Grasses

Chloris gayana Kunth is a cultivated forage with worldwide distribution, based on its wide environmental adaptability. This review addresses some of the recent findings on C. gayana abiotic stress tolerance resulting from field or controlled conditions trials, focusing on salinity and alkalinity, drought, heat, and water excess. Management of the species under restraining environments is considered—a topic that most published information has concentrated on since a comprehensive review that was published in 2004. The main novel findings since then refer to the growing relevance role C. gayana is adopting in saline and alkaline soil amelioration, either through its association with mycorrhizal fungi or with trees in silvopastoral systems. This key trend is highlighted as a promising area for the development of sustainable production practices. Research gaps are identified. Among them, the development of standardized methodology guidelines for cultivar evaluation to guide adoption decisions and breeding efforts to improve its nutritive value under stress conditions. Tools for molecular intervention of the species that have become available since the previous reviews are also mentioned. Full article

This study investigated the effects of controlled burns on biomass dynamics and fire behavior in areas of stricto sensu grassland in southern Brazil. The experiment consisted of conducting controlled burns in three experimental plots divided into five subplots, with data collection on fire behavior (rate of spread, fireline intensity, residence time, and heat released) followed by monitoring of vegetation recovery over 19 months. To assess the influence of fire on biomass increase, the Gompertz model was fitted, correlating the Absolute Growth Rate (AGR), the time to peak productivity and the time at which the growth curve reaches 95% of the asymptote with the fire behavior variables. The results demonstrated that low-intensity controlled burns were effective in reducing fuel load. Correlation analysis indicated that fire behavior variables had little influence on the rate of vegetation recovery, suggesting that the ecosystem tolerates low-severity disturbances well. The Gompertz model showed a satisfactory fit (R² = 0.86 for total biomass), proving to be a useful tool for management. It is concluded that the use of low-intensity prescribed burns is a viable and safe practice for protected areas. Full article

Methods capable of inferring the nutritional requirements of forage cultivars from related genotypes may help generate preliminary fertilization recommendations when experimental information is limited. This study evaluated whether model identity analysis can be used to infer the nitrogen requirement of Mulato II hybrid grass from the response patterns of its progenitor species, Urochloa brizantha cv. Marandu and Urochloa decumbens cv. Basilisk. A greenhouse experiment using pots filled with an Oxisol was conducted using a completely randomized design in a 3 × 5 factorial arrangement, with three grasses and five nitrogen doses (0, 100, 200, 300, and 400 mg dm⁻³). Forage production, tiller density, and nutritive value were evaluated during establishment and regrowth phases. Linear and quadratic regressions were fitted, and significant models were compared using model identity tests. When model differences were detected, intercepts and parameters were further compared using F-tests. In both establishment and regrowth phases, Mulato II showed response patterns similar to Urochloa brizantha for most evaluated variables, with model identity observed except for tiller number and crude protein concentration. In contrast, Mulato II differed from Urochloa decumbens for all measured traits. Therefore, under the greenhouse conditions evaluated, the nitrogen requirement of Mulato II is more closely related to that of Urochloa brizantha, demonstrating the potential of model identity analysis as a tool for generating preliminary fertilization recommendations for forage cultivars from related genotypes before field validation. Full article

Nitrogen fertilization is widely recognized as a key factor influencing tropical grass productivity; however, its effectiveness may vary according to pasture developmental stage and management practices. This study evaluated the effects of five nitrogen rates (0, 75, 150, 225, and 300 kg ha⁻¹) and two post-cutting residual heights (20 and 30 cm) on the productive, morphological, and nutritional characteristics of Aruana grass (Megathyrsus maximus cv. Aruana) under irrigated conditions. Treatments were arranged in a randomized complete block design with a split-plot structure. Nitrogen was applied as urea in three split applications following simulated grazing events. Herbage mass, dry matter yield, morphological composition, chemical composition, and in vitro dry matter digestibility were evaluated. No interaction was detected between nitrogen fertilization and residual height. Nitrogen fertilization did not affect forage production, morphological composition, chemical composition, or digestibility under the conditions of this study. Residual height influenced forage accumulation, with greater herbage mass and dry matter yield observed at 20 cm than at 30 cm (p = 0.006), without affecting forage quality. These preliminary findings indicate that residual height may be an important factor affecting forage accumulation in irrigated Aruana grass during pasture establishment. Additional studies conducted over multiple growing seasons and environmental conditions are required before definitive management recommendations can be made. Full article

Silages produced from different forage species exhibit substantial variability in chemical composition, digestibility, and fermentation characteristics, which may influence forage quality and preservation efficiency in livestock systems. This study evaluated the nutritional and fermentative variability of silages produced from six forage species (Zea mays L., Sorghum bicolor L., Medicago sativa L., Helianthus annuus L., Cenchrus purpureus, and Saccharum officinarum L.) using multivariate analytical approaches. A database comprising 237 observations, obtained from 24 independent ensiling experiments, was analyzed. Chemical composition, fermentative parameters, and in vitro dry matter digestibility were evaluated through principal component analysis (PCA), canonical discriminant analysis (CDA), and Pearson correlation analysis. Significant differences among forage species were detected (p < 0.05). PCA explained 76.2% of the total variance in the chemical dataset and 85.1% in the fermentative dataset, revealing clear multivariate patterns among silage types. Chemical composition traits provided greater discrimination among silages than fermentative variables, particularly through differences in fiber fractions, soluble carbohydrates, digestibility, and buffering capacity. Corn and sorghum silages were associated with greater starch availability and favorable fermentation profiles, whereas elephant grass and sugarcane exhibited higher fiber concentrations. Alfalfa showed greater crude protein concentration and digestibility, while sunflower was characterized by elevated lignin concentration. Overall, multivariate analyses provided an integrated interpretation of nutritional and fermentative relationships among silages, highlighting species-specific responses to ensiling and their implications for forage conservation and livestock production systems. Full article

Sweet potato (Ipomoea batatas (L.) Lam.) aerial biomass has potential as an alternative forage resource for ruminants in semi-arid regions; however, the fermentative behavior of different genotypes remains poorly understood. This study evaluated the fermentation profile, nutrient losses, and chemical composition of silages produced from the aerial parts of ten sweet potato accessions cultivated under agroecological conditions. Wilted biomass from each accession was pooled, homogenized, and ensiled in four mini-silos used as subsamples for fermentation characterization. Hierarchical clustering identified two distinct groups, indicating clear genotype-dependent variation in silage performance. Accessions BGH-UNIVASF 8 and 16 showed superior fermentation efficiency, characterized by greater dry matter recovery, lower effluent and gas losses, and more stable fermentation profiles. In contrast, several high-yielding accessions exhibited greater fermentation losses, indicating a trade-off between biomass productivity and preservation efficiency. Total digestible nutrients varied among accessions but were not consistently associated with fermentation quality. Overall, the results demonstrate that silage quality in sweet potato is strongly genotype-dependent and highlight the importance of integrating agronomic, nutritional, and fermentative traits when selecting accessions for silage production under semi-arid conditions. Full article

This study evaluated the effect of a combined treatment of biostimulants on the recovery of low-maintenance turfgrass grown in central Chile. During the summer of 2025, a trial was conducted in Melipilla (central Chile) in an area planted with turfgrass sods consisting of a mixture of warm- and cool-season grasses under weekly mowing conditions. Three doses of the biostimulant treatment were applied at 15-day intervals, maintaining a controlled irrigation regime based on daily turfgrass evapotranspiration. The turf quality during the study was evaluated using vegetation indices based on RGB digital image analysis (VARI and TGI). During the trial period, only the treated group showed a significant improvement relative to its initial condition in one of the two evaluated indices (VARI). Comparative analyses across evaluation dates revealed significant differences between the treatment and the procedural control, which represented the non-maintained condition and the deterioration targeted by the trial, whereas no significant differences were detected with the irrigated control. These preliminary findings suggest that biostimulant treatments could represent a feasible tool for improving the appearance and recovery of turfgrass recurrently affected during summer conditions in urban areas of central Chile. However, future studies should include repeated damage–recovery events and incorporate multispectral indices, such as NDVI, to strengthen the robustness of the results. Full article

Characterized as one of the most controversial and widely used grasses in various regions, buffelgrass (Pennisetum ciliare (L.) Link) is considered a significant and problematic invasive exotic species and an adaptable and resilient forage source with relatively high biomass production and resistance to harsh agroecological conditions. Objective: The objective of this documentary research is to present a systematic review of buffelgrass dynamics, focusing on its global management and specifically on the arid regions of Mexico, particularly Sonora. This review highlights its forage potential, invasive capacity, adaptability, and the different scales of its multifactorial relationship within the productive-environmental sphere. Methods: Information on buffelgrass in various regions of the world, with an emphasis on arid regions, was reviewed and summarized. This information was gathered from a selection of 59 articles, considering common aspects such as appropriate methodologies, location within the geographical limits of aridity, and originating from Web of Science repositories. The search criteria included “Pennisetum ciliare and Cenchrus ciliaris”, “invasion”, “livestock”, “forage”, “sustainability”, and “restoration”, among other key concepts, with a timeframe limited to the year 2026. This allowed for the definition of thematic axes for the descriptions presented. Main results: The results highlight various treatments in agriculture and livestock farming, its use in combination with other grasses, and the implementation of adjuvants, which improves its performance. In this regard, its use as a substitute for primary forage with 500 mm of annual irrigation is emphasized, achieving biomass production levels of up to 18.4 t ha⁻¹. Conclusions: Buffelgrass in vulnerable arid territories, such as Sonora, Mexico, could improve soil cover, nutrient content, and biological presence; however, in a state of equilibrium, it can cause alterations that are difficult to reverse and that compromise local ecology and water resources. Full article

Fires are an ecological force that often mediates the balance between native and exotic plants in communities. We monitored post-fire vegetation dynamics in a Pinus pinaster plantation and adjacent grasslands 9, 15, and 18 months after the fire, evaluating structural and compositional changes through multivariate analyses. The invasive alien Acacia longifolia cover increased significantly in the plantation (p = 0.0006), while pine needle cover declined significantly (p = 0.0027), and P. pinaster cover did not change significantly over time (p = 0.063), although it showed an increasing trend towards the late stage. Both A. longifolia and pine needles were negatively associated with native species cover. Native cover remained consistently higher in continuous grasslands, with a significant Time × Site interaction. Post-fire succession in the plantation was associated with sequential abiotic and biotic filters, and the increase in A. longifolia may have contributed to reduced native recovery through competitive effects. These results suggest that fire alone may be insufficient to restore native grassland conditions within afforested systems and that early post-fire control of A. longifolia may be necessary to redirect succession. Full article

Wearable sensors and remote sensing technologies are rapidly increasing opportunities to measure grazing animal behavior, energetics, and performance in extensive rangeland systems. However, despite significant advances in device capabilities, the livestock sector lacks an ecological framework that connects sensor data to the metabolic processes driving animal growth and efficiency. In this paper, we apply the movement ecology paradigm to grazing beef cattle as a demonstration of how metabolic theory, animal behavior, and landscape heterogeneity interact to influence energy budgets. We first describe the mechanistic relationships among basal metabolism, thermoregulation, activity, and forage intake, highlighting how movement patterns reflect underlying metabolic states. Next, we review key variables measurable through modern sensors, including GPS, accelerometers, rumen temperature boluses, and remote sensing of forage quantity and quality and explain how these data can be integrated into an information system to estimate energy expenditure, resource selection, and physiological stress. Finally, we show how combining movement, behavioral, and landscape data can yield meaningful indicators of performance and health, paving the way for precision livestock management grounded in ecological principles. Integrating metabolic and movement ecology with emerging technologies offers a strong framework for enhancing efficiency, welfare, and sustainability in grazing beef systems. Full article

Ecotypic variation in tall fescue (Lolium arundinaceum (Schreb.) Darbysh.), with differences in phenology, may affect the performance of mixtures with alfalfa (Medicago sativa L.). However, the effects of ecotypic variation within mixtures remain largely unexplored. The aim of this study was to evaluate the aerial dry matter (ADM) production and radiation model components of alfalfa–tall fescue mixtures, with particular emphasis on their implications for radiation interception and radiation use efficiency (RUE) at the canopy level. We evaluated from March 2017 to May 2018 in the Pampas (Argentina) monocultures of alfalfa and tall fescue Mediterranean and Continental ecotypes, and their mixtures with a sowing ratio 1:1 under frequent defoliation without fertilization. ADM was higher in alfalfa monoculture and mixture with the Mediterranean ecotype than the mixture with the Continental ecotype (+20%; 3225 kg ha⁻¹). Alfalfa monoculture exhibited the highest radiation interception, whereas the mixture with the Mediterranean ecotype compensated for reduced interception through increased RUE (≈10%). The Continental mixture exhibited lower interception indicating stronger interspecific competition. Tall fescue monocultures were the least productive due to low interception and RUE. These findings highlight the potential of Mediterranean tall fescue ecotype and the importance of species/ecotype selection for grassland productivity. Full article

The objective of this study was to assess the contribution of oat (Avena sativa L.) and common vetch (Vicia sativa) hay supplementation as a forage-based strategy to improve the environmental and productive performance of grazing systems in the high Andean zone through its effects on enteric methane (CH₄) emissions and live weight gain. Twenty heifers grazed native grasses, and only half of the group received the supplement. The experiment was conducted as a crossover design. Methane emissions were quantified through sulfur hexafluoride methodology. Native pastures were characterized by low protein content, while lignin was lower in the oat hay plus common vetch hay than in the native grass mixture. On average, heifers consumed 7 kg dry matter per day (p ≥ 0.05) and ingested 24% more crude protein when supplemented (p = 0.0001). Digestible and metabolizable energy intakes were also significantly higher in supplemented animals (p ≤ 0.05). Live weight change was positive for supplemented animals (245 g/d). Net CH₄ production ranged from 179.6 to 196.3 g/d (p = 0.183). However, when CH₄ emissions were expressed relative to crude protein or acid detergent lignin intake, supplemented diets were found to emit less than native grass-based diets (p ≤ 0.05). These results suggest that supplementation with oat hay plus vetch is a feeding alternative for heifers during the dry season in the Peruvian Andean region to increase animal productivity without affecting CH₄ emissions. Full article

Neem (Azadirachta indica A. Juss) extracts are widely used in agriculture as organic pesticides, but their effects on soil microbiota are uncertain. This study evaluated the impact of aqueous extracts of neem leaves and seeds on soil microbial activity, maize (Zea mays L.) development, and arbuscular mycorrhizal fungus (AMF) dynamics. The experiment used a 2 × 3 + 1 factorial design, with two extract sources (leaf and seed), three concentrations (5%, 10%, and 20%), and a control. The soil treated with 20% seed extract showed the highest microbial respiration (16,512 mg C-CO₂·kg⁻¹·day⁻¹) and total organic carbon (15.10 g·kg⁻¹) but the lowest microbial biomass (1330 mg·kg⁻¹) and microbial quotient (0.10%), indicating a stressed microbial environment. Paradoxically, maize plants under this same treatment exhibited a superior height, stem diameter, and biomass. Furthermore, the AMF spore density significantly increased in the seed extract treatments, suggesting a stress-induced reproductive response. These findings reveal that, although neem seed extract can negatively affect soil microbiota, it promotes maize growth, likely due to its organic and bioactive compounds. Thus, neem extract demonstrates potential as an organic input, but its application must be carefully managed due to potential ecological trade-offs. Full article

Forage grasses are an important component of livestock systems due to their contribution to animal feed, soil conservation, and carbon sequestration. In the face of climate change, analyzing stomatal characteristics allows us to understand the mechanisms of adaptation and tolerance to environmental stress. Therefore, the objective of this study was to determine the stomatal characteristics and trichome density of ten forage grasses present in a pine-oak dominated ecosystem. Sampling was carried out in October and November 2022 on a 1938 ha area. Mature, healthy leaves were selected, and epidermal impressions were obtained from the adaxial and abaxial surfaces using the cyanoacrylate method. Observations were made with an optical microscope at 400× magnification, quantifying stomatal density, trichome density, number of epidermal cells, and stomatal index per mm². The results indicated that nine species were amphistomatic, while Schizachyrium scoparium exhibited an epistomatic pattern. Muhlenbergia arizonica showed the highest stomatal density, and Setaria parviflora the lowest. It is concluded that there is high stomatal variability among species, highlighting its importance for the management and improvement of pastures. Full article

This study evaluated combinations of defoliation frequencies and intensities to identify grazing strategies that optimize forage accumulation and morphological composition in mixed pastures of Marandu palisadegrass (Urochloa brizantha cv. Marandu) with the legume Macrotyloma axillare. Treatments consisted of pre-grazing heights of 30 and 40 cm (defining defoliation frequency) combined with post-grazing heights of 15 and 20 cm (defoliation intensity), in a 2 × 2 factorial randomized block design with four repetitions. Forage accumulation rate, morphological component mass, and leaf area index (LAI) were evaluated under rotational stocking. The highest forage accumulation rates of grass and its stems occurred at a pre-grazing height of 30 cm. A taller pre-grazing height (40 cm) resulted in greater pre-grazing forage mass, leaf and stem mass of Marandu palisadegrass and LAI, but it also increased the amount of dead material and post-grazing stem mass. The greatest Macrotyloma forage accumulation occurred under grazing strategies of 30–20 cm and 40–15 cm. Lenient defoliation (20 cm post-grazing height) favored post-grazing leaf mass, whereas severe defoliation (15 cm) favored stem mass. Marandu palisadegrass showed higher LAI at 40 cm pre-grazing height (4.7) than at 30 cm (3.6), with slightly greater values under 20 cm (4.3) than 15 cm (4.1) post-grazing height, while Macrotyloma axillare exhibited low LAI. Across all grazing strategies, the legume mass decreased over time. Therefore, future studies should explore alternative grazing strategies and periodic reseeding of Macrotyloma axillare to maintain its presence in mixed tropical pastures. Full article

Stress caused by suboptimal temperatures (ST) represents a stress that limits growth in all grasses without inhibiting their activity and induces alterations in photosynthetic performance. We evaluated the responses of photosynthetic parameters and leaf elongation between two groups of grass genotypes with different levels of tolerance to ST, belonging to phylogenetically distant species. Responses to ST depended on the type of parameter and on the genotypic group. Leaf elongation traits showed discriminatory power, especially the area under the leaf elongation curve, which integrated the early and transient effects of stress over time. The photosynthetic parameter PI_ABS showed lower discriminatory power compared with the area under the leaf elongation curve. However, a deeper analysis of other photosynthetic parameters revealed an increase in energetic connectivity between Photosystem II centers in tolerant, but not in sensitive, genotypes. A subsequent analysis of leaf and cellular parameters of early leaf elongation dynamics indicated that ST reduced meristematic activity in all genotypes, but the tolerant genotype group maintained a greater accumulation of mature cells compared with the sensitive genotype group. Overall, the results suggested a response to ST in tolerant genotypes, but not in sensitive genotypes, related to the early dynamics of leaf and cellular growth parameters to partially compensate for the restrictive effect of ST on leaf elongation not recorded. In parallel, they also indicated a response of the tolerant genotypes to ST in terms of photosynthetic parameters, probably as a pathway to maintain cellular homeostasis, to prevent photooxidative damage in PSII under stress. However, the relationship between both responses does not appear to be strictly linear, but rather would be mediated by coordinated adjustments in the temporal dynamics of growth, suggesting a functional integration between photosynthetic performance and the cellular mechanisms that regulate leaf expansion under ST stress. Full article

When subjected to a combination of abiotic stresses in the field, such as saline and thermal stress, plants can suffer devastating effects on their development. Regarding millet, little is known about the effects of temperature and salinity on its germination and initial development. Therefore, the objective of this study was to evaluate the germination responses and initial development of millet seedlings subjected to thermal and saline stresses. The experiment was conducted in a completely randomized design with 16 treatments in a 4 × 4 factorial scheme, four salinity levels (0.0—control, 100, 200, and 300 mM) and four temperatures (10, 20, 30, and 40 °C). The germination percentage, average germination time, germination speed index, shoot length, and primary root length of seedlings were evaluated. The different salinity concentrations and temperatures significantly influenced all the variables studied, gradually reducing with increasing salinity and decreasing temperature, with optimal ranges at higher temperatures and lower salinity levels. It is concluded that the ideal conditions for germination and initial development of millet are as follows: a temperature between 20 and 30 °C and the absence of salinity. They tolerate concentrations of up to 200 mM and temperatures of 40 °C. On the other hand, high salinity and low temperature can delay and/or inhibit germination. Full article

Sorghum is a resilient crop important for sustainable intensification in semi-arid regions, yet the impact of variable seeding rates on its early development remains under-researched. This research investigated the early establishment of hybrid sorghum under three seeding strategies, ”Uniformise” (medium density across all zones), “Optimise” (increased density in low-soil apparent Electrical Conductivity (ECa)), and “Maximise” (increased density in high-soil ECa), at the Herdade da Comenda (Innovation Center—Elvas, Portugal). Crop performance was monitored over 33 days, the established window for safe direct grazing, using Unmanned Aerial Vehicle (UAV) multispectral imagery to derive the Normalised Difference Vegetation Index (NDVI) and Canopy Cover (Cveg), alongside physical sampling of plant height and biomass. Statistical analysis revealed that both the seeding strategy and soil variability significantly affected early growth. The “Uniformise” strategy recorded the highest plant height, NDVI, and Cveg values, whereas the “Optimise” strategy performed the poorest. Additionally, an accumulation of 407.5 Growing Degree-Days (GDDs; °C) accelerated the phenological cycle by five days relative to the climatological normal. Despite differences in vegetative vigour, no statistically significant variations were observed in final biomass across the strategies. These results indicate that while the “Uniformise” approach provided a more balanced environment for early establishment under these specific Mediterranean conditions, the lack of biomass differentiation highlights the potential for resource optimisation. The study demonstrates that UAV-based remote sensing is a useful diagnostic tool to identify these spatial limitations, providing the data to refine variable-rate seeding (VRS) algorithms and improve the economic efficiency of precision sowing. Full article

Brachypodium distachyon has become a widely studied model plant due to its small genome, ease of cultivation under controlled conditions, and value for synteny and molecular studies. Regarding disease, Fusarium is one of the main fungal genera infecting cereal crops, F. cerealis, F. graminearum, F. poae, and F. pseudograminearum being isolated frequently from several agricultural regions. Therefore, the present study aimed to evaluate three pathosystems, combining three hosts (B. distachyon, barley, and wheat) with four Fusarium species to confirm the use of B. distachyon in Fusarium–crop system models. Three controlled experiments were performed to assess the impact on seeds, roots, and spikes. Variables such as germination inhibition, McKinney’s index, percentage of necrosis, area under the disease progress curve, disease incidence, disease severity, and grain weight were measured. Regarding Fusarium species, the results confirm that F. pseudograminearum could be more aggressive on roots, while F. graminearum affects spikes more severely. In contrast, F. cerealis and F. poae are generally moderate to weak pathogens with irregular behaviour depending on the plant species or genotype. No clear varietal resistance pattern emerged except for wheat genotypes with a known resistance/susceptibility QTL. The present study highlights the importance of using multiple experiments for accurate phenotype characterisation, as relying on a single technique is insufficient. In conclusion, the results presented in the manuscript provide valuable insights into Fusarium spp.–B. distachyon interactions and resistance selection based on seed, root, and spike assessments. Moreover, this work confirmed the use of Brachypodium as a model plant for Fusarium–plant interaction studies. Full article