Brachiaria sp. grasses are widely used in planted pastures in Brazil. ‘Mulato II’ is a productive Brachiaria hybrid (B. ruziziensis × B. decumbens × B. brizantha) with high nutritive value, but it has not been evaluated under continuous stocking in Brazil, despite this method being widely used by producers. The objectives of this research were to quantify the effects of three canopy heights (10, 25, and 40 cm), maintained by mimicking continuous stocking, and two N rates (50 and 250 kg ha–1 yr–1) on herbage accumulation (HA), grazing efficiency (GE), and nutritive value of Mulato II during two summer rainy seasons in Piracicaba, Brazil. The N rates were chosen so that canopy height effects could be evaluated under distinctly different grass growth rates. Grass HA increased linearly (8640 to 13,400 kg DM ha–1 yr–1), in vitro digestible organic matter (IVDOM) decreased linearly (652 to 586 g kg–1), and GE decreased (linear and quadratic; 65 to 44%) as canopy height increased. There were no height × N rate interactions for these responses. Mulato II was less productive (7940 vs. 13 380 kg ha–1 yr–1) and had lesser IVDOM (581 vs. 652 g kg–1) at the lower N rate. Thus, although GE and IVDOM were greatest for 10 cm, HA was 36% less for the 10‐ than the 40‐cm height, and despite greatest HA occurring at 40 cm, both GE and IVDOM were greater at shorter heights. These data suggest that ∼25‐cm canopy height is optimal for continuously stocked Mulato II.

Grasses within the Cynodon genus are widely used perennial forages, and ‘Tifton 85’ (Cynodon spp.) is one of the most popular commercial cultivars. Jiggs and Vaquero are new C. dactylon (L.) Pers. grasses, but there is little information comparing their performance with Tifton 85 under tropical conditions. The objectives were to describe and explain variation in seasonal herbage accumulation (HA) and nutritive value of irrigated Tifton 85, Jiggs, and Vaquero bermudagrasses in response to harvest frequency (14, 28, and 42 d). The trial was performed for 2 yr in Piracicaba, Brazil, on a Kandiudalfic Eutrudox soil. In the warm season, total HA of Jiggs was similar to Tifton 85, and both were more productive than Vaquero. Under the 42‐d frequency, Jiggs had greater annual HA than the other grasses (28.5 vs. 23.7 and 20.1 Mg ha−1, for Tifton 85 and Vaquero, respectively), but when harvested every 28 d, Tifton 85 and Jiggs HA were similar (18.5 Mg ha−1). For the 42‐d harvest interval in the cool season, Jiggs had the greatest HA (10.2 Mg ha−1). Less frequent harvests in both seasons resulted in greater HA. Tifton 85 had a greater proportion of leaves than Jiggs and greater in vitro digestible organic matter (IVDOM) than the other grasses in the warm season. Considering these responses, harvest frequency of Jiggs and Tifton 85 should be ∼28 d in the warm season, while that of Vaquero should be ∼42 d. No single harvest management will be appropriate for all Cynodon grasses.

Improved grazing management can increase the output of many tropical forage–livestock systems. Adjusted grazing management techniques have been proposed for producers that are willing to exploit the growth potential of available forage resources. The objective of this research was to describe and explain variations in herbage accumulation dynamics and organic reserves of cultivar Xaraés palisadegrass [Brachiaria brizantha (Hochst. ex A. Rich.) Stapf syn. Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster] under three grazing managements during spring and summer growing seasons of 2 yr. Pastures were grazed every 28 d (28‐d) or at intervals defined by two levels of pre‐graze canopy light interception (LI). These LI‐based treatments are referred to as “target grazing” (TG) at 95% LI and “delayed grazing” (DG) at ≥ 97.5% LI. Pastures managed using TG and 28‐d showed a similar herbage accumulation rate (HAR) (112 kg DM ha–1 d–1) (P > 0.05), both lesser than DG (141 kg DM ha–1 d–1). Although TG and 28‐d showed similar daily HAR, stem proportion in the stubble was more variable for 28‐d over the growing season. Stem proportion in the stubble was greater for DG (43.8%) and 28‐d (40.4%) than for TG (34.2%). The TG management showed greater total non‐structural carbohydrate (TNC) pools in roots (238 g m–2) than DG (136 g m–2) and 28‐d (199 g m–2), suggesting less dependency of organic reserves. The TG was optimal strategy for intensive grazing management of Xaraés palisadegrass pastures.

Long-term stand persistence is a desirable characteristic of sustainable grassland ecosystems, and tillering dynamics is an important determinant of persistence. Grazing intensity and nutrient supply affect tiller density, weight, and survival. Understanding the relationships among these factors can help optimize performance of grazed pastures. The objective of this research was to determine the effects of canopy height (10, 25, and 40 cm; maintained under mimicked continuous stocking) and N fertilization (50 and 250 kg ha −1 yr −1 ) on the tiller dynamics and canopy stability index (SI) of 'Mulato II' hybrid brachiariagrass (Brachiaria spp. syn. Urochloa spp.) during two growing seasons. Tiller population density (TPD) increased by 9% with greater N fertilization and decreased linearly from 1,130 to 900 tillers m −2 as canopy height increased from 10 to 40 cm. Tiller weight (TW) increased from 0.39 to 1.46 g as canopy height increased from 10 to 40 cm, but TW decreased by 9% with a greater N rate. Tiller appearance rate increased by 30% and tiller survival rate (TSR) decreased by 13.5% as N rate increased. The TSR was greater for 25-and 40-cm than for 10-cm canopies (81, 82, and 74 tillers per 100 tillers per 30 d, respectively). The SI increased from 0.91 to 1.0 with increasing canopy height from 10 to 40 cm. Mulato II canopies followed the tiller size-density compensation mechanism, displaying phenotypic plasticity in response to canopy height, but these results suggest a 25-cm canopy height is near optimal for continuously stocked Mulato II brachiariagrass pastures.

Pasture management, including the control of grazing intensity and fertilization, can trigger plant physiological and morphological responses that affect plant growth and impact stand persistence. The objective of this research was to quantify the effects of three canopy heights (10, 25, and 40 cm), maintained by mimicking continuous stocking, and two N rates (50 and 250 kg ha−1 yr−1) on canopy carbon exchange rate (CER), plant‐part accumulation, and organic reserves of ‘Mulato II’ brachiariagrass hybrid (Brachiaria brizantha × B. decumbens × B. ruziziensis), also known as Convert HD 364 (Dow AgroSciences, São Paulo, Brazil) during two summer rainy seasons in Piracicaba, Brazil. Leaf CER was greater for the 10‐cm height, but canopy CER, plant‐part accumulation, root mass, and root reserves were less in 10‐ than 40‐cm canopies, although this was not associated with stand deterioration after 2 yr. Leaf was the predominant plant part, and leaf accumulation rate increased linearly from 70 to 100 kg dry matter (DM) ha−1 d−1 as canopy height increased from 10 to 40 cm. Increasing N rate from 50 to 250 kg N ha−1 yr−1 affected plant growth, increasing CER, leaf area index, and the rates of leaf, stem, and dead herbage accumulation. The senescence‐to‐growth ratio (S:G) was not affected by N rate, indicating that the increase in rate of dead material accumulation with greater N rate was a result of an increase in the accumulation rates of all plant parts. Taller canopy heights (25 or 40 cm) are recommended for Mulato II under continuous stocking.

Growth analysis of forage crops allows integration of photosynthesis, respiration, and allocation of photosynthate from estimates of physiological and morphological indices. These measurements help explain differences in growth potential between plants across seasons and in response to harvest management. The objective was to describe and explain patterns of growth of ‘Tifton 85’ (Cynodon spp.) and Jiggs [C. dactylon (L.) Pers.] bermudagrasses to three harvest frequencies (14, 28, and 42 d) during 2 yr. Grasses showed different growth patterns during the cool and warm seasons. Crop growth rate (CGR) was similar during the warm season (69 kg ha–1 d–1), but Jiggs had greater relative growth rate (RGR) and lesser stubble mass and residual leaf mass. Jiggs had greater net assimilation rate (NAR) than Tifton 85 during the warm (14.2 vs. 11.4 kg dry matter [DM] m–2 d–1, respectively) and cool seasons (6.9 vs. 2.5 kg DM m–2 d–1, respectively). Tifton 85 partitioned more biomass to leaf than Jiggs (leaf weight ratio [LWR] of 0.35 vs. 0.28 kg kg–1). The 14‐d harvest frequency reduced CGR, RGR, and NAR of both grasses. Small changes in RGR occurred beyond 28 d of regrowth, but leaf area ratio (LAR) and LWR decreased, suggesting that grasses should be harvested ∼ every 28 d during the warm season. Longer regrowth periods during the cool season increased both CGR and RGR. Harvest management affects differently the growth and morphological components of Jiggs and Tifton 85 in this environment.

Understanding seasonal changes in herbage accumulation (HA) and canopy characteristics of tropical grasses aids management of forage-livestock systems and optimizes use of novel cultivars in traditional and integrated systems. The objective of this study was to describe and explain seasonal HA and canopy characteristics of three standard brachiariagrass cultivars in southeastern Brazil under conditions of N fertilization and irrigation: 'Basilisk' signalgrass [Brachiaria decumbens (Stapf.); syn. Urochloa decumbens (Stapf) R. D. Webster]; two commercially released palisadegrass [B. brizantha (Hochst. Ex A. Rich.) Stapf.; syn. U. brizantha (Hochst. ex A. Rich.) R. D. Webster] cultivars, Marandu and Xaraés; and unreleased selections of palisadegrass, Arapoty and Capiporã. Grass plots were mechanically harvested every 28 d during the warm season and every 42 d during the cool season to 15-cm stubble starting in September 2005 and ending in September 2008. Capiporã and Xaraés were the most productive (15.6 and 14.6 Mg dry matter [DM] ha −1 , respectively) despite having greater seasonality of growth. Arapoty did not show advantages over the cultivars Basilisk and Marandu, with similar total annual HA (∼11 Mg DM ha −1). Arapoty and Basilisk forage averaged 50% more stems than the other grasses in the warm season. Leaf area index (LAI) and light interception (LI) at harvest did not vary among grasses in Year 1, with an average of 3.1 and 90.3%, respectively, and were generally greater for Marandu in Year 2. Capiporã and Xaraés are options for intensive pasture-based livestock production systems and for pasture diversification in tropical areas because of their good HA with great leaf proportion.

Understanding the effects of grazing management on tillering dynamics of forage grasses may help identify management practices that optimize pasture production, stability, and ultimately, persistence. The objective of this research was to evaluate the effects of two grazing frequencies (regrowth interrupted when the canopy was 70 cm tall or at 95% canopy light interception [LI]) and two grazing intensities (reduction of 29 [lenient] or 57% [standard] of initial canopy height) in ‘BRS Zuri’ guineagrass [Megathyrsus maximus (Jacq.) B.K. Simon & S. W. L Jacobs (syn. Panicum maximum Jacq.)], under rotational stocking and on herbage accumulation rate (HAR), tiller appearance rate, tiller mortality, tiller survival rate, tiller stability index (SI), tiller population density (TPD), tiller mass (TM), apical meristem height, and tiller half‐life during two summer rainy seasons in Piracicaba, Brazil. The experimental design was randomized complete block, with a 2 × 2 factorial arrangement. The HAR was not affected by treatments in the first year, averaging 100 kg dry matter ha−1 d−1, but was greater under lenient than standard grazing (146 and 81 kg dry matter ha−1 d−1, respectively) in the second year. In both years, there were no treatment effects on TPD and TM. The use of 95% LI associated with standard defoliation increased the variability in SI. Great tiller population renewal indicated by short tiller half‐life, varying from 31 to 75 d, classifies Zuri as an exploitative cultivar. Zuri guineagrass maintained tiller SI under the grazing treatments imposed but had greater HAR under lenient grazing.