Erick Rodrigo da Silva Santos

Cool‐season annual grasses are important components of Florida forage systems, providing high‐quality forage when warm‐season perennial grasses are dormant. Strategies such as using alternative species and adjusting planting dates may extend the grazing season, improve resilience to weather variability, and increase producer profitability. In this 2‐year study, we evaluated the herbage accumulation (HA) of seven cool‐season grasses planted either in January or February and harvested twice during the cool season. The evaluated grasses included three oat ( Avena sativa L.) cultivars—‘Cosaque’, ‘Horizon 201’, and ‘Legend 567’—as well as ‘Trical 342’ triticale (× Triticosecale spp.), ‘FL401’ rye ( Secale cereale L.), ‘Earlyploid’ ryegrass ( Lolium multiflorum Lam.), and ‘SoilSaver’ black oat ( Avena strigosa Schreb.). On average, SoilSaver, Legend 567, and FL401 produced greater total HA (2500 lb ac ⁻¹ ) than Cosaque and Horizon 201 (1060 lb ac ⁻¹ ), whereas Earlyploid ryegrass and Trical 342 were intermediate among all entries. Cosaque, FL401, Earlyploid ryegrass, and Trical 342 had greater HA when planted in January than when planted in February. In contrast, SoilSaver produced greater HA when planted in February rather than in January, whereas Legend 567 performed well at both planting dates. Except for Earlyploid ryegrass, all entries had greater HA in the first harvest. SoilSaver black oat ranked second in both harvests. In the first harvest, SoilSaver was outperformed by Legend 567 oat and FL401 rye. In the second harvest, SoilSaver was outperformed by Earlyploid ryegrass. Overall, SoilSaver black oat, Legend 567 oat, and FL401 rye were among the most productive entries and represent promising options for enhancing cool‐season forage production in Florida.

Animal excreta represent one of the primary pathways for nutrient return to pastures. We investigated the spatial distribution pattern of dung pads during seven grazing cycles over two years and the nutrient concentration in forage and cattle dung in different systems in a subhumid tropical region. The treatments were: (I) brachiaria grass (Brachiaria decumbens syn. Urochloa decumbens Stapf R. D. Webster) + gliricidia (Gliricidia sepium (Jacq.) Kunth ex. Walp.; B+G); (II) brachiaria grass + sabia (Mimosa caesalpiniifolia Benth.; B+S); [...] ABSTRACT Animal excreta represent one of the primary pathways for nutrient return to pastures. We investigated the spatial distribution pattern of dung pads during seven grazing cycles over two years and the nutrient concentration in forage and cattle dung in different systems in a subhumid tropical region. The treatments were: (I) brachiaria grass (Brachiaria decumbens syn. Urochloa decumbens Stapf R. D. Webster) + gliricidia (Gliricidia sepium (Jacq.) Kunth ex. Walp.; B+G); (II) brachiaria grass + sabia (Mimosa caesalpiniifolia Benth.; B+S);

Legumes can form symbiotic associations with rhizobia and fix atmospheric nitrogen (N), contributing N to forage systems when grown in mixtures with non‐N‐fixing species. Ball clover (BC; Trifolium nigrescens Viv.) is a cool‐season annual legume with strong reseeding potential due to its production of hard seed. We evaluated BC seeding rates (2, 4, or 6 lb ac ⁻¹ ) in mixtures with annual ryegrass (RG; Lolium multiflorum Lam.) to identify an optimal rate for pasture production systems and compared these mixtures with RG monocultures receiving either 0 or 45 lb N ac ⁻¹ (RG + N). Seeding rates did not affect herbage accumulation during establishment or in the following year. However, BC + RG mixtures produced less herbage accumulation than RG + N during establishment (1280 vs. ≥2800 lb ac ⁻¹ ) following reseeding (2900 vs. 1720 lb ac ⁻¹ ). RG grown in a mixture exhibited intermediate δ ¹⁵ N values (1.62‰, on average) between RG and RG + N, indicating the uptake of both soil‐derived N and N transferred from BC fixation. Seeding BC at 4 or 6 lb ac ⁻¹ increased the legume proportion in the sward to ∼50%, enhanced biological N fixation (BNF; 24.8 lb N ac ⁻¹ , average), and resulted in total shoot N yields comparable with RG + N. Therefore, seeding BC at 4 lb ac ⁻¹ provides benefits comparable with seeding at 6 lb ac ⁻¹ at a lower cost, whereas seeding at 2 lb ac ⁻¹ represents the most economical option, with a lower clover proportion (30%) and BNF (16 lb N ac ⁻¹ ) during the establishment year.

Belowground plant structures are integral to nutrient cycling in grassland ecosystems. However, relative to herbage responses, few studies have examined the belowground dynamics of warm‐season perennial forages under different management practices. This study evaluated root‐rhizome responses and decomposition dynamics of a perennial legume (rhizoma peanut [RP; Arachis glabrata Benth. ‘Ecoturf’]) under continuous stocking (Grazing) and 56‐day clipping (Haying) intervals across three 56‐day periods in 2018 and 2019. In 2019, root‐rhizome mass was greater under Haying than Grazing in two out of three periods, peaking at 14,980 kg organic matter (OM) ha⁻¹. Conversely, root‐rhizome N concentration was lower with Haying than Grazing (12 vs. 14 g kg⁻¹). Root‐rhizome growth rate was greater in 2018 than in 2019 (18.0 vs. 10.5 kg OM ha⁻¹ day⁻¹). In 2019, Grazing exhibited greater biomass (0.0013 vs. 0.0010 g g⁻¹ day⁻¹) and N (0.0016 vs. 0.0011 g g⁻¹ day⁻¹) decay rates than Haying. Root‐rhizome N pools for 2018 and 2019 averaged 159 and 192 kg N ha⁻¹, with 86% and 93% N remaining post‐incubation, respectively. During a 56‐day period, N disappearance was 22.3 kg N ha⁻¹ in 2018 and 13.4 kg N ha⁻¹ in 2019, equating to 70 and 40 kg N ha⁻¹, respectively, over the 168‐day growing season. With RP covering 30% of the pasture, root‐rhizomes contribute an estimated 12–21 kg N ha⁻¹ per season. Root‐rhizome dynamics in RP were influenced by defoliation management, though responses varied between years.

The pasture–animal interface of warm-season perennial grass–legume mixed pastures has never been investigated in forage-based equine systems. Therefore, this 2-year study investigated the herbage and animal responses under 84-day continuous stocking in mixed pastures of rhizoma peanut (RP, Arachis glabrata Benth) and bahiagrass (BG, Paspalum notatum Flüggé) with 30 kg nitrogen (N) ha⁻¹ (BG-RP) compared to BG pastures fertilized with 120 kg N ha⁻¹ (BG-N₁₂₀) and no N (BG-N₀). Measurements were taken every 14 days, except for intake and in vivo digestibility, which were measured every 28 days. BG-N₁₂₀ had the highest stocking rate (p = 0.01; 3.7 AU ha⁻¹) in 2019, while BG-N₀ had the lowest (p = 0.01; 2.6 AU ha⁻¹) in 2020. Crude protein and digestible energy were greatest (p < 0.05) for BG-N₁₂₀ and BG-RP in some of the evaluation days in 2019 but similar across pastures in 2020. Crude protein digestibility was greatest (p < 0.05) for BG-RP in the late season. Intake was less (p = 0.03) for horses grazing BG-RP (3.2%BW) compared to BG-N₀ (5.0%BW). Nonetheless, no differences (p > 0.05) were observed among pastures for body measurements. The results indicate that BG-RP pastures can improve forage nutritive value and maintain horse body condition while maintaining similar stocking rate to monoculture bahiagrass with high N fertilizer rates.

Incorporating forage legumes into grass swards has the potential to enhance the sustainability of pasture systems and reduce reliance on nitrogen fertilizers. The aim of this study was to assess the on‐farm performance of bahiagrass (BG; Paspalum notatum Flüggé)–rhizoma peanut (RP; Arachis glabrata Benth.) mixtures compared to BG monocultures in three diverse environments across Florida. Three forage treatments were employed at all locations: BG in monoculture (Bh), BG + Ecoturf RP (Eco), and BG + Florigraze RP (Flo). Significantly greater herbage accumulation rates were observed for BG + Ecoturf RP (37 kg DM ha⁻¹ day⁻¹, where DM is the dry matter) and BG with Florigraze RP (35 kg DM ha⁻¹ day⁻¹) in comparison with BG in monoculture (30 kg DM ha⁻¹ day⁻¹). Crude protein and in vitro digestible organic matter concentrations were greater for RP binary mixtures compared with monoculture BG across all locations. In North and South Florida, BG + Ecoturf RP exhibited greater RP belowground biomass than BG + Florigraze RP. Additionally, biological N₂ fixation increased linearly as the proportion of RP increased. Integration of RP germplasm Ecoturf and the Florigraze cultivar into BG pastures in North, Central, and South Florida led to increased rates of herbage accumulation and improved herbage nutritive value compared to BG monoculture. Overall, North and South Florida exhibited more favorable responses to the inclusion of RP compared to Central Florida.

Sustainable intensification of livestock systems implies greater efficiency in resource utilization resulting in greater output of products and other ecosystem services per unit of resource input. Integrating forage legumes into livestock systems is a viable way to reduce the input of industrial N fertilizer, reducing the use of fossil fuels and helping to mitigate global warming, a major problem during the Anthropocene. Some forage legumes have greater concentrations of secondary compounds, such as condensed tannins, that might reduce the emission of greenhouse gases (GHG) from ruminant eructation and excreta. Furthermore, forage legumes might enhance cattle performance because of greater nutritive value, resulting in greater production per unit of GHG released. Shortening the production cycle and improving cattle reproductive efficiency could have a major impact on reducing the overall carbon footprint of the system. Grazing systems with more diversified plant species are typically more resistant and resilient, adapting to current climate changes during the Anthropocene. Novel technologies might accelerate the development of future grazing systems using forage legumes as a key component. Breeding efforts for the next‐generation legumes must focus on adaptation and potential use for mitigation of negative environmental impacts. There are examples of successful integration of forage legumes into livestock systems in different regions of the world, with a major reduction in off‐farm inputs and maintaining the system productive. These successful examples could be used to increase adoption and improve the efficiency of current livestock systems.

Limpograss (Hemarthria altissima) is a warm-season perennial grass that has the potential to feed livestock during scarcity periods. This study evaluated the intake, nutrient digestibility, and animal performance of beef heifers fed ‘Gibtuck’ limpograss silage combined with different levels of a range cube supplementation. Twenty-four heifers (330 ± 16 kg live weight) were submitted to four different treatments with 6 replicates: (1) control, no supplementation + limpograss silage ad libitum; (2) 1.4 kg of supplement + limpograss silage ad libitum; (3) 2.8 kg of supplement + limpograss silage ad libitum; and (4) 4.2 kg of supplement + limpograss silage ad libitum. The apparent total tract digestibility of dry matter, organic matter, and crude protein showed a positive quadratic effect with increasing supplementation levels (p = 0.001, p = 0.002, and p < 0.0001, respectively). Overall, the supplement improved diet digestibility and total DM intake but reduced silage intake, indicating a combined effect (substitutive and additive effect) of the protein supplement. The increasing level of protein supplement increased the average daily gain with a quadratic effect (p ≤ 0.0001). Limpograss silage associated with supplementation can improve diet digestibility and increase the animal performance of growing heifers, providing an alternative for livestock in North Florida.

Bermudagrass [Cynodon dactylon (L.) Pers.] is an important forage source for ruminants in tropical and subtropical regions of the world; nevertheless, little is known about the productive and nutritional characteristics of new accessions and cultivars originating from breeding programs. Five bermudagrass cultivars (Tifton 85, Jiggs, Florida 44, Callie, and Newell) and five accessions (276, 282, 323, 286, and Missouri) were tested during the 2018 and 2019 growing seasons. Genotype × harvest interactions were detected for herbage accumulation (HA), crude protein (CP), and nitrogen yield (p < 0.05). In June, all bermudagrass genotypes showed significant variation in HA, with accession 286 being more productive than Jiggs (4.42 vs. 3.24 Mg DM ha⁻¹ harvest⁻¹, respectively, where DM is dry matter). In October, however, accession 323 had greater CP than Callie, accession 286, Newell, and Tifton 85, with average CP values of 155, 128, 136, and 137 g kg⁻¹ DM, respectively. Average in vitro digestible organic matter for accession 323 (450 g kg⁻¹ DM) was similar to that of Tifton 85 and Newell but greater than that of Missouri (393 g kg⁻¹ DM). Genotypes displayed unique responses to all traits across harvest dates. According to the principal component analysis, the accession Missouri exhibited low productive and nutritive value properties. The accession 286 showed greater CP concentration while still productive; thus, this accession will be further examined for future release to livestock or hay producers in subtropical regions worldwide.

Management practices might alter soil chemical properties. This study evaluated soil chemical properties in a forage cactus Opuntia stricta (Haw.) Haw. (‘Orelha de Elefante Mexicana’) (OEM) production system in the Brazilian semiarid region. The experiment was established in June 2011, and the design was a split-split-plot in randomized complete blocks, in which the main plots were formed by distinct levels of organic fertilizer (cattle manure) (0, 10, 20, and 30 Mg ha⁻¹ year⁻¹), the subplots were formed by different levels of N inorganic fertilizer applied as urea (0, 120, 240, and 360 kg N ha⁻¹ year⁻¹), and the sub-subplots were distinguished by the distinct OEM harvesting frequency (annual or biennial). Soil samples were collected for chemical analysis, C and N contents analysis, and stocks analysis at 0 to 10 and 10 to 20 cm depths in August 2019. Organic fertilizer contributed to a linear increase in soil pH, Ca²⁺, Na⁺, sum of bases (SB), cation exchange capacity (CEC), and base saturation (V) at both depths (p < 0.05). With the application of 30 Mg ha⁻¹ year⁻¹ of cattle manure, there was storage of approximately 126 Mg C ha⁻¹ and 13 Mg N ha⁻¹ at 0 to 20 cm depths. Managing OEM with organic fertilizer and a biennial frequency of harvesting affects the soil’s chemical characteristics in cactus orchards, and it is a sustainable alternative for semiarid regions.