Accumulation Characteristics and Hydrological Effects of Litter in Mixed Robinia pseudoacacia Plantations
[Objective]Studying the accumulation characteristics and hydrological effects of typical mixed Robinia pseudoacacia plantations is crucial for deeply investigating the water conservation capacity of artificial forests on the Loess Plateau.[Methods]This study focused on five different mixed planting patterns of Robinia pseudoacacia in the loess hilly region,including R.pseudoacacia × Hippophae rhamnoides,R.pseudoacacia × Amorpha fruticosa,R.pseudoacacia × Pinus tabuliformis,R.pseudoacacia × Prunus davidiana,and R.pseudoacacia × Prunus sibirica,with pure R.pseudoacacia plantations serving as a control for comparative analysis.Through field investigations and laboratory experiments,quantitative research was conducted on the accumulation,water-holding capacity,and evaporation characteristics of litter in these mixed plantations.[Results](1)The total litter accumulation in different mixed R.pseudoacacia plantations ranged from 0.29 to 1.01 kg/m2,with semi-decomposed litter accounting for more than 60%in all cases.Except for the mixture with A.fruticosa,the leaf litter accumulation in other mixtures was higher than that in pure R.pseudoacacia plantations.(2)After 24 hours,the water-holding capacity of litter from different mixtures stabilized with no significant differences.The trend for different organs was leaf>grass>fruit>branch.Furthermore,the effective interception and storage capacity of R.pseudoacacia × A.fruticosa was the largest(1.74 kg/m2),and the effective storage capacity of semi-decomposed litter was greater than that of undecomposed litter(p<0.05).(3)Evaporation of semi-decomposed and undecomposed litter reached a stable stage after 84 and 60 hours,respectively.The evaporation amount and rate followed the same trend as water-holding capacity,in the order of leaf>grass>fruit>branch.(4)During the water-holding and evaporation coupling process,a significant logarithmic relationship existed in the water-holding phase(R2≥0.84,p<0.01),while a significant power function relationship was observed in the evaporation phase(R2≥ 0.94,p<0.01).The natural water content of litter was reached indoors and outdoors between 48~60 hours and 24~36 hours,respectively.[Conclusion]Overall,the hydrological effect of R.pseudoacacia×A.fruticosa litter was optimal.These findings provide a scientific basis for vegetation restoration,soil and water conservation projects,and ecological benefit evaluation in the region.