Soil microbial functions are affected by organic matter removal in temperate deciduous forest

Abstract

A growing demand for renewable carbon (C) has led to intensified forest management resulting in the use of forest residues (e.g. canopy, bark or litter layer) as energy sources with potential modifications of soil properties and tree productivity. Because microbes mediate the recycling of C and nutrients sequestered in organic matter, we investigated the effects of organic matter (OM) removal on soil properties, root surfaces, microbial functions and abundance using a new observational forest network. We compared leaf litter and logging residue removal plots to reference plots in six beech forests located in the northern half of France. After three consecutive years of OM removal, C and nitrogen (N) pools were not affected, but OM exportation decreased the cation exchange capacity and available phosphorus (P) pool by respectively 12% and 30% in the topsoil (0-5 cm depth). Fine root surface area significantly increased by 21% in the subsoil (5-10 cm depth) in response to OM removal. Enzymatic activities involved in N and P mobilisation decreased from 12 to 38% with the manipulation of OM. Community-level profiling (CLPP) based on BIOLOG approach revealed that the metabolic potential of the microbial community strongly decreased in response to OM removal. Our results indicated that intensive forestry could affect microbial functions implicated in nutrients mobilisation. We demonstrated that soil organic matter (SOM) content is a predictor of microbial functions resistance to forest residue removal. We recommend that intensive forestry should be reduced or limited in beech forests characterised by low soil OM contents.

Effects of Litter and Root Manipulations on Soil Bacterial and Fungal Community Structure and Function in a Schrenk’s Spruce (Picea schrenkiana) Forest

“…With the development of molecular biology technology, scholars have expanded the focus of attention from soil microbial community composition to functional prediction. Studies have indicated that soil microbial function are closely related to the quantity of plant detritus input into soil ( Maillard et al, 2019 ; Wang et al, 2020b ; Feng et al, 2022 ). For example, Wang et al (2019) suggested that litter addition can increase the functional groups associated with soil microbial C metabolism, while NL has a negative effect on microbial functional groups.…”

Removing Harvest Residues from Hardwood Stands Affects Tree Growth, Wood Density and Stem Wood Nutrient Concentration in European Beech (Fagus Sylvatica) and Oak (Quercus spp.)

“…After 3 years of carrying out treatments in the same experimental plots as those used in our study, Maillard et al(2019), did not nd any change in the soil pH of the treatment plots, but the CEC of the soil was signi cantly decreased. At present, after 5 years, we have found a signi cant increase in the ratio of Al/Mg (p = 0.001) in the treatment plots (Fig.…”

“…Generically, soil fertility in the site Darney was comparatively poorer than site Champenoux (Akroume et al, 2016). To evaluate the treatment effect, i.e., RHRL on soil properties, a study was conducted by Maillard et al 2019 at site Darney in beech trees after 3 years of the establishment of experimental plots. The study found that, the total soil N, soil organic C, soil organic matter (SOM) and pH were not impacted by removing harvest residuals, but removing harvest residuals signi cantly affected the other soil parameters measured in the 0-5cm soil layer (Fig.…”

“…The forest oor is recognised as the major pool of S available to trees (Cronan et al, 1978;Yanai, 1998), and the availability of S in a soluble form is highly correlated with fungi and bacterial interactions in forest soils (Strickland and Fitzgerald, 1978). Thus, the removal of soil litter as well as the signi cant reduction in topsoil enzymatic activities due to the removal of harvest residues (Maillard et al 2019) can explain the extensive loss of S in the treatment plots.…”

“…The objective of this study was to identify and quantify how the reduction of nutrient availability in the soil, resulting from the removal of harvest residues and litter, affects tree growth, wood density and nutrient concentration in tree stems as well as the remobilization of nutrients stored in the pith of the stem wood. For this purpose, we studied two sites belonging to the MOS (Manipulation de la Matière Organiques des Sols) network (Akroume et al, 2016), which was established in 2013 to study the impact of removing harvest residues on ecosystem functioning, including the effects on soil biodiversity (Elie et al, 2018, Maillard et al 2019). We analyzed the oldest (close to pith) and the newly formed (close to bark) tree rings in increment cores extracted from European beech (Fagus sylvatica) and oak (Q. petraea, Q. robur) trees at both sites.…”