Adaptive multi-paddock grazing management’s influence on soil food web community structure for: increasing pasture forage production, soil organic carbon, and reducing soil respiration rates in southeastern USA ranches

Abstract

Background Measurement of two grazing management’s influence on pasture productivity, soil food web structure, soil organic carbon and soil microbial respiration efficiency was conducted on five southeastern US, across-the-fence ranch pairs to compare adaptive multi-paddock grazing (AMP) management, using short grazing events with planned, adaptive recovery periods, to conventional grazing (CG) management, with continuous grazing at low stock density. Methodology A point-in-time experimental field analysis was conducted to compare five AMP or CG ranch pairs to better understand the influence of grazing management on (a) standing crop biomass productivity; (b) soil food web community population, structure and functionality; (c) soil organic carbon accrual; and d) soil-C (CO2) respiration kinetics. Results AMP grazing systems outperformed CG systems by generating: (a) 92.68 g m−2 more standing crop biomass (SCB), promoting 46% higher pasture photosynthetic capacity (Two sample Mann-Whitney; Z = 6.1836; no DF in MW; p = 6.26 × 10−10; Effect size = 0.35) (b) a strong positive linear relationship of SCB with fungal biomass (R = 0.9915; F(1,3) = 175.35; p = 0.015); fungal to bacterial (F:B) biomass ratio (R = 0.9616; F(1,3) = 36.75; p = 0.009) and a soil food web proxy (R = 0.9616; F(1,3) = 36.75; p = 0.009) and a concurrent very strong inverse relationship with bacteria biomass (R = −0.946; F(1,3) = 25.56; p = 0.015); (c) significant predator/prey interactions with an inverse relationship with bacterial population biomass (R = − 0.946; F(1,3) = 25.56; p = 0.015) and a positive relationship with total protozoa enumeration (R = 0.9826; F(1,3) = 83.68; p = 0.003) when compared to SCB; (d) a 19.52% reduction in soil C (CO2) respiration rates (Two sample t-test; T = −2.3581; DF = 52.3541; p = 0.0221; Effect size = 0.59); and (e) a 20.6% increase in soil organic carbon (SOC) in the top 10 cm of soil profile (Two sample Mann–Whitney; Z = 2.6507; no DF in MW; p = 0.008; Effect size = 0.24). Rancher conversion to AMP grazing strategies would appear to regenerate soil food web population, structure, diversity and biological functionality helping to improve: carbon flow into plant biomass, buildup of soil carbon, predator/prey nutrient cycling and soil microbial respiration efficiency while offering improved climate resilience and a strategy to increase the capture and storage of atmospheric CO2 in soils of the world’s rangeland.

Opportunities to increase soil carbon sequestration in grazing lands in the southeastern United States

“…Grazing practices evaluated in the studies included grazing intensity (Conant et al, 2003; Dubeux et al, 2006; Silveira et al, 2013; Wang et al, 2014), stocking methods and defoliation regimen (Apfelbaum et al, 2022; Dubeux et al, 2006; Franzluebbers et al, 2012; Franzluebbers & Stuedemann, 2009; Gomez‐Casanovas et al, 2018; Johnson et al, 2022; Mosier et al, 2021; Wilson et al, 2018; Xu et al, 2021), and nutrient management (Franzluebbers & Stuedemann, 2009; Silveira et al, 2013). There was a general consensus that in long‐term studies, increased grazing intensity resulted in greater soil C stocks.…”

“…Apfelbaum et al (2022),Johnson et al (2022), andMosier et al (2021) evaluated the effect of continuous versus adaptive multipaddock stocking on soil C stocks and soil respiration. Based on soil type, topography, and land-use history, five paired sites in Mississippi, Alabama, and Kentucky were selected for the study.…”

The Health of Vineyard Soils: Towards a Sustainable Viticulture

“…From a biological perspective, SOM is strongly and positively related to the functionality of the soil biological community. Indeed, as the SOM content increases, the abundance, activity, diversity, food web structure, and stability of the soil biological community are all enhanced [114][115][116]. A functional biological community is what distinguishes a healthy soil [6].…”