The Role of Plant Litter in Driving Plant-Soil Feedbacks

Abstract

Most studies focusing on plant-soil feedbacks (PSFs) have considered direct interactions between plants, abiotic conditions (e. g., soil nutrients) and rhizosphere communities (e.g., pathogens, mutualists). However, few studies have addressed the role of indirect interactions mediated by plant litter inputs. This is problematic because it has left a major gap in our understanding of PSFs in natural ecosystems, where plant litter is a key component of feedback effects. Here, we propose a new conceptual framework that integrates rhizosphere-and litter-mediated PSF effects. Our framework provides insights into the relative contribution of direct effects mediated by interactions between plants and soil rhizosphere organisms, and indirect effects between plants and decomposer organisms mediated by plant root and shoot litter. We distinguish between three pathways through which senesced root and shoot litter may influence PSFs. Specifically, we examine: (1) physical effects of litter (layer) traits on seed germination, soil structure, and plant growth; (2) chemical effects of litter on concentrations of soil nutrients and secondary metabolites (e.g., allelopathic chemicals); and (3) biotic effects of saprotrophic soil communities that can perform different functional roles in the soil food web, or that may have specialized interactions with litter types, thereby altering soil nutrient cycling. We assess the role of litter in PSF effects via physical, chemical and biotic pathways to address how litter-mediated feedbacks may play out relative to, and in interaction with, feedbacks mediated through the plant rhizosphere. We also present one of the first experimental studies to show the occurrence and species-specificity of litter-mediated feedbacks and we identify critical research gaps. By formally incorporating the plant-litter feedback pathway into PSF experiments, we will further our understanding of PSFs under natural conditions.

Prokaryotic Community Composition and Extracellular Polymeric Substances Affect Soil Microaggregation in Carbonate Containing Semiarid Grasslands

“…The bacterial abundance (as expressed by bacterial 16S rRNA gene copy number) was not significantly affected by sampling distance but tended to be highest at a distance of 35 cm from Anthyllis at RH and 35 cm from Macrochloa at AB (Supplementary Figure S4A). These findings do not fully support our hypothesis of an overall effect of sampling distance driven by canopy coverage and plant litter input (Goberna et al, 2007;Fierer, 2017;Tecon and Or, 2017;Veen et al, 2019). Nevertheless, a minor effect of plants on the soil prokaryotic community was found and further studies might reveal larger differences between plant species when considering the rhizosphere.…”

On-Site Use of Plant Litter and Yard Waste as Mulch in Gardening and Landscaping Systems

“…Over time, the improved soil conditions increase net primary productivity (NPP) and overall ecosystem functioning of the gardening or landscaping habitats [11]. As reported for natural ecosystems, the pedogenic and floral components of the system tend to strengthen each other through a web of positive feedbacks [7,21], generating the formation of "fertility islands" [22], in which pedogenesis and vegetation productivity continuously foster each other (Figure 3). Such a mechanism can be clearly demonstrated for spontaneously established vegetation, which acts as a trap for aeolian or alluvially transported plant litter (Figure 4).…”

Social networking in crop plants: Wired and wireless cross‐plant communications

“…Plant debris in minimum‐tillage and no‐tillage systems may enhance slow‐release of infochemicals. Plant debris can affect the next crop by modifying the soil microbiome community and activity, by increasing soil fertility, or by acting as an infochemical source (Veen et al, 2019; Wang, Wu, et al, 2020).…”