Perennial Grass Pastures Research Articles

Indirect and interactive effects drive impacts of prescribed fire and invasive grass on a native wetland herb

Understanding the indirect and interactive effects of environmental stressors is critical to planning conservation interventions, but such effects are poorly understood. For example, invasive species may modify fire effects by altering fire intensity or frequency, increasing or decreasing their abundance in response to fire, and/or changing the trajectory of post‐fire recovery. Without a clear understanding of the direct, indirect, and interactive effects of prescribed fire and invasive species on native plants, managers cannot design effective conservation measures and risk exacerbating invasion through fire or wasting resources on approaches that do not yield desired results. In this study, researchers worked directly with the manager of a wet meadow in southern Idaho to explore how prescribed fire would directly and indirectly impact an iconic native herb (Camassia quamash) in areas invaded by a perennial pasture grass (Alopecurus arundinaceus). We found that spring prescribed fire increased the abundance of invasive A. arundinaceus, which indirectly strengthened its suppression of C. quamash growth and reproduction. In contrast, fire reversed the negative influence of A. arundinaceus on C. quamash survival. Survival rates of C. quamash were higher after fire in areas with greater invasive grass abundance. This study points to the importance of understanding the indirect and interactive effects of prescribed fire and invasives on native plants across their life cycle for restoration projects and suggests fire, at least in spring, is not an appropriate management strategy for reducing A. arundinaceus invasion at this site.

Effect of plantation age on plant and soil C:N:P stoichiometry in Kentucky bluegrass pastures

Plant and soil C:N:P stoichiometry reflects the element content and energy flow, which are important for biogeochemical cycling in ecosystems. Although plantation age has been verified to affect leaf C:N:P stoichiometry in alfalfa plants, its effect on plant and soil C:N:P stoichiometry in grass remains poorly documented. A 10-year field experiment of Kentucky bluegrass (Poa pratensis) was used to test how plantation age affect plant and soil C:N:P stoichiometry in a perennial rhizomatous grass pasture. This study demonstrated that leaf C:N, C:P, and N:P ratios exhibited a rapid increasing trend from 2 to 6 years of age, whereas leaf C:N showed a slight decreasing trend, and leaf C:P and N:P maintained stability from 6 to 9 years of age. Stem C:N and N:P were not different among plantation ages, while stem C:P increased from 2 to 4 years of plantation age and then maintained stability from 4 to 9 years of plantation age. Root N:P showed an increasing trend from 2 to 6 years of plantation age and relative stability from 6 to 9 years of plantation age, whereas root C:N and C:P showed decreasing trends from 2 to 9 years of plantation age. Although soil C:P did not differ among nine plantation ages, soil C:N and N:P remained relatively stable from 2 to 6 years of plantation age. However, soil C:N showed a decreasing trend, while soil N:P showed an increasing trend after 6 years of plantation age. The results from an ecological stoichiometric homeostasis analysis further showed that N in the leaf, stem, and root and P in the stem had strict homeostasis, whereas P in the leaf and root showed plastic and weakly homeostatic status, respectively. These results present a pattern concerning the plantation age in relation to plant and soil C:N:P stoichiometry in a perennial grass and provide useful information for N and P management in Kentucky bluegrass pastures.

Hard-seeded temperate annual legumes establish better in a tropical grass pasture when autumn-sown than spring-sown in a summer dominant rainfall zone, Australia

ABSTRACT Temperate annual legumes can be effective companion species in tropical perennial grass pastures. These legumes are commonly sown in autumn following establishment of the grasses. However, it may be more effective to establish a seed bank before sowing the grass, or possibly sow the legumes as hard seed/pod in spring when the tropical grass pasture is sown. A study was conducted in northern New South Wales to compare establishment, regeneration and productivity of three hard-seeded legumes: bladder clover (Trifolium spumosum) cv. Bartolo, biserrula (Biserrula pelecinus) cv. Casbah and French serradella (Ornithopus sativus) cv. Margurita. The legumes were sown four times: either one or two autumns before digit grass (Digitaria eriantha) cv. Premier was established, the autumn following grass establishment or sown at the same time as the grass as either hard seed/pod segments or scarified seed (total of five treatments). While seasonal conditions influenced establishment success, autumn was the optimal time to sow temperate annual legumes to achieve a productive mixed pasture. The legumes can be sown 1–2 autumns before or in the autumn following grass establishment. Legume plant populations of spring sown hard seed/pod segments were lower than those autumn sown but they increased the following year.

Belowground carbon allocation, root trait plasticity, and productivity during drought and warming in a pasture grass.

Sustaining grassland production in a changing climate requires an understanding of plant adaptation strategies, including trait plasticity under warmer and drier conditions. However, our knowledge to date disproportionately relies on aboveground responses, despite the importance of belowground traits in maintaining aboveground growth, especially in grazed systems. We subjected a perennial pasture grass, Festuca arundinacea, to year-round warming (+3 °C) and cool-season drought (60% rainfall reduction) in a factorial field experiment to test the hypotheses that: (i) drought and warming increase carbon allocation belowground and shift root traits towards greater resource acquisition and (ii) increased belowground carbon reserves support post-drought aboveground recovery. Drought and warming reduced plant production and biomass allocation belowground. Drought increased specific root length and reduced root diameter in warmed plots but increased root starch concentrations under ambient temperature. Higher diameter and soluble sugar concentrations of roots and starch storage in crowns explained aboveground production under climate extremes. However, the lack of association between post-drought aboveground biomass and belowground carbon and nitrogen reserves contrasted with our predictions. These findings demonstrate that root trait plasticity and belowground carbon reserves play a key role in aboveground production during climate stress, helping predict pasture responses and inform management decisions under future climates.

Current Scenario and Perspectives for Nitrogen Fertilization Strategies on Tropical Perennial Grass Pastures: A Review

Traditional Nitrogen (N) fertilization practices for tropical perennial grass are still based on annual amounts, following flat N rates instalments. This strategy does not consider variations in climatic conditions along the growing season, their impacts on the plant’s demand and the soil N availability. At regrowth cycles where the amount of soil N released from mineralization or through animal excreta surpass the plant’s demand, most of the N may be lost (as ammonia, nitrate, and nitrous oxide), increasing production costs and environmental pollution. This paper examines current N fertilization and discusses possible gaps in knowledge for the definition of more precise fertilization guidelines in pasture-based livestock systems based on tropical perennial grasses. More precise fertilization practices, based upon site and seasonal-specific recommendations, will substantially contribute to the establishment of best fertilization guidelines. Sustainable approaches can be defined by combining the identification of regrowth cycles where high N rates are required, with enhanced efficiency fertilizers, and/or using grass species with the potential for biological nitrification inhibition. The lack of information on tropical grasses requirements, and soil and climatic factors driving the N fate into the mineralization and immobilization processes and how these factors affect plant’s N demand, still prevents opportunities for tactical applications and the establishment of best management guidelines.

Fermentation Quality of Silages Produced from Wilted Sown Tropical Perennial Grass Pastures with or without a Bacterial Inoculant

High growth rates and rapid reproductive development and associated decline in feed quality of sown tropical perennial grass pastures present management challenges for livestock producers. Conservation of surplus forage as silage could be an effective management tool. Experiments were conducted to evaluate the fermentation quality of silages produced from tropical grasses. Five species (Chloris gayana, Megathyrsus maximus, Panicum coloratum, Digitaria eriantha and Cenchrus clandestinus) were ensiled without additives after a short, effective wilt at dry matter (DM) contents ranging from 302.4 to 650.1 g kg−1. The fermentation profile of all silages in 2019 was typical for high DM silages, but in 2020 ammonia (% of total nitrogen: NH3-N), acetic acid and pH levels were higher. In 2020 M. maximus (302.4 g kg−1 DM) was poorly preserved with 20.2% NH3-N. The DM content of all other silages exceeded 350 g kg−1 and fermentation quality was generally good. In a second experiment, M. maximus was ensiled at 365 g kg−1 chopped and 447 g kg−1 DM chopped and unchopped, either without or with Pioneer 1171® (Lactobacillus plantarum and Enterococcus faecium) or Lallemand Magniva Classic® (L. plantarum and Pediococcus pentasaceus) bacterial inoculant. Inoculants increased lactic acid production, reduced pH and improved fermentation compared to Control, but D-lactate, L-lactate and acetic acid production differed between inoculants. Unchopped silages had higher pH and NH3-N and better preserved protein fraction than chopped silages at the same DM content. In both experiments, wilting increased water soluble carbohydrates by 0.5–31.5 g kg−1 DM and ensiling increased degradation of the protein fraction. We concluded that a rapid and effective wilt combined with a bacterial additive resulted in well preserved tropical grass silages.

Perennial pasture grass invasion changes fire behaviour and recruitment potential of a native forb in a temperate Australian grassland

Invasive grasses can modify fire regimes of native ecosystems leading to changed ecosystem structure, composition, and functioning. Temperate grasslands in Australia are currently being invaded by a suite of exotic perennial pasture grasses, but their effects on ecosystems remain largely unknown. We aimed to determine the effect of invasion by the exotic perennial grass Phalaris aquatica on fire behaviour, as well as the regeneration potential of an endangered forb in temperate native grasslands in south-eastern Australia. Frequently burnt native grasslands invaded by exotic grasses were found to have two times more fuel than grasslands dominated by native grasses; in less-frequently burned native grasslands, exotic grasses contributed to fuel loads that were five times higher than native grasslands. Exotic-dominated grasslands burned differently than native grasslands; fire intensities were three times higher in exotic-dominated grasslands and had a wide variability in fire residence times. Soil heating was positively related to fire residence time but had no clear relationship with fire intensity. Seed germinability of Leucochrysum albicans var. tricolor (Hoary Sunray, Asteraceae) was reduced by exotic grass-fueled fire and increasing fire residence times. The observed changes in fire behaviour represent an invasion-driven shift in the ecosystem’s fire regime. By increasing fuel mass, fire residence time increased, and this influenced seed survival and subsequent germinability. Increased fire intensity following invasion highlights that invasive grasses can increase the fire-risk of grasslands. Maintaining native grasslands free of invasive pasture grasses therefore has environmental and fire-risk benefits.

Genetic diversity among wild and cultivated germplasm of the perennial pasture grass

Phalaris aquatica L. (phalaris) is a cool-season perennial grass originating from the Mediterranean Basin, north-west Africa and Middle Eastern regions that is used for livestock agriculture mainly in temperate areas with dry summers. It has been the subject of breeding programs in Australia, South America, New Zealand and the USA. Increased knowledge of relationships between wild and cultivated germplasm through use of molecular markers has the potential to facilitate future breeding gains. For this purpose, we conducted an analysis of P. aquatica by using 3905 polymorphic DArTseq SNP markers. Genetic diversity as measured by expected heterozygosity was similar for wild (HE = 0.14; n = 57) and cultivated (HE = 0.13; n = 37) accessions. Diversity in wild germplasm was generally continuous in nature, largely related to geographical location, with a division at the broadest scale into eastern and western clades, with more admixture in the western than the eastern clade. Structure analysis of wild germplasm indicated six subpopulations consistent with country of origin, with some admixture among subpopulations likely resulting from natural and human influences. There were nine subpopulations among wild and cultivated accessions combined. This population structure should be considered if genomic selection is applied in P. aquatica. Analysis of molecular variance indicated that 71% of the genetic variation occurred within subpopulations and 29% among subpopulations. Genetic distances were low among cultivated germplasm from most countries except the USA, which was more distinct. Evaluation of material from the US pool by breeding programs in other countries, and additional material from the less utilised eastern clade, may be worthwhile.

Growth, Rhizosphere Carboxylate Exudation, and Arbuscular Mycorrhizal Colonisation in Temperate Perennial Pasture Grasses Varied with Phosphorus Application

Phosphorus (P) fertiliser is applied regularly to the nutrient-poor sandy soils in southwestern Australia to elevate and/or maintain pasture production. This study aimed to characterise differential growth, root carboxylate exudation, and mycorrhizal responses in three temperate perennial pasture grasses at variable P supply. Tall fescue (Festuca arundinacea L. cv. Prosper), veldt grass (Ehrharta calycina Sm. cv. Mission), and tall wheatgrass (Thinopyrum ponticum L. cv. Dundas) with five P rates varying from 0 to 100 mg P kg−1 soil were evaluated in a controlled environment. Rhizosphere carboxylate exudation and mycorrhizal colonisation were assessed. Veldt grass produced the maximum shoot dry weight, highest agronomic phosphorus-use efficiency at low P supply, as well as the highest specific root length and shoot P content at all P rates. Across species, the maximum shoot weight was obtained at 20 and 50 mg P kg−1 soil, which differed significantly from the two lowest P rates (0 and 5 mg P kg−1 soil). Phosphorus application influenced carboxylate exudation, with plants exuding acetate only in the zero P treatment, and citrate and malonate in the P-supplemented treatments. In all three species, acetate and malonate were the major carboxylates exuded (37–51% of the total). Only tall wheatgrass released trans-aconitate. Citrate and malonate concentrations in the rhizosphere increased with P supply, suggesting their important role in P acquisition. Phosphorus applications reduced arbuscular mycorrhizal colonisation and increased root diameter as the P rate increased. Root carboxylate exudation in low-P soil played a role in mobilisation of P via P solubilisation, but the role of exuded carboxylate in soils well supplied with P might be diminished.

Nitrogen and Potassium Fertilisation Influences Growth, Rhizosphere Carboxylate Exudation and Mycorrhizal Colonisation in Temperate Perennial Pasture Grasses

Optimisation of potassium (K) use efficiency in pastures on sandy soil is challenging. We characterised growth response, root carboxylate exudation and mycorrhizal colonisation in three perennial pasture grasses: tall fescue (Festuca arundinacea L.), veldt grass (Ehrharta calycina Sm.) and tall wheatgrass (Thinopyrum ponticum L.) in two glasshouse experiments with: (1) four K rates (0, 40, 80 and 120 mg K kg-1 soil), and (2) four N and K treatments (no N and K (–N–K), 81 mg N kg-1 soil but no K, 80 mg K kg-1 soil but no N, and N at 81 and K at 80 mg kg-1 soil (+N+K)) in low-K sandy soil. Veldt grass had the highest shoot dry weight and shoot P content, but the lowest mycorrhizal colonisation. Potassium fertilisation had no significant impact on exudation of citrate and oxalate. The K0 plants had significantly lower exudation of acetate and total carboxylates than K40 plants. The +N+K plants had maximum shoot growth at both harvests (30 and 60 days after sowing (DAS)) and highest N and K shoot contents at 60 DAS. The –N–K plants exuded maximum amounts of citrate and malate at 30 DAS, but at 60 DAS tall fescue had the highest rhizosphere concentrations of citrate and malate in the +N+K treatment. At 60 DAS, mycorrhizal colonisation was significantly lower with than without N and K fertilisation. We concluded that pasture grasses could yield well even in inherently low-K soil without external K fertilisation and mycorrhizal symbiosis. However, the +N+K plants had the highest yield and root carboxylate exudation.

Smutgrass Control in Perennial Grass Pastures

This 4-page document provides an overview of smutgrass biology, control, and general recommendations. Written by Brent Sellers, Neha Rana, José Luiz C. S. Dias, and Pratap Devkota, and published by the UF/IFAS Agronomy Department, revised October 2020.
 Original publication date February 2000 (Sellers, Ferrell, and Mullahey). Revised November 2009, January 2015.
 Revised February 2018 (Sellers, Rana, Dias, and Devkota), and October 2020 (this version)
 Previous versions: 
 Sellers, Brent, Jason Ferrell, and John Mullahey. 2009. “Smutgrass Control in Perennial Grass Pastures”. EDIS 2009 (10). https://journals.flvc.org/edis/article/view/118261.

Soil nitrate leaching under grazed cool-season grass pastures of the North Central US.

Nitrate leaching from agricultural cropping systems contributes to widespread and devastating eutrophication of water bodies globally. In the North Central USA, this problem is acute, with millions of dollars spent annually in efforts to clean up recreational and drinking water. The frequent soil disturbance and exogenous nitrogen (N) amendments applied in annual cropping systems make them major sources of ground- and surface-water nitrate pollution. Perennial grasslands under managed livestock grazing have been touted for their ability to retain soils and nutrients while simultaneously providing milk and meat to society. The present study provides an evaluation of the peer-reviewed literature addressing nitrate leaching loads beneath corn, pasture and prairie in temperate humid and sub-humid regions of the US, with a focus on cool-season grass pastures. Inputs of exogenous N to these agroecosystems comes from wet and dry deposition, livestock manure from imported feed, biological fixation and inorganic N fertilizer. Nitrate loads were highest beneath corn and lowest beneath restored prairie and switchgrass managed for bioenergy. Cool-season grass pastures had relatively low levels of nitrate leaching loads where little or no N was applied. However, where grazed perennial grasslands had inorganic N applied, nitrate leaching loads rivaled those of corn in some cases. When producing milk and meat from livestock, grazed perennial cool-season grass pastures should reduce nitrate leaching loads compared to growing corn that is used to feed livestock in confinement. However, cool-season grass pastures can lose significant nitrate to leaching with moderate- to high-levels of exogenous N inputs. © 2020 Society of Chemical Industry.

Growth and nutrient uptake of temperate perennial pastures are influenced by grass species and fertilisation with a microbial consortium inoculant

AbstractBackground: The low fertility of sandy soils in South‐Western Australia is challenging for the establishment of temperate perennial pastures.Aims: To assess whether microbial consortium inoculant may improve plant growth by increasing nutrient supply, root biomass and nutrient uptake capacity.Methods: Five temperate perennial pasture grasses–cocksfoot (Dactylis glomerata L. cv. Howlong), phalaris (Phalaris aquatica L. cv. Atlas PG), tall fescue (Festuca arundinacea L. cv. Prosper), tall wheatgrass (Thinopyrum ponticum L. cv. Dundas), and veldt grass (Ehrharta calycina Sm. cv. Mission) were tested in a controlled environment on the growth and nutrition with the microbial consortium inoculant and rock mineral fertiliser.Results: Veldt grass produced the highest shoot and root growth, while tall fescue yielded the lowest. Rock mineral fertiliser with or without microbial consortium inoculant significantly increased root and shoot biomass production across the grass species. The benefit of microbial consortium inoculation applied in conjunction with rock mineral fertiliser was significant regarding shoot N content in tall wheatgrass, cocksfoot and tall fescue. Shoot P and K concentrations also increased in the five grass species by microbial consortium inoculation combined with rock mineral fertiliser in comparison with the control treatment. Arbuscular mycorrhizal (AM) colonisation decreased with rock mineral fertilisation with or without microbial consortium inoculant except in cocksfoot.Conclusions: The response to microbial consortium inoculation, either alone or in combination with rock mineral fertiliser, was plant species‐dependent, indicating its potential use in pasture production.

Root-mycorrhizae interactions contributed to organic carbon density in the sandy soil profiles of adapted grazing lands

Grazing lands occupy a substantial area around the world and could serve as carbon sink if soil organic carbon sequestration potential is increased. In subtropical climates, grazing lands are more commonly situated on low productive sandy soil profiles with poor soil attributes for carbon sequestration. Soil acidity limits root and beneficial microbial interactions, both critical for increasing soil organic carbon (SOC) sequestration. Adapted grazing and forage (vegetation) management could help to improve root-microbe interactions and SOC stocks in the soil profile. The objective of this study was to quantify SOC density in the soil profile along with aboveground and belowground biomass pools, as influenced by long-term cattle grazing of different forage systems managed with or without inorganic nitrogen (iN) fertilization. The following treatments were implemented continuously for the last 30 years. Warm season perennial grass (C4, Cynodon dactylon) pastures were either over-sown with C3 ryegrass (Lolium multiforum; C4-C3G) or clover (Trifolium sp.; C4-C3L), in order to extend the grazing season into cool season months. Grass-based pastures (C4-C3G) were fertilized, called inorganic treatment (iN), while clover systems (C4-C3L called organic N) did not receive iN fertilization (oN). The two forage systems were further split to compare high and low grazing pressure (HG and LG). Forage, root and microbial biomass and SOC density were estimated from soil cores sampled separately during C4 and C3 grazing seasons. Results indicated that SOC density (Mg ha−1) at soil profile level (0–60 cm) was higher under low grazing pressure compared to high, and in iN fertilized compared to oN treatments. However, subsoil (20–60 cm) SOC stocks were significantly higher under oN compared to iN treatments. Forage biomass and root biomass were higher under iN and HG treatments, but arbuscular mycorrhizae (AM) biomass was decreased. There were no consistent trends for other microbial biomass pools in response to GP or N treatments. It can be concluded that higher SOC density in the surface and subsoil in response to GP and N management were largely due to differences in microbial biomass, but not plant biomass productivity. Among the belowground biomass pools, AM was most responsive to experimental factors and their interaction effects, and thus could be a reliable metric to optimize grazing and achieve stewardship goals.

Control of Nuttall's thistle in perennial grass pastures

AbstractNuttall's thistle (Cirsium nuttalli DC) is a biennial species that deters grazing during dry seasons in Florida when forage is limited. Although management of other thistle species has been extensively studied, information on Nuttall's thistle control is limited. Field studies were conducted to compare the effectiveness of aminopyralid, dicamba, and 2,4‐D for Nuttall's thistle control applied at two different timings (rosette vs. bolting). A second experiment was conducted to determine the most effective aminopyralid rate through field dose–response studies. Although control of bolting plants was initially greater than control of rosette thistle at 15 d after treatment (DAT), no differences were detected between growth stages at 30 and 60 DAT. Excellent control (>90%) was achieved at 60 DAT with both rates of dicamba + 2,4‐D [4.0 + 11.4 and 6.0 + 17.2 oz acid equivalent (ae) acre−1] and aminopyralid at 0.77 oz acre−1, whereas aminopyralid at 0.26 oz ae acre−1 and both rates of 2,4‐D (7.0 and 14.0 oz ae acre−1) provided 82, 80, and 78% control, respectively. The dose–response field experiment indicated that the aminopyralid effective dose required for 90% control (ED90) was 0.34 and 0.94 oz ae acre−1 for rosette and bolting thistle at 30 DAT, respectively. No difference between timings was detected at 60 DAT and the aminopyralid ED90 value was 0.27 oz acre−1. These data indicate that dicamba + 2,4‐D (6.0 + 17.2 oz ae acre−1) effectively controlled Nuttall's thistle; similar performance can be obtained with low aminopyralid rates (0.27 oz ae acre−1).

Integrated crop‐livestock effects on soil carbon and nitrogen in a semiarid region

AbstractIntegrated crop−livestock (ICL) system effects on soil organic carbon (SOC) and total nitrogen (TN) are highly variable due to differences in ecoregion‐specific management practices, historical land use, and inherent climatic/edaphic attributes. Few studies have evaluated ICL system effects on SOC and TN in semiarid regions, where soil attributes change slowly. This study quantified ICL system effects on SOC and TN in a long‐term experiment near Mandan, ND. Effects of three residue management treatments (Grazed, Removed, Control) on SOC and TN were determined at five depths (0−0.08, 0.08−0.15, 0.15−0.31, 0.31−0.61, and 0.61−0.91 m) in 1999 and 2014. No‐till practices were employed throughout the study following conversion of perennial grass pastures. A significance criterion of P ≤ .10 was used to assess treatment effects as the experimental design was constrained to two replications. Residue management affected SOC and TN in near‐surface depths only, with greater concentration of SOC and TN at 0−0.08 m under Grazed compared to Removed in 2014 (P = .0844 and .0576). When expressed on an equivalent mass basis, SOC stocks were greater under Grazed and Control compared to Removed. Soil organic C and TN stocks increased over time in the Control by 11.2 Mg C ha−1 and 1.2 Mg N ha−1, respectively (P = .0728 and .0868). Soil organic C stocks also increased over time under the Grazed treatment by 10 Mg C ha−1 (P = .0630). Study results highlighted the importance of residue retention and livestock grazing for increasing SOC and TN in ICL systems under semiarid conditions.

Tropical Soda Apple: Biology, Ecology and Management of a Noxious Weed in Florida

Revised! SS-AGR-77, a 5-page illustrated fact sheet by Brent Sellers, Jay Ferrell, J. Jeffrey Mullahey, and Pat Hogue, informs readers about this serious weed problem in perennial grass pastures and native areas of Florida. It details the weed's taxonomy, biology, ecology, chemical control, biological control and management. Includes further sources of information. Published by the UF Department of Agronomy, February 2009. SS-AGR-77/UW097: Tropical Soda Apple: Biology, Ecology, and Management of a Noxious Weed in Florida (ufl.edu)

Evaluation of White Clover (Trifolium repens L.) Germplasm for Different Agro-Morphological Traits Diversity in Mid-Himalayan Region

White clover (Trifolim repens L.) is one of the most nutritious and widely grown forage legumes in the world. It is also a common component of cool season perennial grass pastures in Indian Mid-Himalayas. Being an important component of temperate grassland, diminutive efforts have been made in genetic improvement of white clover through comprehensive evaluation of germplasm collection. In present study, total 258 germplasm accessions of white clover were characterized under field conditions for the genotypic variation in twenty five agro-morphological traits. Characterized germplasm showed sufficient variation among the populations for qualitative traits, biomass yield and seed yield as revealed by range and coefficient of variation. Association analysis showed that dry matter yield was positively correlated with seed yield components traits. Principal component analysis revealed that first seven principal components accounted more than 60% of total variation. Out of 258, ten high biomass producing populations were selected and further evaluated for biomass yield, crude protein and seed yield potential. Average biomass yield of three populations viz., RRCPL-13 (15.74 q/ha/year), RRCPL-19 (17.25 q/ha/year), RRCPL-27 (18.79 q/ha/year) were better than the check variety Palampur Composite-1 (14.99 q/ha/year). Results of this study will help in designing future strategy in white clover improvement program for the development of new varieties. Also, the seeds extracted from Legon 18 had higher viability than BAG 14/001 at all maturity stages.

Phenotypic Plasticity and Other Forage Responses to Grazing Management of Ecoturf Rhizoma Peanut

Forage–livestock systems in the southeastern United States are based on N‐fertilized perennial grass pastures, with minimal legume contribution. The legume rhizoma peanut (RP, Arachis glabrata Benth.) can persist and spread in grazed mixtures with C4 grasses, and Ecoturf RP is of particular interest because it is relatively decumbent and may vary its growth habit in response to defoliation management. The objective was to quantify effects of grazing frequency and intensity of Ecoturf on herbage accumulation (HA), canopy characteristics, storage organ mass, and total nonstructural carbohydrate (TNC) concentration. Treatments were the factorial combinations of three levels of regrowth interval (RI; 1, 4, and 7 wk) between grazing events and two levels of post‐grazing stubble height (SH; 4 and 8 cm). For the 4‐cm SH, HA increased from 8.4 to 10.5 Mg ha−1 in 2015 and from 9.8 to 13.6 Mg ha−1 in 2016 as RI decreased from 7 to 1 wk. The effect of RI was less pronounced for the 8‐cm SH. When grazed to a 4‐cm SH, herbage bulk density and post‐grazing leaflet mass increased linearly as RI decreased from 7 to 1 wk in both years. Changes in root‐rhizome mass and TNC pool during 2 yr of grazing were not affected by SH or RI. Ecoturf adapted to frequent, close grazing by increasing herbage bulk density and positioning leaves close to the soil surface, allowing rapid regrowth after defoliation without depleting reserves. Ecoturf is tolerant of a range of grazing strategies, showing promise for use in pastures.

Mycotoxins in Florida Pastures

Beef cattle producers in Florida have expressed concerns about the potential presence of mycotoxins in summer perennial forages. In other regions of the US, mycotoxins in forage crops have caused productivity and economic losses. This 3-page fact sheet provides information about the current state of knowledge regarding mycotoxins in Florida perennial grass pastures. Written by Marcelo Wallau, Brittany Justesen, Ann Blount, Luiz Ferraretto, Glen Aiken, and Aaron Stam, and published by the UF/IFAS Agronomy Department, August 2018. http://edis.ifas.ufl.edu/ag422