly differences in soil temperature among different stands under different treatments(P<0.05).Moreover,the soil temperature of P.tabulaeformis forest is the highest,followed by mixed forest,and the lowest in P.crassifolia forest.(2)The soil humidity in the three forest stands in summer was lower than that in spring and autumn.Moreover,there were significant monthly differences in soil temperature among different stands under different treatments(P<0.05).During the whole measurement period,the average soil humidity in the forest under the removal treatment was the highest in P.crassifolia forest,followed by mixed forest,and the lowest in P.tabuliformis forest,while the control and double litter treatments were the lowest.The mixed forest is the highest,P.crassifolia forest is the second,and P.tabulaeformis is the lowest.The average soil humidity of forest gaps under the litter removal treatment was the highest in P.crassifolia forest,followed by P.tabuliformis forest,and the lowest in mixed forest,while the control and double litter treatments showed the highest in P.crassifolia forest,followed by mixed forest,and the lowest in P.tabuliformis forest(3)Soil respiration in summer and autumn was higher than that in spring for three stands.During the whole measurement period,The soil respiration of the three stands showed significant monthly differences(P<0.05),and soil respiration of the three stands showed significant monthly differences.The average soil respiration performance of the mixed forest under the removal and control litter treatments was the highest in the forest,followed by P.crassifolia forest,and the lowest in P.tabulaeformis forest.The double litter performance was the highest in Pcrassifolia forest,followed by mixed forest,and the lowest in P.tabulaeformis forest.The average soil respiration of forest gaps under removal,control and double treatments was the highest in P,crassifolia forest,followed by mixed forest,and lowest in P.tabulaeformis forest(4)The soil respiration carbon emissions under the internal removal and control treatments of the three stands were the highest in mixed forest,followed by P.crassifolia forest,and the lowest in P.tabulaeformis forest.The double litter treatment was the highest in P.crassifolia forest,followed by mixed forest,and the lowest in P.tabulaeformis forest.The soil respiration carbon emissions of forest gaps are the highest in P.crassifolia forest,followed by mixed forest,and the lowest in P.eformis forest.(5)By establishing the single-factor model and the two-factor model between soil respiration and soil temperature and humidity,the three stand.Under different litter treatments,soil temperature and humidity had the greatest comprehensive effect on soil respiration,followed by soil temperature on soil respiration,and soil humidity had the lowest effect on soil respiration-Moreover,the temperature sensitivity coefficient Q10 values of soil respiration in the three forest stands are all between 1.4 and 3.2,which is within the range of the Q10 value of forest soil respiration in my country.