Final report for GS14-135
Field screening trials of nineteen winter pea (Pisum sativum) genotypes and five faba bean (Vicia faba) genotypes were installed across multiple locations in North Carolina from 2014 through 2017. The winter pea genotypes are being screened for multiple end uses including use as a grain, forage, and cover crop. Winter pea is being screened in monoculture and in mixture with barley, oats, and wheat for the different end uses. Faba beans are being screened in monoculture. Results will catalyze cultivar release of regionally adapted winter legumes for the Southeast USA.
- Conduct field screening trials to assess available winter pea and faba bean germplasm for genotypes that exhibit desirable attributes for use as grain, forage, and cover crops in the Southeast.
- Evaluate nutritive value and protein content for all genotypes to determine value as soybean replacers in livestock feed rations.
- Catalyze the development and release of regionally adapted cultivars through the provision of recommendations on successful winter pea and faba bean genotypes.
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Pea for grain production: Winter pea (Pisum sativum L.) is desirable for grain production in the Southeast USA to increase feed protein availability; however, there has not been previous effort devoted to maximize pea genetics for grain production in this region. Studies were conducted at six environments in North Carolina to assess winter pea grain production potential from 2014 to 2016. Nineteen winter pea genotypes were planted in monoculture and in mixture with three wheat genotypes with differing maturities. Pea cold tolerance, biomass production, disease incidence, maturity, lodging, and both pea and wheat grain yield were assessed.
Pea for cover crop use: Winter pea (Pisum sativum L.) can be used as a forage and cover crop in the Southeast USA; minimal effort has been devoted to maximize pea genetics for forage and cover crop production in this region. Studies were conducted from 2015 to 2017 in North Carolina screening eighteen winter pea genotypes for forage and cover crop end uses and comparing these genotypes to crimson clover and hairy vetch. All legume genotypes were harvested across four timings to understand the influence of maturity on biomass and quality. Legume cold tolerance, disease incidence, biomass production, quality, and N release were estimated. Legume and small grain cover crops are combined in mixture to provide N fertility and weed suppression for the following cash crops. Some effort has been dedicated to developing regionally adapted crimson clover and hairy vetch cultivars for use in the Southeast USA; less effort has been devoted to identifying appropriate winter pea cultivars for cover crop use in the region. Studies were conducted from 2015 to 2017 in North Carolina to compare winter pea to crimson clover and hairy vetch for production in mixture with small grains for cover crop use. Five winter pea genotypes, one crimson clover cultivar, and one hairy vetch cultivar were screened with barley, oats, and wheat. Legume cold tolerance, legume disease, species competition, and biomass production were assessed.
Faba beans: Five faba bean genotypes were screened from 2014 to 2017 at three locations in North Carolina each growing season. Each year a bulk harvest occurred for the remaining seed from each genotype. We did not take any measures to prevent out-crossing between the pea genotypes. Biomass was collected in 2017.
Pea for grain production: The growth of only one pea genotype was severely inhibited by cold. Disease incidence was influenced by pea genotype but not growth in monoculture or mixture with wheat. At the environments with heavy Sclerotinia pressure, grain yield of all pea genotypes was severely inhibited. All wheat genotypes reached physiological maturity prior to any pea genotype, and the two species were harvested simultaneously using a combine with minimal difficulties. Winter pea yield was affected by pea genotype but not growth in monoculture or mixture. Pea yield was greater with early maturing varieties; grain potential across all pea genotypes was likely restricted by excessive heat during flowering. Many winter pea genotypes screened in this study out-yielded the current winter pea readily available in North Carolina. These results indicate that winter pea and wheat can be grown simultaneously and that regional winter pea varietal recommendations will help enhance pea grain yield in the Southeast USA.
Pea for cover crop use: There was considerable variation in disease incidence among the pea genotypes depending on biotic stressors at each environment. At the North Carolina environments, several pea genotypes produced similar biomass to crimson clover and hairy vetch across harvest timings. N release was estimated for each legume genotype; the high biomass producing peas and hairy vetch released N at similar quantities at three of the four harvest timings. The evaluated pea genotypes varied considerably for quality traits, including protein, lignin, and cellulose. Relative forage quality declined as biomass harvest was delayed, and was generally higher with all pea genotypes than crimson clover or hairy vetch. These results show wide genetic variation in the pea genotypes screened for biomass and quality; this variation could be utilized in breeding efforts to enhance winter pea production in the region. In the mixture study, peas were able to recover from cold injury at the North Carolina environments. A robustly growing small grain aided in legume cold tolerance at some environments. Oats were more competitive in mixture with the legume genotypes than barley or wheat. At the Coastal Plain environments where soil residual N is generally low, all legume species dominated the cover crop mixture and winter pea produced similar biomass in mixture as crimson clover and hairy vetch. At the Piedmont environment where residual N is generally higher than in the Coastal Plain, the small grain dominated the cover crop mixture. Hairy vetch was the most competitive legume with the small grains across environments; crimson clover and winter pea genotypes produced a more homogenized cover crop mixture when grown with the small grains. The variability in total biomass composition across environments in this study demonstrates the importance of site specific cover crop seeding rate recommendations for production in mixture.
Faba beans: Each year faba bean performance improved presumably due to enhanced cold tolerance and disease resistance from bulk harvesting the surviving seed each year. In 2017, the faba beans were producing in excess of 5,000 kg/ha at several locations.
Educational & Outreach Activities
Two extension publications have been created. One is currently available at the North Carolina State University Organic Grains Website and the other involving the grain potential of pea is going through official University publication channels and will be available shortly. One additional extension publication will be released on the use of pea and faba bean as legume cover crops in the Southeast region. These extension publications will be available through the North Carolina State University Extension system and will be distributed in the North Carolina State University Organic Grain Production Newsletter.
Three scientific publications involving this research are in preparation for publication. This Southern SARE supported research was also a large component of Rachel Atwell's dissertation entitled 'Optimizing Short-term Cover Crop Benefits through Genotype Screening and Management.'
Results from this research were presented at three official North Carolina State University Field Days. These include the Organic Production Field Day hosted in Rocky Mount, NC on July 21,2017, the Rowan Small Grain Field Day hosted in Salisbury, NC on May 11, 2017, and the Central Piedmont Small Grain Field Day hosted in Salisbury in April 2016.
Additionally this research was discussed with stakeholders at a Cover Crop Meeting and Field Day in Smithfield, NC on April 21, 2017, at the Lee County Area Farmers Meeting in Sanford, NC on February 2, 2017, at the Peanut and Cotton Extension Agent training in Wilson, NC on January 18, 2017, and at the North Carolina Agricultural Consultants Association Annual Meeting in Raleigh, NC on December 2, 2017.
Scientific presentations were given at the American Society of Agronomy meetings in 2015 and 2016.
There were several growers who expressed interest in winter pea for the different end uses following field presentations. Our results have been released to stakeholders in the Southeast USA in hopes to catalyze cultivar development for use by farmers in the region. These results have been made available at various extension events, in extension publications and results will be published in a high-impact journal. We have presented these results at several field days, county extension agent training, crop consultant training, and academic meetings. Subsequent field trails will investigate additional agronomic production practices of winter legumes that are of interest to farmers in Southeast USA.
Field studies evaluating winter pea for grain potential were successfully installed at six environments in North Carolina from 2014 to 2016. These environments included Clayton, Kinston, and Salisbury, North Carolina. The information from these studies has been made available to growers and other agricultural stakeholders through multiple outlets described in greater detail in other areas of the report.
Field studies evaluating winter pea and faba bean for cover crop potential were successfully installed at six environments in North Carolina from 2015 to 2017. These environments included Clayton, Kinston, Rocky Mount, and Salisbury, North Carolina. The information from these studies has been made available to growers and other agricultural stakeholders through multiple outlets described in greater detail in other areas of the report.
There are several major things we learned about pea and faba bean production over the duration of this experiment.
- Heat is likely a large limiting factor to grain fill in winter peas and is a restriction on maximizing yield. Effort should be devoted to developing earlier flowering peas which are less susceptible to heat injury during flowering.
- Pea and wheat can be harvested simultaneously for grain in the Southeast.
- Several pea genotypes can produce as much biomass as crimson clover and hairy vetch in the Southeast.
- Disease pressure is the largest challenge in pea production in the Southeast region; improving disease resistance in pea germplasm is important for the success of this crop in the Southeast region.
- Bulk selections within each faba bean genotype appears to have been successful in creating regionally adapted populations; research is underway to understand the genetic progress made with these bulk selections and the feasibility of using faba bean as a legume cover crop.
We are very appreciative of the funding we received from Southern SARE. We have multiple follow-up projects being conducted as a result of this research from a diverse set of funding sources. This research will be invaluable in enhancing environmental and economic sustainability for producers in the region.