Effect Of Fire Disturbance On Litter Decomposition Of Larix Gmelini Forest

The decomposition of forest litter directly affects the material transformation and energy flow of the entire forest ecosystem,and the original forest habitat after fire is changed.Therefore,litter decomposition research under fire disturbance becomes particularly important.In this study,the net bag method was used to monitor the decomposition rate of litter within two years and the dynamic changes of litter N and P within one year in the burned plots of different ages in Daxing'an Mountains to reveal the law of decomposition of litter under fire disturbance and pass the determination of 1987 "5·6)The decomposition rate of litter in the natural renewal and afforestation plots after the fire,and the effects of post-fire afforestation and natural regeneration on litter decomposition were investigated.The results show:(1)The decomposition rate of upper needles at the first two years is smaller than that at the first and then larger than the control sample.With the increase of the number of years of fire,the fire disturbance has an increasingly stronger effect on the decomposition rate of the upper needles,while the fire disturbance affects the lower needles.The effect is exactly the opposite of the upper needles.In the 10 years after the fire disturbance,the decomposition rate of the upper and lower needles both promoted.10 years after the fire disturbance,the decomposition rate of the upper broad-leaved leaf was inhibited,and the inhibitory effect was gradually reduced with the increase of the fire years?and the decomposition rate of the upper broad-leaved leaf was promoted at 29 years after the fire disturbance.After 10 years and 29 years of fire disturbance,the decomposition rate of broad-leaved lower leaves was inhibited.With the increase of the number of years after fire disturbance,the inhibitory effect gradually decreased.Three years after the fire disturbance and 10 years after the fire disturbance,the decomposition rate of the branchlets was inhibited,and the decomposition rate of the branchlets was promoted 29 years after the fire disturbance.In general,in the 29 years of fire disturbance,with the increase of the number of years of fire disturbance,the fire disturbance promotes the decomposition of litter from inhibition,and as the number of years of fire disturbance increases,the promotion effect is gradually strengthened,and the lower litter is compared with the upper litter.There is hysteresis in response to fire disturbances.(2)By monitoring the dynamic changes of litter N and P within one year,it was found that the three litters of needle,broadleaf and branchlets showed direct release and enrichment-reduction alternately,and there were multiple element migration patterns,while the fire After the disturbance,there was no significant change in the litter N and P migration.The dynamic changes of N.P element migration and litter decomposition rate had no obvious rules.(3)After 29 years of fire disturbance,the overall performance was that the decomposition rate of needles in artificial afforestation plots was greater than that of natural regeneration plots after fire(P<0.01).Under the broad-leaf approach to soil treatment,the broadleaf decomposition rate of the fire-like plots was greater than that of the control plots in the first non-growth season,the growth season,and the second non-growth season,with a large difference of 0.73-3.41%/month.(P<0.05).The dynamic change of the decomposition rate of branchlets under artificial afforestation mode has no obvious regularity compared with the natural regeneration after the fire.