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United States Department of Agriculture (USDA) 2021

HARNESSING SOIL HEALTH TO MITIGATE GREENHOUSE GAS EMISSIONS IN SEMI-ARID PASTURE ECOSYSTEMS

Soil Health Greenhouse Semi-arid

United States Department of Agriculture (USDA) National Institute of Food and Agriculture

Titre : HARNESSING SOIL HEALTH TO MITIGATE GREENHOUSE GAS EMISSIONS IN SEMI-ARID PASTURE ECOSYSTEMS

Identification : 1025246

Pays : Etats Unis

Durée : START : 02 JAN 2021 TERM : 01 JAN 2024

Résumé
Researchers are challenged with developing agricultural systems that use limited resources effectively while improving production in the face of land degradation and increased climate variability. This is especially critical in semi-arid systems that are vulnerable to soil erosion, nutrient depletion, and extreme water scarcity. A sustainable and economically feasible management option is converting high-input row crop systems to grazed perennial grasslands. These are managed to provide high-quality forage for animal performance while improving soil health and conserving water and nutrient resources by minimizing disturbance and adding continuous soil cover. Enteric methane (CH4) production from cattle is a potential sustainability tradeoff in these systems, but it is likely possible to offset these impacts through integrated soil-plant-animal management. Preliminary data for our study indicates that adding legumes can both increase soil microbial uptake of CH4 and improve forage quality for livestock in semi-arid pastures, which improves resource efficiency, sustainability, and productivity. Our project uses long-term forage treatments in grazed semi-arid pastures to determine how management regulates soil greenhouse gas (GHG) fluxes. Through greenhouse manipulations and field measurements, we investigate how nutrient and forage management increases soil CH4 uptake while improving soil health in semi-arid pastures. We also use soil data from this study along with paired plant and animal productivity data from this long-term site to model GHG dynamics under different managements and environmental scenarios. The results of our study will ultimately help us create more efficient and resilient semi-arid agricultural systems across the globe.

Objectifs
The long-term goal of our program is to design management strategies that convert limited water supply into profitable plant and livestock commodities while building productive, climate-resilient soils. The program has demonstrated progress in lowering the nitrogen and water footprints of integrating crops and pasture-based livestock and specifically of alfalfa (Medicago sativa L.) as a driver of these resource conversions. What is missing is quantification of the scale of GHG exchange between soil and atmosphere as affected by alfalfa in comparison with what is known of enteric CH4 emissions from cattle. Our overall objective in this project is to determine how legume inclusion and management mechanistically influence GHG emissions, particularly CH4, and resource efficiency, particularly water use, in grazed semi-arid pastures. We are pursuing the following specific objectives:Discover how differing levels and forms of soil nitrogen regulate the presence and activity of CH4-cycling soil microbes and GHG soil fluxes.Quantify how legume presence and density influence GHG flux in established long-term pastures that contain either a perennial grass monoculture receiving N fertilizer or grass-legume mixtures not receiving N.Model GHG emissions under different pasture management practices and evaluate mitigation scenarios that optimize resource use and productivity.

Performing Institution : TEXAS TECH UNIVERSITY
Investigator : Slaughter, L. C. ; West, CH, P.. ; Acosta-Martinez, VE, . ; Deb, SA, .

AWARD TOTAL : $500,000

Présentation : USDA (NIFA)

Page publiée le 2 décembre 2021