Evaluation of Limpograss (\u3cem\u3eHemarthria altissima\u3c/em\u3e) Breeding Lines under Different Grazing Managements

Limpograss (Hemarthria altissima (Poir.) Stapf et C.E. Hubb.) is a stoloniferous, warm-season perennial grass from South Africa. It is frequently used to extend the grazing season in poorly drained soils of subtropical regions (Quesenberry et al. 2004). The cold tolerance of limpograss allows it to grow at temperatures below which other commonly used warm-season grasses (e.g. bermudagrass) remain productive. Use of limpograss has helped to reduce forage shortfall during winter, therefore, reducing feeding costs. In the past 30 years, the area planted to limpograss in Florida, USA has grown faster than that of any other forage grass species. It is estimated that over 0.2 million ha are planted to limpograss (Quesenberry et al. 2004). Recent University of Florida research with limpograss has focused on developing new hybrids which incorporate the persistence of the most widely used cultivar ‘Floralta’ with the digestibility of ‘Bigalta’. Preliminary clipping and grazing trials evaluated 50 breeding lines and identified 5 lines (designated 1, 4F, 10, 32 and 34) with superior performance. With an overall program goal of identifying the best limpograsses for cultivar release, the specific objective of this experiment was to investigate the forage productivity and sward canopy characteristics of these 5 breeding lines, compared to Floralta, in response to different grazing management strategies

The Use of Sunn Hemp as Forage in Florida

Sunn hemp (Crotalaria juncea L.) is a warm-season annual legume that has been widely used as cover crop; however, there is potential to use sunn hemp as forage in subtropical regions. The objective of this study was to evaluate management practices to improve the efficiency of using sunn hemp as a forage crop. The study was conducted in Ona, Florida, USA from 2016 to 2018 and tested the factorial arrangement of five sunn hemp genotypes (Crescent Sunn, Ubon, Blue Leaf, and AU Golden) and two harvest times (60 d after seeding or flowering) with four replicates. There was a cultivar × harvest period effect on HA, crude protein (CP), and in vitro digestible organic matter (IVDOM) concentrations. Herbage accumulation was greater at flowering than 60 d harvest for all cultivars; however, the magnitude of increase was greater for Blue Leaf and Crescent Sun than AU Golden and Ubon. AU Golden and Ubon flowered at 83 and 92 d after seeding, while Blue Leaf and Crescent Sun flowered or were harvested at 166 d after seeding. AU Golden and Crescent Sunn had the greatest CP at 60 d harvest, and Blue Leaf and Ubon had the least CP concentrations. AU Golden and Crescent Sun had the greatest IVDOM at 60-d harvest; however, AU Golden and Ubon had greater IVDOM than Blue Leaf and Crescent Sun at flowering. Sunn hemp may be a feasible warm-season annual legume to be used in forage systems in Florida and harvest 60 d after seeding would results in forage with greater nutritive value

Challenges and Opportunities to Increase Carbon Sequestration in Subtropical Grazing Lands

Livestock production has a significant environmental footprint. However, adoption of regenerative grazing land management practices can serve as a means of producing food with lower, or even net positive environmental impacts. Globally, much of the grazing land ecosystems are degraded due to improper management. This is particularly true in the southeastern US, where extensive areas of planted pastures are degraded due to inadequate nutrient and soil management. In this presentation, we will discuss the opportunities and challenges associated with increasing soil and ecosystem C sequestration in subtropical grazing lands through regenerative management practices. Introductio

Nutrient Return from Plant Litter and Cattle Excretion Grazing on N-Fertilized Grass or Grass-Legume Pastures in North Florida

Nutrient recycling via plant litter and livestock excreta is an important ecosystem service provided by grasslands. This study determined nutrient return via these pathways in three grazing systems. The experiment was conducted from May to October (2016 and 2017) and treatments were: 1) Nitrogen fertilized bahiagrass (Paspalum notatum Flügge) pastures (112 kg N ha-1) during the warm-season, overseeded with a mixture (56 kg ha-1 of each) of ‘FL 401’ cereal rye (Secale cereale, L.) and ‘RAM’ oat (Avena sativa, L.) during the cool-season (BGN); 2) Ecoturf Rhizoma peanut (Arachis glabrata Benth.)/bahiagrass pastures during the warm-season, overseeded with similar rye/oat mixture fertilized with 34 kg N ha-1 plus a mixture of clovers (Trifolium incarnatum L., T. pretense L., and T. nigrescens L.) during the cool-season (BGRP); 3) unfertilized bahiagrass pastures during the warm-season, overseeded with similar rye/oat grass/clover mixture + 34 kg N ha-1 during the cool-season (BG). Litter mass was evaluated every 5wk. Litter decomposition was evaluated with incubation periods of 0, 2, 4, 8, 16, 32, 64, 128, and 256 days. Urine and fecal samples were collected for N concentration analysis. There was a net return of 47 kg N ha-1 season-1 via litter in all three systems without differing among them. In addition, litter decomposition rates were not different in the three systems. Conversely, N returned via excreta (urine and feces) was greater (63, 27, and 51 kg N ha-1 season-1) than that returned via litter (58.6, 41.6, and 41.2 kg ha-1 season-1). When assessing the proportions of N returning to the system via litter or excreta, no differences were observed among treatments, and on average 65.1 % of the N returned via excreta vs. 34.9 % returning via litter. The introduction of legumes could reduce the inputs from N fertilizers in grazing systems and keep the productivity similar because of more efficient N cycling

Ecosystem Services Provided by Overseeding Aeschynomene Into Bahiagrass Pastures in South Florida

Aeschynomene (Aeschynomene americana L.) is a warm-season annual legume commonly overseeded into warm-season perennial grass pastures in tropical and subtropical regions. Although aeschynomene usually increases forage production and nutritive value, there is limited information about the ecosystem services provided by this legume. The objective of these studies was to evaluate the effects of overseeding aeschynomene into bahiagrass (Paspalum notatum Flüggé) pastures on nutrient dynamics and microbial N-cycling gene abundances. The studies were conducted in Ona, FL, from April to March 2019-2020 and 2020-2021. Treatments were the split-plot arrangement of two forage systems treatments (overseeding aeschynomene into bahiagrass or bahiagrass monoculture; main plots) and two N fertilization levels [0 (control) and 60 kg N ha-1 ; sub-plot], distributed in a randomized complete block design with four replicates. Forage characteristics were evaluated 8-wk after seeding and every 35 d thereafter. The static chamber technique was used to estimate nitrous oxide (N2O) emissions. The litter bag technique was used to estimate organic matter (OM) and N decomposition. Nitrogen-cycling gene abundances were measured by qPCR. Bahiagrass-aeschynomene had greater crude protein concentration than bahiagrass monoculture but there was no difference in forage accumulation. Nitrogen fertilization increased forage accumulation and daily N2O emissions. Litter from bahiagrass-aeschynomene had greater OM and N decomposition rates than bahiagrass only, and N fertilization did not affect litter decomposition. There were no differences in N-cycling microbial gene abundances among treatments. Overseeding aeschynomene into bahiagrass may provide additional ecosystem services, but the magnitude is conditional to the establishment and proportion of aeschynomene in the pasture botanical composition

Release of a New Forage Bermudagrass Cultivar from the USDA-NPGS Cynodon Collection

Warm-season perennial grasses are the backbone of the pasture-based livestock industry in the southeastern USA. In Florida specifically, bahiagrass (Paspalum notatum Flugge) and bermudagrass (Cynodon spp.) support 1 million head of cattle and 15,000 beef cattle operations. Bermudagrass is the most widely planted forage species in the southeastern USA, planted in approximately 15 million ha and used for grazing, hay and silage. The genus Cynodon is native to southern Africa and germplasm collections have revealed a high degree of genetic variability within the genus. The United States Department of Agriculture National Plant Germplasm System (USDA-NPGS) maintains a collection of bermudagrass plant introduction (PIs) in Griffin, GA, USA and the USDA Georgia Coastal Plains Experiment Station, Tifton, GA, maintains additional forage germplasm. Multi-location trials were established in 2014 in four states (FL, GA, NC and OK) to screen the collection for herbage accumulation (HA) and nutritive value (NV). Due to the large genotype by environment interaction for HA across states, we focused on selecting accessions adapted to South Georgia and Florida. Several PIs showed improved HA and NV compared to ‘Tifton 85’ across several trials and years. Particularly, PI 316510 produced high HA in Citra, FL and Tifton, GA, had improved NV traits, and faster establishment compared to Tifton 85. We confirmed that PI 316510 is tetraploid by chromosome counts and flow cytometry. The PI 316510 has been released by the University of Florida under the name “Newell”

Uncommon Trimethoxylated Flavonol Obtained from Rubus rosaefolius

This study shows the evaluation the antiproliferative effect of the extract, fractions, and uncommon compounds isolated from R. rosaefolius leaves. The compounds were identified by conventional spectroscopic methods such as NMR-H1 and C13 and identified as 5,7-dihydroxy-6,8,4′-trimethoxyflavonol (1), 5-hydroxy-3,6,7,8,4′-pentamethoxyflavone (2), and tormentic acid (3). Both hexane and dichloromethane fractions showed selectivity for multidrug-resistant ovary cancer cell line (NCI-ADR/RES) with total growth inhibition values of 11.1 and 12.6 μg/ml, respectively. Compound 1 also showed selective activity against the same cell line (18.8 μg/ml); however, it was especially effective against glioma cells (2.8 μg/ml), suggesting that this compound may be involved with the in vitro antiproliferative action

agronj_102_4_AJ10-0106 Sollenberger.indd

ABSTRACT High-yielding bioenergy crops remove large quantities of soil nutrients. Nutrients must be replenished in a manner that minimizes production costs and negative environmental impact. Class A municipal biosolids (MBS) were evaluated as an alternative nutrient source to inorganic fertilizer for 'Merkeron' and Chinese Cross elephantgrasses (Pennisetum purpureum Schum.) in a 2-yr fi eld experiment in Florida. Elephantgrass plots received 0, 33, 67, or 100% of total N applied (350 kg ha -1 yr -1 ) from MBS, with the remainder from NH 4 NO 3 . Dry matter (DM) yield, tissue N and P concentrations and removal, and soil C and P concentrations were assessed. Elephantgrass yield decreased linearly from 24.2 to 20.1 (Merkeron) and 24.3 to 16.9 Mg ha -1 (Chinese Cross) as the percentage of N supplied by MBS increased from 0 to 100. Nitrogen removal decreased from 208 to 127 kg ha -1 yr -1 over the same range of N from MBS. Phosphorus removal ranged from 28 to 43 kg ha -1 yr -1 , but the eff ect of N source was not consistent. Th ere was no eff ect of percentage of N from MBS treatment on soil responses including water-extractable (WEP), Mehlich-1, or total P, nor was there an eff ect on total C concentration in the Ap horizon. Replacing 33% of N from inorganic fertilizer with N from MBS reduced elephantgrass biomass production 0 to 11%, so there is potential benefi t to including MBS in a fertilization program for bioenergy crops, even in situations where MBS are limited to P-based application rates

Pharmacological characterization of Solanum cernuum Vell.: 31-norcycloartanones with analgesic and anti-inflammatory properties

Cycloeucalenone (1) and 24-oxo-31-norcycloartanone (2) obtained from Solanum cernuum Vell. were assayed to explore their pharmacologic roles. Previous studies showed that (2) has selective activity against lung tumor cell line (NCIH460) which expresses high levels of COX-2, suggesting its role in inflammatory process, and also a link between chronic inflammation and cancer-associated process. Dichloromethane crude extract (DCE) significantly reduced writhing and stretching induced by 0.8 % acetic acid at a dose of 100, 300, and 600 mg/kg, po; oral administration of different doses of (1) and (2) also displayed significant analgesic and anti-inflammatory effects in the writhing acetic acid test (p < 0.0001). Selected oral doses of both compounds (100 and 50 mg/kg) were assayed in the carrageenan-induced paw edema model. Compound (2) showed significant activity during the early phase (1.5–6 h) and also in the late phase (48 h) (p < 0.01). The anti-nociceptive activity observed for the compounds (1) and (2) and DCE was found to be related to the inhibition of different mediators involved in inflammation and nociceptive process. Both compounds decreas COX-2 protein expression, although only compound (2) reached a significant response (p < 0.05 vs control). However, in vitro Sirtuin 1 activity and TNF-a production in THP-1 macrophages were not affected