Warm-Season Legumes – Challenges and Constraints to Adapting Warm-Season Legumes to Transition Zone Climates with Examples from \u3ci\u3eArachis\u3c/i\u3e

Grass pastures in monoculture are the predominant system in transition zone climates, where warm-season perennial grasses are usually cultivated. Mixed grass-legume pastures are worldwide recognized for having advantages over pure stands, including pasture longevity, N input from biological fixation, efficient nutrient cycling, and greater animal production. The genus Arachis encompasses important and successful warm-season forage legume species cultivated in mixed pastures or in pure stands. Arachis pintoi and Arachis glabrata are potential tropical forage species that can be used in transition zone climates. Mixed pastures with these legumes have been shown to be resilient systems, able to withstand short-term perturbations, like pests, diseases, drought, or flooding. Wide adoption of A. glabrata is constrained by its high cost and slow establishment period. This species has low potential to produce seeds, and rhizomes are required for propagation. Although great seed production is verified in some A. pintoi genotypes, vegetative propagation is also most often used, since seeds are produced underground, and a large-scale commercial seed production depends on the development of an efficient seed harvester. Developing new cultivars with persistent link between seed and peg is a great challenge for breeders. A. pintoi spreads faster than A. glabrata in tropical regions, and the genetic variability for lateral expansion and ground cover in mixed stands must be better understood in humid subtropical climates. The evaluation of Arachis wild germplasm has already shown genetic variability for traits of interest for use in mixed pastures. Studies have also shown that there is genotype x environment interaction considering tropical and subtropical climates. The greatest chances of success in obtaining more adapted, productive, and faster establishing Arachis cultivars for transition zone climates seems to be no longer in the identification of superior wild accessions but in the hybridization and selection through specific breeding programs

New Insights for Benefit of Legume Inclusion in Grazing Systems

The benefits and challenges of legume inclusion in grazing systems have been well documented over time and across different regions. Recent investigations have provided novel insights into the benefits of legume inclusion in grazing systems. Our objective is not to provide a wide overview of the benefits of legume inclusion but to explore novel insights of recent advancements made from studies evaluating legume inclusion in grazing systems. Efficiency of resource use through legume inclusion in grazing systems can reduce the water footprint associated with beef production through improvements in forage nutritive value and animal performance. These efficiencies also translate into improvements in nutrient cycling and nutrient transfer, which are critical for sustaining productivity of grazing systems. Moreover, evidence exists highlighting the importance of root contact between grasses and legumes for sharing N. Provisioning of floral resources from legumes has also been shown to be important for providing habitat for pollinator species. Lastly, soil microbial abundance of microorganisms associated with N2 fixation can be altered according to species present within a pasture, especially when legumes are present. Insights derived from such recent studies continue to provide evidence for the need to continue to develop legume-based grazing agroecosystems

Is There a Need for Tailored Graduate Programs for International Students?

International studies often present opportunities for capacity development and mentorship for students to equip them with the knowledge and skills to address the challenges in their home countries. Typically, international graduate students are drawn from diverse educational and cultural backgrounds different from those in their host countries. Adjusting to these changes might be challenging and time-consuming, thus influencing their academic journey. Understanding these challenges might provide international students the opportunity to address them in time and, where possible, seek help. In this paper, we discuss some graduate program-related challenges international students face and provide potential recommendations that might result in tailored programs. It is anticipated that such programs will effectively prepare international graduate students to adapt quickly to new conditions in their host countries and optimize the learning process while acquiring the appropriate tools for their future careers. We conducted a literature search that focused mainly on articles related to international graduate students in the US. Five challenges were explored: Cultural and language barriers, technological literacy and competency, mentorship, career development, and course structure and research priority areas. Graduate programs need to help students identify these challenges while helping them create an ideal environment for excellence. Such programs need to provide adequate support structures, making them known to students at the beginning of their programs. Although it is not feasible to change an entire educational program to accommodate all the needs of international graduate students, pressing concerns need to be identified for action

Weed Management Affects Pasture Productivity and Animal Performance

Weed can be defined as any plant growing in undesirable locations. Weeds are considered one of the main challenges in agricultural fields. Weeds affect pasture productivity mainly because of the competition for limited resources such as nutrients, water, and light with forage plants. Weeds encroach pastures spontaneously and spread quickly through the farm and neighboring areas, making their control difficult. In addition, weeds can affect forage nutritive value, grazing behaviour, voluntary forage intake, animal health, and consequently animal performance. The low efficiency of mechanical weeding and the global concern about indiscriminate use of herbicides impose challenges for producers in grazing systems. These factors justify the importance of proper weed management to minimize financial losses and environmental impacts and drive the research effort in this area. Currently, some strategies including grazing management, grass and legumes integration, and site-specific weed spraying have demonstrated potential to improve the efficiency of weed supression and increase the productivity and profitability of livestock systems. This review aims to discuss about the main effects of weed encroachment in grasslands regarding pasture productivity and animal performance, as well as emphasize potential strategies for weed management

Pastos e manejo do pastejo de áreas dependentes de chuva.

Sistemas pecuários de produção em condições de sequeiro. Manipulação da vegetação da caatinga para exploração pecuária. Caatinga rebaixada. Caatinga raleada. Caatinga rebaixada-raleada. Caatinga enriquecida. Caatinga desmatada. Sugestões de modelos de exploração e de tecnologias com potencial para manter a sustentabilidade da produção agropecuária. Sistemas sem uso da caatinga e com espécies forrageiras cultivadas. Sistemas com uso da caatinga para produção animal. Sistemas com uso da caatinga para produção animal. Espécies de forrageiras apropriadas para exploração em áreas de sequeiro

Herbage and Livestock Responses for N-Fertilized and Grass-Legume Grazing Systems

Forage legumes provide an alternative N source in grazing systems. The objective was to evaluate plant and animal responses in N-fertilized or grass-legume-based systems under continuous stocking during winter and summer, from 2016-2019. The three treatments consisted of year-round forage systems including winter and summer forage components. The first system (Grass+N) included N-fertilized (112 kg N ha-1 yr-1) ‘Argentine’ bahiagrass (Paspalum notatum) pastures during the summer, overseeded with a mixture (56 kg ha-1 of each) of ‘FL 401’ cereal rye (Secale cereale) and ‘RAM’ oat (Avena sativa) during winter with a second application of 112 kg N ha-1 yr-1. Total annual fertilization for this treatment was 224 kg N ha-1 yr-1. System 2 (Grass + clover) included unfertilized Argentine bahiagrass during summer, overseeded with a similar rye-oat mixture, plus a mixture of clovers [17 kg ha-1 of ‘Dixie’ crimson (Trifolium incarnatum), 6.7 kg ha-1 of ‘Southern Belle’ red clover (Trifolium pratense), and 3.4 kg ha-1 ball clover (Trifolium nigrescens), fertilized with 34 kg N ha-1 during winter. System 3 (Grass+CL+RP) included the germplasm Ecoturf rhizoma peanut (Arachis glabrata; RP) and Argentine bahiagrass during the summer, overseeded with the same a similar rye-oat-clover mixture used in System 2 and fertilized with 34 kg N ha-1 during winter. Pastures were continuously stocked using variable stocking rates. Results indicate that clover inclusion during winter improved herbage distribution along the grazing season. Integrating RP during summer increased steer ADG by nearly 80% compared with Grass+N or Grass+Clover (bahiagrass monocultures during summer). While N fertilizer allowed for greater stocking rates, it did not improve animal performance throughout the year. Overall, similar gain per area was achieved in Grass+CL+RP than Grass+N, with lesser N-fertilizer inputs

Herbage Responses and Performance of Mature Horses Grazing Warm-Season Perennial Grass-Legume Mixed Pastures

Legume-grass mixtures may be a useful alternative to nitrogen-fertilized grass monocultures, but pasture and animal responses have not been assessed for pastures grazed by horses in Florida. This 2-yr study compared pasture and horse responses of continuously stocked, mixed pastures of rhizoma peanut (RP, Arachis glabrata Benth) and bahiagrass (BG, Paspalum notatum Flüggé) receiving 30 kg nitrogen (N)/ha (RP-BG) compared with BG pastures fertilized with 120 kg/N ha (BG-N) or with no N (BG-No N). Herbage mass was similar among treatments in 2020 and for most evaluation days in 2019. In 2019, stocking rate (AU/ha) was greater in BG-N (3.9) than in RP-BG (3.7) and BG-No N (3.1). In 2020, BG-No N (2.6) had the lesser stocking rate compared with BG-N (2.9) and RP-BG (2.9), with RP-BG not differing from BG-N. Herbage crude protein (CP) and digestible energy were similar across treatments in 2020, but they were greater for BG-N and RP-BG than BG-No N at some evaluation days in 2019. Except for CP, treatment did not affect nutrient digestibility by horses. Digestibility of CP was greatest for RP-BG in the late season. In the RP-BG treatment, proportion of RP in the pasture (~29%) was not affected by sampling date, and RP comprised 18.4% of the diet. Nonetheless, no differences were observed among treatments for body weight and condition score. The results indicate that intercropping legumes into warm-season perennial pastures can improve some measures of nutritive value and maintain horses’ body condition with similar stocking rate as N-fertilized bahiagrass pastures, while contributing to development of sustainable grazing systems for horses with reduced off-farm nitrogen inputs

Diurnal Variation in Forage Nutrient Composition and Metabolic Parameters of Horses Grazing Warm-Season, Perennial Grass-Legume Mixed Pastures

Although warm-season, grass-legume mixed pastures have improved nutritive value and may reduce negative environmental impacts relative to nitrogen-fertilized grass monocultures, no study has been done to evaluate their effect on diurnal variation of non-structural carbohydrates (NSC) and other nutrients, and on the metabolic responses observed in horses’ blood and fecal samples. This 2-yr study aimed to investigate the circadian variation in nutrient composition and the fecal and blood metabolic responses in horses grazing these pastures. Forage, fecal, and blood samples were collected every 28 days at 0600, 1200, 1800, and 0000 h, in two years, for measurement of diurnal variation in forage nutrient composition and fecal and blood metabolites. Forage nutrient composition was affected by time of the day, with digestible energy (DE) and NSC increasing at 1800 h, crude protein decreasing after 1200 h and the fiber components increasing at 1200 h. Fecal lactate and blood insulin were also affected by time of the day. Fecal lactate increased from 0600 to 1200 h. Insulin levels were greater at 1800 than at 0600 h. The increased insulin level followed the increased concentration of NSC in the forage. In conclusion, warm-season, grass-legume mixed pastures show a diurnal pattern in forage nutrient composition, with increased NSC later in the afternoon. However, the metabolic responses observed in this study were not sufficient to predispose horses to metabolic dysregulation. The results also indicate that restricting grazing to the morning may reduce the forage nutritive value, with decreased concentration of DE and increased concentrations of the fiber components, which may decrease diet digestibility

Below Ground Benefits of Cactus \u3ci\u3eOpuntia stricta\u3c/i\u3e Under Rangeland Conditions in Laikipia, Kenya

Cactus Opuntia stricta primarily invades arid and semi-arid lands (ASALs), which form more than 80% of Kenya’s landmass. The ability of the plant to tolerate poor soils and accumulate biomass under low precipitation has resulted in studies into its potential use by pastoral communities for biofuel and livestock feed. However, few studies have assessed the below-ground benefits associated with cactus under rangeland conditions. In this study, we evaluated the root contributions of the invasives cactus Opuntia stricta under rangeland conditions in Laikipia, Kenya. The experiment was laid out in a randomized complete block design with ten (10) replicates, each measuring 30 × 30 m. Each block was further subdivided into three plots of 10 x 30m Three clusters were randomly selected from each plot for roots and soil samples starting from the center of the cluster (C) to the outside in a gradient of three radii, R1, R2 and R3. Data was collected for root (dry root biomass, % carbon and % nitrogen) and soil (pH, bulk density, % moisture and % nitrogen) characteristics. Significant differences in total root mass, root carbon, and root nitrogen were observed under varying cluster gradients. Root mass ranged from 4527.0 to 9242.0 kg/ha for the outermost radius (R3) and the cluster’s center, respectively. Similarly, except for the soil nitrogen, statistical differences were observed for soil bulk density, percent soil moisture and percent nitrogen along the different cluster gradients. The soil bulk density ranged from 1.2±0.02 (center) to 1.5±0.01 g cm3 (radius 2). Findings from this study demonstrate the important contribution of the invasive cactus species in sustaining the ecological functions of rangeland soils such as those found in Laikipia, Kenya

Nutrient Cycling and Crop Responses on Integrated Crop-Livestock Systems

Integrated crop-livestock systems (ICLS) can bring numerous benefits to crops or livestock systems, such as increase soil C sequestration, farm profitability, and provisioning of ecosystem services. In a changing world, production systems need to become more resilient and sustainable. Specialized agriculture is characterized by a high level of inputs and outputs, and oftentimes specialize in a single crop to simplify management. However, such operational systems stray away from sustainable standards. Furthermore, specialized cropping systems may face problems such as persistence of pests and diseases, loss of biodiversity, stagnant yields, development of herbicide-resistant weeds, soil erosion and consequently loss of soil organic matter. Recombining crops and livestock in a broad and complementary system is to look back into the past to adopt a practice that used to be common centuries ago. With the advancement of technology and better understanding of this management practice, ICLS appear as an option to provide ecosystem services from agricultural lands, while potentially increasing crop production. Such systems have shown benefits as increasing in soil organic matter, increase in biodiversity, and nutrient cycling. There is an array of ICLS, which may include short and long grazing cycles, more than one animal category, crops from many different functional groups, and trees. Here, we will discuss some of the aspects in nutrient cycling and crop responses on ICLS, giving examples to call attention to some of the advantages ICLS can provide