Alex Woodley

Producers are pushing the boundaries of traditional management strategies to achieve their high-yielding soybean goals. Best management practices help some soybean yields of NC to exceed 70bu/A while the historical statewide average yield of soybean mark 35 bu/A level. However, intensive agricultural practices may not provide long-term sustainability in increasing soybean yield levels. Achieving high yields and improving soil properties may differ substantially for each region of NC and require excellent field conditions and hence site-specific and climate-smart management strategies. Especially increasing need for agricultural products, and expensive and limited fertilizer inputs due to global issues require improvements in currently available management strategies like cover cropping and reduced or no tillage. Recently, management practices like those provide minimum disturbance, maximum soil coverage, economically profitable carbon farming, and restore or maintain soil health are critical. This research aims to develop site-specific cover crop and tillage practices where we can get the most benefit from interactions between cover crop and tillage applications to provide high economical return and enhanced soil health conditions. We will conduct plant and soil analysis including soil physical properties, microbial activities, N fixation, soybean yield, and biomass. We will also conduct an economic analysis and carbon credit evaluations. To conduct this project, we will hire a graduate student for 3 years co-sponsored with this grant and startup from department support by Crop and Soil Sciences Department. We are also requesting financial support for field supplies, travel costs, and soil and plant analysis associated with the project.

We will investigate the carryover effects of P fertilization on loblolly pine plantations and the effects on the soil microbial community.

(Project is in support of PSI) Greenhouse trials measuring GHG emissions and soil health parameters in corn using a variety of biological products. In addition, a GHG column experiment measuring high frequency GHG emissions.

The proposed project will use a chronosequence technique to evaluate changes in soil carbon storage and soil health indicators that occur over a 20 yr period from transition from conventional to organic management. Soil samples will be taken from on-farm sites that have been in organic management for a range of time and ensure and event distribution from year 0 to year 20. Soils from nearby abandoned or re-forested sites will be used as the regions maximum potential carbon accrual, while sites in year 0 or 1 of transition will be the theoretical starting point for carbon stock buildup. In addition to the on-farm trials, two intensive field experiments will be established at research stations on the coastal plains. These experiments will focus on carbon stock accrual within the first 3 years of transition from conventional to organic. Treatments will fall along a spectrum on management intensity, ranging from high intensity carbon building with organic amendments to business as usual production systems. This complementary study will allow inferences to be made around if active soil carbon building during transition can push the system further in the chronoseqenece and derive the potential benefits of increased soil health.

Cover crops are capable of mitigating many of the destabilizing factors influencing food and water security including climate change, pesticide resistance, depleted soils, competition among users for water, and decoupled nutrient cycles. Despite the myriad potential landscape-level benefits, cover crop adoption rates remain low. Cover crop use is a knowledge-intensive activity; farmers repeatedly cite management complexity and the lack of site- and system-specific information as barriers to adoption. This is further complicated by inconsistent management recommendations, and at times misinformation, resulting from a lack of coordination, communication, and awareness. Complex interactions in food production among intrinsic factors (climate and soil), management, and genetics exacerbate the issue. Social and political forces also add complexity via regulation and market forces. While there has been considerable research devoted to cover crops, there has been a failure to link impacts of climate, soil, genetics, and management decisions on cover crop performance. There is also a lack of transdisciplinarity and integration in research, education, and extension activities. We propose a transformation of US cropping systems through an information ecology to integrate cover crops and precision agriculture. An information ecology for precision sustainable agriculture would include, at minimum, open source software to reduce the cognitive overload of cover crop use by farmers; low cost hardware to crowdsource farm-scale data to inform cover crop research; and a knowledge commons for data sharing among transdisciplinary and cross-sector teams. An information ecology therefore has the potential to support long-term sustainability of US agricultural systems through the integration of cover crop research and practice.

New injection bars available through Zoske, Bazooka-Farmstar, and Dietrich allow for manure injection into standing corn. Initial results out of Ohio and Minnesota indicate corn can withstand injection below the V5 growth stage without injury. The potential to utilize in-season injection could drastically increase the application window of swine sludge in a corn rotation, allowing the grower/applicator to get in the field when field conditions are optimum, especially in rainy springs such as we saw in 2020. However, there is little information on this injection system in the sandy soils of the Coastal Plain. Therefore, we propose small scale field testing to identify the impact of swine sludge injection on corn yield and quality.

A flux gradient tower is currently being installed at the Tidewater Research Station in Plymouth NC. This systems allows for full field scale measurements of a variety of parameters. The field will be divided into four large quadrants each about ~8 acres in size. A trailer will be located at the center of the plots. Air intake towers will be placed in the center of each quadrant and air will be pulled into a trailers containing analyzers. Carbon dioxide (CO2), nitrous oxide (N2O), water vapor, evapotranspiration, net radiometry, soil moisture and soil temperature will be measured continuously throughout the year. In addition, background soil carbon stocks will be measured and at harvest crop yield, nitrogen uptake and residual soil nitrogen will be determined. This is planned as a 4-year study examining crop rotation management decisions. The following treatments are planned: 1. Business as Usual: Corn - Soybean - Corn - Soybean 2. Sustainable intensification: (Crimson Clover)- Corn-Wheat-Soybean-(Crimson Clover)-Corn-Wheat-Soybean 3. Cover Crop in Rotation: (Crimson Clover)-Corn-(Cereal Rye)-Soybean-(Crimson Clover)-Corn-(Cereal Rye)-Soybean 4. Continuous Corn: Corn-Corn-Corn-Corn This design allows for in-depth assessment of several corn growers identified priority areas. Including the use of cover crops as an N source in corn, the soil carbon sequestration potential of either double-cropping in rotation or using cover crops compared to business as usual corn-soy rotation. The continuous corn allows for an upper baseline of soil carbon sequestration due to the biomass being returned to the soil and also likely an upper baseline for nitrogen dynamics including nitrous oxide emissions and N leaching when compared to more complex rotations. Water budgets can be generated with technology in place, allowing for an assessment of water use dynamics over the 4 year period. Deep soil cores in at end of season will provide insights on N leaching as impacted by cover cropping. Corn will be harvested with yield monitor and grain N uptake will be measured. The 2023 season will be the corn phase of rotation and support is requested for an assessment of baseline soil carbon stocks, in-season nitrogen release dynamics of crimson clover in treatments 2 and 3, in-season N movement assessment after large rainfall comparing fertilizer only N application vs N fertilizer + cover crop N, corn tissue N for nutrient use efficiency assessments and end of season residual soil nitrogen. This is a one-of-a-kind experiment in the southeast and provides a true measure of GHG emissions and crop water use dynamics at a field scale. With the continued push for growers to consider climate-smart practices there is a great need for regional field scale assessments to ensure that these practices maintain or improve productivity in these systems.

On-farm trials will be used to measure mitigation of nitrous oxide and ammonia emissions from nitrogen fertilization of corn with and without the use of a urease and nitrification inhibitor. Control plots receiving zero N will be used to examine inherent soil health in the system and supply power relative to corn yields.

Weed management was identified as a high priority of organic sweetpotato producers who lack chemical control options available to conventional producers. This project will examine the effectiveness of multiple weed management techniques including 1) the use of advanced sweetpotato lines and cultivars with bunching shoot architecture to outcompete weeds for light resources and allow for more efficient use of between-row cultivation, 2) modified planting density to reduce the critical period for weed removal, 3) identification of weed suppressive (allelopathic) lines that can function in a production environment, and 4) utilization of fall-planted cover crops and reduced tillage transplanting operations to reduce the dependence on cultivation. Recognizing that these techniques may have non-target effects, this project will also investigate the insect pest pressure and plant disease occurrences in the test plots. Research-based findings will be shared with stakeholders and the greater scientific community via field days, production meetings, expos, conferences, peer-reviewed journal publications, Extension publications/fact sheets/bulletins, and electronic newsletters, webpages, and social media. Throughout the proposed project, investigators will remain engaged with the US Sweetpotato Stakeholder Advisory Panel to ensure the project remains aligned with industry goals and that meaningful results are effectively communicated to stakeholders nation-wide. Identifying best practices for weed management, in an integrated pest management context, will facilitate the development and improvement of organic sweetpotato production, in line with Goal 1 of the Organic Agriculture Research and Extension Initiative.

This project will conduct collaborative field trials to address farmer-specified agronomic challenges to producing fiber hemp in North Carolina.