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Tree legumes such as Gliricidia sepium (Jacq.) Kunth ex Walp. (Gliricidia) and Mimosa caesalpiniifolia Benth. (Sabia) are important options to enhance drought tolerance of livestock systems and improve the diet of grazing animals. This study assessed productive and nutritional potential of Gliricidia or Sabia in a silvopastoral system (SPS) with signalgrass [Urochloa decumbens (Stapf) R.D Webster]. Treatments were the two SPS allocated in a randomized complete block (three replications). Trees were harvested four times, with 6-month intervals between harvests. Response variables included all dendrometry measurements, dry matter of tree components, chemical composition, δ15N, δ13C, and N derived from the atmosphere (Ndfa). Sabia had greater basal diameter (7.6 ± 1.2 vs. 6.0 ± 1.2 cm; P = 0.045), shaft length (7.5 ± 0.2 vs. 5.5 ± 0.2 cm; P = 0.002), Lorey’s height (7.2 ± 0.3 vs. 5.9 ± 0.3 cm; P = 0.023), tree volume (0.3 ± 0.1 vs. 0.2 ± 0.1 m3; P = 0.014), intermediate branches (14 ± 0.8 vs. 8 ± 0.8 Mg DM/ha; P = 0.004), total leaf biomass (3053 ± 236 vs. 1829 ± 236 kg DM/ha; P = 0.029), dry matter concentration (427 ± 0.4 vs. 252 ± 0.4 g/kg; P = 0.021), lignin (233 ± 0.7 vs. 145 ± 0.7 g/kg DM; P = 0.001), and acid detergent insoluble nitrogen (272 ± 1.2 vs. 168 ± 1.2 g N/kg; P = 0.004). Gliricidia presented greater crude protein (250 ± 0.7 vs. 187 ± 0.7 g/kg DM; P = 0.003), more enriched δ13C (−34 ± 0.2 vs. −35 ± 0.2 ‰; P = 0.006), and Ndfa (65 ± 4 vs. 47 ± 4 %; P = 0.041). Sabia demonstrated continued growth and potential to incorporate nutrients into the soil. Gliricidia had greater potential for biological N2 fixation. Both tree legumes have potential for use in SPS. Gliricidia is recommended when the livestock production is the major goal. Sabia is recommended when timber production is the most desirable activity.

This study evaluated the nutritive value of signalgrass (Urochloa decumbens Stapf R. D. Webster) and sabiá (Mimosa caesalpiniifolia Benth.), and animal performance in grass monoculture pastures and in silvopastoral system (SPS) in the early development stage, in the Agreste of Pernambuco. Four treatments were evaluated in a randomized block design with three replications: signalgrass + Eucalyptus spp.; signalgrass + sabiá; signalgrass monoculture and sabiá monoculture. Holstein × Zebu crossbred calves (170 ± 15 kg BW) were managed under continuous stocking with variable stocking rate (SR). The dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), and in vitro dry matter digestibility (IVDMD) of signalgrass and sabiá were assessed, as well as forage allowance (FA), stocking rate (SR), average daily weight gain (ADG) and weight gain per area (WGA) over eleven evaluation cycles (March 2019 to January 2020). Signalgrass had the highest DM contents in March 2019 and January 2020 (456 and 507 g kg

The presence of arboreal legumes in silvopastoral systems (SPS) may affect litter production and quality, and the characteristics and distribution of soil organic matter (OM). Senescent leaves from two tree legumes [Gliricidia sepium (Jacq.) Kunth ex. Walp. (Gliricidia) and Mimosa caesalpiniifolia Benth. (Sabia)] in SPS with Urochloa decumbens Stapf. R. Webster (signalgrass), and from signalgrass pasture in monoculture (Signalgrass), were collected when still attached to the plant and incubated on the ground during 0, 4, 8, 16, 32, 64, 128, and 256 days. Response variables included the disappearance of dry matter (DM), OM, C, N, lignin, acid detergent insoluble nitrogen, and C:N and lignin:N ratio. Single negative exponential models were adjusted to estimate the relative decomposition rate (k). The decomposition rate (k) of DM, OM, and C was greater for Gliricidia and Signalgrass (P

Silvopasture systems using tree legumes have potential to reduce C footprint of livestock systems in the tropics. This 4-year study evaluated productive responses of signal grass (Brachiaria decumbens Stapf.) and the performance of cattle in silvopastoral systems (SPS) in the sub-humid tropical region of Brazil. The experimental design was randomized complete block with three replications. Treatments were: signal grass + Mimosa caesalpiniifolia Benth.; signal grass + Gliricidia sepium (Jacq.); and signal grass monoculture. Cattle were managed under continuous stocking with variable stocking rate. Herbage mass (HM) was greater on signal grass monoculture (5057 kg DM/ha) than in mixed pastures (3292 kg DM/ha, average). There was interaction (P

Understanding ecological interactions between the arboreal and the herbaceous components is key to get the full benefits from silvopastoral systems. The objective of this 2-yr research was to evaluate productivity and nutritive value of signalgrass (Urochloa decumbens (Stapf.) R. Webster) subjected to shading from the tree legumes Gliricidia (Gliricidia sepium (Jacq.) Steud) or Mimosa (Mimosa caesalpiniifolia Benth.) under different tree canopy management. Trees were planted in double rows and were either unharvested or harvested only one row, leaving the other row unharvested. Response variables for the herbaceous vegetation included canopy height, herbage mass (green leaf blade, green stem, senescent leaves, and senescent stem), herbage accumulation rate, canopy bulk density, and soil moisture. Total herbage mass, green herbage mass, and green leaf mass were affected by treatment × month and harvest management × month interactions. Herbage accumulation rate in Gliricidia was greater (55 kg DM ha−1d−1) than Mimosa (32 kg DM ha−1d−1). Soil moisture was lesser at the Mimosa sites (16.2%) compared with the Gliricidia ones (17.2%), and it was greater between tree rows (21.9%) compared with full sun (11.5%), varying across the season. Harvesting management had a short-term transient effect on herbage responses. Tree canopy management can affect forage quantity and quality, however, these effects are transient and vary with tree spacing. Signalgrass grew faster and had better nutritive value when growing with Gliricidia.

Silvopasture systems (SPS) area management option to enhance delivery of ecosystem services and diversification of income. This study evaluated productive responses of signalgrass (UrochloadecumbensStapf.) in monoculture or in SPS in the sub-humid tropical region of Brazil during six months of the rainy season. The experimental design was randomized complete block with three replications. Treatments were signalgrass + Mimosa caesalpiniifolia Benth. (SPS-Mimosa); signalgrass + Gliricidia sepium (Jacq.) (SPS-Gliricidia); and signalgrass monoculture. Cattle were managed under continuous stocking with variable stocking rate. Response variables included herbage mass (HM), herbage accumulation (HA), stocking rate (SR), average daily gain (ADG), and gain per area (GPA). Herbage mass (HM) was greater (P < 0.0001) on signal grass monoculture (2045 kg DM/ha) than in SPS (1370 kg DM/ha, average for both SPS). Herbage accumulation rate was similar for signalgrass in monoculture and SPS-Gliricidia (avg. 61 kg DM ha-1 d-1), and both were greater than SPS-Mimosa (37 kg DM ha-1 d-1). Average daily gain was greater(P < 0.0001) for SPS-Gliricidia (1.1 kg head-1 d-1), followed by signalgrass in monoculture (0.9 kg head-1 d-1), and SPS-Mimosa (0.3 kg head-1 d-1). Stocking rate ranged from 0.6 animal units (1AU = 450-kg animal) per ha in April to 2.2 AUha-1 in June. Stocking rate and animal performance per area were similar for signalgrass in monoculture and SPS-Gliricidia, and both greater than SPS-Mimosa. Gliricidia enhanced animal performance and provided ecosystem services. Mimosa, however, reduced animal performance likely due to the competition with signalgrass. Mimosa trees, however, are an important source of income (timber used for fence posts) and that might overcome the losses in animal performance.

Silvopasture systems (SPS) area management option to enhance delivery of ecosystem services and diversification of income. This study evaluated productive responses of signalgrass (Urochloadecumbens Stapf.) in monoculture or in SPS in the sub-humid tropical region of Brazil during six months of the rainy season. The experimental design was randomized complete block with three replications. Treatments were signalgrass + Mimosa caesalpiniifolia Benth. (SPS-Mimosa); signalgrass + Gliricidia sepium (Jacq.) (SPS-Gliricidia); and signalgrass monoculture. Cattle were managed under continuous stocking with variable stocking rate. Response variables included herbage mass (HM), herbage accumulation (HA), stocking rate (SR), average daily gain (ADG), and gain per area (GPA). Herbage mass (HM) was greater (P < 0.0001) on signal grass monoculture (2045 kg DM/ha) than in SPS (1370 kg DM/ha, average for both SPS). Herbage accumulation rate was similar for signalgrass in monoculture and SPS-Gliricidia (avg. 61 kg DM ha-1 d-1), and both were greater than SPS-Mimosa (37 kg DM ha-1 d-1). Average daily gain was greater(P < 0.0001) for SPS-Gliricidia (1.1 kg head-1 d-1), followed by signalgrass in monoculture (0.9 kg head-1 d-1), and SPS-Mimosa (0.3 kg head-1 d-1). Stocking rate ranged from 0.6 animal units (1AU = 450-kg animal) per ha in April to 2.2 AUha-1 in June. Stocking rate and animal performance per area were similar for signalgrass in monoculture and SPS-Gliricidia, and both greater than SPS-Mimosa. Gliricidia enhanced animal performance and provided ecosystem services. Mimosa, however, reduced animal performance likely due to the competition with signalgrass. Mimosa trees, however, are an important source of income (timber used for fence posts) and that might overcome the losses in animal performance.

Litter decomposition is an important pathway of nutrient return on grazed pastures and it may be affected by management practices. The objective of this study was to evaluate the effects of stocking rate (2, 3.9, and 5.8 AU ha⁻¹; 1 AU = 450 kg animal live weight) and N fertilization level (0, 150, and 300 kg N ha⁻¹ yr⁻¹) on signalgrass (Brachiaria decumbens Stapf.) litter decomposition. Signalgrass litter was placed in nylon bags and incubated for 0, 4, 8, 16, 32, 64, 128, and 256 d during 2009 and 2010. Litter decomposition rates differed between years and among incubation times. The decomposition rate was less in 2009 than in 2010 (3.46 and 4.20 mg g⁻¹d⁻¹, respectively). Stocking rate had no effect on litter decomposition rate. Decomposition rates were greater for fertilization with 300 vs. 0 kg N ha⁻¹ yr⁻¹ (4.47 vs. 3.29 mg g⁻¹ d⁻¹, respectively), which resulted in less N remaining in fertilized signalgrass litter. Concentrations of N and lignin as well as lignin/N ratio fit linear plateau models, increasing 7, 151, and 25 g kg⁻¹, respectively, during the 256-d incubation period. The effect of year on residual N and C/N ratios highlighted the need for long-term trials that measure the peaks of nutrient release and availability to plants. Data are needed to guide nutrient management decisions in tropical pastures. Pasture N fertilization may shift the balance between litter immobilization/mineralization, altering N dynamics in the litter pool.

O experimento foi realizado com o objetivo de avaliar fatores relacionados à eficiência de pastejo de cinco genótipos de Pennisetum sp. (CE 08 A.D., Venezuela, HV-241, Elefante B e Hexaplóide) no período seco do ano na Zona da Mata de Pernambuco. Os genótipos foram manejados sob lotação rotacionada (44 dias de descanso e quatro dias de pastejo) ao longo de dois ciclos de pastejo. Adotou-se delineamento experimental em blocos ao acaso, com parcelas subdivididas (os genótipos representaram as parcelas e os ciclos de pastejo, as subparcelas) e quatro repetições. As massas de lâmina foliar total, verde e senescente pré-pastejo foram analisadas em seis repetições. O acúmulo e a eficiência de pastejo de lâmina foliar verde foram avaliados em delineamento em blocos casualizados, com quatro repetições. Os genótipos CE 08 A.D. e Elefante B apresentaram maiores massas de lâmina foliar total (1.374 kg de MS/ha) e verde pré-pastejo (737 kg de MS/ha) e maior acúmulo (654 kg de MS/ha/44 dias) e eficiência de pastejo de lâmina foliar verde (80%). No HV-241, a alta eficiência de pastejo (100% do acúmulo lâmina foliar verde) esteve associada ao baixo acúmulo de lâmina foliar verde (155 kg de MS/ha/44 dias). A menor eficiência de pastejo foi observada no Hexaplóide (59% do acúmulo de lâmina foliar verde), possivelmente em virtude das altas perdas sob pastejo (30% da massa de lâmina foliar total pré-pastejo). A massa de lâmina foliar verde diminuiu mais acentuadamente até o segundo dia de pastejo, enquanto as perdas de lâmina foliar total foram maiores no 2º e 3º dias de pastejo. Os genótipos CE 08 A.D. e Elefante B têm potencial para serem utilizados em sistemas de lotação rotacionada na Zona da Mata pernambucana. The experiment was carried out to evaluate factors related to the grazing efficiency of five Pennisetum sp. genotypes (CE 08 A.D., Venezuela, HV-241, Elephant B and Hexaplóide) during the dry period in the Forest Zone of Pernambuco. Genotypes were managed under rotational stocking (44 days of resting and four days of grazing period). It was used a split-plot arrangement in a complete randomized block design (genotypes represented the plots; grazing cycles, the subplots). Six replications were used to determine pre-grazing total leaf blade mass and green and senescent leaf blade mass. Four replications were used for leaf blade accumulation and grazing efficiency and, for these variables, it was used a complete randomized blocks design. The CE 08 A.D. and Elephant B presented greater pre-graze total leaf blade mass, green leaf blade, green leaf blade accumulation, and grazing efficiency, with averages of 1,374 kg DM/ha, 737 kg DM/ha, 654 kg DM/ha/44 days and 80% of the green leaf blade accumulation, respectively. The highest grazing efficiency (100% of the green leaf blade accumulation) occurred at the HV-241 pastures. This high grazing efficiency was associated to the low green leaf blade accumulation (155 kg of MS/ha/44 days). The lowest grazing efficiency was observed for the Hexaplóide (59% of the green leaf blade accumulation), possibly due to high losses under grazing (30% of the pre-grazing total leaf blade mass). The green leaf blade mass decreased mostly until the second grazing day, while the losses of total leaf blade were higher in the second and third grazing days. The genotypes CE 08 A.D. and Elephant B presented potential to be used under rotational stocking, in the Pernambuco Forest Zone.

Grasslands are the major source of feed for ruminants (Zanine 2005). Seasonality of production, however, is a constraint in forage-based systems. Silvopastoral systems combine different components (animals, trees and forages) into an integrated system and may improve forage distribution across seasons. Resource use is usually more efficient both spatially and temporally, increasing land use efficiency (Nair 1993). Tree legumes present potential for silvopastoral systems because they can fix N from the atmosphere, improve cattle diets and lead to a faster N cycle. In addition, trees provide shade and may reduce heat stress for grazing animals in tropical and subtropical grasslands. Leguminous trees are commonly found in these climates and present potential for use in silvopastoral systems. This research studied the pasture characteristics and animal performance of signal grass (Brachiaria decumbens) in a pure stand or in silvopastoral systems with Gliricidia sepium or Mimosa caesalpiniifolia.