Intensive grassland management disrupts below-ground multi-trophic resource transfer in response to drought

Abstract

Modification of soil food webs by land management may alter the response of ecosystem processes to climate extremes, but empirical support is limited and the mechanisms involved remain unclear. Here we quantify how grassland management modifies the transfer of recent photosynthates and soil nitrogen through plants and soil food webs during a post-drought period in a controlled field experiment, using in situ 13C and 15N pulse-labelling in intensively and extensively managed fields. We show that intensive management decrease plant carbon (C) capture and its transfer through components of food webs and soil respiration compared to extensive management. We observe a legacy effect of drought on C transfer pathways mainly in intensively managed grasslands, by increasing plant C assimilation and 13C released as soil CO2 efflux but decreasing its transfer to roots, bacteria and Collembola. Our work provides insight into the interactive effects of grassland management and drought on C transfer pathways, and highlights that capture and rapid transfer of photosynthates through multi-trophic networks are key for maintaining grassland resistance to drought.

Drought intensity alters productivity, carbon allocation and plant nitrogen uptake in fast versus slow grassland communities

“…Previous studies have found that drought reduces C uptake, below‐ground C allocation and soil respiration (Chomel et al, 2019, 2022; Fuchslueger et al, 2014; Ingrisch et al, 2020; Karlowsky, Augusti, Ingrisch, Hasibeder, et al, 2018). Our study suggests that the extent to which such reductions occur depends on drought intensity (Figure 2).…”

Maximizing Photosynthesis and Root Exudates through Regenerative Agriculture to Increase Soil Organic Carbon to Mitigate Climate Change

“…The researchers showed that the industrial system of intensive grazing management using chemicals and high stocking densities per hectare decreased plant carbon capture and its transfer through soil food webs and soil respiration components compared to extensive management. (Chomel et al 2022) They stated that; "…there is growing awareness of the importance of rhizodeposition as a driver of below-ground energy flow and the structure and functions of soil food webs. "…”

“…"Baseline scenarios, those without additional mitigation, result in global mean surface temperature increases in 2100 from 3.7 °C to 4. 8 °C compared to pre-industrial levels." (IPCCC 2014) According to the IPCC: "Mitigation scenarios in which it is likely that the temperature change caused by anthropogenic GHG emissions can be kept to less than 2 °C relative to preindustrial levels are characterized by atmospheric concentrations in 2100 of about 450 ppm CO2eq (high confidence)….…”

“…AM fungi. "(Chomel et al 2022) Researchers compared the soil quality at three Spanish vineyards managed under intensive, regenerative, and minimum impact strategies. They found that the soil carbon stocks were 2.3 and 3.4 times greater in the regenerative and minimal impact vineyards than in the intensive vineyard (Andrés et al 2022).…”

Research Progress of Grassland Ecosystem Structure and Stability and Inspiration for Improving Its Service Capacity in the Karst Desertification Control

“…However, while the global concept of sustainability continues to spread, irrational structural configurations of grasslands (unreasonable cropping patterns and unscientific pasture management, such as planting density, species or grazing methods, etc.) continue to exist, which not only undermines the gains of ecological restoration and conservation, but also exacerbates the conflict between ecological conservation and economic development [ 11 ]. In particular, large-scale cultivation-based rangelands generally have a single planting structure, low biodiversity, high vulnerability and low stability, making it difficult to create a cascade of ecosystem service benefits [ 12 ].…”