Dynamic characteristics of litter decomposition and nutrient release in 4 species of Larix plantations
[Objective]Studying the dynamic characteristics of litter decomposition and nutrient release of different species of plantations of the Larix genus,revealing the pattern of litter decomposition and nutrient release,which is of great significance to the in-depth investigation of the process of material cycling in forest ecosystems,and provides a scientific basis for the management of larch plantation forests.[Method]Four species of 40-year-old Larix plantations(Larix gmelinii,L.principis-rupprechtii,L.kaempferi,and L.olgensis)in the homogeneous habitat were used for the decomposition experiment using net-bagging method of litter.Based on different stages of decomposition,the residual mass of litter was weighed,and the contents of major elements(C,N and P)as well as difficult-to-degrade components(lignin,cellulose and condensed tannins)in the litter were measured.The overall residual rates,mass loss rates and nutrient release rates of litter at each stage of decomposition were calculated,and the Olson index decomposition model was established,which was used to analyze the differences among tree species.Pearson correlation analysis and principal component analysis were conducted to clarify the relationship of litter mass loss rates with initial substrate qualities and nutrient release rates,respectively.[Result]In decomposition to 90 days,the mass loss rate of litter in L.kaempferi plantation was significantly higher than that in L.principis-rupprechtii plantation,with the greatest contribution to mass loss(P＜0.05),and its lignin and cellulose release rates were significantly higher than those in L.olgensis plantation(P＜0.05).The mass loss rate of litter was significantly negatively correlated with the initial C∶N ratio.In decomposition of 90-360 days,the L.principis-rupprechtii plantation had the highest mass loss rate of litter,with the greatest contribution to mass loss,and its lignin release rate was significantly higher than that of L.olgensis plantation(P＜0.05).The mass loss rate of litter was highly significantly negatively correlated with initial lignin content and lignin∶N ratio,and strongly positively correlated with N and lignin release rates.In decomposition of 360-450 days,litter P and lignin release rates were the highest and condensed tannin release rate was the lowest in L.olgensis plantation,and litter cellulose and condensed tannin release rates were significantly higher in L.gmelinii plantation than in the other three Larix plantations(P＜0.05).The mass loss rate of litter was strongly positively correlated with C and cellulose release rates,and strongly negatively correlated with P release rates.In the litter of 4 species of Larix plantations,the C,N elements,lignin and condensed tannins showed a direct release pattern;the P element showed a leaching-enrichment-release pattern;and the cellulose showed a leaching-enrichment pattern.[Conclusion]The initial N,lignin content and C∶N ratio and hardly degradable components release rates of litter were important factors affecting its decomposition.Litter decomposition was the fastest in L.gmelinii plantation,which accelerated nutrient cycling,while litter decomposition was the slowest in L.principis-rupprechtii plantation,which slowed nutrient cycling.This is of great significance to the management of different species of plantations of the Larix genus.
NETL
NSTL
万方数据
