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Over-seeding cool-season annual forages in pastures in the southeastern US provides increased grazing opportunities for livestock and reduces the amount of hay needed during winter. The constant presence of vegetation can benefit soil health, the biological aspect of which has only received cursory investigation to date. Since 2009, a commercial cattle grazing operation located in south Mississippi has been over-seeding a diverse mixture of oats (Avena sativa L.), triticale (X Triticosecale Wittmack), annual ryegrass (Lolium multiflorum Lam.), hairy vetch (Vicia villosa Roth), radish (Raphanus sativus L.), turnips (Brassica rapa L. subsp. rapa), red clover (Trifolium pratense L.), ball clover (Trifolium nigrescens Viv.), and crimson clover (Trifolium incarnatum L.) into pastures dominated by bahiagrass (Paspalum notatum Flugge). Soil health properties were assessed across a heterogeneous landscape from soils collected immediately prior to seeding and following increased spring productivity of cool-season annuals from 2015 to 2017. Samples were collected across a topographic sequence to a depth of 15 and 30 cm. Three samples per site were collected from summit, backslope, and footslope locations. Soil chemical assessments included macronutrients, pH, soil organic matter (SOM), total carbon (TC), and total nitrogen (TN). Fatty acid methyl ester analysis and enzyme assays were used to determine soil microbial community structure and activity. While TC and TN did not change with time (20.5 and 2.4 g kg−1, respectively), SOM increased by 6% from 2015 to 2017. Nitrate-N decreased by 82% from 2015 to 2017. N-acetyl-β-glucosaminidase activity increased by 32%, while β-glucosidase remained constant. Total microbial abundance did not change with time; however, Gram positive bacteria and actinomycetes decreased by 51% and 43%, respectively, from fall to spring. Arbuscular mycorrhizal fungi increased from fall to spring by an average of 45%. This pasture management technique of over-seeding a diverse mix of winter annuals may have resulted in a steady state of TC and TN, while SOM increased and inorganic nitrogen decreased with time, and enhanced the total soil microbial community particularly fungi and their potential enzyme activity. Despite some biological indications of system stability, soil properties potentially limiting to plant growth were identified for some sites, but these limitations were not closely related to topographic position as expected.

Corn gluten meal (CGM) has been used as a supplement for livestock feeding due to its high concentration of digestible nitrogen (N) compounds. Heat damaged CGM (HDCGM), which is not suitable for livestock feeding, may still have value as an organic fertilizer. Objective of the study was to evaluate the impacts of non-feed grade HDCGM on forage production from annual cool and warm season grasses and soil characteristics. Pre-plant incorporated HDCGM at 3 Mg/ha was compared with 4.2 Mg/ha poultry litter (POTL), and 160 kg/ha commercial N fertilizer (COMF), and zero fertilizer (ZERO) for production of the cool-season ‘Prine’ annual ryegrass (Lolium multiflorum), and the warm-season ‘Greentreat’ sorghum × sudangrass (SS) hybrid (Sorghum bicolor). The treatments were repeated at the same site on December 3, 2010 (planted annual ryegrass), May 26, 2011 (planted SS hybrid), October 24, 2011 (planted annual ryegrass) and May 18, 2012 (planted SS hybrid). The HDCGM had 68% more N concentration than POTL, while its P, K, Mg, and Ca were less than half in POTL. The residual N concentration in buried HDCGM and POTL increased in a similar pattern with time in soil. The HDCGM produced less dry matter (DM) of annual ryegrass and SS hybrid than POTL; however, the differences between the two treatments were not statistically significant. All treatments produced more DM in the second than first year. After two years of field test, soil receiving HDCGM contained higher soil organic matter (OM) and N than receiving POTL. Although not as beneficial as POTL for DM production, HDCGM showed potential value as a slow release fertilizer to improve DM production and soil characteristics.

As ruminant species diversify in natural and managed ecosystems in an effort to increase production, so does the need for greater plant diversity. Legume shrub propagation is rarely targeted for this purpose. As an example, the wide range of native perennial, shrub (0.5–3 m) legumes in Texas indicates untapped potential for multiple uses such as forage, ecosystems services, wildlife habitat, fuel, and possibly pulse crops. We propose that concerted programs to identify, collect, characterize, domesticate and commercialize these legumes could lead to multiple benefits in native and cultivated ecosystems characterized by herbaceous, shrubby and arboreal canopies, each contributing to greater herbage and animal productivity than mono-canopy systems. This approach could be applied in Europe and throughout the world.

Summary Efficient ethanol production from lignocellulosic biomass requires highly degradable feedstock; therefore, there is a similarity between forage crop production for ruminant animals and ethanol production from lignocellulosic biomass. Feed value analysis techniques may be used to estimate lignocellulosic biomass quality. Because lignin and its derivatives in cell walls are major compounds interrupting biomass degradation, fiber analysis and in vitro incubation tests were conducted with switchgrass (Panicum virgatum) and energycane (Saccharum spp.) biomass collected at 100 and 120 g lignin (acid detergent lignin) kg−1 DM (dry matter). Mean NDF (neutral detergent fiber) in switchgrass was consistently greater than that of energy cane regardless of lignin levels, while ADF (acid detergent fiber) did not differ. Mean of energycane in vitro true digestibility and digestible neutral detergent fiber were greater than those of switchgrass. The ADF and ruminal fermentation rate averaged by lignin levels differed, while most of the analysis results did not. Based on ADF and NDF concentrations, switchgrass contained a greater concentration of hemicellulose than energycane, while cellulose concentration was similar. Fermentability of energycane was consistently greater than that of switchgrass. Fermentation gas volume was positively correlated with cellulosic biomass degradation for ethanol production. Consequently, fermentation gas kinetic parameters obtained from biomass fermentation with rumen fluid or with yeast indicate that the fermentable pool size is the parameter most closely correlated to ethanol production potential across the species. Results obtained from feed value analyses demonstrate fermentation variability and meaningful relationships between fermentation gas parameters and ethanol production. Thus, the ruminal fermentation process is useful as a screening tool for ethanol production potential of biofuel feedstock. Copyright © 2015 John Wiley & Sons, Ltd.

Demand for animal products is growing faster than for any other agricultural product. As a result, pressure for greater output from cultivated pastures is expected to increase. Assuming cultivated pasture area will decrease with land degradation, conversion to grain crops or urban expansion, the only alternative is to increase productivity per area. We suggest an underutilised solution: increase herbivore diversity on cultivated pastures. We review multiple herbivore species (MHS) ecology in natural ecosystems (rangeland and wildlife parks) for guidelines to implementing this approach in cultivated pasture. In rangeland or natural grassland systems, sequential or simultaneous introduction of MHS results in greater productivity, diversity and resilience of plant as well as animal populations. Replacing historical mono-ruminant systems with MHS or classes on cultivated pasture is currently beyond landowner experience and will stretch cultivated pasture science. This approach becomes more feasible, however, as cultivated pastures increase in plant biodiversity and canopy complexity. We enumerate research and demonstration topics that might promulgate MHS in cultivated pastures.

Preservation of forage crops as silage offers opportunity to avoid the high risk of rain-damaged hay in the humid south-central USA. Recent developments with baled silage or baleage make silage a less expensive option than typical chopped silage. Silage has been important in the region primarily for dairy production, but baleage has become an option for the more extensive beef cattle industry in the region. Silage samples submitted to the Louisiana State University Agricultural Center Forage Quality Lab from 2006 through 2013 were assessed for dry matter (DM) and forage nutritive characteristics of chopped silage and baleage of the different forage types from commercial farms primarily in Louisiana and Mississippi. Of the 1,308 silage samples submitted, 1,065 were annual ryegrass (AR) with small grains (SG), the warm-season annual (WA) grasses, sorghums and pearl millet, and the warm-season perennial (WP) grasses, bermudagrass and bahiagrass, providing the remaining samples. Concentration of DM was used to indicate an effective ensiling opportunity, and AR silage was more frequently within the target DM range than was the WA forage group. The AR samples also indicated a high-quality forage with average crude protein (CP) of 130 g/kg and total digestible nutrient (TDN) near 600 g/kg. The cooler winter weather at harvest apparently complicated harvest of SG silage with chopped SG silage lower in both CP and TDN (104 and 553 g/kg, respectively) than either AR silage or baleage of SG (137 and 624 g/kg for CP and TDN, respectively). The hot, humid summer weather along with large stems and large forage quantities of the WA grasses and the inherently higher fiber concentration of WP grasses at harvest stage indicate that preservation of these forage types as silage will be challenging, although successful commercial silage samples of each forage type and preservation approach were included among samples of silages produced in the region.

Forage legumes have the potential to contribute substantially to warm-season, subtropical and tropical pastures and rangelands. Compared to grasses, they have advantages in accessing subsoil nutrients and moisture; legumes typically concentrate protein in forage, even in infertile soils, and they can also provide ruminants with plant proteins and soluble carbohydrates that increase digestibility of grasses when consumed in legume–grass mixtures. Yet their inclusion in warm-season, subtropical or tropical pasture seed mixes or rangeland rehabilitation is minimal considering the percentage of grasslands coverage in these regions. Why have past diligent attempts failed to develop the germplasm, agronomic techniques, dissemination and ultimate widespread acceptance by land managers in regions where these legumes are widely adapted? Successful forage legume reports indicate that farmers’ participation in technology development, persistence with minimal management, adequate seed supply following release of new ...

Sweet sorghum [Sorghum bicolor (L.) Moench] is recognized as a promising biomass energy crop for meeting the increasing demand for bioenergy feedstocks. Field experiments were conducted at sites in northern and southern Louisiana for 2 yr to assess planting date and harvest maturity effects on yield from primary plantings and ratoon crops. The cultivar M81-E was evaluated using a split plot arrangement of treatments in randomized complete block designs. Planting date from mid-March to early July was the primary plot treatment. Harvest maturity at the early heading (EH) or hard dough (HD) stage was assigned as the subplot treatment. A range of planting dates from mid-March to early June produced substantial yields of biomass and fermentable sugar with appropriate harvest maturity and could support sugar mill operation for up to three additional months. However, sweet sorghum planted in early May and harvested at the HD stage produced 30 to 210% more fermentable sugar than other tested planting dates and maturity combinations. Ratoon crop production was not dependable showing inconsistent tiller growth with resultant low biomass yields. Correlation coefficients of sugar yield with biomass or other quantitative agronomic characteristics were higher than 0.79, while that with brix was only 0.32 (P < 0.0001). Production management in Louisiana from long season cultivars such as M81-E based on a single harvest 150 to 160 d from planting at the HD stage can provide more biomass and fermentable sugar than can production management targeting a ratoon crop.

Bahiagrass (Paspalum notatum Flugge) pastures are widespread in warm climates worldwide and respond to nitrogen (N) fertilizer. Nitrogen fertilization has recently decreased because of increased cost and concerns regarding excessive N in the environment. Responses of bahiagrass to treatments representing three alternative levels of pasture management were assessed. Treatments, each including 56 kg N ha−1 applied for each growth period, were as follows: (i) six harvests with a total of 336 kg N ha−1 annually (referred to as intensive management), (ii) three harvests with 168 kg N ha−1 annually (intermediate management) and (iii) two harvests with 112 kg N ha−1 annually (extensive management). The intensive management produced the most forage with the highest nutritive value. Intermediate management, with only half the amount of N fertilizer, produced at least 80% of the forage yield each year as the intensive management treatment (4-year average of 8236 vs. 9122 kg ha−1 for the intermediate and intensive management treatments respectively) with forage of acceptable nutritive value for some classes of livestock. Limited forage production from the last harvest each year restricts autumn management opportunities, even though crude protein concentration was usually sufficient for some classes of livestock. Extended growth periods, as those that occur with the less-intensive management treatments, provide opportunities to accumulate forage for late-season grazing. Matching livestock enterprises to the forage produced, particularly in terms of nutritive value, can contribute to favourable livestock production responses from a range of bahiagrass pasture management approaches.

Sweet sorghum (Sorghum bicolor (L.) Moench) is widely recognized as a highly promising biomass energy crop with particular potential to complement sugarcane production in diversified cropping systems. Agronomic assessments have led to identification of four cultivars well suited for such sugarcane-based production systems in southern Louisiana. Sweet sorghum biofuel production systems are currently being developed, and research producing large sample numbers requiring ethanol yield assessment is anticipated. Fiber analysis approaches developed for forage evaluation appear to be useful for screening such large numbers of samples for relative ethanol yield. Chemical composition, forage fiber characteristics, digestibility, and ethanol production of sweet sorghum bagasse from the four cultivars were assessed. Measures of detergent fiber, lignin, and digestibility were highly correlated with ethanol production (P < 0.01). The best linear regression models accounted for about 80% of the variation among cultivars in ethanol production. Bagasse from the cultivar Dale produced more ethanol per gram of material than any of the other cultivars. This superior ethanol production was apparently associated with less lignin in stems of Dale. Forage evaluation measures including detergent fiber analyses, in vitro digestibility, and an in vitro gas production technique successfully identified the cultivar superior in ethanol yield indicating their usefulness for screening sweet sorghum samples for potential ethanol production in research programs generating large sample numbers from evaluations of germ plasm or agronomic treatments. These screening procedures reduce time and expense of alternatives such as hexose sugar assessment for calculating theoretical ethanol yield.

Sweet sorghum (Sorghum bicolor (L.) Moench) is currently recognized throughout the world as a highly promising biomass energy crop. Production systems and management practices for sweet sorghum have not been fully developed for the USA, although sporadic research efforts during recent decades have provided some insights into production of sweet sorghum primarily for fermentable sugar production. Field plot experiments were conducted at sites across Louisiana to assess biomass and sugar yield responses to N fertilizer, plant density, and selected cultivars. Although linear increases in stem biomass production and fermentable sugar yield were obtained with increasing N fertilizer rate under irrigated conditions, most of the increase was from the initial 45 kg N ha−1 increment. Nitrogen fertilization increased stem biomass production but not fermentable sugar yield in some non-irrigated environments. Increased plant density contributed to fermentable sugar yield only under growth-limiting conditions, particularly under limited soil moisture. Location effects indicate that sweet sorghum may not be suitable for some sub-optimal cropland and pasture environments in Louisiana. During the primary growing season, cultivar did not affect fermentable sugar yields, although Dale was consistently high in sugar concentration during this period. Nitrogen fertilizer increased fermentable sugar yields only when moisture was not limiting. Overall results indicate that in environments where soil moisture limits plant growth, sugar yield responses are likely from increased plant density and not from increased N fertilization.

Domestication of herbaceous, perennial, warm-season North American legumes can contribute to a wide array of conservation and agricultural objectives. This study examined 'Plains' Germplasm prairie acacia [PPA; Acacia angustissima (Mill.) Kunze var. hirta (Nutt.) B.L. Rob.], panicled tick-clover [PTC; Desmodium paniculatum (L.) D.C.], and 'Crockett' Germplasm herbaceous mimosa (CHM; Mimosa strigillosa Torr & A. Gray) herbage yield, nutritive value, effect of herbage harvest on seed production, and range of adaptation. At Stephenville, TX, on a Windthorst fine sandy loam (fine, mixed, avtive, thermic Udic Paleustalf), herbaceous mimosa yielded the most (P ≤ 0.05) herbage dry matter (DM) of all entries in 2008, 2009, and 2010 (3380, 7510, and 3570 kg ha -1 , respectively). Plains Germp lasm prairie acacia produced the greatest (P ≤ 0.05) seed yields in 2008 and 2009 (1480 and 2590 kg ha -1 , respectively), while CHM yielded the least seed for the first 2 yr after seeding. Overall, PPA had the lowest (P ≤ 0.05) leaf fiber concentrations. Harvest in general negatively (P ≥ 0.05) affected seed yield. Plot cover ratings of these entries seeded along a longitudinal gradient from Knox City (33°26' N, 99°51' W), Stephenville, and Nacogdoches, TX, to Homer, LA, (32°47' N, 93°3' W) indicated that CHM was the quickest to spread via stolons, followed by PPA via rhizomes, while PTC, limited to seed for recruitment, was slower to spread. All three perennial, herbaceous legumes are promising for pasture, rangeland, wildlife habitat, and prairie restoration.

Although big bluestem (Andropogon gerardii Vitman) is used for forage and conservation in the Great Plains, potentially useful Louisiana ecotypes have received little attention. Cloned plants from a robust big bluestem plant collected near Rosepine, LA were assessed for responses to fertilizer and defoliation in a field evaluation of potential forage value. Annual application of nitrogen fertilizer at 50 kg ha−1 did not increase herbage yield until the third year. Clipping twice annually decreased productivity compared to once annually after the second year. Fertilizer effects on forage nutritive value were small. Clipping improved late-season nutritive value largely due to greater stem development of previously undefoliated plants. Limited responsiveness to fertilization and detrimental effects of repeated defoliation on productivity indicate that even this robust local big bluestem ecotype provides little potential as a pasture plant. Potential is indicated for other uses including wildlife habitat and ...

Grazing lands in warm-temperate and subtropical North America have become less diverse. Pastures are typically grass monocultures, while rangelands are generally managed for the grass components. Overstocking, selective herbicides, fire exclusion and heavy rates of nitrogen fertilizer have contributed to near exclusion of native, warm-season legumes. The simplicity of managing grass monocultures, pasture production responses to nitrogen fertilizer and profitability of grass-only systems have limited interest in legume-based approaches. Changing economics and ecological concerns with ecosystem accumulation of industrial inputs contribute to an increasing interest in legumes. Unlike the development of temperate pasture legumes and recent research in the tropics, legumes tolerant of both freezing temperatures and hot weather have received less attention. Poor establishment, limited persistence and potential invasiveness limit currently available introduced species. Native, herbaceous, warm-season legume species occur throughout warm-temperate North America, but little attention has been directed to these plants as potential forage species. Some success with a few native legume species, primarily in the genus Desmanthus, suggests potential for expanded assessment of forage value of the many species available. Current assessments of native legumes, primarily for conservation purposes, provide an opportunity to expand evaluations of these species for pasture and rangeland potential while economics of livestock production and public interest in ecosystem health are supportive. Experiences with legumes of warm-temperate origin in North America, along with results with temperate and tropical pasture legumes globally, provide a starting point for future efforts at incorporating greater legume diversity in pastures and rangelands of subtropical and warm-temperate regions around the world.

Field evaluations of perennial native legumes (Fabaceae) from Louisiana pineland ecosystems revealed differing colonization abilities among species under natural recolonization of disturbed sites. Initial establishment and growth of transplanted seedlings of 5 different species were good in an early field evaluation. In a subsequent evaluation initiated with scarified seeds, poor establishment of herbaceous mimosa ( Mimosa strigillosa Torr. & A. Gray) indicated that populations of this species may be limited by lack of competitiveness of emerging seedlings. Virginia tephrosia ( Tephrosia virginiana (L.) Pers.) produced vigorous upright seedling growth with population expansion in only one year of these evaluations. Initial establishment of prairie snoutbean ( Rhynchosia latifolia Nutt. ex Torr. & A. Gray) was limited by inadequate rainfall in some instances, but under favorable conditions this species was superior in seed production and population expansion. Individual plants of these species were rather short-lived with long-term population survival dependent on seed production and seedling recruitment. Seed germination of these legumes was limited by hard seedcoats. Physical scarification readily overcame this limitation for all species evaluated. Rhynchosia latifolia appears to have potential value for use in reclamation and revegetation plantings because of potential for seed production and establishment of persistent populations under favorable conditions. Mimosa strigillosa has potential to provide superior ground cover and sustainable populations, but limited establishment from seeds indicates that selection from expanded germplasm collections for seedling vigor may be particularly important for successful use of this species. Pitman WD. 2009. Establishment and survival of native legumes on upland sites in Louisiana. Native Plants Journal 10(3): 240–250.

The tree legume Albizia julibrissin Durazz. has potential as a forage plant to overcome forage quality limitations to animal performance on warm-season grass pastures in the southeastern USA. Hardseededness and slow establishment are limitations of this legume, while responses to defoliation have not been fully assessed. Germination, establishment, and response to defoliation were evaluated on a Coastal Plain soil in Louisiana, USA. Germination was limited only by hardseededness with no additional dormancy mechanism involved. Dry heat at 80°C enhanced germination with duration of exposure from 5 to 10 min providing a range in immediate and delayed germination responses. Under adversely dry conditions, establishment was not affected by initial seeding rate from 2.5 to 10 kg/ha. Results from repeated clippings suggest that survival of defoliated plants (R ² = 0.28, P = 0.08), but not regrowth productivity (P > 0.10), was affected by height of defoliation. Lifespan of plants cut at a 10 cm stubble height averaged 641 days, while those cut at 50 cm and 1 m averaged 935 days. Leaf crude protein of 25.9–28.3% was not affected by regrowth age of 44–93 days or by weather conditions. Forage nutritive value of stem regrowth was substantially less than that of leaves and was influenced by age and environment. Although defoliation management will be more critical for stand survival than currently practiced with sod-forming grasses in the region, nutritive value of A. julibrissin leaf regrowth provides a substantial opportunity to enhance animal productivity in the southeastern USA.

Texas bluegrass has potential as a cool-season perennial pasture grass for the south-central USA. Slow stand establishment in competitive environments is a limitation. Forage production of this grass increases with nitrogen (N), and rhizome growth increases with phosphorus (P). Stand responses by Texas bluegrass from three seed sources to seeding rate and a complete mixed fertilizer were assessed from 1997 through 2005 on a Louisiana Coastal Plain site. A linear response (R2 = 0.39, P ≤ 0.0001) to seeding rate in March 1998 persisted through 2005, even though stands at all seeding rates improved over time. Stands did not differ (P > 0.05) among seed sources. At only the higher seeding rates, rhizome mass increased with fertilization. Soil pH decreased with fertilization, and pH was positively correlated with the final stand rating in 2005. Direct stand responses to fertilization were not detected. Lack of competitive advantage, despite growth responses, and soil acidification with fertilization i...

The extensive cow-calf industry in the Gulf Coast Region of the southeastern USA is based on pastures of warm-season perennial grasses, which often provide insufficient forage availability and/or nutritive value in late summer. Several species of summer-growing legumes have potential to increase nutrient availability for nursing calves through creep grazing. Selected warm-season legumes were evaluated at multiple locations across Louisiana. At each location, a treatment with 10% of the pasture area planted to legume was compared to a bermudagrass control treatment. Objectives were to assess both plant and animal factors influencing potential for creep grazing to increase calf weaning weight. Iron-and-Clay cowpea was widely adapted and suited to grazing defoliation although not tolerant of flooding. Aeschynomene was particularly well adapted to silt loam and silty clay loam bottomland soils but was not readily grazed when woody stems developed before stocking. Calves had to learn to utilize creep areas and consume unfamiliar legume species. Both pasture and animal characteristics affected response to legume creep grazing. At the Hill Farm Research Station, the combination of young cows and pastures with limiting nutritive values produced low weaning weights (200 to 215 kg) and resulted in weaning weight increases of from 5 to 7 kg from creep grazing. Benefits were not detected from creep grazing at other locations where calf weaning weights were higher. Creep grazing can contribute to calf weaning weight when forage grazed by the cow herd does not allow calves to attain their genetic potential, however, intensive management is required.

Sericea lespedeza has been an important forage legume in portions of the USA for decades but has recently been recognized as invasive in some ecosystems. Stand characteristics potentially affecting usefulness and invasiveness were assessed on forested and open sites of a Louisiana Coastal Plain landscape. Typical heavy weed competition, which was not overcome by increased seeding rate or extent of seedbed preparation, occurred in full sunlight. An open longleaf pine canopy suppressed competitive herbaceous species and enhanced establishment compared to that in full sunlight. Shade of either longleaf pines or dense overstory of tall weeds reduced productivity but not stands. Sericea lespedeza spread was limited to a few meters during 7 years, apparently due to lack of an effective dispersal mechanism. Long stand life under mature longleaf pines and in the open field along with ability to re-colonize from soil seed reserves contribute to both usefulness of sericea lespedeza for conservation, forage, and wildlife habitat in agricultural landscapes and potential undesired persistence, especially with land-use changes to less intensive management, on Louisiana Coastal Plain landscapes.

Dallisgrass (Paspalum dilatatum Poir.) is an important pasture grass on moist fertile sites in warm climates, however, it is limited in use by periodic low seed quality and resulting erratic availability and establishment difficulties. Due to apomictic reproduction, common pentaploid dallisgrass has not been responsive to traditional plant improvement approaches. Recent research has shown potential for some improvement in forage production and plant persistence with apomictic hexaploid varieties of dallisgrass. Tissue-culture regeneration has been reported to produce somaclonal variation in seed germination of common pentaploid dallisgrass and has recently resulted in availability of potentially useful regenerants of hexaploid dallisgrass. Seed of selected plants from both field and greenhouse environments was evaluated in replicated germination trials to determine whether hexaploid tissue-culture regenerants responded similarly to regenerants from common dallisgrass and to determine whether regenerants expressing potential agronomic usefulness as indicated by preliminary observations differed in germination. The eight germination trials included 299 regenerants with 57 of these being duplicate entries among trials. Germination did not differ among sources of regenerants. Within sources germination differed among regenerants with a few individuals exceeding germination percentage of parent lines in one evaluation of greenhouse-produced seed. Individual regenerants with agronomic potential and high percentage seed germination were identified. The results demonstrate that tissue-culture regeneration can be used to produce improved germination in agronomically useful genotypes of apomictic dallisgrass and suggest that such potential may exist for other recalcitrant plant species.

Systematic performance trials have been conducted in several states for more than 20 yr to evaluate agronomic performance of annual ryegrass (Lolium multiflorum Lam.). Despite development and testing of many annual ryegrass cultivars, the first improved cultivar, Gulf, has remained one of 10 to 12 cultivars recommended for planting in the southeastern USA. Our objectives were to evaluate cultivar yield performance across 12 yr at five locations, to assess cultivar yield distribution within growing seasons, and to estimate cultivar yield stability (consistency of relative performance environments). Efficacy measures were early-season yield (total before 1 March), late-season yield (total after 1 March), and total annual yield. Overall means for all cultivars and individual cultivar performance (for common years) were compared with Gulf or Marshall. Neither location effects nor cultivar X location interactions were found. Cultivar and year effects, plus cultivar × year interactions were detected (P < 0.05) for all three yield responses. Mean early season yields ranged from 2.3 to 4.6 Mg ha -1 , with mean late-season yields ranging from 5.1 to 7.4 Mg ha -1 . No trend existed for mean total yield relative to Gulf or Marshall to increase over time in association with availability of newer cultivars. Given large yearly fluctuation in yields, it is apparent that unpredictable environmental factors, including climate and perhaps pests, are the primary determinants of annual ryegrass performance rather than differences in yield potential among cultivars. Thus, yield stability may be an appropriate selection factor to include among the criteria for development of improved annual. ryegrass cultivars.

Annual ryegrass (Lolium multiflorum Lam.) is a primary forage resource for livestock producers throughout the south-eastern USA during the winter-growing season. It is important for livestock producers to begin grazing annual ryegrass as early as possible and any management practices maximizing early season production could be beneficial. To assess the impact of seeding rate on subsequent yield, yield distribution, quality, seedling density, and end-of-season plant and tiller density, a 2-year study was initiated at four locations in Louisiana. Three annual ryegrass cultivars, varying in seed size, were established at four seeding rates based on pure live seed (PLS) rates of 400, 800, 1200 and 1600 PLS m−2. There was no advantage in total yield from increasing seeding rates beyond 800 PLS m−2. However, first-harvest yields increased from 360 to 930 kg dry matter (DM) ha−1 as seeding rate increased from 400 to 1600 PLS m−2. Crude protein and neutral-detergent fibre concentrations, and in vitro DM digestibility, were not affected by seeding rate. Seedling density and end-of-season plant numbers increased as seeding rate increased. However, stems per plant decreased as seeding rate increased, indicating compensatory tillering for the reduced plant numbers observed at the lower seeding rates. These results indicate first-harvest yield can be increased by planting at higher seeding rates but total yields are not increased.

Annual ryegrass (Lolium multiflorum Lam.) is grown on more than one million ha in the south-eastern USA each year. Recommended and actual seeding rates vary substantially within the region. The objective of this study was to evaluate variation in seed weight, germination, seedling vigour and seasonal yield performance among annual ryegrass cultivars. During 1997, 1998 and 1999, seed from fourteen commercial cultivars was weighed and germinated to determine numbers of pure live seed (PLS) m−2 before yield evaluation at four locations. Seed from ten cultivars was planted at 0·7 and 2·0 cm depth in a greenhouse study to evaluate relative seedling vigour. Cultivar mean single-seed weight ranged from 2·4 to 4·8 mg in 1997, 1·8 to 4·5 mg in 1998, and 2·6 to 4·6 mg in 1999. Seed germination ranged from 78·8% to 98·0% in 1997, 82·3 to 98·3% in 1998 and 77·8 to 98·3% in 1999. Seed number, PLS m−2, ranged from 675 to 1289 in 1997, 710 to 1550 in 1998, and 717 to 1179 in 1999. Among the ten cultivars evaluated for seedling vigour, seedling weight differed between planting depths and a significant cultivar by year interaction was observed. Seedling weight was highly correlated with seed weight at each seeding depth. The effect of increasing number of PLS m−2 on subsequent yield performance, although small, was consistently negative. These results indicate that target plant populations may be obtained more economically by adjusting seeding rates for seed size differences among cultivars and seed lots of annual ryegrass.

Differences among annual ryegrass (Lolium multiflorum Lam.) cultivars for weight gain of grazing steers have been reported, even though plot experiments suggest that forage dry matter yield among cultivars should not be a limiting factor. Likewise, forage nutritive value differences among cultivars have not been assessed. The objectives of this research were to evaluate differences in cumulative forage yield, yield distribution, and nutritive value among 'Gulf', 'Jackson', 'Marshall', 'Rio', 'Rustmaster', and 'Surrey' annual ryegrass. Plots were harvested six times beginning in December at approximate 30-d intervals during the 1997-1998 and 1998-1999 growing seasons. Nutritive value measurements included crude protein (CP), neutral detergent fiber (NDF), in vitro true digestibility (IVTD), and digestible NDF (DNDF). There were no differences among cultivars for cumulative forage yield (P = 0.99). However, for the January harvest, Surrey and Gulf averaged 1030 (±65) kg DM ha -1 , whereas Marshall yielded only 672 (±79) kg DM ha -1 . For the March harvest, yields of all varieties were similar and averaged 1350 (±95) kg DM ha -1 . At the May harvest, Marshall and Jackson yielded 1232 (±123) kg DM ha -1 , whereas Gulf yielded only 929 (±74) kg DM ha -1 . Crude protein concentration differed significantly among harvests with a general decrease from 260 to 120 g CP kg -1 as the growing season progressed. Similar declines in nutritive value occurred for NDF, IVTD, and DNDF. Trends in yield distribution and forage quality may indicate a need for cultivar specific recommendations based on intended forage need and season of use.

Fall armyworm, Spodoptera frugiperda (J.E. Smith), is the major insect pest of bermudagrass, Cynodon dactylon (L.) Pers., in the Southeastern USA. Somaclonal variation in bermudagrass has produced distinctly divergent susceptibilities to fall armyworm under controlled conditions. Plant persistence, productivity, forage quality characteristics, and response to fall armyworm were assessed in field plots at Rosepine, Louisiana from 1995 through 1999. Forage quality characteristics were assessed each year, and natural infestations of fall armyworms were monitored in 1998 and 1999. Most of the somaclonal lines were similar to their parent cultivar in forage yield and quality, and none was consistently superior. Differences in forage quality characteristics among the bermudagrass lines were detected in 1996 and 1997, with little difference among lines in 1998 and 1999. All lines assessed were infested and sustained damage from natural infestations of fall armyworm larvae. Thus despite acceptable forage productivity and quality of most lines, expression of fall armyworm resistance under these field conditions was not detected. This lack of difference under field conditions, despite distinct resistance of some lines under controlled conditions, may primarily be due to either insufficient production of compounds deterring the insects for detectable effects under field conditions or loss of expression of the somaclonally acquired traits even with vegetative reproduction.

Availability of the recently developed cultivar Armadillo provides opportunity for use of burr medic (Medicago polymorpha L.) in the south-central USA where the species has become extensively naturalized. Area of adaptation and effects of seeding rate and P fertilization were identified as insufficiently understood aspects of this cultivar that could potentially determine success of Armadillo burr medic plantings within the region. Thus, objectives were to assess adaptation of this cultivar to both cooler and more humid locations than the south Texas origin of the cultivar and to evaluate effects of initial seeding rate and P fertilization. Neither seeding at 11 or 22 kg ha -1 nor fertilization with 0 or 25 kg P ha -1 affected forage accumulation, which was greater (P < 0.05) in the initial year at Alexandria, LA (3330 kg ha -1 ) than at Rosepine, LA or Stephenville, TX. Seed production, critical for reseeding, was greatest (P < 0.05) at Stephenville, with 344 kg ha -1 , and increased with P at the high seeding rate only. Soil seed reserves 11 mo after seed set was 44% of the initial seed crop at Stephenville and

Management strategies to enhance or preserve nutritive value of rhizoma peanut (Arachis glabrata Benth.) would be beneficial because high plant growth rates and adverse weather at harvest often result in low nutritive value for both pastures and hay along the coastal plain of the lower Gulf Coast. The objective of this study was to determine if a 30- or 60-d harvest frequency or 0, 110, or 220 kg N ha -1 fertilization could be managed to enhance crude protein (CP) yield and nutritive value of rhizoma peanut at three locations in Louisiana. Crude protein, neutral-detergent fiber (NDF), in vitro true digestibility (IVTD), and digestible NDF (DNDF) were measured on Florigraze' rhizoma peanut grown at three Louisiana locations in 1997 and 1998. Nitrogen fertilization increased CP yield approximately 80 kg ha -1 for the 110 and 220 kg N ha -1 treatments at two locations in I of 2 yr. Nitrogen fertilization affected nutritive value at two harvests at two locations in 1998 only. However, nutritive value was consistently lower for 60-d harvests than for 30-d harvests and was more consistent. Rhizoma peanut harvested in 1997 at 30-d intervals had 50 g kg -1 greater CP, 72 g kg -1 greater IVTD, and 40 g kg -1 greater DNDF coupled with 80 g kg -1 lower NDF than rhizoma peanut harvested at 60-d intervals. Likewise, there were seasonal influences on nutritive value. Responses in CP yield and nutritive value observed in this study were influenced more by environment (primarily rainfall) than by N fertilization and harvest management.

Release of 'Georgia-5' tall fescue (Festuca arundinacea Schreb.) expanded the range of this species into the Coastal Plain of the southeastern USA. Initial plantings indicated that responses to lime and P may be greater on infertile, add Coastal Plain soils than reported within the primary area of adaptation. Three field experiments and a greenhouse experiment were conducted on Louisiana Coastal Plain soils. In the field, all combinations of 50 kg P ha -1 , 90 kg K ha -1 , and 4.0 Mg lime ha -1 were applied. In one experiment, all treatments which included P increased establishment-year forage yield, with an increase from 310 kg ha -1 for the control to 1500 kg ha -1 with P alone. Plant responses to lime were obtained at this site in the second year. In the other experiments, drought apparently precluded responses at one site, while plant stands improved with lime at the other site. Linear plant responses to P up to 80 kg ha -1 (soil P of 142 mg kg -1 ) and a quadratic response to lime were obtained in the greenhouse. These results illustrate variation in responses to be expected with fertility, rainfall, and other growing conditions, but still indicate the importance of P and lime to Georgia-5 tall fescue seedlings on acid, infertile Coastal Plain soils. Responses in stand establishment are suggested to soil levels of P and Ca or pH beyond those typically recommended for other regions.

Texas bluegrass (Poa arachnifera Torr.) has shown potential for use as a cool‐season perennial pasture grass in the southern Great Plains, where it occurs as a natural component of rangeland plant communities, and into the western Coastal Plain. Responsiveness of this grass to nitrogen (N) fertilization appeared to be limited to the spring growing period in initial evaluations in Louisiana. A field plot experiment was conducted to assess forage production and quality responses to season of N fertilization on the Syn‐1 population of Texas bluegrass. Winter forage production responses to 50 kg N ha‐1 were obtained in the 1997–98 growing season but not in 1998–99 after stands had been depleted by summer drought. Greatest yield increases resulted from spring N application, however, fall plus winter fertilization provided the most uniform distribution of forage through the cool season. Forage fiber fractions, in vitro digestibility, and crude protein were not affected by N fertilization. Both amount a...

Georgia 5 tall fescue (Festuca arundinacea Schreb.) has the potential to grow in a mixture with warm‐season perennial grasses and provide a year‐round permanent pasture on the Coastal Plain. Season of fertilization with nitrogen (N) was evaluated as a determinant of yield and botanical composition on a Georgia 5 tall fescue‐common bermudagrass [Cynodon dactylon (L.) Pers.] stand on a slope extending from a dry Bowie sandy loam (Plinthic Paleudults) soil to a moist Beauregard sandy loam (Plinthaquic Paleudults) soil. Fertilization with 150 kg N ha−1 split into three applications in the cool season (November, January, and March) over three years resulted in greater tall fescue survival (77% basal cover) than an equal amount of N in the warm season (May, July, and September) or the two N treatments combined (42 and 52% tall fescue basal cover) by March 1998. Tall fescue yields were greatest in May. The harvest frequency of once every two months was perhaps too infrequent, thus allowing shade effects...

Despite limitations in stand establishment, rhizoma peanut (Arachis glabrata Benth.) is the only sustainable, productive, high-quality, perennial, warm-season legume available for the Coastal Plain of the lower Gulf Coast Region. Management to enhance productivity could increase acceptance of this relatively unexploited forage. Yield responses of rhizoma peanut to harvest frequency and N fertilization on Louisiana Coastal Plain soils were evaluated. Nitrogen rates of 0, 85, and 170 kg ha⁻¹ were applied to a Dexter loam soil (Ultic Hapludalfs) in a greenhouse experiment. At three field locations, N rates were 0, 110, and 220 kg ha⁻¹ and harvest frequencies were 30 and 60 d. Soils were the Dexter loam, Tangi silt loam (Typic Fragiudults), and Bowie fine sandy loam (Plinthic Paleudults). In the greenhouse, N accumulated in herbage (30 g kg⁻¹ with 170 kg N ha⁻¹ vs. 20 g kg⁻¹ for the control) with a subsequent linear yield increase. In the field, the only responses to N fertilizer were small increases in N concentration of rhizomes plus stubble. Interactions of harvest frequency and location on herbage yield indicated effects of weather. This effect is illustrated by the 790 kg ha⁻¹ advantage of the 30-d harvest frequency on the Tangi silt loam in May–June vs. the 1930 kg ha⁻¹ advantage of the 60-d harvest frequency on the Bowie fine sandy loam in July–August. Thus, on the Louisiana Coastal Plain, yield of rhizoma peanut is not likely to be increased by N fertilization, and harvest frequency or length of regrowth period is not a reliable determinant of yield. Published as Louisiana Agric. Exp. Stn. article 98-92-0124.

The native rhizomatous cool‐season perennial grass, Texas bluegrass (Poa arachnifera Torn), has recently been recognized again as a plant with considerable potential for range and pasture plantings. Throughout the first half of this century, sporadic efforts at evaluation and commercial use of Texas bluegrass were thwarted primarily by slow stand establishment and difficulties with seed processing. Subsequent advances in seed harvesting, processing, and planting equipment and selection of superior plant genotypes could reduce effects of these limitations. In much of the southern mid‐ and tall‐grass prairie regions and lower southeastern states where Texas bluegrass appears to have potential, there is no currently available sustainable cool‐season forage grass. Effects of initial plant spacing and lime, phosphorus (P), and nitrogen (N) application were evaluated in a field and a green house experiment on acid infertile Louisiana Coastal Plain soils. Stands from transplanting on 10‐ and 30‐cm spaci...

Alysicarpus Necker ex Desv. and Desmodium Desv. have potential for increased use as pasture legumes in warm-temperate and subtropical environments. Seven accessions of D. heterocarpon (L.) DC. and 40 accessions of Alysicarpus, primarily A. vaginalis (L.) DC., were evaluated in Louisiana in 1995 and 1996. Single-row plantings with three replications in randomized complete block designs were established at the Iberia, Rosepine, and Southeast Research Stations. Data collected were visual stand ratings during the 1995 and 1996 growing seasons. An uncharacteristic period of 96 h with only two brief afternoon periods above freezing in February 1996 at Rosepine provided an opportunity to discriminate among entries for winter hardiness and to identify individual plants from each D. heterocarpon entry possessing winter hardiness. Alysicarpus plants did not survive the winter, but several accessions produced reseeded stands in 1996. Performance of the Alysicarpus germplasm was substantially better at the Southeast Station than at other locations, while more Desmodium entries survived at Rosepine than at the other locations despite lower winter temperatures at Rosepine. The surviving D. heterocarpon plants provide a potential source of winter hardiness for development of a perennial warm-season pasture legume for the lower gulf coast region.

Common bermudagrass [Cynodon dactylon (L.) Pers] is a widely used forage on the shallow, droughty coastal plain in southwest Louisiana. Management inputs including fertilizer are typically minimal, even though common bermudagrass has proven as productive as Coastal bermudagrass on these shallow soils. Lack of information about responsiveness of common bermudagrass to specific fertilizer treatments on these soils has led to an evaluation of sources of nitrogen (N) at two rates of N compared to a zero N control and the high N rate plus magnesium (Mg), sulphur (S), and boron (B). At 224 kg N/ha split into four applications, urea produced only 82% as much (P 0.05). Forage production from 448 kg N/ha as ammonium nitrate plus Mg, S, and B was 16% greater (P

Responses of rhizoma perennial peanut (Arachis glabrata Benth.) to rates of phosphorus (P), potassium (K), and a commercial product containing K, magnesium (Mg), sulfur (S), and boron (B) were evaluated on a Louisiana Coastal Plain soil. Although even the highest rate of ? failed to maintain the initial high level of soil P, no response in forage production to ? fertilization was obtained. Annual forage production with ? fertilization of 75 or 150 kg/ha/yr averaged 7,470 kg/ha compared to 6,100 kg/ha of forage for the control. Although yields were similar at the above two rates of K, the 150 kg/ha/yr rate maintained the initial soil ? level, while the 75 kg/ha/yr rate resulted in a decrease in soil ? from 40 to 30 mg/kg over three years. Lack of a response to the commercial product containing Mg, S, and ? at 110 or 220 kg/ha/yr of product indicated that soil levels of these nutrients were adequate for rhizoma peanut under the conditions of this experiment. Unexplained, non‐treatment differences i...

Florida has a substantial cow-calf industry and provides a major market for beef. The state also has extensive undeveloped resources with potential to produce forage-fed beef. Systems of growing beef steers (Bos taurus × B. indicus) on stargrass (Cynodon nlemfuensis Vanderyst var. nlemfuensis) pasture or a high-roughage diet based on sugarcane (Saccharum officinarum L.) bagasse were compared. The level of supplement fed on pasture was also evaluated. The growing period was followed by a short finishing period for all systems. In Exp. 1, cattle provided a 24% crude protein (CP) corn (Zea mays L.) ― based supplement at 1.5% of body weight (BW) during the 161-d winter grazing period gained 0.25 Ib/d more than cattle supplemented at 1.0% of BW

The use of limpograss [Hemarthria altissima (Poir) Stapf et C.E. Hubb.] as a pasture plant is a relatively recent development. Available cultivars possess distinctly different characteristics. «Bigalta» limpograss has been widely planted on peninsular Florida Spodosols, but stand loss under grazing is common. A more persistent cultivar, «Floralta», has recently become the most widely grown limpograss cultivar in Florida. When grown in the same pasture, Bigalta was heavily grazed by yearling steers (Bos indicus L. and Bos taurus L. spp.) before any noticeable grazing of Floralta occurred. A series of grazing trials was conducted to investigate relative forage quality and plant growth responses of the two cultivars under grazing

Ninety-six Brahman crossbred steers (187 ± 3.9 kg) were used to evaluate protein supplements in corn-silage growing diets for 140 d. The following treatments were used: 1, control (7.9% crude protein (CP)); 2, urea (10.3% CP); 3, dehydrated alfalfa (10.0% CP); or 4, soybean meal (SBM) (10.6% CP). Steers were then fed a common finishing diet (80% corn) with 13.4% CP for 120 d. Steers fed the control diet had lower levels of plasma-urea nitrogen, consumed less feed, gained less weight and utilized feed less efficiently than those fed supplemented diets (P

(.)Effects of ammoniation (70 lb/ton) on the feeding value of hays of Pensacola' bahiagrass (Paspalum notatum Flugge), Bigalta' limpograss [Hemarthria altissima (Poir) Stapf and C.E. Hubb], and Ona' stargrass (Cynodon nlemfuensis Vanderyst var. nlemfuensis) were evaluated. Ammoniation increased crude protein content by 2.7 to 8.1 percentage units (.)

Digestibility, intake and performance trials were conducted with cattle to evaluate the effects of physical and chemical treatments on the nutritive value of sugarcane (Saccharum officinarum) bagasse. The four treatments in the digestibility trial were: 1, untreated raw bagasse; 2, steam-pressure treatment with a continuous flow digester (SP); 3, steam-pressure treatment plus pelleting (SPP); 4, steam-pressure treatment, 3% anhydrous ammonia and pelleting (SPA). Steam-pressure treatment and pelleting, both with and without ammoniation, increased voluntary feed consumption (P −1) and feed-to-gain ratios for the four diets were as follows: 1, 0.91 and 8.78; 2, 1.10 and 8.39; 3, 1.12 and 7.72; 4, 1.15 and 7.98. Treatment means did not differ (P > 0.05). SPP bagasse was compared with bermudagrass pellets and corn silage in growing diets for cattle. Ninety-six Brahman crossbred steers (167 kg) were allotted to 12 groups of eight animals (four pens per treatment) for 134 d. SPP bagasse pellets depressed gains and feed conversion ratio (P −1) and feed-to-gain ratio for SPP bagasse pellets, bermudagrass pellets and corn silage diets were 0.42 and 12.90, 1.02 and 7.65, and 0.94 and 5.87, respectively. This investigation demonstrated that feeding pelleted bagasse at 15% of the diet did not reduce performance of finishing cattle fed a high-grain diet. However, when growing cattle were limit-fed a grain-based supplement with free access to bagasse pellets, bermudagrass pellets or corn silage (approximately 70% of the diet), gains and feed efficiency were significantly (P

(...)The objective of this study was to evaluate the potential of such mixtures. Effects of stocking rate and grazing season on botanical composition, herbage availability, and herbage nutritive value were evaluated on a Pomona fine sand (sandy, siliceous, hyperthermic Ultic Haplaquod). Following overseeding of legumes in March 1987, pastures were grazed at three stocking rates in summer 1987 and in spring and summer 1988. Carpon desmodium increased from less than 1% at the start of grazing in 1987 to over 7% of the live herbage in 1988. Combined percentage of aeschynomene plus phasey bean decreased during 1987 from more than 4 to 1.6% (...)