EVALUATING FORAGE GERMPLASM AND MANAGEMENT PRACTICES FOR LIVESTOCK PRODUCTION AND ECOSYSTEM SERVICES

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1018653
• Project Start Date: Feb 1, 2019
• Project End Date: Dec 31, 2023
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIVERSITY OF FLORIDA
G022 MCCARTY HALL
GAINESVILLE,FL 32611

Performing Department
Agronomy

Non Technical Summary
Florida beef and dairy production systems contribute over $1 billion annually to the state's economy. In addition, there are over 500,000 horses in Florida with an associated cash flow of $5 billion per year. Forage is a major component of the diet of all livestock in the state. Planted pastures occupy approximately 3.5 million acres and native grasslands (includes forestland that is grazed) another 6 million acres.In spite of their large contributions to the state's economy, limitations remain among forages currently utilized in Florida. Bahiagrass (Paspalum notatum Flügge), which is grown on approximately 2.5 million acres for forage, produces 85% of its yield during the period from April through September. In addition, in the last five years numerous producers have identified decline of bahiagrass pastures as a major issue. Efforts are needed to identify species to extend the grazing season and to determine the cause of bahiagrass pasture decline.Another pressing need for livestock producers is alternatives to expensive nitrogen fertilizer for forage production. The legume rhizoma peanut (Arachis glabrata Benth.; RP) has become an important component of hay production systems in the state, but establishment has been too expensive to allow its use in pasture-based systems that generate less income per unit land area (e.g., beef production systems). Additional research is needed to define factors affecting rate and success of establishment of rhizoma peanut. There also are limited data on the relative benefits to soil carbon accumulation of year-round production systems based on legumes vs. grasses. These data are needed to more fully define the ecosystem services benefits of various forage systems appropriate for Florida conditions.Thus, there is a need for continued evaluation of potential new forage species and genotypes and improved management practices for Florida forage-livestock systems. This project will 1) assess factors affecting establishment of rhizoma peanut, 2) determine the effect of planting warm-season annual forages simultaneously with Tifton 85 stems on forage production during the planting year and on subsequent establishment of Tifton 85, 3) compare stand establishment and cold tolerance under clipping management of forage grasses from the genera Urochoa and Panicum with Jiggs bermudagrass, 4) identify factors causing bahiagrass pasture decline and test the efficacy of management strategies designed to overcome them, and 5) quantify soil carbon dynamics for year-round forage systems based on legumes vs. N-fertilized grasses.

Animal Health Component

80%

Research Effort Categories

Basic

20%

Applied

80%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
205	0780	1060	80%
102	0110	1060	20%

Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships; 205 - Plant Management Systems;

Subject Of Investigation
0780 - Grasslands, other; 0110 - Soil;

Field Of Science
1060 - Biology (whole systems);

Keywords

rhizoma peanut

bermudagrass

bahiagrass

forage establishment

soil carbon

ecosystem services

Goals / Objectives
1. To shorten the time interval for establishment of rhizoma peanut by identifying determinants of rhizome quality and by assessing the efficacy of management factors designed to increase establishment rate.2. To determine the effect of planting warm-season annual forages simultaneously with Tifton 85 stems on forage production during the year of planting and subsequent stand establishment of Tifton 85 hay fields.3. To compare stand establishment and cold tolerance under clipping management of a Urochloa species, a Panicum species selected for cold tolerance, an existing Panicum cultivar, and Jiggs bermudagrass, a commonly used forage in the region.4. To identify factors causing bahiagrass pasture decline and test the efficacy of management strategies designed to overcome them.5. To quantify soil carbon dynamics for year-round forage systems based on legumes vs. N-fertilized grasses.

Project Methods
Objective 1Treatments will be four rhizoma peanut entries (Tito, Peace, Ecoturf, Florigraze), and rhizomes will be sampled at time of first freeze in fall, monthly during winter, and every 2 wk after new shoots emerge in spring until the end of the planting season in July. Rhizomes will be analyzed for total nonstructural carbohydrate concentration to assess fitness for use as planting material. During the spring through mid-summer planting period, sward canopy characteristics will be quantified, and weather conditions, especially temperature (i.e., growing degree days), will be recorded. Relationships between temperature, canopy characteristics, and rhizome nonstructural carbohydrate concentration will be determined in order to develop predictive capability of when rhizomes will be in good condition for use as planting material. At monthly intervals from March through July, rhizomes will be planted in three-row plots of 1.5-m length. Establishment performance measured during the year of planting in order to characterize the nature of the relationship between rhizome characteristics and establishment success.Objective 2Treatments will be Tifton 85 alone, Tifton 85 + pearl millet, Tifton 85 + sunnhemp, Tifton 85 + pearl millet + sunnhemp at full seeding rate, and Tifton 85 + pearl millet + sunnhemp at half seeding rate. The Tifton 85 will be planted at a rate of 1400 kg of fresh stems ha-1, with stems distributed evenly across each plot and cut into the soil immediately using a light disk. The pearl millet and sunnhemp full seeding rates will be 22 kg ha-1 for pearl millet and 11 kg ha-1 for sunnhemp. The half seeding rates are 11 kg ha-1 for pearl millet and 5.5 kg ha-1 for sunnhemp, and these rates will be used for the half seeding rate treatment only. The five treatments will be distributed in a randomized block design with 4 replicates. Plots will be fertilized with 40 kg N ha-1 and with P and K according to soil test after germination, and with 60 kg N ha-1 after the first and second harvests. Plots will be harvested every 6 weeks to a 15-cm stubble height. Forage samples will be analyzed for CP and in vitro digestible dry matter. An additional sample will be collected from each plot for determination of botanical composition. Tifton 85 percent cover will be measured in fall. In spring of the year after planting, the plots will be fertilized with 60 kg N ha-1 in March and Tifton 85 cover and herbage accumulation measured in June in order to assess the impact of planting annuals on bermudagrass establishment and subsequent productivity.Objective 3This study will compare a local control, Jiggs bermudagrass, with three tropical types including the existing guineagrass cultivar 'Mombasa', a guineagrass selected for greater cold tolerance that we are calling Panicum CT, and 'Camello' Urochloa decumbens.Plots will be 5 x 5 m in area and separated by a 3-m tilled alley on all sides. The four treatments will be arranged in four replicates of a randomized block design. Jiggs bermudagrass will be established vegetatively using stems. It will be planted at a rate of 1400 kg of fresh stems ha-1. Immediately after spreading, stems will be cut into the soil using a light disk. Seed of all three seeded species will be broadcast at 10 kg ha-1, and the entire experiment will be rolled to cover the seeds and firm the seedbed. After germination, P and K will be applied based on soil test and N will be applied at 40 kg ha-1. Plants will not be harvested during the year of planting. In the year after planting, they will be fertilized in spring with 60 kg N ha-1, stand cover assessed, and plants will be defoliated at approximately 6-wk intervals to a 15-cm stubble height. Herbage accumulation, nutritive value, and stand persistence will be assessed.Objective 4 Four, on-ranch sites will be used. The eight treatments are the factorial combinations of with or without lime (0 or according to soil test), with or without potassium fertilizer (0 or 55 kg K2O ha-1), and with or without P fertilizer (0 or 28 kg P2O5 ha-1). Plot size is 5 x 9 m, and treatments are arranged in four replicates of a randomized block design. All plots will receive 55 kg N ha-1 in March. The pastures will be grazed according to the rancher's regular management program except for fertilization.Measurements will include bahiagrass herbage accumulation, nutritive value, and percentage cover, as well as soil nutrient status. To measure herbage accumulation, two, 1-m2 exclusion cages will be placed and securely anchored on each plot after fertilization. The amount of forage present in the caged area will be quantified prior to cage placement using a calibrated disk meter. Every month thereafter throughout the growing season, the sites will be visited and new cage sites chosen. Forage representing what the animals are consuming will be collected to determine crude protein, in vitro digestion, and tissue P and K concentrations. Soil will be sampled before applying treatments and annually thereafter. At the time of initial fertilization and annually thereafter, percent cover of bahiagrass will be measured in two quadrats per plot.Objective 5 Year-round legume or year-round N-fertilized grass systems (combination of a warm-season perennial and an overseeded cool-season annual) were planted in 2011 and management treatments have been imposed since. Changes in soil organic matter will be evaluated over the seven-year period and perhaps longer.The experiment is being conducted at the University of Florida Plant Science Research and Education Unit in Citra, FL (29.24°N, 82.10°W) on a site that was previously under long-term crop production. Treatments are replicated three times in a split-plot arrangement, with main plots (legume or N-fertilized grass) allocated in a randomized complete block design. Perennial species will serve as the main plot (bermudagrass or Florigraze RP). Within each main plot there will be four production systems for a total of 8 treatments. The four production systems are 1) hay production of the warm-season forage; no overseeded cool-season forage; 2) hay production of the warm-season forage during summer and of overseeded cool-season species during winter; 3) grazing of the warm-season forage during summer; no overseeded cool-season forage; and 4) grazing of the warm-season forage during summer and of overseeded cool-season forages during winter. The cool-season forages are rye and annual ryegrass for the N-fertilized grass system and rye, annual ryegrass, and clovers for the legume system.Soil samples were collected from each experimental unit prior to treatments being imposed and will be collected again at the end of seventh experimental year. The soil cores will be taken to a depth of 100 cm and divided into layers of 0 to 10, 10 to 20, 20 to 40, 40 to 80, and 80 to 100 cm. After drying, samples from the 0- to 10 and 10- to 20-cm layers will be sieved through a 2-mm screen and particles greater than 2 mm will be discarded. A 100-g subsample will be taken from the remaining sample and sieved with mesh sizes of 53, 150, and 250 µm in a sieve shaker. Total organic C and total N of each soil layer will be determined by dry combustion using a Carlo Erba NA-1500 C/N/S analyzer on subsamples ground in a ball mill for 5 min. A subsample will be taken from each soil particle size category of the 0- to 10 and 10- to 20-cm layers, with the exception of particles ≤ 53 µm. Soil organic matter fractionation of particles will be determined by decantation with water and density separation into light (LD) and heavy (HD) density SOM fractions. Physical separation of OM will be performed. Both LD and HD-SOM fractions will be analyzed for their C and N concentrations by dry combustion using the analyzer described for total C and N analysis. Particles less than 53 μm will also be analyzed for C and N using the same procedure.

Progress 10/01/20 to 09/30/21

Outputs
Target Audience:The target audiences reached include producers growing forage crops for use by livestock and our peer scientists in the research community. Changes/Problems:We experienced a Covid-related research shutdown in 2020 that delayed progress on several objectives, but we were able to regain momentum once the shutdown ended. This will not have significant negative impacts on our overall achievements in this project. What opportunities for training and professional development has the project provided?Various graduate students have been trained through this process including Liliane Silva (now on faculty at Clemson), Marta Kohmann (soon to be on faculty at West Virginia University), Jack Harling (completed M.S., soon to start Ph.D.), and Haley Hayes (analyzing M.S. thesis data). How have the results been disseminated to communities of interest?Results have been disseminated through refereed journal articles, online extension articles, producer field days and meetings, and extension agent in-service training. What do you plan to do during the next reporting period to accomplish the goals?We are continuing field research under Objectives 1, 3, and 4, and have additional writing and publication to carry out for all five objectives.

Impacts
What was accomplished under these goals? 1. We completed the second year of a planting date study evaluating seasonal changes in rhizome quality and subsequent planting date success. We also published two papers relating to the effect of various management practices on sprouting and new shoot development. 2. We completed the second year of a study assessing the efficacy of planting pearl millet and sunnhemp (annuals) with a perennial species bermudagrass. Data collection and laboratory analyses are complete and data analyses is ongoing. 3. We completed the second year of an experiment evaluating these genotypes in both north and central Florida. We have started a new experiment looking at the effect of grazing frequency on their performance. It will be conducted in 2022 and 2023. 4. Work assessing bahiagrass decline has been completed and manuscripts are in preparation. 5. Graduate student Liliane Silva completed a multi-year experiment looking at soil carbon dynamics and nutrient cycling in legume-grass vs. N-fertilized grass systems. She has two papers accepted that describe this work and several more in preparation.

Publications

• Type: Journal Articles Status: Published Year Published: 2021 Citation: Aryal, P., and L.E. Sollenberger. 2021. Growth temperature and rhizome propagule characteristics affect rhizoma peanut shoot emergence and biomass partitioning. Agron. J. 113:335344.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Aryal, P., L.E. Sollenberger, M.M. Kohmann, L.S. da Silva, K.D. Cooley, and J.C.B. Dubeux, Jr. 2021. Plant growth habit and nitrogen fertilizer effects on rhizoma peanut biomass partitioning during establishment. Grass and Forage Sci. 76:485493.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Barbosa, P.L., V.J. Silva, A.F. Sbrissia, L.E. Sollenberger, and C.G.S. Pedreira. 2021. Herbage accumulation and tillering dynamics of 'Zuri' guineagrass under rotational stocking. Crop Sci. 61:37873798
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Garcia-Jimenez, L., J.C.B. Dubeux, Jr., L.E. Sollenberger, J.M.B. Vendramini, N. Dilorenzo, E.R.S. Santos, D.M. Jaramillo, and M. Ruiz Moreno. 2021. Nutrient excretion from cattle grazing N-fertilized grass or grass-legume pastures. Agron. J. 113:3110-3123.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Jaramillo, D., J.C.B. Dubeux, Jr., L.E. Sollenberger, C. Mackowiak, J.M.B. Vendramini, N. Dilorenzo, L.M. Dantas Queiroz, E.R.S. Santos, L. Garcia, and M. Ruiz-Moreno. 2021. Litter mass, deposition rate, and decomposition in N-fertilized or grass-legume mixed grazing systems. Crop Sci. 61:21762189.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Jaramillo, D.M., J.C.B. Dubeux, Jr., L.E. Sollenberger, J.M.B. Vendramini, C.L. Mackowiak, N. DiLorenzo, L. Garcia, L.M.D. Queiroz, E.R.S. Santos, B.G.C. Homem, F. van Cleef, and M. Ruiz-Moreno. 2021. Water footprint, herbage, and livestock responses for N-fertilized grass and grass-legume grazing systems. Crop Sci. 61:38443858.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Lara, M., V.J. Silva, L.E. Sollenberger, and C.G.S. Pedreira. 2021. Seasonal herbage accumulation and canopy characteristics of novel and standard brachiariagrasses under N fertilization and irrigation in southeastern Brazil. Crop Sci. 61:1468-1477.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Nascimento, H.L.B., B.C. Pedreira, L.E. Sollenberger, D.H. Pereira, C.A. de S. Magalh�es, and F.H.M. Chizzottie. 2021. Herbage accumulation, canopy structure and tiller morphology of Marandu palisadegrass growing in monoculture and in silvopasture. Agroforestry Syst. 95:339-352.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Santos, E.R.S., J.C.B. Dubeux, Jr., C.L. Mackowiak, A.R. Blount, L.E. Sollenberger, D.B. Jaramillo, L. Garcia, D.S. Abreu, R.T. Souza, and M. Ruiz-Moreno. 2021. Herbage responses and nitrogen agronomic efficiency of bermudagrass-legume mixtures. Crop Sci. 61:38153829.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Silva, L.S., L.E. Sollenberger, M.M. Kohmann, J.C.B. Dubeux, Jr., P. Aryal, M.L. Silveira, and J.M.B. Vendramini. 2021. Existing litter mass and N disappearance on year-round N-fertilized grass and legume-based forage systems. Agron. J. 113:51705182.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Wilson, C.H., J.M.B. Vendramini, L.E. Sollenberger, and S.L. Flory. 2021. Root production in a subtropical pasture is mediated by cultivar and defoliation severity. Trop. Grassl.-Forrajes Tropicales 9:144158.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:Reports on results of research were provided to the Florida Cattlemen's Association Research Committee and the Florida Dairymen's Research Committee in the form of written reports and oral presentations. Two YouTube videos were prepared illustrating alfalfa establishment and defoliation management in mixture with bermudagrass. The videos were posted to various extension sites in Florida and regionally throughout the southeastern US. Changes/Problems:The research program shutdown due to Covid-19 caused Objective 1 experiments to be terminated in 2020 due to loss of critical data. That work will resume in 2021. Several other studies experienced minimal delays due to this shutdown, but this did not significantly affect their execution. What opportunities for training and professional development has the project provided?Two graduate students, M.S. student Jack Harling and Ph.D. student Gabriel Pedroso were supported on this project. How have the results been disseminated to communities of interest?Results have been disseminated through written and oral reports to livestock organizations and through YouTube videos distributed online through extension sites. What do you plan to do during the next reporting period to accomplish the goals?Activities will continue under all objectives. Ongoing field and laboratory research will continue for Objectives 1-3. Field and laboratory research has been completed for Objective 4 and 5, and data analysis and preparation of publications will continue in 2021.

Impacts
What was accomplished under these goals? Accomplishments are listed in order of project objectives. 1. Covid-related shutdowns occurred during a critical time in research for this project, so the work was delayed until 2021 and will continue through 2023. 2. Four studies were conducted in 2020, three with alfalfa planted into bermudagrass and one with pearl millet and sunnhemp. These studies will continue during 2021 and are part of the research program of graduate student John Harling. 3. This study was harvested for a second year in 2020. Samples are currently ready for laboratory analyses. Winter survival ratings will be completed in Spring 2021, and data will subsequently be summarized and published. 4. Data collection and summary has been completed for this work. Drafting of publications is nowunderway. 5. This work has been completed in the field and data are currently being analyzed for publication and publications prepared.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Aryal, P., L.E. Sollenberger, M.M. Kohmann, L.S. da Silva, E.M. Shepard, K.D. Cooley, D.L. Rowland, and J.C.B. Dubeux, Jr. 2020. Rhizoma peanut genotype and planting date affect biomass allocation patterns and establishment performance. Crop Sci. 60:16901701. https://dx.doi.org/10.1002/csc2.20142
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Cooley, K.D., L.E. Sollenberger, M.M. Kohmann, A.S. Blount, J.C.B. Dubeux, Jr., M.L. Silveira, L.S. da Silva, and P. Aryal. 2020. Rhizoma peanut herbage and root-rhizome responses to extended regrowth periods. Crop Sci. 60:28022813. https://dx.doi.org/10.1002/csc2.20236
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Reyes-Cabrera, J., J.E. Erickson, R.G. Leon, D.G. Quadros, M.L. Silveira, and L.E. Sollenberger. 2020. Bahiagrass pasture and elephantgrass bioenergy cropping systems differ in root traits. Agron J. 112:48104821. https://doi.org/10.1002/agj2.20382
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Silveira, M.L., C.B. Brandani, M.M. Kohmann, J. Erickson, J. Reyes-Cabrera, R. Leon, L.E. Sollenberger, V. Piotto, D. Quadros, and S. Mello. 2020. Short-term effects of converting perennial pastures to bioenergy cropping on soil C and N dynamics in a Florida Ultisol. Soil Sci. Soc. Amer. J. 84:12331246. https://dx.doi.org/10.1002/saj2.20081.

Progress 02/01/19 to 09/30/19

Outputs
Target Audience:Producers and producer organizations County extension agents Other scientists Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Four graduate students and one postdoc have trained in the project, with those who have completed their work now employed in academic positions and one in the process of finishing her degree. How have the results been disseminated to communities of interest?Results have been disseminated through popular press articles for producers and extensionists, journal articles for scientists, and by talks given at producer conferences and scientific meetings. What do you plan to do during the next reporting period to accomplish the goals?We will finalize work on Objective 5.

Impacts
What was accomplished under these goals? Goals 1-4 were previously accomplished. For goal 5, we have determined that N-fertilized grass systems have greater above-ground plant litter and in many cases greater below-ground biomass than legume-based systems. Results are pending, but these advantages appear to lead to greater soil C, showing soil C is often related to below-ground biomass.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Sollenberger, L.E., M.M. Kohmann, J.C.B. Dubeux, Jr., and M.L. Silveira. 2019. Grassland management affects delivery of regulating and supporting ecosystem services. Crop Sci. 59:441459.
• Type: Journal Articles Status: Awaiting Publication Year Published: 2019 Citation: Cooley, K.D., L.E. Sollenberger, A.R. Blount, L.S. da Silva, M.M. Kohmann, P. Aryal, J.C.B. Dubeux Jr., and M.L. Silveira. A modified ingrowth core to measure root-rhizome accumulation of perennial forage species. Agron. J. (in press).
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Kohmann, M.M.*, L.E. Sollenberger, J.C.B. Dubeux, Jr., M.L. Silveira, L.S.B. Moreno. 2019. Legume proportion in grassland litter affects decomposition dynamics and nutrient mineralization. Agron. J. 111:1079-1089.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Santos, E.R.S., J.C.B. Dubeux, Jr., R.C. Menezes, C.L. Mackowiak, L.E. Sollenberger, M. Ruiz-Moreno, D.M. Jaramillo, L. Garcia, and L.M.D. Queiroz. 2019. Particulate soil organic matter in bahiagrass-rhizoma peanut mixtures and their monocultures. Soil Sci. Soc. Amer. J. 83:658-665.