Grasses, Volume 4, Issue 3 (September 2025) – 11 articles

This study evaluated the effect of Acacia melanoxylon inclusion in Medicago sativa silage on chemical composition, fermentation quality, in vitro digestibility, gas production, and energy value. Due to its high moisture content, M. sativa presents challenges for ensiling. A. melanoxylon, a woody legume with high dry matter (DM) content, was tested as a structural additive. Five treatments were prepared—control (100% M. sativa) and mixtures with 6, 12, 24, and 48% A. melanoxylon (fresh basis)—and ensiled for 45 days under vacuum. Silages were analyzed for DM, crude protein, fiber fractions, pH, ammonia nitrogen, in vitro digestibility, gas production kinetics, and estimated energy values (ME and NEL). Increasing Acacia raised DM (17.75 ± 0.04 → 28.45 ± 0.11%) and reduced pH (5.86 ± 0.01 → 4.53 ± 0.01) and NH₃-N/Total N (11.38 ± 0.10% → 8.05 ± 0.10%), indicating improved fermentation quality. Conversely, crude protein, digestibility (IVDMD 62.61 ± 0.05% → 48.02 ± 0.16%), and cumulative gas at 96 h decreased, as did energy values (ME 5.91 → 4.45 MJ/kg DM; NEL 3.13 → 2.02 MJ/kg DM) at higher inclusion levels; gas-kinetic parameters reflected the same trend (lower b and c). Overall, A. melanoxylon acts as a structural co-ensiling option that increases DM and supports fermentation quality while clearly delineating nutritional and fermentability trade-offs; low-to-moderate inclusion (6–12%) appears advisable to balance process benefits against acceptable nutritional penalties. Full article

As traditional forage crops demand substantial water, exploring alternatives with lower water demands can mitigate the strain on water supplies. This pot study evaluated five annual warm-season forages (forage sorghum (FS) [Sorghum bicolor (L.) Moench], prussic acid-free forage sorghum (PF) [Sorghum bicolor subsp. Drummondii], sorghum x sudangrass hybrid (SS) [Sorghum bicolor x drummondii], sudangrass (SU) [Sorghum sudanense (Piper) Stapf], and pearl millet (PM) [Pennisetum glaucum (L.) R. Br.]) under two different irrigation treatments (40% and 80% ETo). Morphological (leaf area, leaf count, plant height), biomass yield, nutritional content (nitrogen (N), acid detergent fiber, and in vitro true digestibility (IVTD)), and water use efficiency (WUE) parameters were assessed at 35 and 49 days after planting (DAP). Irrigation effects varied with time, more strongly influencing nutritive value at 35 DAP and morphological traits at 49 DAP. WUE was significantly affected by irrigation at both timepoints. No single forage consistently outperformed across all metrics. PF and SU had the most biomass (p < 0.01), while PM had the greatest N content (p < 0.01). However, PF and SU had the highest WUE for biomass and digestible dry matter (p < 0.01). These findings suggest PF and SU may improve forage system sustainability under limited water availability. Full article

This study examines the growth dynamics of Nassella tenuis (Phil.) Barkworth, a palatable perennial tussock grass, abundant in the natural grasslands of Central Argentina. It focuses on the effects of water regimes and grazing history. Plants were collected from sub-humid and semiarid grasslands with contrasting grazing histories (grazed and ungrazed) and cultivated under controlled conditions. Key growth traits, such as leaf elongation, senescence, and net growth rates, as well as tiller production, were assessed across the growth cycle. The results reveal that sub-humid grasslands favor faster growth rates and higher tiller production, while semiarid grasslands exhibit lower growth rates, potentially reflecting adaptive strategies for water-limited environments. Seasonal analysis revealed distinct life cycle patterns: plants from sub-humid grasslands exhibited higher elongation rates during autumn and spring, whereas growth in semiarid plants remained consistently low across seasons. Grazing history significantly influenced growth patterns, with grazed plants showing reduced tiller numbers and growth rates but lower senescence rates, particularly in semiarid grasslands. These findings underscore the importance of aligning grazing management practices with the growth dynamics of N. tenuis and the water regime of the site to optimize forage production while maintaining grassland resilience. Full article

Pearl millet (Pennisetum glaucum L.) is a promising crop for silage production in the Cerrado biome, but its use is still limited, and the ideal age for ensiling has not been well defined. This study aimed to evaluate the ADRf 6010 pearl millet hybrid at four harvest ages for ensiling: 75, 85, 95, and 105 days after planting (DAP). Forage production (green and dry forage mass), chemical composition, and fermentation parameters were analyzed. Harvested forage was chopped into 2.0 cm particles and treated with a concentration of 1 × 10⁵ CFU/g (Colony Forming Units; Lactobacillus plantarum CNCM I-3736 and Pediococcus acidilactici CNCM I-4622) of fresh forage. Forage mass increased linearly with harvest age. At 105 days of growth, the crop yielded 65,980 kg/ha of fresh forage and 15,569 kg/ha of dry matter. The dry matter (DM) and neutral detergent fiber (NDF) concentrations also increased with advancing harvest age. The concentrations of crude protein (CP), non-fibrous carbohydrates (NFC), and in vitro dry matter digestibility (IVDMD) decreased with increasing harvest age before ensiling. In the silages, pH, ammoniacal nitrogen (NH₃-N), effluent loss, gas losses, and silage density decreased linearly, while DM recovery increased. With advancing harvest age, there was a positive linear increase in the concentrations of DM, NDF, and acid detergent fiber (ADF). On the other hand, CP, NFC, and IVDMD showed a negative linear trend. Based on the results, the ADRf 6010 pearl millet hybrid demonstrated high forage yield and favorable fermentative characteristics when harvested at different growth stages during the summer season. Advancing harvest age resulted in increased forage mass, dry matter content, and dry matter recovery, along with reduced fermentation losses such as effluents and gases. Although later harvests led to reductions in crude protein concentration and in vitro digestibility, these effects were compensated for by the higher dry matter yield per hectare and better preservation conditions. Thus, ADRf 6010 pearl millet is a promising crop for silage production under tropical conditions. Full article

Forage sorghum (Sorghum bicolor (L.)) is a cereal native to Africa and belongs to the family Poaceae. It is a forage with a C4 photosynthetic pathway that stands out for its ability to adapt to different environments; it is able to produce even in unfavorable circumstances. The objective of this study was to analyze the attenuating effect of the brassinosteroid hormone in the form of 24-epibrassinolide on forage sorghum plants subjected to water deficit and rehydration. A completely randomized design (CRD) was used in the experiment. A 2 × 3 × 5 factorial arrangement was used, with two water conditions (water deficit and rehydration), three brassinosteroid doses (0 nM, 50 nM, and 100 nM as 24-epibrassinolide), and five replicates. The experiment was conducted in a greenhouse. Sorghum seeds were sown in pots with a capacity of 3 kg of substrate. Analyses were performed on the roots and leaves of sorghum plants at different growth stages. The macronutrients (N, P, K, Ca, and Mg) were analyzed in the soil physics laboratory. As a result, the content of N, P, K, Ca, and Mg decreased under a water deficit and was then restored by the hormone 24-epibrassinolide, which was able to restore these nutrients. The effect of the hormone under rehydration had a positive effect, increasing the levels of nutrients. Given the above, it was possible to conclude that there were no significant divergences between the treatments during the period of irrigation suspension. Among the tested concentrations, 50 nM of 24-epibrassinolide showed the most consistent improvements in nutrient concentrations under water-deficit conditions, suggesting a potential role in mitigating nutritional imbalance during stress. Rehydrated plants maintained nutrient levels similar to the controls regardless of 24-epibrassinolide application. However, it is important to note that nutritional quality indices such as crude protein and total digestible nutrients (TDN) were not evaluated in this study, which limits direct conclusions about the forage nutritional value. Full article

Biodegradable hydroretentive polymers, such as UPDT^®, have emerged as promising alternatives to synthetic hydrogels, particularly in pasture systems where sustainable water management is crucial. These materials enhance subsurface drip irrigation by maintaining soil moisture, which supports germination and early root development until roots access deeper water reserves. However, their degradation dynamics in tropical forage systems remain poorly characterized, posing a challenge to long-term application strategies. This study aimed to evaluate the effects of different UPDT^® doses (0, 7.5, 15, 22.5, and 30 kg ha⁻¹) on the morphological and agronomic traits of Mombaça grass under controlled conditions. After a uniformity cycle, treatments were evaluated across four cultivation cycles with monitored irrigation to avoid water deficits. Morphogenetic traits such as number of live leaves (NLL), final number of emerging leaves (NEmL), leaf appearance rate (LAR), and stem elongation rate (SER), as well as shoot dry mass (SDM), were analyzed. Results showed that morphological variables responded quadratically to polymer doses during the initial and intermediate cycles. In the final cycle, reductions in these traits and in water productivity suggested the onset of polymer degradation and loss of hydroretentive capacity. Agronomic traits were influenced throughout all cycles, with the fourth cycle showing the highest SDM due to elevated temperatures. These findings highlight the need to better understand the degradation kinetics of biodegradable hydrogels such as UPDT^® in tropical pastures. Field trials are recommended to define optimal reapplication intervals and integrate degradation monitoring into irrigation planning, ensuring long-term sustainability in pasture management. Full article

Sulfur-containing fertilizers increase production costs, which leads to low utilization of this nutrient. Thus, evaluating how the absence of sulfur influences the early development of Urochloa brizantha is essential. Study was conducted in a greenhouse at the Federal University of Rondonópolis in a completely randomized design, with six treatments in a 3 × 2 factorial scheme, and eight replications. Three cultivars of U. brizantha (Marandu, Xaraés and Piatã) were evaluated under two fertilization strategies: with or without sulfur fertilization. Sufur presence increased the number of leaves and forage mass, in which cultivar Xaraés presented the greatest means. Piatã was the cultivar most sensitive to sulfur deficiency at establishment, which reduced forage mass, number of leaves and number of tillers by 42%, 32%, and 45%, respectively. Despite these differences between cultivars, sulfur efficiently increased the forage yield. Sulfur fertilization increased the concentrations of nutrients in the plants without significantly affecting the uptake of nitrogen, phosphorus, potassium, calcium and magnesium. Sulfur omission resulted in increased phosphorus uptake in all grass. In contrast, Marandu grass exhibited the greatest reduction in sulfur uptake. Therefore, the use of sulfur in the fertilization of grasses is recommended, it is important to evaluate the responses of each cultivar to better adjust the fertilization management. Full article

Arbuscular mycorrhizal (AM) fungi (AMF) form a symbiotic association with terrestrial plants and increase growth and productivity. The relationships between the growth of centipedegrass (CG) and AMF are not well understood. We monitored the growth and AM colonization of CG growing on the four slopes (north, east, south, and west) of a pasture, to obtain information on aspect differences in the soil chemical properties–grass–AMF association. Soil properties almost always varied between the slope aspects. The total soil N, C, EC, and moisture tended to be highest on the northern aspect, whereas the soil available P and pH tended to be highest on the western and southern aspects, respectively. Despite the aspect differences in the microclimate and soil properties, CG grew well in all aspects, showing similar dry matter weights (DMW) for the fouraspects. Furthermore, the AM colonization of CG, in any characteristic structures (internal hyphae, vesicles, and arbuscules), was not significantly different between the slope aspects on most measurement occasions, although the colonization usually varied between the seasons and years. There were no relationships between the DMW and AM characteristic structure colonization and between the DMW and soil chemical properties. However, the colonization of the arbuscules and vesicles of the CG had a correlation with some soil chemical properties. The results suggest that AM colonization on CG growing in a hill pasture did not differ between the slope aspects. This may be a factor contributing to the high adaptability of the grass to all slope aspects. Full article

Records from 2012 to 2019 for two herds were analyzed to determine how tall fescue (Schedonorus arundinaceus (Schreb.) Dumont) endophyte (Epichloë coenophialum) status affected the productivity of spring-calving cows and calves. Pastures either contained tall fescue with wildtype endophyte (high levels of ergot alkaloids) or novel- or endophyte-free tall fescue (largely ergot alkaloid free). The experimental design was a randomized complete block with year as the replication unit. Forage samples from the farm with toxic endophyte-infected tall fescue contained 1136 ± 413 ppb total ergot alkaloids, while forage from the non-toxic pastures on the second farm contained 118 ± 83 ppb total ergot alkaloids. Artificial insemination pregnancy rates and calving rates were greater (p < 0.05) for cows that grazed non-toxic tall fescue (51.2 ± 2.8% and 93.5 ± 1.4%, respectively) than for cows on toxic endophyte-infected tall fescue (43.3 ± 2.8% and 88.8 ± 1.4%, respectively). Birth weights and weaning weights were greater (p < 0.05) for calves from the non-toxic tall fescue system (37 ± 1 kg and 278 ± 8 kg, respectively) than for calves from the toxic endophyte-infected tall fescue system (33 ± 1 kg and 254 ± 8 kg, respectively). Raising cattle on tall fescue without the toxic endophyte improved cow and calf productivity. Full article

Molybdenum fertilization represents a viable alternative for improving forage quality, potentially complementing or enhancing the effects of nitrogen fertilization. This study aimed to determine whether foliar or soil application of molybdenum would increase the crude protein content and digestibility of sorghum cultivated as a monoculture or intercropped with cowpea. The first experiment followed a 2 × 2 + 2 factorial design, including two application methods (foliar or soil), two cropping systems (monoculture or intercropping), and two additional control treatments (with and without molybdenum). In the second experiment, a split-plot design was used to assess the effects of molybdenum fertilization on the in situ digestibility of sorghum from monoculture and intercropping systems. Molybdenum fertilization increased the levels of crude protein, total carbohydrates, and soluble fractions. It also enhanced the disappearance rate, potential degradability, and effective degradability of sorghum, regardless of the application method or cropping system. Foliar or soil application of molybdenum is recommended to optimize the crude protein content and in situ digestibility of sorghum cultivated either as a monoculture or intercropped with cowpea. Full article

Three purple prairie clover (PPC; Dalea purpurea Vent.) varieties, namely Common seed (CS), AC Lamour (ACL) and Bismarck (BIS), were established in plots of irrigated land (rain-fed plus irrigation, Lethbridge, AB) and dryland (rain-fed only, Swift Current, SK) to assess its agronomic characteristics and nutritive value under different ecoclimate and growing conditions in Western Canada. Each seed source was replicated in four test plots arranged as a randomized complete block design at each experimental site. Forage mass on dry matter (DM) basis, canopy height, proportions of leaf and stem and nutritive value were determined at vegetative (VEG), full flower (FF) and late flower (LF) phenological stages. The forage masses of the three PPC varieties were similar (p < 0.05) at each phenological stage with the mean values for VFG, FF and LF being 4739, 4988 and 6753 kg DM/ha under the Lethbridge irrigated conditions, and 1423, 2014 and 2297 kg DM/ha under the Swift Current dryland conditions. The forage mass was higher (p < 0.001) under Lethbridge irrigation than under Swift Current dryland conditions and increased (p < 0.05) with maturity. The three varieties had similar concentrations of organic matter (OM), neutral detergent fibre (NDF), acid detergent fibre (ADF) and crude protein (CP) and in vitro DM digestibility (DMD) at each phenological stage, but CP concentration and in vitro DMD decreased (p < 0.001) whilst NDF and ADF concentration increased (p < 0.001) with maturity. Purple prairie clover grown at Lethbridge irrigated land had higher (p < 0.001) DMD, OM and CP, but lower (p < 0.001) NDF, ADF and condensed tannin concentrations than that grown at Swift Current dryland conditions. These results indicate that PPC has great potential as an alternative legume forage for the cattle industry. Full article