Location: Plant Science Research
Project Number: 6070-21600-001-000-D
Project Type: In-House Appropriated
Start Date: Oct 24, 2023
End Date: Oct 23, 2028
Objective 1: Quantify sustainability of southeastern US crop and livestock systems (including agroforestry systems such as silvopasture) with indicators of productivity, environmental performance, and socioeconomic acceptability. Sub-Objective 1.A: Assess production and environmental impacts from long-term farming system trials as part of the Center for Environmental Farming Systems (CEFS) in Goldsboro, NC, including the Farming Systems Research Unit trial initiated in 1999 and a silvopasture experiment initiated in 2007. Sub-Objective 1.B: Assess forage production, soil organic C and N fractions, and root-zone enrichment calculations in response to grassland restoration with switchgrass seeding following initial termination of previous grass stand with no-till and plow-till techniques. Soil organic C and N stocks are important indicators of soil fertility and health of the land; they are the main constituents in soil organic matter (SOM). Our goal is to assess the impact of soil organic matter redistribution and recovery with restoration of grassland following termination of the original sward. Sub-Objective 1.C: Synthesize production, environmental, and socioeconomic information from on-going and previous crop and grazing land studies into a series of technology transfer engagements with the USDA Southeast Region Climate hub, including development of tools, guidance documents, and other resources for enhancing outcomes for producers in the region. Objective 2: Characterize root-zone enrichment of soil organic matter and soil ecosystem properties of the region’s predominant agroecological farming systems. Sub-Objective 2.A: Determine root-zone enrichment of soil organic C and N fractions under pasture-based livestock production systems in Virginia and surrounding states. Sub-Objective 2.B: Determine root-zone enrichment of soil organic C and N fractions under conservation cropping systems in North Carolina and surrounding states. Sub-Objective 2.C: Develop improved fertilizer recommendation systems based on the contributions of soil-test biological activity, microbial diversity, and community structure affecting mineralizable soil N supply in cotton and warm-season grasses. Objective 3: Investigate molecular and physiological mechanisms associated with heat and ozone stress in soybean and wheat germplasm to understand management implications and usefulness for plant breeding. Sub-Objective 3.A: Discover shoot and root traits that contribute to heat stress tolerance in soybean and wheat germplasm. Sub-Objective 3.B: Discover shoot and root traits that contribute to ozone tolerance in soybean and wheat germplasm. Sub-Objective 3.C: Investigate physiological and molecular responses to separate and combined heat and ozone stress. Sub-Objective 3.D: Analyze root-associated soil microbial diversity and community that respond to C and N sink-and-source balance between plant and soil under heat and ozone stress.
Soil organic C and N, particulate organic C and N, soil-test biological activity, net N mineralization, bulk density, water infiltration, penetration resistance, and routine soil-testing analyses will be evaluated from soil collected from two long-term farming system trials located at the Center for Environmental Farming System in Goldsboro NC. The same soil quality tests will be evaluated from soil collected at different depths from trial plots established at eight research station locations in NC and pasture-based livestock production systems in Virginia. Soil aggregation will be from the ratio of water-stable to dry-stable distribution. Soil texture will be from hydrometer for clay and sieve for sand. The sand fraction will be analyzed for particulate organic C and N. Production and performance data from cattle and forage will be collected annually along with soil resource evaluation data. Soil microbiome will be analyzed based on bacterial and fungal sequences. Soil quality and health as well as crop yield and field management practices will be evaluated to develop recommendations for growers. Data will be developed summary and guidance documents related to conservation agricultural systems, such as no-till cropping, cover cropping, distributed animal manure application, diverse crop rotations, managed grazing systems, and agroforestry systems. Scientific reports as well as environmental and socioeconomic information will be synthesized into a series of technology transfer engagements with the USDA Southeast Region Climate hub, including development of tools, guidance documents, and other resources for enhancing outcomes for producers in the region. Soybean and wheat genetic varieties selected in consultation with plant breeders will be screened for response to heat stress and elevated ozone air pollution using temperature gradient greenhouses (TGG) and open-top chambers (OTC), respectively. Plant physiological and phenotypical traits, harvest indexes, and yield will be evaluated. Soybean and wheat genetic varieties carrying both heat and ozone stress resilience isolated from heat or ozone stress screenings will be planted in the field-based Air Exclusion System (AES) and treated with separate and combined heat and ozone stresses. Photosynthesis rates, chlorophyll fluorescence, as well as day and night respiration will be measured for the same leaf cohort in the early and late developmental stages using Li-Cor 6400RT devices. Leaves used for gas exchange will be harvested to analyze ascorbic acid content and oxidation state as well as proteome. To analyze C and N source and sink allocation dry plant materials will be milled to a fine powder. The percentage of total C and N will be determined using a macro combustion system. Soil and rhizosphere microbes will be collected in the early and late developmental stages for microbiome analyses. Soil microbial diversity and network changes associated with stress resilience under separate and combined elevated ozone and heat stress will be characterized and coordinated with plant physiological and phenotypical results.