Digitaria Eriantha Research Articles

Perennial grass and herb options to extend summer–autumn forage in a drought‐prone temperate environment

AbstractBackgroundThe ability to finish livestock on pasture over the summer–autumn period could improve the profitability of red meat enterprises in drought‐prone temperate regions. In south‐eastern Australia, traditional perennial options are limited by poor warm‐season performance (phalaris, Phalaris aquatica L.) and widespread environmental constraints (lucerne, Medicago sativa L.). We aimed to identify perennial species suitable for summer–autumn finishing.MethodsWe tested pure swards of summer‐active perennial grasses and herbs (20 cultivars across 14 species) in replicated small‐plot experiments at two sites on the Southern Tablelands of New South Wales, Australia. We assessed early persistence, productivity and warm‐season nutritive characteristics over 2–3 years.ResultsLucerne and chicory (Cichorium intybus L.) persisted well through drought and produced herbage of high quantity and quality through summer–autumn. Digit grass (Digitaria eriantha Steud.) was highly persistent and productive but nutritive values were generally poor. Cocksfoot (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.), perennial ryegrass (Lolium perenne L.), prairie grass (Bromus willdenowii Kunth.) and plantain (Plantago lanceolata L.) were productive but less persistent through drought, while nutritive values were sometimes inadequate.ConclusionsChicory is a good alternative to lucerne, given its excellent summer–autumn performance, ability to survive droughts and superior acid soil tolerance. If appropriate management resolves issues with persistence and nutritive value, several of the other species could also be used to close the warm‐season feed gap in drought‐prone temperate environments.

Hard-seeded temperate annual legumes establish better in a tropical grass pasture when autumn-sown than spring-sown in a summer dominant rainfall zone, Australia

ABSTRACT Temperate annual legumes can be effective companion species in tropical perennial grass pastures. These legumes are commonly sown in autumn following establishment of the grasses. However, it may be more effective to establish a seed bank before sowing the grass, or possibly sow the legumes as hard seed/pod in spring when the tropical grass pasture is sown. A study was conducted in northern New South Wales to compare establishment, regeneration and productivity of three hard-seeded legumes: bladder clover (Trifolium spumosum) cv. Bartolo, biserrula (Biserrula pelecinus) cv. Casbah and French serradella (Ornithopus sativus) cv. Margurita. The legumes were sown four times: either one or two autumns before digit grass (Digitaria eriantha) cv. Premier was established, the autumn following grass establishment or sown at the same time as the grass as either hard seed/pod segments or scarified seed (total of five treatments). While seasonal conditions influenced establishment success, autumn was the optimal time to sow temperate annual legumes to achieve a productive mixed pasture. The legumes can be sown 1–2 autumns before or in the autumn following grass establishment. Legume plant populations of spring sown hard seed/pod segments were lower than those autumn sown but they increased the following year.

Seedling emergence of tropical perennial pasture species in response to temperature used to determine sowing time recommendations

Tropical pasture grasses and legumes can be highly productive and persistent and fill the summer-autumn feed gap typical of temperate pasture systems in southern Australia. However, more information is needed on optimum temperature range for seedling emergence because this will influence sowing time recommendations. A replicated field experiment was conducted at 5 locations in New South Wales over a 12-month period to determine the optimum temperature for emergence of a range of tropical species: Rhodes grass (Chloris gayana Kunth), Makarikari grass (Panicum coloratum L. var. makarikariense Gooss.), kikuyu grass (Cenchrus clandestinus (Hochst. ex Chiov.) Morrone), digit grass (Digitaria eriantha Steud.), panic grass (Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs), paspalum (Paspalum dilatatum Poir.), Urochloa hybrid (Urochloa decumbens × U. ruziziensis × U. brizantha), 2 cultivars of Desmanthus virgatus (L.) Willd. (cultivars ‘Marc’ and ‘JCU2’), D. bicornutus (S. Watson), D. leptophyllus (Kunth) and D. pernambucanus (L.) Thell.). Rhodes grass emerged satisfactorily over the longest time across all sites, exhibiting the greatest temperature range over which emergence occurred, while Makarikari grass and panic grass had the narrowest temperature range for emergence. The temperature for 50% emergence differed between the tropical species and whether the soils were warming or cooling. Rhodes grass had the lowest 50% emergence temperature (17 °C) while paspalum had the highest (22 °C). Results showed that temperature for 50% emergence is a useful indicator for determining sowing time in warming soils.

In vitro CHEMICAL AND FERMENTATIVE CHARACTERISTICS OF TROPICAL PASTURES AT DIFFERENT AGES OF REGROWTH

The low nutritive value of pastures in tropical regions represents a limitation in the productivity of grazing ruminants. The objective was to determine the in vitro chemical and fermentative characteristics of nine tropical grasses (Aruana [Panicum maximun Jacq. cv. Aruana], Bermuda [Cynodon dactylon L.], Estrella de África [Cynodon Cynodon nlemfuensis Vanderyst], Insurgente [Brachiaria brizantha Hochst. Stapf.], Llanero [Andropogon gayanus Kunth], Mombaza [Panicum maximun Jacq. cv. Mombaza], Pará [Brachiaria mutica Stapf], Pangola [Digitaria eriantha Steud.], and Tanzania [Panicum maximun Jacq. cv. Tanzania]) at three regrowth ages (30, 45, and 60 days). The chemical analysis was used to determine the concentrations of dry matter (DM), crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and ash (Ce). The in vitro trial measured partial (24, 48, and 72 h) and cumulative biogas and methane production, fermentation kinetics estimators (A, b, and k), dry matter degradation (DMD) and detergent neutral fiber degradation (NDFD), pH, and ammonia nitrogen (N-NH3). The experimental design was completely randomized at each regrowth age. In conclusion, based on chemical analysis and fermentative characteristics, Pangola and Estrella pastures performed better at each regrowth age.

Vegetative Flow Resistance for Erosion Control Using Grass Species from the Caribbean Region

Vegetative channels convey runoff effectively, prevent flooding, protect soil against erosion, avoid the formation of gullies, maintain adequate water quality, and reduce the generation of sediments. The degree of retardance as a measure of the drag force on the vegetation cover is a crucial parameter for determining resistance to water flow in these channels. This research developed a new procedure to assess Manning’s coefficient and retardance index for vegetation using four Caribbean Area grass species: Bahía Grass (Paspalum notatum), Zoysia Grass (Zoysia sp.), Pangola Grass (Digitaria eriantha), and Bermuda Grass (Cynodon dactylon). The USDA-NRCS Caribbean Area identified 16 species as vegetative lining for waterways and proposed a classification according to the degree of vegetative retardance. The category for these species was developed for use in the Western Gulf Region and required validation for the Caribbean region. A modified universal log law fitted the velocity distributions above the vegetative lining in the experiments. The energy equation for a gradually varied flow, the momentum equation, and Manning’s equation provided a solution for Manning’s coefficient. The procedure allowed us to assign a degree of retardance to the species obtained by comparing Manning’s coefficients with those from USDA-NRCS. Results show that retardance degrees published in the Puerto Rico Erosion and Sedimentation Control Handbook for Developing Areas apply to the species tested in this project. This research identified a new retardance degree for Pangola grass when the plant height is less than 0.15 m. The experimental values for Manning’s coefficient are also recommended for use in overland flow conditions.

The twolined spittlebug (Hemiptera: Cercopidae) invades Hawaiʻi: establishment, biology, and management of a destructive forage grass pest

Abstract The twolined spittlebug, Prosapia bicincta (Say) (Hemiptera: Cercopidae), is a major economic pest of turfgrass, forage grass, and sugarcane. Native to the southeast United States, it impacts rangelands and the landscape trade by damaging pastures, golf courses, urban landscapes, and lawns. This insect pest was reported and confirmed in Hawaiʻi for the first time in 2016, the first species in the family Cercopidae to invade Hawaiʻi. On Hawaiʻi Island, P. bicincta is severely devastating Hawaiʻi’s beef cattle industry. Since its initial detection, P. bicincta has rapidly expanded its range across an estimated 72,183 ha area on Hawaiʻi Island, and it continues to disperse to new locations. In areas of high infestation, this pest has caused 100% dieback of key pasture grasses for livestock forage, including kikuyu (Pennisetum clandestinum Hochst. Ex Chiov) and pangola (Digitaria eriantha Steud) grasses, leading to the establishment of low-quality forage grasses and weeds. Additionally, this pest may affect the Hawaiʻi landscape trade and impact golf courses, urban landscapes, and homeowners. The taxonomy, detection history, range, biology, ecology, economic damage, and management strategies for P. bicincta are discussed.

Spatio-temporal status of vegetation, soil and cattle serum minerals in degraded communal rangelands of the Eastern Cape, South Africa: implications for livestock sustainability and management interventions

In this study, we examined forage, soil and cattle serum mineral status, and their relationships in severely (SD) and less severely (LSD) degraded rangelands, South Africa. Such evidence is essential to inform rangeland policies and interventions. In each rangeland, three villages were identified, and sites near, at intermediate and far distance from homesteads were selected. Soil from LSD had generally greater macro and microelement levels than soil from SD rangelands. Soil elements (i.e. N, P, Mg and Cu) displayed variations at local scale (between villages or distance points from homestead) depending on degradation condition. Degradation level significantly influenced the local distribution of grasses between the distance points from the homestead (Themeda triandra Forssk., Aristida congesta Roem. & Schult.) and between villages [Digitaria eriantha Steud., Eragrostis curvula (Schrad.) Nees, T. triandra]. Forage biomass was low (range: 45–223 kg ha−1) in both degraded conditions. During the dry periods, cattle grazing SD rangelands had most serum minerals below a critical level, but pastures showed Cu and N deficiencies only. We conclude that the low forage yield may limit animal mineral intake. On the other hand, the great abundance of grasses with high forage values (60–76%) indicates that degraded areas may be regenerated. In SD rangelands, complete mineral supplementation is recommended during the dry period.

Fermentation Quality of Silages Produced from Wilted Sown Tropical Perennial Grass Pastures with or without a Bacterial Inoculant

High growth rates and rapid reproductive development and associated decline in feed quality of sown tropical perennial grass pastures present management challenges for livestock producers. Conservation of surplus forage as silage could be an effective management tool. Experiments were conducted to evaluate the fermentation quality of silages produced from tropical grasses. Five species (Chloris gayana, Megathyrsus maximus, Panicum coloratum, Digitaria eriantha and Cenchrus clandestinus) were ensiled without additives after a short, effective wilt at dry matter (DM) contents ranging from 302.4 to 650.1 g kg−1. The fermentation profile of all silages in 2019 was typical for high DM silages, but in 2020 ammonia (% of total nitrogen: NH3-N), acetic acid and pH levels were higher. In 2020 M. maximus (302.4 g kg−1 DM) was poorly preserved with 20.2% NH3-N. The DM content of all other silages exceeded 350 g kg−1 and fermentation quality was generally good. In a second experiment, M. maximus was ensiled at 365 g kg−1 chopped and 447 g kg−1 DM chopped and unchopped, either without or with Pioneer 1171® (Lactobacillus plantarum and Enterococcus faecium) or Lallemand Magniva Classic® (L. plantarum and Pediococcus pentasaceus) bacterial inoculant. Inoculants increased lactic acid production, reduced pH and improved fermentation compared to Control, but D-lactate, L-lactate and acetic acid production differed between inoculants. Unchopped silages had higher pH and NH3-N and better preserved protein fraction than chopped silages at the same DM content. In both experiments, wilting increased water soluble carbohydrates by 0.5–31.5 g kg−1 DM and ensiling increased degradation of the protein fraction. We concluded that a rapid and effective wilt combined with a bacterial additive resulted in well preserved tropical grass silages.

Effects of Hydrolysable Tannin Supplementation on Nutrient Intake, Milk Production and Milk Somatic Cell Count in On-farm Dairy Cows

This study examined the effects of hydrolysable tannin (HT) supplementation on nutrient intake, milk production and milk somatic cell count in on-farm dairy cows. Fifty-four Holstein Friesian crossbred cows weighing 450 to 500 kg and were subjected to an experiment for 49 days. Dairy cows were divided into 3 groups, which were 1) the control group without HT supplementation and the HT supplementation groups, which received HT products (15 g/day), 2) one contains 3.15 g/day of HT and 3) another contains 6.30 g/day of HT. Hydrolysable tannin was extracted from sweet chestnut wood (Castanea Sativa Mill.). Dairy cows received HT products on the top of concentrate (22 % CP) in the morning after milking. Total mixed ration (TMR), pangola grass (Digitaria eriantha) hay and concentrate were offered according to animal nutrient requirements. The results showed that supplementation of HT has no influence (p > 0.05) on the nutrient intake, milk yield and milk composition when compared to the control group. In addition, the increased levels of HT caused quadratic increases in fat:protein at pre-treatment and treatment periods (p < 0.05; p = 0.06, respectively), while differential somatic cell count (DSCC) at treatment and post-treatment periods showed a quadratic decrease (p < 0.05; p < 0.05, respectively), with supplementation of HT product containing 6.30 g HT/day (p < 0.05) being the lowest. Therefore, it can be concluded that supplementation with HT product does not affect nutrient intake, milk yield, however, it could reduce DSCC and probably improve udder health in on-farm dairy cows.
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 A quantitative performance comparison of Radio over Free Space Optical links
 WDM increases the capacity while the MIMO links help to maintain the transmission range
 A combination of WDM and MIMO RoFSO links is identified to be the best

Stability of milk from dual purpose cows with different types of feeding

Objective: To establish milk stability using the alcohol test in cows with different feeding strategies in the tropical dairy system. Design/methodology/approach: Ten crossbred Holstein x Zebu cows whose milk frequently tested positive to the alcohol test were housed in individual yards and distributed into two groups. Experiment 1. T1: cows consumed dry Pangola grass (Digitaria eriantha); T2: cows consumed green Maralfalfa grass (Pennisetum violaceum). Forage was provided ad libitum. Experiment 2. T1 cows were supplemented with a concentrate with higher crude protein and metabolizable energy percentage than T2 cows; this percentage was gradually increased up to 4.0 kg. Milk was subjected to alcohol testing. Variance analyzes were performed under categorical data models. Results: Higher percentages of cases that tested positive for alcohol were observed in cows that consumed dry grass than in cows that consumed green grass (P<0.05). The concentrate addition to diets based on dry or green forage reduced the positive case percentage. Implications: A balanced diet improves milk stability. Findings/conclusions: The improvement in the cows’ nutritional value decreases the percentage of milk with positive results in the alcohol test.

Pastures and Climate Extremes: Impacts of Cool Season Warming and Drought on the Productivity of Key Pasture Species in a Field Experiment.

Shifts in the timing, intensity and/or frequency of climate extremes, such as severe drought and heatwaves, can generate sustained shifts in ecosystem function with important ecological and economic impacts for rangelands and managed pastures. The Pastures and Climate Extremes experiment (PACE) in Southeast Australia was designed to investigate the impacts of a severe winter/spring drought (60% rainfall reduction) and, for a subset of species, a factorial combination of drought and elevated temperature (ambient +3°C) on pasture productivity. The experiment included nine common pasture and Australian rangeland species from three plant functional groups (C3 grasses, C4 grasses and legumes) planted in monoculture. Winter/spring drought resulted in productivity declines of 45% on average and up to 74% for the most affected species (Digitaria eriantha) during the 6-month treatment period, with eight of the nine species exhibiting significant yield reductions. Despite considerable variation in species’ sensitivity to drought, C4 grasses were more strongly affected by this treatment than C3 grasses or legumes. Warming also had negative effects on cool-season productivity, associated at least partially with exceedance of optimum growth temperatures in spring and indirect effects on soil water content. The combination of winter/spring drought and year-round warming resulted in the greatest yield reductions. We identified responses that were either additive (Festuca), or less-than-additive (Medicago), where warming reduced the magnitude of drought effects. Results from this study highlight the sensitivity of diverse pasture species to increases in winter and spring drought severity similar to those predicted for this region, and that anticipated benefits of cool-season warming are unlikely to be realized. Overall, the substantial negative impacts on productivity suggest that future, warmer, drier climates will result in shortfalls in cool-season forage availability, with profound implications for the livestock industry and natural grazer communities.

The life cycle of Puccinia digitariae on Digitaria eriantha and Solanum species in South Africa

ABSTRACT Rust fungi are important plant pathogens and have been extensively studied on crops and other host plants worldwide. This study describes the heterecious life cycle of a rust fungus on Digitaria eriantha (finger grass) and the Solanum species S. lichtensteinii (large yellow bitter apple), S. campylacanthum (bitter apple), and S. melongena (eggplant) in South Africa. Following field observations, inoculation studies involving telial isolates collected from Digitaria plants produced spermogonia and aecia on S. lichtensteinii, S. campylacanthum, and S. melongena. Likewise, inoculation of finger grass with aeciospores collected from the aforementioned Solanum species produced uredinia on D. eriantha. Pennisetum glaucum (pearl millet varieties Milkstar and Okashana, as well as 17 experimental lines) and S. elaeagnifolium (silverleaf nightshade or bitter apple) were resistant to the rust isolates. Morphological descriptions and molecular phylogenetic data confirmed the identity of the rust on Digitaria as P. digitariae, herein reinstated as a species and closely related to P. penicillariae the pearl millet rust, also reinstated. Puccinia digitariae has a macrocyclic, heterecious life cycle in which teliospores overwinter on dormant D. eriantha plants. Aecia sporulate on species of Solanum during spring and early summer to provide inocula that infect new growth of Digitaria.

In vitro anthelmintic activity of extracts from coffee pulp waste, maize comb waste and Digitaria eriantha S. hay alone or mixed, against Haemonchus contortus

In vitro anthelmintic activity of extracts from coffee pulp waste, maize comb waste and Digitaria eriantha S. hay alone or mixed, against Haemonchus contortus

Field-scale calibration of the PAR Ceptometer and FieldScout CM for real-time estimation of herbage mass and nutritive value of rotationally grazed tropical pasture

Destructive sampling method is regarded as the standard approach for evaluating pasture herbage. However, non-destructive methods for managing pastures are rapidly gaining acceptance because they provide faster results that can influence real-time decision-making. The objective of this study was to calibrate the PAR Ceptometer and FieldScout CM as non-destructive tools for real-time prediction of herbage mass and nutritive value, respectively of rotationally grazed pasture. Sixty (60) herbage samples were cut from three (3) rotationally grazed paddocks to determine herbage mass (HM) and nutritive value [crude protein (CP), apparent neutral detergent fiber (aNDF), apparent acid detergent fiber (aADF) and in vitro organic matter digestibility (IVOMD)] after leaf area index (LAI) and light interception (LI) [PAR Ceptometer], sward height (SH) and chlorophyll index (CI) [FieldScout CM] measurements were taken. There were strong positive correlations between sward physical characteristics and CI (r2 = 0.74 to 0.90) and between CI and CP (r2 = 0.81). The LAI (Y=4,287x−1762)and LI (Y=149.9x−5,925) accounted for 81 % and 75 % of variability in HM, respectively. The CI accounted for a maximum of 68 % variability of CP. However, concordance correlation coefficient (CCC) of these prediction models were poor. Models with highest prediction accuracy for HM were those with SH (cb= 0.89) and LAI (cb= 0.81). Regression bias was the main sources of error for HM prediction models, while the primary error for CI predicted aNDF (75.4 % MSPE) and IVOMD (95.5 % MSPE) occurred at random. It was concluded that the PAR Ceptometer produced unreliable estimates of HM while the FieldScout CM is capable of producing reliable predictions of aNDF and IVOMD of rotationally grazed mixed Brachiaria arrecta and Digitaria eriantha pastures.

Associative bacterial diversity of pangolão, a stressresilient tropical grass

Some forage species, such as pangolão grass (Digitaria eriantha Steud. cv. Survenola), are resilient in tropical semi arid regions. A possible reason for this is the presence of endophytic and rhizospheric microorganisms. Thus, this study evaluated the diversity of associative bacteria in pangolão grass. Bacteria associated with the roots, culm, leaves, and rhizospheric soil were isolated and characterized in three municipalities of Pernambuco, Brazil. An initial phenotypic characterization was followed by a genotypic assessment by based repetitive extragenic palindromic-polymerase chain reaction (BOX-PCR) and partial sequencing of the 16S rRNA gene. We obtained 325 phenotypically-characterized isolates grouped into 243 strains with 100% similarity by BOX-PCR. The most diverse sampling environment was Araripina, and all factors affected bacterial diversity. There were 135 groups with 90% similarity, that were represented by a single strain each for sequencing. Among the sequenced strains, 118 showed 96.84–99.9% similarity with previously described strains, whereas 17 could not be identified. The following 18 genera were identified from three phyla, five classes, seven orders, and 13 families: Achromobacter, Agrobacterium, Bacillus, Burkholderia, Curtobacterium, Enterobacter, Herbaspirillum, Kosakonia, Ochrobactrum, Paenibacillus, Pantoea, Priestia, Pseudomonas, Rhizobium, Serratia, Shinella, Stenotrophomonas, and Variovorax. The diversity of endophytic and rhizospheric bacteria may contribute to the resilience of pangolão, as various strains of these genera have been described as plant growth promoters. This is the first evaluation of pangolão bacterial diversity under tropical semi arid conditions. Since several of the genera include strains known to promote plant growth, we propose further research to evaluate this on crops.

A lucerne-digit grass pasture offers herbage production and rainwater productivity equal to a digit grass pasture fertilized with applied nitrogen

In recent years, livestock producers have widely sown tropical perennial grasses, such as digit grass (Digitaria eriantha), in the frost-prone summer dominant rainfall zone of eastern Australia. Tropical grasses require substantial nitrogen inputs to maintain water productivity and forage quality. Perennial legumes offer a potential nitrogen source for these perennial grasses when sown in a mixed sward. Lucerne (Medicago sativa) is the perennial legume most widely sown in grazing systems in south-eastern Australia. In this study, conducted over the period 2014–2018, we compared the soil water dynamics and rainwater productivity of pure stands of digit grass (fertilized with applied nitrogen), lucerne, desmanthus (Desmanthus virgatus) and leucaena (Leucaena leucocephala) and binary mixtures of digit grass (not fertilized with applied nitrogen) with each legume. We found that often growing season actual evapotranspiration (ETa) was similar among the treatments (P > 0.05), but rainwater productivity (kg DM/ha.mm) and proportion (%) of legume herbage mass were not (P < 0.05). Our results showed that the lucerne-digit grass mix was equally productive and efficient as fertilized digit grass (P > 0.05), particularly in the latter three seasons. However, lucerne dominated the herbage mass (c. > 67% legume). Leucaena production was delayed by frost and severely impacted by competition with digit grass, and generally underperformed both lucerne and desmanthus. This observation did always not hold when alfalfa mosaic virus (AMV) impacted desmanthus in specific seasons. Our experiment has shown that a mixed sward of lucerne-digit grass is highly productive and offered high rainwater productivity. Both desmanthus and leucaena, in mixes with digit grass, provided useful contributions of legume herbage mass, in specific seasons and under specific conditions, but both underperformed overall compared with lucerne.

Contribution of Soil Type to Quantity and Nutritional Value of Grass Species on the South African Highveld

The biggest threat to cattle production in most South African communal areas is poor management of grazing, which negatively affects vegetation and soil structures. This study was conducted to assess the spatial variation of grass species density, production potential and quality in Breyten (Hutton soil type), Davel (Avalon soil type), and Wesselton (Clovelly soil type) communal rangelands in the highveld region of Mpumalanga province. Three 100 m transects per grazing area, placed at 50 m intervals (0, 50, and 100 m) were used to collect soil samples at 200 mm depth. A 100 m permanent line point method, replicated three times (50 m apart) per site, was used to identify and collect grass species samples. Grass species were classified according to life form, palatability, ecological status, and abundance. Grasses species were also harvested for chemical composition and in vitro ruminal dry matter degradability determination. Soils from the study areas had an acidic pH range (3.5–4.5). Hutton soil had the highest (p &lt; 0.05) nitrate (N-NO3) concentration (0.770 mg/kg) compared to Clovelly (0.030 mg/kg) and Avalon (0.533 mg/kg) soil types. Thirty-one grass species composed of 28 turf perennials, two weak perennials and one perennial creeping grass were identified across the study areas. About 16% of identified grass species were classified as highly palatable, 39% as moderately palatable, and 32% as unpalatable. Across all the soil types, Digitaria eriantha had the highest (p &lt; 0.05) crude protein (CP) (106.5 g/kg DM) content when compared to other grass species. In the Avalon soil type, D. eriantha had the lowest (p &lt; 0.05) neutral detergent fiber (NDF) (696.4 g/kg DM). Across all soils, D. eriantha, Aristida congesta, Eragrostis curvula, Eragrostis gummiflua, and Eragrostis plana grasses had the same (p &gt; 0.05) 48-h in vitro ruminal dry matter degradability Hutton soil had a higher proportion of common and dominant grass species as well as more palatable species with higher crude protein content than Avalon and Clovelly soils. However, for all three rangelands, there is a need for supplementary feeding to enhance the production efficiency of livestock given that the nutritive value of grasses was low.

Foraging behaviour and dry matter intake by lambs in a silvopastoral system

Dry matter intake, nutritional contribution of forage to the diet and Lamb foraging behavior were assessed in a silvopastoral system. Twelve Pelibuey female lambs (6.3 months of age, 23.74 ± 3.5 kg live weight), were randomly assigned to two treatments: pastures of Digitaria eriantha (monoculture) or pastures of D. eriantha and Guazuma ulmifolia (silvopastoral). During a 15 day period, lambs foraged individually in 20.14 m2 paddocks each day; time spent grazing and browsing were assessed by scan sampling; dry matter intake was estimated (day 11-15), using the chromic oxide (Cr2O3) method, and metabolizable energy (ME) and protein (CP) ingested by the lambs were estimated. Data analyses were performed using a complete randomized design (dry matter intake) and a repeated-measure design (ME and CP, foraging time) with factorial treatment structure of season (windy and dry) and pasture (monoculture and silvopastoral). Voluntary intake (season*treatment interaction, p = 0.015) was lower in the windy-silvopastoral treatment (448.5±38.2 g day-1) than in the other treatments (625.8±38.2 to 680.5±38.2 g day-1). The contribution of ME (719.7-1190.2 kcal·day-1) and CP (53.7-100.7 g day-1) was low to cover the lamb requirements in all treatments, because forage availability and dry matter intake were low. Lambs dedicated from 6.65±0.26 to 7.50 ± 0.26 h to foraging; time spent grazing was longer that browsing in the silvopastoral system (p &lt; 0.0001). The time dedicated to foraging, intake, and nutritive quality of forage from in both pasture types did not provide nutrients and energy during any season for maintenance of the lambs.

Aptitud para la implantación y supervivencia de gramíneas forrajeras estivales nativas y exóticas en la provincia de La Pampa, Argentina

Grasslands in arid and semiarid regions suffer ecological degradation and production limitations. A management alternative to reverse this situation is the sowing of mega­thermal forage species. The objective was to evaluate vegetative and reproductive characters for the establishment of native and introduced forage grasses of the semiarid pampean region. The species evaluated were: the native Leptochloa crinita and Pappophorum caespitosum and the introduced ones Eragrostis curvula, Eragrostis superba, Tetrachne dregei, Digitaria eriantha and Panicum coloratum. Survival (Ix), Canopy height (AM), Canopy diameter (DM), Number of tillers (NM), Length of floral stems (LVF), Number of floral stems (NVF), Number of seeds per plant (NSP) and Weight of thousand seeds (PMS) were determined. Survival, 3 months after implantation, was high and without significant differences between species. P. coloratum obtained the highest values regarding: NVF (3 and 12 months), LVF (12 months), DM (10 and 12 months) and PMS (4 and 14 months after its implantation). D. eriantha obtained the highest values in: LVF (3 months) and AM (3 and 12 months); while E. curvula in NM (10 and 12 months), T. dregei in NSP (14 months) and P. caespitosum in NSP (4 months after implantation) and had significant differences with the rest of the species. It is feasible to implant the evaluated species, because they show high survival, good propagation by tillering (introduced) and high seed production (native).

Influence of Tree Density on Vegetation Composition and Soil Chemical Properties in Savanna Rangeland of Eastern Cape, South Africa

The proliferation of woody species alters the vegetation structure, leading to loss of rangeland productivity. It aimed to assess the influence of tree density on vegetation and soil chemical properties at three levels of encroachment; open, moderate and dense. Each level of encroachment was replicated 3 times, a 5000 m2 plot was marked per replicate. Four belt transects 200 m2 were placed per plot. Woody species within each belt transect per replicate were identified and recorded to evaluate woody species composition. Grass species composition was assessed using a step point method. Soil was sampled per replicate and analysed for chemical properties. Results showed that 71% of grasses were increasers and 29% decreasers. Digitaria eriantha and Eragrostis obtusa were the most dominant species. Vachellia karoo and Aloe ferox were the most dominant woody species. The dense had high nitrogen (1.48%) compared to the moderate (0.23%) and the open (0.17%). Increaser species, soil carbon, soil pH increased with the increase of tree density. It was concluded that the replacement of highly palatable grasses with inferior ones was due to improper rangeland management practices. It was recommended that land users form rangeland management associations and set up conservation agreements for proper management of resources.