Brief Summary of Minutes of Annual Meeting

The meeting was held on June 29 and 30, 2022 as part of the summer board meeting of the Southern Cover Crop Council (SCCC) in Lexington, KY. Outreach activities were discussed on June 29 at the University of Kentucky’s Pirri Equine Teaching Pavilion at North Farm. The outreach objective was addressed on June 29. An update was provided on the progress that had been made on data verification for the SCCC Cover Crop Species Selector Tool and what remains to be done. Plans for a grower video project were finalized and GoPro cameras were distributed to participants who committed to recruiting a grower in their state. Plans were made to develop a webpage with sample videos and a GoPro video protocol.

The research review meeting was conducted on June 30 and was held at the meeting room of the Hyatt Regency Lexington. Meeting started with an introduction of all project participants. Dr. Vitalis Temu moderated the meeting. Meeting started with remarks from the NIFA representatives, Dr. Mathieu Ngouajio and Dr. Bisoondat Macoon. This was followed by objective report presentations.  Audrey Gamble presented the report for Objective 2 [Select and evaluate summer and winter cover crop germplasm for regional adaptability and determine the appropriate timing of planting, seeding rates, utilization of cover crop goods (includes grazing), and termination to optimize benefits without adversely affecting cash crop cycles]. Dr. Gamble presented results from two multi-state trials on seeding rates for cool-season grain cover crops and cool-season legume cover crops that were conducted as part of this objective.

Nithya Rajan presented the report for Objective 3 [Assess the influence of cover crops on soil moisture, nutrient cycling, and soil microbiology]. As the new leader of Objective 3, Dr. Rajan proposed ideas for continuing activities under objective 3. Some of the research ideas that were proposed for pursuing external grants included cover cropping strategies in regions where raised beds are common in row cropping systems. Another idea that was presented was putting together a review article on the influence of cover crops on soil moisture, nutrient cycling, and soil microbiology. The team is planning to continue the meetings and leveraging activities.

Carlene Chase presented the report for Objective 4 [Characterize cover crop efficacy for enhancing cropping system resilience to weeds, pests, and plant pathogens]. An update was provided for two studies: (1) a national USDA-NIFA-funded study aimed at elucidating the effect of cover crop termination timing on pests, diseases, and corn performance and (2) developing seeding rate recommendations for US-1136, US-1137, and US-1138 cowpea cover crop germplasm lines. Cowpea biomass production, weed suppression, and resistance to root-knot nematode infestation will be assessed again in summer 2022.

Dr. Jake Mowrer presented the report for Objective 1 [Identify a common set of biological and economic measures that can be applied across crop and cover crop combinations throughout the region to generate a region-wide database]. The Objective 1 team is looking at various soil health indicators and economic indicators of soil health. The team is planning to rank critical biological, chemical, and physical properties which are indicators of soil health based on stakeholder feedback and discussions. Team is also discussing various other activities including proposals, white papers, and a review paper.

Mickie Swisher and Jorge Ruiz-Menjivar presented objective 5 report [Generate an economic database that researchers, technical advisors, and farmers can use to assess the short and long-term economic outcomes of cover crop use]. The team provided an update on their ongoing think tanks, grower meetings, and outreach programs.

The meeting was wrapped up with a discussion about future multistate trials and planning activities for grant proposals and journal articles. Meeting was adjourned at 3.00 PM.

Objective 1:

Concepts have been proposed for (1) grouping soil health indices by soil property evaluated (not just biological indicators, but also physical and chemical) and (2) assessing the value of each relevant soil health indicator based on stakeholder group affected. An authorship team has been formed to prepare a review manuscript on the applicability of soil health indices to the southeastern region. Plans for the upcoming year include seeking soil health-specific funding opportunities as an objective team. Other ongoing writing projects include an Extension article and an opinion article.

Objective 2:

Cover crops can create sustainable crop production systems while protecting soil and water resources. Evaluation of cover crop germplasm across multiple locations is useful to harness the full potential of cover crops to provide sought benefits. Collaborators in ten states participated in a multi-state trial to evaluate winter legume cover crop species and seeding rates from 2019-2022. This study assesses productivity and adaptability of winter legume cover crops (i.e., crimson clover, berseem cover, hairy vetch, common vetch, winter pea) and will be used to develop site-specific recommendations for legume cover crop management.

Objective 3:

The team continued to leverage ongoing research for this objective. There are a number of ongoing experiments in participating states where cover crops are being evaluated for its impact on soil moisture, nutrient cycling, and soil microbiology. Depending on the location and the type of cover crop used, varying responses were found. The team has several graduate students working on the projects related to Objective 3.  Team members are also actively seeking external grants to address goals related to Objective 3.

Objective 4:

The second year of a national study to elucidate the effect of rye cover crop termination timing on pests, diseases, and corn performance in a no-till corn-soybean rotation is ongoing with 5 southern states participating. Results from the first year indicate that the effects of termination time on cover crop biomass, weed suppression, and corn root rot severity varied by location. In several states where significant effects were observed, post-plant cover crop termination decreased weed infestation at corn V5 stage but tended to increase seedling root rot severity.

An evaluation of cowpea germplasm lines US-1136, US-1137, and US-1138 was conducted in summer 2021 in seven states (Alabama, Florida, Georgia, Kentucky, Louisiana, Texas, and Virginia) plus Puerto Rico. The objectives were to (1) determine the lowest seeding rates for each germplasm line that provide maximum cover crop biomass production and weed suppression, (2) determine the termination dates that optimize cover crop shoot biomass and nitrogen credits, and (3) evaluate the host status of US-1136, US-1137, and US-1138 to plant-parasitic nematodes under field conditions. Averaged over location, cowpea shoot biomass increased in a quadratic manner as seeding rate increased from 40 to 120 lb/ac. Shoot biomass with the three lines did not differ at 6 and 8 weeks after planting (WAP) but US-1136 and US-1138 had higher biomass than US-1137 at 10 WAP. Compared to the nontreated weedy control, all cowpea rates significantly suppressed weed biomass. Seed multiplication was repeated in Florida in summer 2021 to allow for a repeat of the study in summer 2022. 

Objective 5:

The team is continuing the development of farmer think tanks and conducting grower field assessments to guide their work. They have recruited five more growers for the think tank this year, as before each from a different state. The most recent discussion included a lengthy analysis of the ability of cover crops to “bank” nitrogen and potash for a cash crop following a cover crop. The main conclusion reached was that meaningful reductions in N and K application can be achieved, but not over the short term. They have developed on-line versions of both the grower field assessments and the think tanks and have offered them to other Hatch team members. Farmers in the most recent field assessment have suggested that the team maintain the virtual venue because it is more cost effective in terms of both time and money for growers and for the research team. A team from the University of Florida (UF; Colleges of Liberal Arts and Agricultural and Life Sciences) is working on the revisions of a manuscript titled “Knowledge mapping of the extant literature on the environmental impacts of cover crops—A scientometric study.” The paper is in its second-round revisions (“minor revisions” in the last round), and we expect this manuscript to be accepted this Fall. The publication outlet is Environments (Q1 Scopus CiteScore: 5.2). Dr. Ruiz-Menjivar is conducting an overarching study that seeks to examine factors influencing farmer adoption of cover crop adoption using the “Theory of Planned Behavior (TPB)”. Collaborators include researchers at the Center for Public Issues Education at UF for this activity. As of 30 August 2022, they have collected responses from 51 farmers in Florida. Farmers are recruited through various organizations, including the Florida Farm Bureau, National Women in Agriculture Association-Florida Chapter, Florida Black Farmers and Agriculturalists Association, Florida Organic Farmers, and Farmworker Association of Florida. Approval to conduct research with human subjects has been obtained: IRB protocol IRB#202102640. The team is planning to work on the analysis and manuscript preparation based on this work in the Spring of 2023.

Aryal, P., C.A. Chase, and G. Maltais-Landry. 2021. Developing recommendations for US-1136, US-1137, and US-1138 cowpea germplasm lines for use as cover crops in Florida. ASA, CSSA, SSSA International Annual Meeting, Salt Lake City, UT. https://scisoc.confex.com/scisoc/2021am/meetingapp.cgi/Paper/138891. [Abstract].

Garcia Calvo, B., E. Haramoto, M. Allen, S.K. Carter, P. Aryal, and C.A. Chase. 2021. Cowpea as a summer cover crop: Effect of germplasm and seeding rate on weed biomass. Proceedings of the 76^th North Central Weed Science Society, p.74. http://ncwss.org/wp-content/uploads/2021-FINAL-NCWSS-Proceedings.pdf. [Abstract].

Aryal, P. and C.A. Chase. 2022. Rye cover crop termination timing effects on weed suppression in no-till corn. Proceedings of the Southern Weed Science Society, Volume 74. [Abstract]

Aryal, P. and C.A. Chase. 2022. Rye cover crop termination timing effects on weed suppression in no-till corn. Florida Weed Science Society meeting, Waimauma, FL. [Abstract]

Govindasamy, P., R. Liu, T. Provin, N. Rajan, F. Hons, J. Mowrer, and M. Bagavathiannan 2021. Soil carbon improvement under long‐term (36 years) no‐till sorghum production in a sub‐tropical environment. Soil Use and Management, 37(1), 37-48.

Haddad, S.A., J. Mowrer, and B. Thapa. 2022. Biochar and compost from cotton residues inconsistently affect water use efficiency, nodulation, and growth of legumes under arid conditions. Journal of Environmental Management, 307, 114558.

Mowrer, J., Dembele, G., Strzelec, A., and Thapa, B. 2022. Amending Soil with Biochar from Available Agricultural Wastes to Improve Sustainability of Cotton Production in Mali. Agrosystems, Geosciences, and Ecosystems.  https://acsess.onlinelibrary.‌wiley.com/doi/10.1002/agg2.20298.

Ouattara, A., B. Koulibaly, D. Dakouo, P. Bazongo, K. Coulibaly, J. Mowrer, and B.H. Nacro.  Effects of three cropping management systems on crop yield and soil chemical characteristics of tropical ferruginous soil in West of Burkina Faso (accepted African Journal of Agricultural Research (AJAR) 083121).