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ARS Home » Plains Area » El Reno, Oklahoma » Oklahoma and Central Plains Agricultural Research Center » Agroclimate and Hydraulics Research Unit » Research » Publications at this Location » Publication #412456
Research Project: Impacts of Variable Land Management and Climate on Water and Soil Resources

Location: Agroclimate and Hydraulics Research Unit

Title: Contribution of mixed cover crops to carbon neutral agriculture and livestock forage gaps

Author
item Fortuna, Ann-Marie
item STARKS, PATRICK - Retired ARS Employee
item Moriasi, Daniel

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/28/2024
Publication Date: 7/22/2024
Citation: Fortuna, A., Starks, P.J., Moriasi, D.N. 2024. Contribution of mixed cover crops to carbon neutral agriculture and livestock forage gaps. Abstract. SWCS July 21-24, 2024 Myrtle Beach,SC

Interpretive Summary:

Technical Abstract: Routine removal of carbon (C) via harvest and/or grazing in agroecosystems prevents achievement of a net zero C balance. However, the performance of a given system relative to a specified C “neutral” baseline such as a native warm-season southern tall grass prairie (STGP) serves as an indicator of C neutrality. Incorporation of fertilized, rain-fed, cool and warm season, mixed forage cover crops have potential to provide forage and year-round ground cover that may reduce erosion and promote retention of soil organic C (SOC). Research was conducted to compare biomass production of mixed forages to STGP and winter wheat (Triticum aestivum), establish whether roots of mixed forage in no-till systems can enhance C neutrality relative to tilled wheat management, and determine legacy effects of prior land management on SOC stocks. Agroecosystems include: STGP; a continuously tilled winter wheat; and two conservation tillage systems, a long-term (1976-2018) minimal disturbance system planted to continuous winter wheat; and a second minimal disturbance system previously in STGP (~40 yr) prior to conversion to minimal disturbance fertilized cool and warm season forage mixes. The cool season mixes contained 4-to-5 forages with winter wheat comprising the majority (2018-22). As a result, biomass hayed from mixes was comparable to continuous wheat management. Aboveground biomass of warm season forage mixes (2018-22) varied from 1676 to 8064 kg ha-1 (844 to 3629 kg C ha-1) and belowground from 130 to 560 kg ha-1 (59 to 252 kg C ha-1). The STGP above ground biomass ranged from 3494 to 4301 kg ha-1 (1572 to 1935 kg C ha-1) and below ground from 2450 to 2820 kg C ha-1 (1102 to 1269 kg C ha-1). These values indicate that hayed biomass was sufficient to fill a forage gap but below ground C returned from warm season mixes did not result in significant C sequestration. Changes in SOC concentrations before conversion in 2018 and 2022 were restricted to the 0-15-cm depth and were determined by the time an agroecosystem was managed as STGP. USDA is an equal opportunity provider and employer.