Marandu Palisadegrass Research Articles

Supplementation of lamb ewes with different protein sources in deferred marandu palisadegrass (Brachiaria brizantha cv. marandu) pasture

ABSTRACT The objective of this study was to evaluate the effect of different protein sources on the performance of lamb ewes and their offspring supplemented in deferred pasture. The treatments were the different protein sources: soybean meal, cotton cake, babassu cake and coconut cake. The ewes were weighed and evaluated for their body condition score during the gestation, parturition and weaning phases. The lambs were weighed at birth and at weaning. The structural variables and chemical composition of the pasture were evaluated during the usage period. Grass height and forage mass were higher when the ewes were in the gestation and weaning stages. The leaf mass was not altered during the pasture usage with a mean value of 566.1kg ha-1 DM. The highest levels of crude protein in the leaf blade were observed during the parturition and weaning phases. The body weight of the ewes did not differ between the sources with averages 45.0, 39.9 and 36.6kg for the gestation, parturition and weaning phases, respectively. Weights at birth and at weaning had an effect from protein sources, with the highest values observed in the lambs of ewes who received soybean meal and babassu cake supplementation. The lambs of ewes supplemented with soybean had higher average daily gain and total gain. Babassu, coconut and cotton cakes can replace soybean meal in supplementation of ewes in deferred pasture.

Physiological responses and forage accumulation of Marandu palisadegrass and Mombaça guineagrass to nitrogen fertilizer in the Brazilian forage‐based systems

AbstractIn Brazil, the livestock systems are mainly forage‐based, and nitrogen inputs are an uncommon practice, despite its great benefits. The objective was to evaluate the effect of nitrogen input on the physiological responses of Marandu palisadegrass (Urochloa brizantha [Hochst. ex A. Rich.] R. D. Webster) and Mombaça guineagrass (Megathyrsus maximus [Jacq.] B. K. Simon & S. W. L. Jacobs), and its impacts on the forage accumulation rate (FAR). The experiment was carried out in Sinop, MT, Brazil, in a randomized block design with a 2 × 2 × 5 factorial arrangement (two cultivars: Mombaça and Marandu; unfertilized and fertilized [50 kg N ha−1 cycle−1]; and five seasons: autumn 2015, winter 2015, spring 2015, summer 2015 and autumn 2016) with three replicates. The experimental period was from March 2015 to June 2016, when plots were harvested to mimic intermittent stocking. Fertilized Mombaça presented greater FAR pastures (74.0 kg DM ha−1 day−1) than unfertilized (26.6 kg DM ha−1 day−1) and Marandu fertilized (52.5 kg DM ha−1 day−1), with the greatest values during the summer (147.6 kg DM ha−1 day−1). The greatest leaf (A) and canopy photosynthesis (CP) rates occurred on fertilized pastures during the summer 2015 and autumn 2015. Marandu presented 19% greater A than Mombaça. During the winter, under water stress, Marandu had greater water use efficiency (WUE). However, during the summer 2015 and autumn 16, Mombaça had the greatest WUE (12.76 μmol CO2/mol H2O). In all seasons, Marandu presented the greatest chlorophyll index, which may support the greatest photosynthetic rates. It was concluded that Mombaça was highly responsive to nitrogen input during the rainy season with accumulation over 140 kg DM ha−1 day−1 and is recommended to intensified systems. Marandu had the greatest WUE in the lower precipitation seasons and is an alternative to a year‐round strategy in forage‐based systems.

Spittlebug damage on tropical grass and its impact in pasture-based beef production systems

Spittlebugs are the main pest of tropical pastures and Marandu palisade grass (Urochloa brizantha cv. Marandu) is the most representative cultivated pasture in the tropics. Our objective was to characterize Marandu palisade grass responses subjected to Mahanarva (Hemiptera: Cercopidae) attack and to estimate the losses in terms of beef production from pasture-based systems. A set of five experiments were carried out. Three consecutive years of monitoring showed that Mahanarva spittlebugs increased their abundance after first rains with three to four peaks throughout the wet season. A decrease of 66% on herbage yield was observed in the greenhouse trial, with an average decrease of 61% on pools of calcium, magnesium, phosphorus, sulfur, potassium, crude protein, neutral-detergent fiber and in vitro digestible dry matter of Marandu palisade grass. Results from field experiments corroborated with greenhouse trial showing decreases on herbage yield varying from 31 to 43% depending on level of fertilization and grazing severity of Marandu palisade grass. Finally, an unprecedented 154-ha field experiment indicated that Mahanarva decreases 74% the beef productivity (i.e. kg body weight ha−1) of Nellore heifers grazing Marandu palisade grass.

The effect of spray solution storage time on nicosulfuron efficacy applied in Urochloa brizantha cv. Marandu

Nicosulfuron is the commonly used herbicide for the control of annual weeds and broadleaf weed species in maize production. However, little is known about the length of time nicosulfuron can remain in the spray tank prior to application in the field without impacting efficacy. The objective of this study was to evaluate the effect of different storage times of the nicosulfuron spray solution on phytotoxicity, production and physiology of Marandu palisadegrass [Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster cv. Marandu]. The experiment was analyzed in a 6 × 5 factorial arrangement with a complete randomized design. The treatments were six storage times of the nicosulfuron spray solution (0, 6, 12, 24, 48 and 72 h) applied in the Marandu palisadegrass, and five evaluation periods (0, 7, 14, 21 and 60 days after application). Phytotoxicity by the nicosulfuron in the Marandu palisadegrass had parabolic pattern as a function of the interaction between storage time and evaluation period. The photosynthetic rate decreased as a function of the days after nicosulfuron application and showed a discrete increase as a function of the spray solution storage time. Nicosulfuron solution acidifies with time and the effects on phytotoxicity decreased by 30% after 72 h.

Parameterization of the APSIM model for simulating palisadegrass growth under continuous stocking in monoculture and in a silvopastoral system

Sustainable intensification of livestock production systems has become a global demand. In silvopastoral systems, contrasting shading levels caused by the presence of trees interferes in the productive responses of the pasture under grazing. The environment in which plants develop in a pasture canopy is dynamic and complex due to the nature of soil-plant-animal interactions. These dynamic aspects can be rationalized, evaluated, and explained using mathematical modeling. The objective of the present study was to parameterize the APSIM-Tropical Pasture model to simulate palisadegrass [Brachiaria brizantha (Hochst A Rich) Stapf, syn. Urochloa brizantha] growth under continuous stocking and variable stocking rate, in a full sun system and in contrasting shading conditions of a silvopastoral setting with eucalyptus (Eucalyptus grandis W. Hill ex Maiden × Eucalyptus urophylla S. T. Blake). Trees were planted in triple-row groves, with three groves per 2-ha silvopasture area. The spacing between groves was 30 m, and tree density was 135 ha−1, in East-West orientation. The data used to calibrate and validate the model were collected in a 36-month experiment with full sun and shade treatments of the silvopastoral setting in Sinop, MT, Brazil. Live forage mass estimates had coefficient of determination varying between 0.76 and 0.94, Willmott agreement index ranged from 0.93 to 0.96, and root mean square error between 275 and 610 kg DM ha−1. The APSIM-Tropical Pasture model can simulate Marandu palisadegrass growth under continuous stocking with variable stocking rate, but improvements are needed to better simulate the effect of N fertilizations in different periods on growth. The model can simulate pasture growth under shading levels but our simulations did not consider competition for soil moisture, which should be considered in the future, since it can be an important factor for other silvopastoral designs or microclimatic conditions.

Nitrous oxide emissions and forage accumulation in the Brazilian Amazon forage‐livestock systems submitted to N input strategies

AbstractIn the Brazilian Amazon, nitrogen input strategies are required to maintain forage–livestock systems productivity. However, greenhouse gases (GHG) emissions mitigation from tropical soils is also a global demand. This research aims to assess productivity and nitrous oxide (N2O) emissions from Oxisol cultivated with Marandu palisade grass (Brachiaria brizantha [Hochst. Ex A.Rich.] Stapf) submitted to nitrogen (N) input strategies (N fertilization and biological N fixation) in the Brazilian Amazon. The treatments were the following: control (unfertilized); U40 (fertilized with 40 kg N/ha as urea); U80 (fertilized with 80 kg N/ha as urea); AS40 (fertilized with 40 kg N/ha as ammonium sulfate); AS80 (fertilized with 80 kg N/ha as ammonium sulfate); and IAB (inoculated with Azospirillum brasilense). From January to March 2016, soil N2O emission, forage accumulation (FA) and relative emission (RE) were assessed during two 28‐day cycles. The FA was greater in the U80 and AS80 than in control and IAB. The highest peaks of soil N2O flux occurred from 4 to 7 days after N fertilization, primarily in the highest N rates treatments. Overall, 40 kg N/ha resulted in higher N2O flux than control and IAB, which were lower than 80 kg N/ha regardless of the N source. The lowest fluxes occurred in the control and IAB (below 20 μg N‐N2O m−2 hr−1). All of the emission factors (EF) calculated for both fertilizers and rates were lower than 0.35%, which is below the 1% established by the IPCC. Our results indicate the need for discussion of the EF in the pasture intensification to contribute to avoid deforestation and mitigating emissions. The inputs of 40 kg N/ha per application with urea or ammonium sulfate, due to the low EF and RE, are recommended as a pasture N input strategy in the Brazilian Amazon.

Herbage accumulation, nutritive value and beef cattle production on marandu palisadegrass pastures in integrated systems

Diversification of monoculture grass pastures may provide opportunity for increased productivity, efficiency, and sustainability of forage-livestock systems. Our objective was to compare herbage accumulation (HA), nutritive value, and animal performance on a grass monoculture control and two alternative systems, all based on ‘Marandu’ palisadegrass [Brachiaria (syn. Urochloa) brizantha (A. Rich.) Stapf] in the Amazon Biome. Alternatives were a crop-livestock system based on soybean [Glycine max (L.) Merr.] and palisadegrass, and a eucalyptus [Eucalyptus urograndis (hybrid of E. grandis W. Hill ex Maiden and E. urophylla S. T. Blake) clone H13]-palisadegrass silvopasture. From July 2017 to May 2018 all experimental units were stocked continuously with beef cattle using a variable stocking rate to maintain a palisadegrass canopy height of 30 cm. The grass monoculture and silvopasture systems had similar HA (13,200 kg dry matter [DM] ha−1) and herbage accumulation rate (HAR; 40 kg DM ha−1 day−1), whereas crop-livestock resulted in greater HA (127%) and HAR (158%) than the other systems. Animal weight gain ha−1 for crop-livestock was 860 kg, 15% greater than for grass monoculture and silvopasture systems (average of 750 kg). Greatest palisadegrass HA and animal performance following 2 years of soybean production support the crop-livestock as an alternative for sustainable intensification. The similar HA and gain ha−1 in the seventh year of the silvopasture and grass monoculture indicates tree-pastures systems need wider arrangements to warrant long-term productivity. The maintenance of soil fertility, appropriate grazing management, and animal nutritional supplementation can greatly improve forage-based systems in the Amazon Biome.

Beef cattle responses to pre-grazing sward height and low level of energy supplementation on tropical pastures.

The objective of this study was to investigate the effects of energy supplementation and pre-grazing sward height on grazing behavior, nutrient intake, digestion, and metabolism of cattle in tropical pastures managed as a rotational grazing system. Eight rumen-cannulated Nellore steers (24 mo of age; 300 ± 6.0 kg body weight [BW]) were used in a replicated 4 × 4 Latin square design. Treatments consisted of two levels of energy supplementation (0% [none] or 0.3% of BW of ground corn on an as-fed basis) and two pre-grazing sward heights (25 cm [defined by 95% light interception (LI)] or 35 cm [defined by ≥ 97.5% LI]) constituting four treatments. Steers grazed Marandu Palisadegrass [Brachiaria brizantha Stapf. cv. Marandu] and post-grazing sward height was 15 cm for all treatments. Forage dry matter intake (DMI) was increased (P = 0.01) when sward height was 25 cm (1.86% vs. 1.32% BW) and decreased (P = 0.04) when 0.3% BW supplement was fed (1.79% vs. 1.38% BW). Total and digestible DMI were not affected by energy supplementation (P = 0.57) but were increased when sward height was 25 cm (P = 0.01). Steers grazing the 25-cm sward height treatment spent less time grazing and more time resting, took fewer steps between feeding stations, and had a greater bite rate compared with 35-cm height treatment (P < 0.05). Energy supplementation reduced grazing time (P = 0.02) but did not affect any other grazing behavior parameter (P = 0.11). Energy supplementation increased (P < 0.01) diet dry matter digestibility but had no effect on crude protein and neutral detergent fiber digestibilities (P = 0.13). Compared with 35-cm pre-grazing sward height, steers at 25 cm presented lower rumen pH (6.39 vs. 6.52) and greater rumen ammonia nitrogen (11.22 vs. 9.77 mg/dL) and N retention (49.7% vs. 20.8%, P < 0.05). The pre-grazing sward height of 25 cm improved harvesting efficiency and energy intake by cattle, while feeding 0.3% of BW energy supplement did not increase the energy intake of cattle on tropical pasture under rotational grazing.

In vitro ruminal fermentation parameters and methane production of Marandu palisadegrass (Urochloa brizantha) in a silvopastoral system associated with levels of protein supplementation

AbstractThe addition of protein supplementation in a silvopastoral system can contribute to improved forage intake and digestibility. Our objective was to evaluate in vitro ruminal parameters, digestibility and gas production of Marandu palisadegrass [Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster] in a silvopastoral system and compare this to parameters obtained from diets with protein supplementation. Forage was sampled during the growing season (November to April) in 2016/17 and 2017/18. In vitro incubation treatments consisted of four levels of protein supplement (20% of crude protein; CP) in the diet (0.1, 0.2, 0.3 and 0.4 g/kg of body weight). The neutral detergent fibre, acid detergent fibre and indigestible neutral detergent fibre concentrations were highest in the first year. In the second year, CP concentration was 21% greater than in the first year. There was a linear increase for digestion rate, a quadratic effect for lag time and a linear decrease for average digestion time as supplementation levels were increased. The least lag time and digestion time occurred in the second year. There was no supplementation effect on ruminal pH, acetate and butyrate concentrations. Second‐year in vitro dry matter digestibility (IVDMD) was greater than in the first year. Increases in supplementation levels linearly enhanced IVDMD and reduced methane (CH4) production. The inclusion of a protein supplement contributed to reduced CH4 and increased volatile fatty acids production; therefore, we recommended the supplement inclusion of &gt;0.28 g/kg of BW for animals grazing in well‐managed palisadegrass pastures.

Initial height and nitrogen fertilisation on deferred pastures of marandu palisadegrass

In deferred pastures, nitrogen fertilisation and pasture height at the beginning of the deferment period modify the structure and nutritive value of forage. This work was conducted to determine the nitrogen (N) doses and sward heights that were adequate for the deferment of Brachiaria brizantha cv. Marandu syn. Urochloa brizantha cv. Marandu (marandu palisadegrass). Two sward heights (15 and 30 cm) and four N rates (0, 40, 80,120 kg/ha) at the beginning of the deferment period were evaluated in a randomised block design and a factorial scheme with three replications. At the end of the deferment period, the numbers of live and dead tillers, the numbers of tillers with different sizes, the masses of live leaf lamina, dead leaf lamina, live stem and dead stem, the litter mass and the crude protein and neutral detergent fibre contents of the forage were evaluated. With nitrogen fertilisation, there was an increase in the masses of live leaf and live stem in the deferred canopy. With the application of 80 kg/ha of N, the litter mass was higher in the deferred canopy with a height of 30 cm, in relation to that with a height of 15 cm. The highest canopy presented greater stem mass and worse nutritional value when compared to the lowest one. In order to improve forage characteristics, marandu palisadegrass can be deferred by 15 cm and fertilised with 80 kg/ha N. When marandu palisade grass is deferred to 30 cm, nitrogen doses lower than 80 kg/ha can be applied.

Unravelling the relationship between a seasonal environment and the dynamics of forage growth in grazed swards

AbstractIt is well reported in the scientific literature that pastures can have similar net forage accumulation when managed with contrasting structures. However, we hypothesized that the dynamics of forage accumulation in grazed swards is linked to seasonal‐environmental conditions. Marandu palisadegrass (Brachiaria brizantha [Hochst. ex A. Rich.] was used as the forage species model. The experimental treatments were four grazing heights (10, 20, 30 and 40 cm) allocated to experimental units according to a randomized complete block design with four replicates and evaluated throughout four contrasting environmental seasons (summer, autumn, winter–early spring and late spring). Under rainy and warm periods, greater net forage accumulation was observed in pastures maintained taller; on the contrary, during the mild and dry periods, net forage accumulation rate reduced as grazing height increased. Such patterns of responses were related to compensations between tiller population density and tissues flows during summer and late spring and the reduced capacity of taller canopies to compensate lower population with greater growth rates during autumn and winter–early spring. Grazed swards changed their patterns of forage growth as they transitioned from favourable to more abiotic stressful conditions, suggesting that seasonal adjustments in grazing intensities are necessary in order to maximize forage production.

Tillering and characterisation of tillers on marandu palisadegrass deferred and fertilised with nitrogen

Evaluations of tillering dynamics and characteristics of the individual tillers allow the changes that occur in the growth and structure of the deferred and nitrogen (N) fertilised pasture to be understood. This work was carried out to evaluate the tillering and morphological characteristics of basal tillers in deferred canopies of Brachiaria brizantha syn. Urochloa brizantha cv. Marandu (marandu palisadegrass) submitted to two N doses (50 and 200 kg ha-1). The evaluations were carried out at the beginning, middle and end of the deferment period. The experimental design was completely randomised in split-plot design with four replications. Tiller appearance rate (TAR) was higher at the beginning than in the middle and at the end of the deferment period, contrary to that observed for the number and weight of the tiller. Tiller mortality rate (TMR) was higher at the end than at the beginning and in the middle of the deferment period. The tiller population stability index (SI) was similar at the beginning and middle, but lower at the end of the deferment period. The leaf area of the tiller was higher in the middle compared to at the beginning and end of deferment. N dose did not influence TAR, TMR and SI. The canopy fertilised with 200 kg ha-1 of N presented a higher number and weight of tiller compared to the canopy fertilised with 50 kg ha-1 of N. The N increases the number and weight of tillers, but does not change tillering dynamics during the deferment period for marandu palisadegrass. The tillering decreases and the morphological composition of the tiller worsens with the increase in the deferment period in marandu palisadegrass.

Microclimate effects on canopy characteristics of shaded palisadegrass pastures in a silvopastoral system in the Amazon biome of central Brazil

Abstract Forage grass canopies may be affected by the shaded microclimate in silvopastoral (SP) systems throughout the year. This in turn may affect forage plant characteristics. Our objective was to assess microclimate effects on the responses of Marandu palisadegrass {Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster [syn. Brachiaria brizantha (Hochst. ex A. Rich.) Stapf.]} under continuous stocking in an SP system with Eucalyptus urograndis (hybrid of Eucalyptus grandis W. Hill ex Maiden and Eucalyptus urophylla S. T. Blake). Trees were planted in triple rows (grove), with three groves per 2-ha silvopasture experimental unit (11° 51′ S, 55° 35′ W). The spacing between groves was 30 m, and tree density was 135 ha–1, in East-West orientation. Microclimate and forage plant variables were evaluated from December 2016 to March 2018 in the treatments consisting of “full sun” (FS) grass monoculture pasture and at three distances from the grove: 7.5 m North (7.5 N), 15 m (15), and 7.5 m South (7.5S). Photosynthetically active radiation (PAR) was greatly affected and positively associated with most of the responses of Marandu palisadegrass. On average, PAR reduction in relation to FS was 8, 24, and 40 % for 15, 7.5 N, and 7.5S, respectively. The greatest maximum temperatures (35.8 °C) and the least minimum temperatures (15.8 °C) were registered during the Winter. Both forage accumulation rate (∼ 45 kg ha−1 d-1) and leaf accumulation rate (∼ 19 kg ha-1 d-1) were similar between FS and 7.5S (most shaded distance). Shade tolerance mechanisms of palisadegrass under grazing were associated with increases in specific leaf area and leaf proportion, allowing shaded pastures to sustain productivity at levels equivalent to those of pastures without shade.

The morphogenesis of marandu palisadegrass at fixed or variable heights in different seasons of the year

Height variations in a sward over the year may be efficient for increasing plant growth, compared with maintenance of the sward at a constant height. Thus, this experiment was conducted from February 2013 to May 2014 to characterise the development of Urochloa brizantha syn. Brachiaria brizantha cv. Marandu (marandu palisadegrass), managed under three defoliation strategies: constant height (30 cm during the entire experimental period), increasing height (15 cm in the winter, 30 cm in the spring, and 45 cm in the summer), and decreasing height (45 cm in the winter, 30 cm in the spring, and 15 cm in the summer). The experimental design was completely randomised, in a split-plot arrangement, with four replicates. Phyllochron was higher in the winter, but leaf and stem elongation rates and the number of live leaves per tiller were lower compared with the spring and summer. In the summer, the swards under increasing height displayed a higher phyllochron than those under decreasing and constant height. When comparing seasons, the highest leaf senescence rate occurred in spring. In the winter, the sward with increasing height had shorter leaves and stems, in contrast to the summer. The sward under decreasing height showed a high stem elongation rate in the spring. Marandu palisadegrass has great flexibility in terms of defoliation management and a typical seasonal development pattern. Modifying the sward height results in a gradual change in the development of marandu palisadegrass and generates residual effects on the subsequent season.

Number and morphology of tiller age groups during summer in Marandu palisadegrass pastures previously used under deferred grazing

The relative contribution of young, mature and old tillers in the canopy influences the production and structure of the pasture. The objective with this work was to evaluate the balance between tiller appearance and tiller death (BAL) during spring and early summer, the morphology and percentages of young, mature and old tillers in Brachiaria brizantha cv. Marandu (marandu palisadegrass) with three conditions in late winter: short (24.1 cm), tall (49.0 cm) and tall (50.0 cm)/mown (8 cm). Tall and tall/mown pastures presented higher BAL in September and October, respectively. In January, BAL was higher in short and tall/mown pastures than in tall pasture. The tiller number was higher in short pasture, intermediate in tall/mown pasture and lower in tall pasture. The percentage of old tillers was higher in short and tall pastures compared to tall/mown pasture. The percentage of live leaf lamina reduced, while the percentage of dead leaf lamina increased with tiller age. Mowing of the tall marandu palisadegrass pasture in late winter increases the renewal of tillers in the spring and decreases the percentage of old tillers in the summer. The old tillers present worse morphology than young tillers.

Seasonal alteration in sward height of Marandu palisade grass (Brachiaria brizantha) pastures managed by continuous grazing interferes with forage production

Changes in sward height of pastures managed by continuous grazing according to climatic seasonality may alter tillering and forage production. In order to evaluate the feasibility of seasonal alteration in sward height of Marandu palisade grass pastures (Brachiaria brizantha (Hochst. ex A.Rich.) R.D. Webster; syn. Urochloa brizantha (A.Rich.) Stapf) under continuous grazing management, we studied two constant sward heights (15 cm and 30 cm), and one height that was initiated at 30 cm, reduced to 15 cm in June (dry and cold season) and returned to 30 cm in December (wet and hot season) (30–15–30 cm). Pastures managed at 30–15–30 cm had a greater tiller appearance rate (22 tillers/100 tillers.30 days) than those maintained at 15 cm and 30 cm (16 and 17 tillers/100 tillers.30 days, respectively). In the 30–15–30 cm pastures, a lower accumulation rate of dead material was observed during the dry and cold season (June–August), which resulted in a higher leaf and lower dead material accumulation rate during the second growth season (wet and hot season, December–January). Planned reduction in sward height during the cold season can be used safely because it permits better seasonal distribution and utilisation of forage production without compromising the stability of Marandu palisade grass pastures.

Climate risk and seasonal forage production of Marandu palisadegrass in Brazil.

This study aimed to characterize Brachiaria brizantha cv. Marandu seasonal production (seasonality) and its variation (climate risk) yearlong throughout Brazil. Data from weather stations in Brazil (1963-2009), were associated with an empirical herbage accumulation rate (HAR; kg DM ha-1 day-1) model which considers growing degree-days adjusted by a drought attenuation index. Simulations were performed under 20, 40, 60 and 100 mm of soil water holding capacities (SWHCs). HAR's means and standard deviations were calculated for the seasons of the year. Thereafter, cluster analysis and calculations were performed to gather similar weather stations and characterize seasonality and climate risk indexes. Cluster analysis resulted in four Groups per SWHC. The north of Brazil (Group 1) presented the lowest seasonality and climate risk indexes and low need for precautions. In the middle west (Group 2), the seasonality index ranged from medium-high to high. Winter and Summer presented the lowest and highest production, respectively. In the south of Brazil, some regions in the southeast and northeast (Group 3), Winter presented the lowest production and highest climate risk index, probably due to low temperatures. The northeast (Group 4) presented a seasonality index that ranged from medium-high to very high and low productions.

PSIV-B-27 Late-Breaking: Effects of grazing management and nitrogen fertilization on Marandu palisade grass production in silvopastoral systems

Abstract Integrated systems have been gaining prominence in recent years, especially the crop-livestock-forestry, which, in addition to being an alternative income per area, increase fertility and organic matter content in the soil, and protect animals against weather conditions. However, there is still a lack of knowledge about the management of pastures under such conditions. Therefore, the aim of this research was to evaluate the grazing management and nitrogen fertilization in Marandu palisade grass consorted with Eucalyptus to obtain the greater of forage production. The experimental design was a randomized block, arranged in split-plot, the plots were composed of two eucalyptus spacing (12 x 2 or 12 x 3) and Marandu monoculture, the subplots were composed of the nitrogen fertilization rate (0, 100, 200 kg N/ha using ammonium sulfate). The higher DM accumulation rate was observed at 200 kg N ha-1 (69.29 kg DM ha-1 day), while there was no difference between the treatments without fertilization and 100 kg N ha-1 (P &amp;gt; 0.001). DM accumulation rate increased by 30.01% when fertilization increased from 100 kg N ha-1 to 200 kg N ha-1. Marandu palisade grass with 200 kg N ha-1 showed the highest production (28.82 t ha-1) independent of spacing. In the silvopastoral system, the greater accumulation of forage was observed when handled with 80% of the light interception (LI), corresponding to a height of 67 cm. Therefore, we conclude that Marandu grass in a silvopastoral system, without N fertilization, should be managed with a pre-grazing height of 60 cm and 73% LI. Marandu grass in a silvopastoral system, with 100 kg N ha-1 fertilization, should be managed with a height of 68 cm and 84% LI, and, with 200 kg N ha-1, should be managed at 80% of LI for the greater pasture utilization and development.

What is the maximum nitrogen in marandu palisadegrass fertilization?

AbstractThe absence of nutrient replacement, especially nitrogen (N), is one of the main causes of grazing system underutilization and tropical climate pasture degradation. Therefore, N is a very important nutrient in the pasture maintenance; however, it is necessary to know the maximum limit to be used of this nutrient, since fertilization increases production cost. Thus, the objective of this study was to identify the N dose that provides the highest production of marandu palisadegrass (Brachiaria brizantha cv. Marandu), and the fertilization effect on pasture degradation process and forage nutritive value. Treatments consisted in the application of : 0 (control), 25, 50, 75 and 100 kg N ha−1 cycle−1 of regrowth. The evaluations were carried out during the summers (November to April) of 2015/2016 and 2016/2017. The highest dry matter yield (DMY) and forage accumulation rate (FAR) occurred between doses of 50 and 75 kg ha−1 cycle−1, with no change in productive potential at higher doses. The reduction in mineral content and the increase in crude protein (CP) are the main changes in the nutritional value of marandu palisadegrass, with no pronounced effect on in vitro dry matter digestibility (IVDMD), indigestible neutral detergent fiber (iNDF) and potentially digestible dry matter proportions of CP in the cell wall (CPCW) and in cellular content (CPCC).The productive effect of nitrogen fertilization under marandu palisadegrass is the increase in DMY and FAR. Thus, the use of nitrogen fertilizers in pasture systems with marandu palisadegrass has a greater impact on the area gain than the individual gain, assuming these systems, the use of nitrogen doses of 50 to 75 kg ha−1 cycle−1.

Forage and animal production on palisadegrass pastures growing in monoculture or as a component of integrated crop–livestock–forestry systems

AbstractTo meet the global demand for animal protein, sustainable intensification of existing livestock systems may be possible, especially through integration of livestock with crops or forestry. Thus, our objective was to compare forage production and animal performance in grass monoculture and integrated systems in the Brazilian Amazon biome. The four systems were (a) livestock (L) with Marandu palisadegrass {Brachiaria brizantha (Hochst. ex A. Rich.) R. D. Webster} as monoculture, (b) palisadegrass pastures integrated with eucalyptus trees (Eucalyptus urograndis; hybrid of Eucalyptus grandis W. Hill ex Maiden and Eucalyptus urophylla S. T. Blake) arranged in three‐row groves with groves spaced 30 m apart (livestock–forestry; LF), (c) palisadegrass after two years of crops (crop–livestock; CL) and (d) palisadegrass after two years of crops with single rows of eucalyptus trees spaced 37 m apart (crop–livestock–forestry; CLF). From July 2016 to July 2017, all experimental units were continuously stocked using a variable stocking rate. Greater herbage accumulation (HA) occurred in CL and CLF in comparison with L and LF (21,310, 24,050, 19,500 and 18,890 kg DM/ha respectively). The gain per hectare of L, LF and CL (average of 932 kg ha–1) was less than CLF (1,190 kg ha–1). Average daily gain was similar among systems (0.69 kg/day). We conclude that integrated systems can support similar (LF or CL) or greater (CLF) levels of animal production than palisadegrass monocultures while increasing diversity of outputs, thereby providing a greater range of viable systems for livestock production in the Brazilian Amazon biome.