Panicum Maximum Research Articles

Effects of Seed Proportion on Forage Yield of Greenleaf Desmodium (<i>Desmodium intortum)</i> and Guinea Grass (<i>Panicum maximum)</i> Mixture at Adami Tulu Agricultural Research Center

Establishing of grass-legume pastures is one of the recognized strategies for enhancing both quantity and quality of feed resources. Therefore, determining the impact of seed proportion on the nutritional qualities and forage yield of combinations of guinea grass and green leaf desmodium is the goal of this study. A Randomized Complete Block Design (RCBD) with three replications was used to arrange five seed proportions of desmodium and guinea grass. Analysis of variance revealed that variations in treatments have significant differences (p<0.05) on panicum heights, desmodium tillers, and Desmodium height. In addition, the effects of years showed significant (p<0.05) effects on panicum tiller, desmodium height, and percentage of coverages. Interaction of treatments with years showed a significant effect on tiller per plant and plant heights while the other parameters weren’t influenced. The combined mean of dry matter and percentage of coverage have showed significant differences (p<0.05) between the treatments. This result reveals that the seed proportion have effect on the dry matter and percentage of plant coverages. The aggressivity index also has significant mean differences (P<0.05) between the treatments. Legumes with the lowest proportion (25%) performed less competently than those with the highest proportions (75%) and 50% D. intortum. The crowding coefficient of P. maximum and D. intortum mixed forage showed significance differences (P<0.05). However, the value of seed proportion on crowding coefficient of panicum maximum and desmodium intortium were more than one. The LER has significant differences (P<0.05) due to ratio of P.maximum and D.intortium mixture and its value at T2, T3, and T4 showed as to be (LER>1) that revealed the yield advantages. Cobined mean results showed that there is significance difference (P<0.05) of CP, Ash, ADF, NDF and ADL due to different seed proportion mixture. In addition the CP of panicum incurred from 8.24% to 18.55% by mixing different seed proportion of D.intortium. An integration of legume forage with grasses improves the feed quality and quantity. Thus, based on the dry matter, yield advantage and nutritive values the integration of 75% and 50% desmodium is recommended for use in the study areas and similar agro-ecologies.

Prescribed fire and grass mulch impact on selected soil properties and amelioration potentials of amendments under an agricultural field in Ile-Ife, Nigeria

Prescribed fire (slash and burn) tends to impede the sustainable functionality of soil in agricultural systems. However, the use of amendment has a potential to reverse these negative effects. Prescribed fire is still used by farmers in Nigeria for land preparation before planting. This has continued to increase soil degradation in Nigeria with no agronomic activities that could ameliorate this effect in view. This study therefore examined the influence of prescribed fire and grass mulch on selected soil physical properties and organic carbon immediately after burning, and the potential of amendment to improve the soil properties negatively affected by fire. The prescribed fire treatments consisted of 200 °C and 500 °C fire intensities using Megathyrsus maximus (a large perennial bunch of grass that is dominant in the study area) as the fuel and also served as the grass mulch. Cured poultry manure at 7.5 t ha−1 was combined with urea at 40 kg N ha−1 and applied as a combined amendment while a single dose of urea was applied at 80 kg N ha−1 as an inorganic amendment. The experiment was carried out across three cropping seasons on maize (Zea mays L.) in 2019 and 2020. Soil water repellency (SWR), bulk density (Db), soil unsaturated hydraulic conductivity (Kunsat), water stable aggregates (WSA), soil strength (SS), and soil organic carbon (SOC) were determined immediately after burning and three months after amendments were applied. Data obtained were subjected to analysis of variance and means separated using the Duncan multiple range test at p≤0.05. Results showed that prescribed fires increased SWR by an average of 50.1 and 62.7 % for 200 °C and 500 °C intensities, respectively compared with the control. Three months later, the SWR was reduced by 25.9 % and 62.3 % for 200 °C and 500 °C, respectively when no amendment was added. Notably, the addition of sole urea and cured poultry manure + urea reduced the SWR by 50 % and 48.5 %, respectively in the 200 °C intensity, and 62.2 % and 62.7 % in the 500 °C intensity, respectively. Also, Kunsat was reduced by an average of 49.6 and 62.2 % by 200 °C and 500 °C intensities, respectively just after burning. However, it was not improved three months after the prescribed fires despite the applied amendments. The prescribed fire of 200 °C and grass mulch had no significant influence on OC just after the fire. Also, amendments did not significantly improve OC three months after prescribed fire. Therefore, the non-improvement of other soil properties, after the applied amendments, showed that further study is required to determine the required rate of the applied amendments that will significantly improve other soil properties negatively affected by prescribed fire in agricultural soils.

Recombinant GH3 β-glucosidase stimulated by xylose and tolerant to furfural and 5-hydroxymethylfurfural obtained from Aspergillus nidulans

The β-glucosidase gene from Aspergillus nidulans FGSC A4 was cloned and overexpressed in the A. nidulans A773. The resulting purified β-glucosidase, named AnGH3, is a monomeric enzyme with a molecular weight of approximately 80 kDa, as confirmed by SDS-PAGE. Circular dichroism further validated its unique canonical barrel fold (β/α), a feature also observed in the 3D homology model of AnGH3. The most striking aspect of this recombinant enzyme is its robustness, as it retained 100% activity after 24 h of incubation at 45 and 50 ºC and pH 6.0. Even at 55 °C, it maintained 72% of its enzymatic activity after 6 h of incubation at the same pH. The kinetic parameters Vmax, KM, and Kcat/KM for ρ-nitrophenyl-β-D-glucopyranoside (ρNPG) and cellobiose were also determined. Using ρNPG, the enzyme demonstrated a Vmax of 212 U mg − 1, KM of 0.0607 mmol L − 1, and Kcat/KM of 4521 mmol L − 1 s − 1 when incubated at pH 6.0 and 65 °C. The KM, Vmax, and Kcat/KM using cellobiose were 2.7 mmol L − 1, 57 U mg − 1, and 27 mmol –1 s − 1, respectively. AnGH3 activity was significantly enhanced by xylose and ethanol at concentrations up to 1.5 mol L − 1 and 25%, respectively. Even in challenging conditions, at 65 °C and pH 6.0, the enzyme maintained its activity, retaining 100% and 70% of its initial activity in the presence of 200 mmol L − 1 furfural and 5-hydroxymethylfurfural (HMF), respectively. The potential of this enzyme was further demonstrated by its application in the saccharification of the forage grass Panicum maximum, where it led to a 48% increase in glucose release after 24 h. These unique characteristics, including high catalytic performance, good thermal stability in hydrolysis temperature, and tolerance to elevated concentrations of ethanol, D-xylose, furfural, and HMF, position this recombinant enzyme as a promising tool in the hydrolysis of lignocellulosic biomass as part of an efficient multi-enzyme cocktail, thereby opening new avenues in the field of biotechnology and enzymology.

Qualitative Production of Mixture Silage within a Sustainable Concept

Climate change and seasonality in forage production have caused alterations in animal feed. Thus, this study evaluated the composition of silages from soybean (Glycine max (L.) Merrill) mixed with tropical grasses. The experimental design was randomized blocks with four replications. Treatments were silage from soybeans, silage from soybeans with Aruana Guinea grass (Megathyrsus maximus cv. Aruana), and silage from soybeans with Congo grass (Urochloa ruziziensis cv. Comum). Silos were stored for 60 days in the laboratory at room temperature. The silage from soybeans with Aruana Guinea grass showed the highest contents of dry matter, crude fiber, neutral detergent fiber, insoluble nitrogen in neutral detergent fiber, and insoluble nitrogen in acid detergent fiber but the lowest levels of crude protein and ether extract. The highest content of mineral material and hemicellulose was observed in the silage from soybeans with Congo grass. The silages from soybeans and soybeans with Congo grass showed no significant differences for acid detergent fiber and lignin. In conclusion, the use of tropical grasses as a component to improve the quality of silage from soybeans is an alternative for forage conservation in ruminant production systems, especially at the dry season.

Effect of nitrogen fertilization and shading on morphogenesis, structure and leaf anatomy of Megathyrsus maximus genotypes.

The use of exotic grasses of African origin for pastures in Brazil has been a major advancement in livestock production, but little is known about the responses of these grasses to nitrogen fertilizers associated with shading. In this study, the morphogenetic, structural, and leaf anatomical characteristics of Megathyrsus maximus cultivars' Tamani and Quênia were investigated as a function of N dose and shade. Morphogenetic and structural characteristics and leaf anatomy were studied under three shading levels (0, 30, and 50 %) and four N doses (0, 100, 200, and 300 kg N ha-1) to simulate growth in a silvopastoral system. When comparing the cultivars, Quênia was more efficient in terms of phyllochron up to fertilization with 100 kg N ha-1. The leaf senescence rate of Tamani was higher than that of Quênia at the 30 and 50 % shade levels. The total area (TA) occupied by leaf tissues decreased in Quênia as a function of the increase in N fertilization, whereas the TA of Tamani did not change. The thickness of the adaxial epidermis was greater in Quênia (0.68 µm) than in Tamani (0.50 µm) when not fertilized. The area occupied by the mesophyll was greater in both cultivars when they received fertilization equivalent to 300 kg N ha-1. Quênia grass has a smaller phyllochron than Tamani grass, due to the rapid reconstruction of its photosynthetic apparatus, especially when it receives higher levels of nitrogen fertilization. However, Tamani grass has a greater distribution of plant tissues. The mesophyll area is larger in Tamani grass due to the greater presence of chloroplasts, which facilitates digestion by animals. The Tamani modified the leaf anatomical tissues more significantly in relation to shading, whereas the Quênia modified them in relation to N fertilization, which reinforces the suggestion of a more appropriate use of Tamani in silvopastoral systems.

FTIR Characterization of Bioactive Functional Groups Present in Crude Extract of Mycoherbicides Produced from Consortium Culture of Rhizosphere Fungal Isolates

ABSTRACT Consortium culture can be a relatively cheap and environment-friendly technology for producing secondary metabolites like pesticides (herbicides). This study produced some metabolites from a consortium culture of fungal isolates obtained from the rhizospheres of Panicum maximum, Ipomoea involucrata and Amaranthus viridis. The isolates from rhizospheres of the above-named plants were co-cultured using Czapek broth and were incubated in an incubator shaker for 28 days. The co-culture combinations were: Aspergillus welwitschiae and Trichoderma hamatum (consortium 1), Aspergillus welwitschiae and Aspergillus aculeatus (consortium 2), and Aspergillus aculeatus and Trichoderma hamatum (consortium 3). Crude extracts from each consortium were characterized using Fourier Transform Infrared Spectroscopy (FTIR). The FTIR results showed that consortium 1 had peak spectra range from 418.57 cm−1 (S–S stretch of aryl disulfides) to 3462.34 cm−1 (alcohol, aliphatic primary amine), consortium 2 had peak spectra range from 420.5 cm−1 (halo compound) to 3456.65 cm−1 (alcohol, aliphatic primary amine) and consortium 3 had peak spectra from 457.14 cm−1 (halo compound) to 3448.84 cm−1 (alcohol, aliphatic primary amine). Some of the compounds produced by the consortia were pesticidal in nature and are hence, considered a potential technology in developing organic pesticides.

Evaluation of co-culture of cellulolytic fungi for enhanced cellulase and xylanase activity and saccharification of untreated lignocellulosic material.

Bioethanol production from lignocellulosic materials is hindered by the high costs of pretreatment and the enzymes. The present study aimed to evaluate whether co-cultivation of four selected cellulolytic fungi yields higher cellulase and xylanase activities compared to the monocultures and to investigate whether the enzymes from the co-cultures yield higher saccharification on selected plant materials without thermo-chemical pretreatment. The fungal isolates, Trichoderma reesei F118, Penicillium javanicum FS7, Talaromyces sp. F113, and Talaromyces pinophilus FM9, were grown as monocultures and binary co-cultures under submerged conditions for 7days. The cellulase and xylanase activities of the culture filtrates were measured, and the culture filtrates were employed for the saccharification of sugarcane leaves, Guinea grass leaves, and water hyacinth stems and leaves. Total reducing sugars and individual sugars released from each plant material were quantified. The co-culture of Talaromyces sp. F113 with Penicillium javanicum FS7 and of T. reesei F118 with T. pinophilus FM9 produced significantly higher cellulase activities compared to the corresponding monocultures whereas no effect was observed on xylanase activities. Overall, the highest amounts of total reducing sugars and individual sugars were obtained from Guinea grass leaves saccharified with the co-culture of T. reesei F118 with T. pinophilus FM9, yielding 63.5% saccharification. Guinea grass leaves were found to be the most susceptible to enzymatic saccharification without pre-treatment, while water hyacinth stems and leaves were the least. Accordingly, the study suggests that fungal co-cultivation could be a promising approach for the saccharification of lignocellulosic materials for bioethanol production.

Production and nutrients value of local forage plant in the coastal region of Lebak-Banten

Abstract The coastal region of Lebak-Banten is home to 30% of the total buffalo population in the Lebak district. To develop the buffalo population in the area, forage plants (FP) need to be available year-round. However, the coastal region is categorized as a marginal area due to its limitations such as high salinity and partial acidity. Developing FP in the coastal area involves introducing superior, salinity or acidity tolerant FP, or increasing production of local FP through cultivation techniques. Research was conducted using a survey method based on distance from the beach (25-100 m, 1 km, and 5 km), reflecting the relocation habits of farmers during both dry and rainy seasons The result of the exploration were cultivated in the Ciawi experimental garden utilizing a randomized completely block design with 5 replications. Cultivated grass was also observed, and the parameters measured were productivity and nutritional value of the forage. Results showed that 15 types of FP could be grown on acidic land, and 5 types on saline land. Axonopus grass had the highest production on a 1m2 area, while Illat Kerbau grass had the highest production per clump. In the saline land, Jotang grass (Comelina benghalensis 1238.33 g/m2) and Japanese grass (584.40 g/m2) had the highest productions. The highest production after planting was achieved with Binuangeun grass (Dactyloctenium aegyptium (38.77 g/clump) and Benggala (Panicum maximum) cv Mombasa grass (2846.7 g/clump) for local and cultivated grasses, respectively. These results demonstrate the potential for developing local grass varieties tolerant to salinity or acidity through breeding or cultivation techniques to achieve optimal production.

Solid Formulation of <em>Trichoderma virens</em> for the Management of Banana Anthracnose Caused by<em> Colletotrichum musae</em>

Trichoderma spp. widely used as biocontrol agents for controllin g a wide range of plant diseases. Banana anthracnose caused by Colletotrichum musae is a prominent, widely distributed postharvest disease. This study was carried ou t to assess the effectiveness of locally isolated Trichoderma virens against C. musae and the mass producti on of T. virens using locally available, low-cost solid substrates. T. virens was tested for the inhibition of C. musae isolate in -vitro and in-vivo by dual plating and inoculating into two varieties of ripened banana: Kolikuttu and Cavendish, respectively. For mass production, T. virens was inoculated into different solid substrates including scraped coconut waste, sawdust, tea waste, seeds from rice, finger millet, and maize, dried pieces of water hyacinth plant, paddy straw, and Panicum maximum leaves; regularly taken spore co unts (cfu/g) and checked for viability by plating after 12 weeks of storage. The pathogen inhibition percentag e by T. virens was 74.10%. Disease severity was 0% in Kolikuttu and 19% in Cavendish after 5 days of T. virens spore appli cation (1x107 spores/ml). Significantly higher (p≤0.05) mean spore production resulted in rice seeds (9.345x109 spores/g) compared to the other substrates and the least resulted in sawdust (1.808x109 spores/g) at the 8th week after T. virens inoculation. Spores of T. virens were viable in all the tested substrates throughout the study period. The results conclude that T. virens is capable of controlling banana anthracnose and can be efficiently mass-produced by using rice seeds, dried pieces of P. maximum leaves, and f inger millet seeds as substrates.

Effect of Diet on Carcass and Meat Quality in Rabbits

A trial was conducted to assess the growth performance of Soviet Chinchilla rabbit under different feeding regimes at Livestock Farm Complex, Madhavaram Milk Colony, Chennai-51. Thirty Soviet Chinchilla weaned bunnies of both sexes aged around six weeks were randomly selected and divided into three groups namely T1 (Guinea grass + Concentrate), T2 (Hydroponic Maize + Concentrate) and T3 (Hydroponic Cowpea +Concentrate). All the groups were reared under similar intensive system of management. The dressing percentage of rabbits in T1, T2 and T3 were 59.40±0.87,60.20±1.50 and 61.20±0.97 respectively. There was no significant difference in dressing percentage between the treatment groups. The meat bone ratio in T3 was significantly higher than T1 and T2. The carcass characteristics did not differ between the treatment groups. It is concluded from this study the hydroponic fodder production technology can be recommended for broiler rabbit production in urban, peri-urban areas where land availability for fodder production is a constraint.

Effect of Integrated Nutrient Management Practices on Physiological Growth Parameters of Perennial Fodder Crops in Custard Apple Based Horti-Pastoral System

A field experiment was conducted to assess the impact of integrated nutrient management practices on perennial fodders within a custard apple based horti-pastoral system during the Rabi season of 2021 at the Agroforestry Research Block of Professor Jayashankar Telangana State Agricultural University, Rajendranagar, Hyderabad. The study featured two main plots dedicated to the fodder species Cenchurus ciliaris (Anjan grass) and Megathyrsus maximus (Guinea grass), while six nutrient management practices along with a control were implemented as sub plots in a split-plot design. Results revealed that M. maximus has recorded significantly higher Physiological growth parameters viz., CGR, RGR at different growth stages in first cut. Among the integrated nutrient management practices, higher CGR values were recorded at 45 DAI with the application of75% RDN + 25% N through PGLM (13.47 g m-2 day-1) which was on par with –the application of 75% RDN + 25% N Through PM (12.78 g m-2 day-1) and RGR found non-significant. The experiment concludes that M. maximus found best for horti-pastoral system with PGLM or PM supplemental nutrient management.

Radiological impact of 226Ra, 232Th and 40K in fodders from Penang, Malaysia

The plant acts as an important route for the transfer of radionuclides from the soil to animals, leading to the transfer of radiation to human food products such as beef and milk. Therefore, the level of radioactivity in fodder plays a crucial role in deciding whether cattle may be allowed to graze in a certain area. In this study, the activities of 226Ra, 232Th and 40K were measured via gamma-ray spectrometry on different fodder samples, including napier leaves, rice straw, corn stalks, guinea grass, mixed pasture, palm oil leaves and palm kernel collected from Penang, Malaysia. Theoretical calculations were also conducted to estimate the levels of these radionuclides in caw's products (beef and milk), as well as their potential radiological impact on local consumers. On average, the annual effective dose due to ingestion of radionuclides in milk was 11.39 μSv y−1, whereas in beef it was 5.63 μSv y−1. These values are significantly lower than the worldwide average of 290 μSv y−1. Research confirmed that farmers' usage of the aforementioned feeds did not cause any radiation-related health risks.

Urea fertilization for potentializing beef cattle performance in agroforestry systems in the humid tropics

AbstractThis study hypothesized that urea fertilization could optimize animal performance in an agroforestry system. This study evaluated how increasing rates of N fertilization (0, 100, 200, and 400 kg N ha−1 year−1) using urea (CH4N2O) affected forage mass, nutritive value, and beef cattle (Bos indicus) performance in an agroforestry system with Massai grass (Megathyrsus maximus Jacq. cv. Massai) and legume tree (Mimosa caesalpiniifolia Benth.), in the humid tropic region of Brazil, over 2‐year period. The experiment was carried out in a randomized complete block design with four treatments (N fertilizer rates) and three replications. Forage mass was positive and linearly affected by N fertilization (p = .0236, R2 = 0.92), ranging from 1297 to 1583 kg DM ha−1 under 0 and 400 kg N ha−1 year−1, respectively. There was greater average forage mass during the rainy period (1826 kg ha−1) (p < .05). Crude protein in green forage mass increased linearly (p = .0041, R2 = 0.91) in function of the N applied. Cattle average daily gain showed a positive quadratic response to the rates of N applied (p = .0298, R2 = 0.97), ranging from 0.46 kg to 0.68 kg animal day−1; and the gain per area increased linearly from 1.84 to 2.68 kg LW ha−1 day−1 (p = .0640, R2 = 0.96). The findings indicate that applying 200 kg N ha−1 year−1, split‐applied during the rainy season, would yield acceptable outcomes in terms of forage mass, nutritive value, and animal performance for this type of agroforestry system.

Intensively Reared Nelore Steers with Levels of Concentrate and Protein Sources during the Dry Season.

The objective of this study was to evaluate the effect of different nutritional strategies on the intensification of beef cattle farming on pastures during the dry period of the year. Eighty male cattle (testers) were randomly allocated to 16 paddocks formed with Mombaça grass (Megathyrsus maximus), totaling five animals (testers) per paddock. The strategies consisted of two LCs [10 and 16.7 g·kg-1 body weight (BW)] and two PSs with DDGS and SBM in a completely randomized design with a 2 × 2 factorial arrangement. The chemical, structural, and productive characteristics of the forage were evaluated, as well as the performance, productivity, and serum parameters of the supplemented animals. The forage presented a greater L:C (p = 0.033) and CP content (p = 0.007) when the lowest LC was used. Animals that received the highest LC had the highest supplement intake (p < 0.001) and the lowest pasture intake (p < 0.001). The nutritional strategy with an LC of 16.7 g·kg-1 of body weight (BW) resulted in a greater increase in total BW, i.e., 200 kg·BW ha-1 more. Therefore, higher levels of concentrate ensure greater productivity for beef cattle grazing, and DDGS can replace SBM in supplements used in the intensive raising of beef cattle on pasture without compromising the performance and productivity of the animals.

Expression Profiling of MSP1 Gene Involved in Mega-gametophyte Development in Ploidy Series of Guinea Grass (Panicum maximum Jacq.)

Hybrid seeds are playing important role in increasing agricultural production. However, process of hybrid seed development involves high cost for most of the major crops. Under such situation apomixis can play crucial role in creation of one-time hybrid and maintain it for multiple generations. Apomixis and polyploidy are interrelated with each other and expression of apomixis completely relies on polyploidy. Guinea grass (Panicum maximum Jacq.) provides ideal system for research on apomixis and polyploidy because of its extensive diversity in morphological, cytological, biochemical, and molecular characteristics. The experiment was carried out in the eight-ploidy series i.e. 3x, 4x, 5x, 6x, 7x, 8x, 9x, 11x and one obligate sexual Guinea grass genotype SRP75. Considering role of MSP1 gene in apomeiosis, its expression was studied in guinea grass at three developmental stages of spikelet viz., pre-meiotic, meiotic and post-meiotic. Findings of this study highlight the complex regulation of MSP-1 expression during different developmental stages and across various ploidy levels in guinea grass. At pre-meiotic stage, except 4x, downregulation pattern of MSP1 was observed in all the ploidy levels. But opposite was observed in the post-meiotic stage.

Synthesis and Characterization of Cross-Linked Aggregates of Peroxidase from Megathyrsus maximus (Guinea Grass) and Their Application for Indigo Carmine Decolorization.

We present the synthesis of a cross-linking enzyme aggregate (CLEAS) of a peroxidase from Megathyrsus maximus (Guinea Grass) (GGP). The biocatalyst was produced using 50%v/v ethanol and 0.88%w/v glutaraldehyde for 1 h under stirring. The immobilization yield was 93.74% and the specific activity was 36.75 U mg-1. The biocatalyst surpassed by 61% the free enzyme activity at the optimal pH value (pH 6 for both preparations), becoming this increase in activity almost 10-fold at pH 9. GGP-CLEAS exhibited a higher thermal stability (2-4 folds) and was more stable towards hydrogen peroxide than the free enzyme (2-3 folds). GGP-CLEAS removes over 80% of 0.05 mM indigo carmine at pH 5, in the presence of 0.55 mM H2O2 after 60 min of reaction, a much higher value than when using the free enzyme. The operational stability showed a decrease of enzyme activity (over 60% in 4 cycles), very likely related to suicide inhibition.

Improving growth and productivity of Guinea grass (Panicum maximum) using some biostimulants from Azolla pinnata and vermicompost.

Improving growth and productivity of Guinea grass (Panicum maximum) using some biostimulants from Azolla pinnata and vermicompost.

CARACTERÍSTICAS ESTRUTURAIS E PRODUTIVAS DO CAPIM MOMBAÇA SOB SOMBREAMENTO, NA FASE DE ESTABELECIMENTO

Forage grasses can be subjected to conditions that reduce the amount of light, either through intercropping with annual crops or through integration with tree species (silvopastoral system). Therefore, the objective of this work was to evaluate the productive and structural characteristics of grass. mombaça (Megathyrsus maximus), in the establishment phase, subjected to four levels of artificial shading (0, 30, 50 and 70%). The experimental design was completely randomized, with five replications. For this, plant height - PH, tiller length - TL, leaf/stem ratio (LSR), leaf dry mass, stem, dead and total material, tiller population density, individual tiller weight and number of leaves were evaluated. living and dead. Shading of 50% induced greater production of total dry mass (TDM), with no significant effect of TDM for the full sun and 30% treatments. A reduction in the number of tillers (NL) was observed as light was restricted, as well as an increase in plant height, tiller length and tiller dry weight. It is noteworthy that the highest average heights were found in 50 and 70% shading, as well as the highest individual tiller weights. The lowest production of total shoot dry mass and lowest LSR were found in the most severe shading. From the analysis of all variables, it can be inferred that mombaça grass presents better acclimatization in the range of 30 and 50% shading, which gives this cultivar good phenotypic plasticity, thus, the establishment of pasture is recommended in light to moderate shading. Therefore, the mombaça forage grass has potential for use in the silvopastoral system.

Applying the fermentability coefficient concept in tropical grass silages

Two experiments were carried out to evaluate whether the fermentability coefficient (FC) concept is applicable to Megathyrsus and Urochloa genera and whether the forage nitrate content alters the fermentation pattern of the respective silages. Guinea grass [Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs (Syn. Panicum maximum Jacq.) cv. MG18 Aries II] and palisade grass [Urochloa brizantha (Hochst. ex A. Rich) R.D. Webster (syn. Brachiaria brizantha (A. Rich) Stapf) cv. Marandu] were used in both experiments. In experiment 1, a broad range of FC was induced by different dry matter (DM) content and soluble carbohydrates (SC):buffering capacity (BC) ratio. The DM content was modified by wilting (i.e., guinea grass: direct cut at ∼200 g/kg, wilted to ∼300 and ∼400 g/kg; palisade grass: direct cut at ∼250 g/kg and wilted to ∼400 g/kg) while the SC:BC ratio was modified by addition of glucose [0, 5 and 10 g/kg of fresh matter (FM)] resulting in a factorial arrangement of 3 × 3 for guinea grass and 2 × 3 for palisade grass, with three replications per treatment. In experiment 2, five doses of sodium nitrate (0, 0.15, 0.30, 1.5 and 3.0 g/kg FM) were added factorially to DM and glucose levels used in experiment 1, leading to a factorial arrangement of 3 × 3 × 5 for guinea grass and 2 × 3 × 5 for palisade grass, with three replications per treatment. Regression analyses were performed using the REG procedure of SAS. An independent dataset of tropical grasses and their silages (n = 226) was used to validate the FC model. The FC equation obtained for tropical grasses in the current study did not diverge from the model derived from temperate forages (i.e., FC = DM + 80 × SC:BC), as the regression slopes were similar (79 vs. 80; P = 0.92). There was a linear negative correlation between FC and minimum content of nitrate required to inhibit butyric fermentation, confirming the clostridia-inhibiting role of nitrate in tropical grass silages too. However, the effect size differed between grass genera. In conclusion, as proposed for temperate forages, FC values ≥350 markedly decreases the risk of butyric fermentation, whereas FC values ≥400 completely suppress butyric fermentation in tropical grasses with moderate levels of nitrate and epiphytic lactic acid bacteria (LAB). The FC required to curtail butyric fermentation decreased linearly with nitrate concentration. Nevertheless, the minimum nitrate content to inhibit Clostridium development during silage fermentation depended on the forage species.

Water use of Guinea grass as affected by rainfed local conditions and practices in Sub-Saharan Africa

Ongoing efforts are currently being made to rehabilitate drought-affected pastures in Sub-Saharan Africa. One approach being explored is the introduction of non-native grass species, such as Megathyrsus maximus (Guinea grass). This study aims to investigate the water use of Guinea grass in semi-arid environments under rainfed conditions. Additionally, it aims to a better understanding of the variability of water use in Guinea grass through the utilization of the Bagging machine learning algorithm. Split-plot field experiments were carried out over two consecutive rainy seasons (2020-2021). The treatments included two in-situ rainwater harvesting practices, RWH (ridging plus terracing and terracing alone), three seeding rates, SR (1.5, 2.5, and 3.5 kg ha-1), and two soil nitrogen fertilization rates, SF (95 kg N ha-1 and 0 kg N ha-1). These treatments were compared to a control plot that involved zero-tillage, no fertilization, and no rainwater harvesting. The collected datasets were analyzed using R, SPSS 15, and spreadsheets. The results showed significant differences in plant indices and soil moisture content among the treatments. However, the treatments had insignificant effects on seasonal actual crop evapotranspiration (ETa), which ranged from 1.93 to 3.29 mm day-1. The interactions between SR and RWH were found to have significant impacts on water use. The Bagging algorithm revealed that the variability in ETa could be attributed to SR (42%), RWH (31%), and SF (26%), respectively. The implementation of rainwater harvesting practices resulted in a significant reduction in water usage, saving 86% of the green water used with a water footprint of 0.25 m3 kg-1, compared to 1.7 m3 kg-1 for no adoption of RWH conditions. The water use of rainfed Guinea grass was also found highly sensitive to dry spells. Further detailed studies using multiple-layer models are recommended to gain a better understanding of the non-linear interactions in semi-arid environments.