Changes in accrued and sequestered carbon in agroecosystems implementing single standard conservation practices vs. the integration of multiple conservation practices

Authors: Fortuna, Ann Marie; Starks, Patrick; Moriasi, Daniel

Submitted to: Workshop Proceedings
Publication Type: Other
Publication Acceptance Date: 8/3/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary: An important function of soil is to protect water quality at the edge of field and across a watershed. Soil health as defined by Doran and others is "the capacity of a living soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and promote plant and animal health." “Water quality describes the condition of the water, including chemical, physical, and biological characteristics, usually with respect to its suitability for a particular purpose” (National Oceanic and Atmospheric Administration (NOAA)). Currently, data is lacking in a number of areas that would enhance the soil and watershed health nexus. The connection between soil health and water quality is accepted intuitively but has only a limited basis in research. Regarding research design, land management practices are commonly used as a proxy for soil condition, but we have limited ability to predict soil infiltration, biological activity, and other soil processes based on land management. The goal of this special collection of papers in the Journal of Environmental Quality is to frame research issues and to inspire new approaches and collaborations for tackling the challenge of leveraging soil health to strengthen water management. Authors will share results of plot-field-watershed-scale observations, modeling and statistical approaches as well as other novel methodologies for understanding the soil and water nexus. In addition, the Special Section will complement an associated Symposium for the 2021 Universities Council on Water Resources and National Institutes for Water Resources (UCOWR).

Technical Abstract: Recent additions to the National Conservation Practice Standards codes include best management practices (BMP) that when mplemented as a suite of BMPs within an agroecosystem have the potential to improve and or maintain soil health, yield, plant biomass and climatic resilience. Agroecosystems compared are a remnant southern tall grass prairie (STGP) in conservation cover management, code 347, a continuously tilled winter wheat management in conservation nutrient management, code 590 and two conservation tillage managements systems with different previous land management. The long-term minimal disturbance system (code 345) was planted to continuous winter wheat and periodic summer forages until 2018 when the system was converted to fertilized cool and warm season forage cover crops (codes codes 327,328,511,590). The second minimal disturbance system was in STGP for ~40 yr prior to conversion to minimal disturbance fertilized cool and warm season forage cover crops. Highly variable weather and climate require adaptive wheat, livestock management practices to mitigate adverse impacts of climate variation. Incorporation of fertilized, rain-fed, mixed forage cover crops can mitigate this gap while increasing plant cover for improved soil health and nutrient cycling. This research compares shifts in accrued and sequestered C measured via particulate organic matter C (POMC), residual of acid hydrolysis C (ACH) and total soil organic C (TSOC) across the previously described agroecosystems with single or multiple conservation management practices. Both stacked conservation systems in minimal till continuous forage cover crop covers are expected to increase accrued biologically active C fractions (POMC) prior to potential shifts in whole soil C. The minimal till system previously in STGP is expected to contain greater ACH (sequestered C) and POMC (accrued C) relative to the long-term minimal till and tilled systems. The USDA is an equal opportunity provider and emloyer.