Short-term changes in soil properties after prescribed fire and mulching with fern in Mediterranean forests

Prescribed fire,although having low intensity and being able to reduce the risk of wildfire may modify soil properties in the short term,with possible increases in runoffand erosion risk.Soil mulching with vegetation residues is one of the most common post-fire management strategies.Residues of fern,which is abundant on the Mediterranean forest floor,may be used to replace straw for mulching fireaffected areas.However,the effects of prescribed fires are not completely understood,and there is no data regarding the use of fern to protect soil after fire in the literature.To fill this gap,selected soil chemical parameters were analyzed,on a comparative basis,in three Mediterranean forests(pine,oak and chestnut)in Calabria(Southern Italy).These parameters were measured immediately and one year after fire in unburned,burned and not treated,and burned and mulched soils.Changes in soil chemical properties among the different treatments were significant,and the effects of the prescribed fire and mulching were dependent on the time elapsed from their application and forest species.In general,mulching was not effective in limiting the changes in the monitored soil properties compared to the pre-fire values.Each forest species showed different temporal trends in changes of soil properties.

Mulching as best management practice to reduce surface runoff and erosion in steep clayey olive groves

No-tillage and soil mulching with pruning residues,applied in olive groves of the semi-arid Mediter-ranean environment,as erosion control practices still practice not fully studied.This study has evaluated the saturated hydraulic conductivity(Ksat),surface runoff(SR)and soil erosion(SL)under rainfall at plot scale throughout two years in four different management practices,total soil cover with a net(SP),mechanical tillage(MT)and mulching by vegetal residues at 3,5·10^(3) and 17,5·10^(3) kg ha^(-1) of dry matter(NTR350 and NTR1750),in an olive grove of Southern Italy.Ksat varied between 1.6(MT)and 25.1(NTR1750)mm/h.A clear reduction in runoff and soil losses was detected for the mulch-based practices when compared to MT,from 20 to 32%in the runoff coefficient and 75-80%in SL,with higher reductions in the NTR1750.This reduction in SL can be mainly explained by the reduction in SR and rain-splash,interrill and rill erosion,due to protection by mulch residues,which increased the vegetal cover and organic matter content of mulched plots.The vegetal cover was on average higher in SP(33%),NTR1750(25%)and NTR350(22%),and lower in MT(12%).The mean organic matter content of soil was 2.01%,1.69%,1.34%and 0.82%for NTR1750,NTR350,SP and MT respectively.Overall,the results quantify the impact of soil mulching with pruning residues at different doses,which will provide guidelines to control and mitigate the hydrological response of clayey and steep soils in Mediterranean olive groves,analysing the associated environmental and economic benefits.