Forage species selection for transitional organic production in the Southeastern United States

Despite the vast production markets for forage and organic products nationally, so far limited work has been done to develop organic forages specifically for Middle Tennessee or the mid-South in general. The present organic research field focuses on vegetable and grain production; however, forage production offers an easier transition for producers moving into certified organic agriculture. The present study seeks to evaluate several forage blends for optimizing forage production under low-input transitional organic conditions. Ideally a forage system could be tailored to the beef cattle operations of Middle Tennessee, the dominant forage consumption market in this region of the mid-South. I hypothesize that organic forage production offers a sustainable pathway for beef cattlemen. This study is being conducted at the Middle Tennessee AgResearch and Education Center, in Spring Hill, TN. The forage selections consisted of the following: a tall fescue (Schedonorus arundinaceus) monoculture, a bermudagrass (Cynodon dactlyon) monoculture, a tall fescue and alfalfa mixture (Medicago sativa), a bermudagrass and alfalfa mixture, and an annual rotation (winter wheat [Triticum aestivum] and winter pea [Pisum sativum] mixture rotated with a sorghum-sudangrass [Sorghum bicolor x Sorghum sudanese] and cowpea [Vigna unguiculata] mixture). Plots were established during the 2017-2018 growing season following a fallow orchard. Regular production measurements began in the 2019 calendar year when the plots achieved full organic certification status. On the basis of both agronomy and economics, the annual rotation is the optimal species selection for transitioning producers, though the tall fescue and tall fescue-alfalfa selections require reduced labor inputs and would better serve soil conservation outcomes, pursuant to the organic production paradigm

Evaluation of a cool-season grass-white clover mixture for low-nitrogen input lawns

Turfgrass lawns require supplemental nitrogen (N) to maintain green color and seasonal shoot density. Improper lawn fertilization with excess N or phosphorus has the potential to contaminate both surface and groundwater. Thus, to reduce the reliance on supplemental N fertilization, alternative strategies or novel turf systems like grass-legume mixtures need explored. White clover ( Trifolium repens L.) is a stoloniferous legume that biologically fixes N from the atmosphere and adds N into the soil via mineralization. The objective of this field study was to evaluate the persistence and feasibility of a cool-season grass-clover lawn mixture. A lawn grass mixture with and without a novel white clover ‘Microclover’ (MC) was grown at two annual N rates (0 and 98 kg N ha-1 yr-1) for two growing seasons. Dry matter yield (DMY), yield component analysis (YCA), visual appearance, canopy greenness, clover populations, and flower production were measured. Total DMY ranged from 3815 to 15583 kg ha-1 and turf that received supplemental N produced the most DMY, 15583 and 13136 kg ha-1, respectively, for turf with and without MC. By contrast, unfertilized turf with and without MC produced 8754 and 3815 kg ha-1, respectively. The YCA in year two showed that MC contributed approximately 15% to DMY in unfertilized turf, and 3% in turf receiving supplemental N. All treatments except the unfertilized turf without MC demonstrated acceptable visual quality and where supplemental N was applied, the highest visual quality was observed. In year two, the unfertilized grass-only turf lacked vigor and was affected by two leaf blighting diseases, red thread and dollar spot, resulting in localized patches of brown, dead turf which negatively impacted visual appearance. Canopy greenness was highest in turf with MC receiving supplemental N, and lowest in unfertilized turf without MC, while unfertilized turf with MC and turf without MC receiving supplemental N were identical. Clover populations decreased over the two years regardless of supplemental N. Clover in the turf receiving supplemental N decreased substantially (17 to 1%), while slightly less in the unfertilized turf (14 to 5%), which also affected subsequent flower numbers measured in year two. In a second study, the effect of annual N-rate (0, 98, 146, 195 kg N ha-1 yr-1) on MC population changes was assessed using a poultry manure fertilizer. Although the MC populations again decreased over time, roughly 25 to 11 % across all treatments, there was surprisingly no difference due to any N-rate. This observation, demonstrates that in the future, various N-sources deserve further exploration for their compatibility with grass-legume systems. Overall, these results highlight the influence of traditional N fertilization practices on DMY, visual quality, canopy greenness, and MC persistence in a cool-season lawn grass mixture with and without MC. Further, this study demonstrated that a grass-MC lawn can persist and provide reasonable visual lawn quality and is a potentially feasible option for lawns in the cool-humid region where minimal supplemental N is the goal

Enhancing the Sustainability of Integrated Biofuel Feedstock Production Systems

As use of second-generation biofuel crops increases, so do questions about sustainability, particularly their potential to affect fossil energy consumption and greenhouse gas emissions. Nitrogen (N)-fixing legumes interseeded into switchgrass (Panicum virgatum L.) may be an alternative to inorganic fertilizer in forage-feedstock systems. Research herein is divided into four general experiments: I). N replacement and feedstock impacts from legume intercrops and biochar in switchgrass; II). N-fixation rates in intercrop systems; III). impacts of biofuel systems under enhanced climate change; and, IV). projected sustainability of regional switchgrass production. Approaches included: characterization of feedstock/forage quality traits based on legume, biochar and synthetic-N applications, and harvest timing; quantification of nitrogenease activity in legumes via two techniques (15N [isotopic] enrichment and N-difference); and, determine impacts from regional switchgrass production, N-input sensitivities, and legume-intercropping via life cycle assessment (LCA). Results suggest pigeon pea, sun hemp, red clover, and partridge pea intercrops, and in some instances, biochar may supply analogous-N to that of synthetic fertilizers to Panicum species. Specifically, selected legume fixation may exceed recommended inorganic-N levels (67 kg [kilogram] N ha-1 [hectare]) in both temperate humid and semiarid tropical pasture/feedstock systems. N-difference method may be used to measure biological fixation, as it estimated comparable fixation rates to that of benchmark 15N enrichment values. Furthermore, harvest timing can be manipulated to obtain desired feedstock traits. Specifically, overwintering harvests minimized phosphorus and potassium removal, and maximize ethanol yield, hemicellulose, and in field dry-down [10.84 vs. 24.81% (P≤0.05)]. However, yield losses were observed (22%). Forage yields were generally more responsive to legumes, and legume intercropping may increase switchgrass forage quality (P-1rate. Intercropping selected legumes in switchgrass may enhance forage/feedstock quality and yield while reducing non-renewable inputs and greenhouse gas emissions

INCORPORATION OF SUMMER ANNUAL MIXTURES INTO GRAZING SYSTEMS IN KENTUCKY

Utilizing summer annual grass-legume forage mixtures has the potential to improve forage yield and nutritive characteristics, and/or animal performance during times when cool-season pasture growth is limited by high temperatures. Legumes can utilize atmospheric nitrogen, which can increase crude protein and forage digestibility in mixtures. As nitrogen application generally improves both the yield and nutritive characteristics of summer annual forages, but can have a negative effect on legume competitiveness, nitrogen fertilizer recommendations for legume-containing summer annual mixtures are not well established. Two experiments were conducted to determine the feasibility of utilizing summer annual mixtures in Kentucky, USA. The first experiment was a small plot study. The objective was to evaluate the effects of increasing botanical diversity and N application rates on the yield, botanical composition, and nutritive characteristics of summer annual forage mixtures. The second experiment was a grazing study that evaluated the effects of increasing summer annual species diversity on forage yield and nutritive value, and animal performance. In the first experiment, N rates of 0, 56, 112, 168, and 224 kg N ha-1 were applied to a sudangrass monoculture, a three-species mixture, and an 11-species mixture. Sward biomass in three out of four environments increased as N application increased (average of 14 kg DM ha-1 per kg N ha-1; p \u3c 0.05). As all treatments were dominated by grass species, mixture complexity had no effect on forage DM accumulation for three out of four environments (4000, 5830, and 7280 kg DM ha-1 averaged over N rates for three environments; p \u3e 0.05). Swards were dominated by sudangrass and pearl millet (73 and 24% in simple mixtures, and 62 and 22% in complex mixtures, respectively), resulting in low functional diversity, likely due to high grass seeding rates. Mixture complexity also did not affect most nutritive characteristics (p \u3e 0.05). Although N application up to 224 kg N ha-1 often had a positive impact on forage quality parameters, forages in three out of four environments would not support the nutritional demands of growing or lactating cattle when averaged across harvests. A sensitivity analyses showed that applying N resulted in positive net returns only when hay prices were very high and N prices were low. When pasture utilization rates and hay feeding/storage losses are accounted for, enterprise budgets determined grazing to have 10% greater expenses than haying. In the second experiment, yearling angus-cross beef calves were assigned to graze one of three summer annual forage treatments, a sorghum-sudangrass monoculture, a simple three-species mixture, or a complex 12-species mixture. Animals grazed for an average of 40 days per year without supplementation. Forage yield was not different between treatments (P \u3e 0.85). Although several forage quality parameters were affected by mixture, none provided useful insight into differences observed in average daily gain (ADG). In 2017 and 2019, calves grazing the monoculture and simple mixture had higher ADG than calves grazing the complex mixture (2017: 0.79 vs. 0.66 kg/day, P \u3c 0.03; 2019: 0.59 vs. 0.43 kg/day, P \u3c 0.03). In 2018, there were no differences in ADG (P \u3e 0.3); however, calves only gained 0.01 kg/day, possibly due to lower nutritive value of more mature forages. Forages in 2018 were abnormally tall and calves were observed to be flightier and more agitated. The added stress of a low-visibility environment may have contributed to poor gains. Taller forages may also have limited dry matter intake and/or sward utilization since calves could not reach the top of the plants. In these studies, increasing species diversity did not improve forage yield, nutritive characteristics, or animal performance. This was likely due to heavy grass competition and poor legume establishment. If sward diversity is of interest, care must be taken to select compatible species, utilize appropriate seeding rates, and implement management that will promote less well-adapted species. Under the constraints of these experiments, utilizing summer annuals in forage systems in Kentucky would only be economical when hay costs were high, when production costs were low, and when animal performance was enhanced

Managing soil fertility in organic farming systems

Complex relationships exist between different components of the organic farm and the quantity and quality of the end products depend on the functioning of the whole system. As such, it is very difficult to isolate soil fertility from production and environmental aspects of the system. Crop rotation is the central tool that integrates the maintenance and development of soil fertility with different aspects of crop and livestock production in organic systems. Nutrient supply to crops depends on the use of legumes to add nitrogen to the system and limited inputs of supplementary nutrients, added in acceptable forms. Manures and crop residues are carefully managed to recycle nutrients around the farm. Management of soil organic matter, primarily through the use of short-term leys, helps ensure good soil structure and biological activity, important for nutrient supply, health and productivity of both crops and livestock. Carefully planned diverse rotations help reduce the incidence of pests and diseases and allow for cultural methods of weed control. As a result of the complex interactions between different system components, fertility management in organic farming relies on a long-term integrated approach rather than the more short-term very targeted solutions common in conventional agriculture

Effects of management on biodiversity and productivity of grazed grassland

Die Nutzung von Beweidung zur Erhaltung und Förderung von Biodiversität wird allgemein als positiv erachtet, da so strukturell diverse Flächen erhalten werden können. Die Auswirkungen unterschiedlicher Managementszenarien auf die Artenvielfalt sind zwar weitreichend untersucht, auf Langzeitexperimenten jedoch sehr rar. Mit unserem ersten Experiment wollten wir die Frage beantworten, welche Nutzungsintensität am besten geeignet ist, um Diversität von Insekten zu fördern. Das dafür genutzte Langzeitexperiment wurde 2002 mit zwei Beweidungsintensitäten etabliert und eine dritte Intensitätsstufe 2005 eingeführt. Zwischen 2002 und 2004 sowie 2010 und 2011 wurde der Einfluss der Beweidungsvarianten auf die Insektendiversität im Sinne des Artenreichtums und der Abundanz von Heuschrecken (Orthoptera) und Tagfaltern (Lepidoptera) aufgenommen. Wie erwartet, zeigte sich bei intensivster Beweidung die geringste Diversität. Trotzdem war die extensivste Beweidung nicht vorteilhafter als die mittel intensive Beweidung. Aus diesem Grund empfehlen wir eine mittelstarke Beweidung, da diese besonders geeignet ist um eine ausreichende Narbenhöhe und eine strukturell diverse Grasnarbe zu schaffen. Dieses Management zeichnet sich durch vielfältige ökologische Nischen aus, die einer Bandbreite von unterschiedlichen Arten Habitat bieten, wovon besonders weniger mobile Herbivoren wie Heuschrecken profitieren können. Wenn Pflanzendiversität im Vordergrund steht, muss auch die Art des Weidetiers betrachtet werden, da sich die Tierarten in ihren Beweidungseigenschaften unterscheiden und demnach auch Vegetation und Narbenstruktur beeinflusst werden können. In einem zweiten Experiment haben wir deshalb den Einfluss von Rindern und Schafen in Monobeweidung als auch in Mischbeweidung untersucht. Eine Hälfte der Parzellen wurde mit Herbiziden gegen Dikotyle behandelt um den Weidetiereffekt in Abhängigkeit der Narbenzusammensetzung zu analysieren. Das Experiment wurde zwischen 2007 und 2011 beweidet und die Vegetationszusammensetzung jeweils vor jeder Beweidungsperiode und zusätzlich im Jahr 2012 aufgenommen. Die beiden Narbentypen zeigten wie erwartet deutliche Unterschiede in Zusammensetzung und Diversität. Dahingegen unterschieden sich die Weidetier-Varianten nur marginal voneinander. Die Rinderparzellen wiesen zwar eine höhere alpha-(Artenreichtum) als auch beta-Diversität auf, allerdings war dieser Effekt nur in einem Jahr auf jeweils einem Narbentyp zu finden. Zusammenfassend können gewöhnliche Weiden in ihrer Vegetationszusammensetzung und -diversität mithilfe unterschiedlicher Tierarten nur geringfügig gesteuert werden. Es konnte lediglich ein marginaler Vorteil von Rinder- gegenüber Schafbeweidung festgestellt werden Auf demselben Experiment waren wir weiterhin daran interessiert, wie pflanzliche Diversität und agrarische Produktivität miteinander verbunden sind. Unsere Ergebnisse verneinen jedoch einen positiven Zusammenhang. Weiden besitzen wahrscheinlich ein genügend großes Arteninventar auch bei artenarmer, herbizidbehandelter Ausprägung, so dass eine komplementäre Ressourcennutzung bereits ausgeschöpft wird. Im Gegensatz dazu enthielten die artenreicheren Futterproben tatsächlich mehr Rohprotein und weniger ADF, so dass von einer gesteigerten Futterqualität gesprochen werden kann. Diese Ergebnisse könnten jedoch auch durch ein erhöhtes Vorkommen von Leguminosen erklärt werden, da auf dem Versuch aufgrund des Designs eine hohe Korrelation von Artenreichtum mit Kräutern und Leguminosen besteht. Hinsichtlich der unterschiedlichen Weidetiere konnte kein signifikanter Effekt weder auf Primärproduktivität noch auf Futterqualität festgestellt werden. Über alle Jahre hinweg zeigte sich vor allem die Phytodiversität als förderlich für die Lebendmassezunahmen der Lämmer. Zudem konnte die Mischbeweidung zu einer gesteigerten Wachstumsintensität von Lämmern und Mutterkühen beitragen. Zusammenfassend kann Beweidung genutzt werden um die Narbenstruktur zu steuern, was vor allem durch eine Anpassung der Beweidungsintensität erreicht werden kann. Nachfolgend wird sich die Intensität auf die Biodiversität aus, die jedoch durch die Wahl des Weidetieres nur recht geringfügig beeinflusst wird. Auch wenn die Primärproduktivität nicht mit dem Artenreichtum verbunden war, so kann durch das Hinzukommen von Kräutern und Leguminosen doch eine Steigerung der Futterqualität erreicht werden, die sich auch in höheren Lebendmassezunahmen der Lämmer wiederspiegelt. Demnach kann durch ein geeignetes Graslandmanagement Einfluss auf die Biodiversität genommen werden, welche wiederum das Potential besitzt, die tierischen Leistungen zu steigern

100% Organic Livestock Feeds – preparing for 2005

A project entitled “100% Organic Livestock Feeds – Preparing for 2005” looking at the implications for organic farmers of the removal of the current derogation to use a percentage of non-organic livestock feeds. 1) Researching the required volume of feed stuff, in particular protein crops, and potential for feed production within Wales. 2) Researching the suitability of alternative protein sources, and evaluating livestock systems regarding the potential for a reduction in energy and protein levels. 3) Proposing strategies for the development and stimulation of the industry

Sod seeding of forages, Station Bulletin, no.526

The Bulletin is a publication of the New Hampshire Agricultural Experiment Station, College of Life Sciences and Agriculture, University of New Hampshire, Durham, New Hampshire