https://www.ajol.info/index.php/ajrfs/issue/feed African Journal of Range and Forage Science 2024-01-04T06:13:54+00:00 Publishing Manager publishing@nisc.co.za Open Journal Systems The African Journal of Range &amp; Forage Science is the leading rangeland and pastoral journal in Africa. The Journal is dedicated to publishing quality original material that advances rangeland ecology and pasture management in Africa. <br /><p><strong></strong>Read more abou the journal <a href="http://www.nisc.co.za/products/4/journals/african-journal-of-range-and-forage-science" target="_blank">here</a>. </p> https://www.ajol.info/index.php/ajrfs/article/view/261725 Book Review: ‘An Ecological Guide to the Bush’ 2024-01-03T13:48:55+00:00 Ian McDonald ian@unigradcollege.co.za <p>No abstract.</p> 2024-01-04T00:00:00+00:00 Copyright (c) 2024 https://www.ajol.info/index.php/ajrfs/article/view/261723 Associative nitrogen fixation could be common in South African mesic grassland 2024-01-03T13:37:31+00:00 Craig D Morris morris@ukzn.ac.za Danvir R Ramesar morris@ukzn.ac.za Richard J Burgdorf morris@ukzn.ac.za <p><strong>Non-symbiotic nitrogen-fixing bacterial diazotrophs closely associated with the roots of grasses probably contribute most of the new nitrogen acquired to sustain productive natural grasslands, yet their ecology is poorly understood, especially in southern Africa. We looked for genetic evidence, using qPCR and gel electrophoresis, for the presence of the bacterial </strong><strong><em>nifH </em></strong><strong>gene associated with the roots of four grass species (20 plants each) in a mesic grassland in South Arica, which would indicate the potential for N fixation by diazotrophs. Grasses most tolerant of low N (</strong><strong><em>Aristida junciformis</em></strong><strong>) were predicted to harbour the most diazotrophs, especially compared to those most responsive to fertiliser N (</strong><strong><em>Eragrostis curvula</em></strong><strong>). However, the </strong><strong><em>nifH </em></strong><strong>gene was found in all 80 root samples and did not differ in copy number between species. Sequencing of a representative sample confirmed the identity of the </strong><strong><em>nifH </em></strong><strong>gene. The recently burned half of the grassland had 60% more relative </strong><strong><em>nifH </em></strong><strong>gene copy numbers than the area burned 15 months previously, suggesting that grass growth stimulated by fire could recruit diazotrophs. Given their ubiquity and importance in the N economy of grasslands, research is required to characterise root-associated diazotroph communities, quantify their N fixation rates, and understand their environmental controls.</strong></p> 2024-01-04T00:00:00+00:00 Copyright (c) 2024 https://www.ajol.info/index.php/ajrfs/article/view/261724 Nutritional properties and <i>in vitro</i> gas production in cactus pear (<i>Opuntia stricta</i>) and cassava (<i>Manihot esculenta</i>) shoot silages 2024-01-03T13:41:25+00:00 Cleyton de Almeida Araújo glayciane_gois@yahoo.com.br Marcelo de Siqueira Pinto glayciane_gois@yahoo.com.br Getúlio Figueiredo de Oliveira glayciane_gois@yahoo.com.br Jessica Maria da Conceição da Silva Rodrigues glayciane_gois@yahoo.com.br Diego de Sousa Cunha glayciane_gois@yahoo.com.br Claudenilde de Jesus Pinheiro Costa glayciane_gois@yahoo.com.br Daniel Anderson de Souza Melo glayciane_gois@yahoo.com.br André Luiz Rodrigues Magalhães glayciane_gois@yahoo.com.br Gherman Garcia Leal de Araújo glayciane_gois@yahoo.com.br Fleming Sena Campos glayciane_gois@yahoo.com.br Glayciane Costa Gois glayciane_gois@yahoo.com.br <p><strong>This study evaluated the effects of different inclusion levels of cactus pear (</strong><strong><em>Opuntia stricta</em></strong><strong>) (at 0%, 15%, 30% or 45% on fresh matter basis) ensiled with shoots of cassava (</strong><strong><em>Manihot esculenta</em></strong><strong>) on the mineral nutrients, carbohydrates fractionation, nitrogen compounds and </strong><strong><em>in vitro </em></strong><strong>gas production, using a completely randomised design consisting of four treatments and five replicates per treatment, totalling 20 experimental units. There were significant increases (</strong><strong><em>p </em></strong><strong>&lt; 0.05) in the concentrations of Mg, B, Fe, total carbohydrates and fraction A+B1 (non-fibre carbohydrates) with increased cactus pear inclusion, whereas nitrogen and fractions B2 (available fibre) and C (insoluble protein, indigestible in rumen and intestine) significantly decreased (</strong><strong><em>p </em></strong><strong>&lt; 0.05) with the inclusion. The inclusion of cactus pear significantly (</strong><strong><em>p </em></strong><strong>&lt; 0.05) reduced crude protein content and the fractions A (non-protein nitrogen) and B3 (insoluble protein with a slow degradation rate in the rumen) in the silages. Fraction B1+B2 (rapidly degraded true protein + insoluble protein with an intermediate degradation rate in the rumen</strong><strong>) </strong><strong>significantly increased (</strong><strong><em>p </em></strong><strong>&lt; 0.05) with increasing levels of cactus pear inclusion. Gas production parameters showed a quadratic effect for Ca, Mn, observed gas volume, estimated gas volume by the bicompartmental model, rate of degradation of fibre carbohydrates, and rate of degradation of non-fibre carbohydrates (</strong><strong><em>p </em></strong><strong>&lt; 0.05). The use of cactus pear increased the content of soluble sugars in mixed silages made with the aerial part of cassava plants. However, gas production was low with the inclusion of 45% cactus pear. Based on the overall results, the combination of 45% cactus pear with 55% of the aerial part of cassava in mixed silages is recommended.</strong></p> 2024-01-04T00:00:00+00:00 Copyright (c) 2024 https://www.ajol.info/index.php/ajrfs/article/view/261718 Histological arrangements of plant tissue of different elephant grasses as influenced by their genotypes 2024-01-03T13:11:38+00:00 Thaíse Virgínia Freire Ramos Peixoto janersoncoelhozoo@gmail.com Alexandre Carneiro Leão de Mello janersoncoelhozoo@gmail.com Mércia Virginia Ferreira dos Santos janersoncoelhozoo@gmail.com Márcio Vieira da Cunha janersoncoelhozoo@gmail.com Rejane Magalhães de Mendonça Pimentel janersoncoelhozoo@gmail.com Luiz Henrique Gonçalves da Silva janersoncoelhozoo@gmail.com Djalma Euzébio Simões Filho janersoncoelhozoo@gmail.com Janerson José Coelho janersoncoelhozoo@gmail.com <p><strong>Elephant grass genotypes display a variety of morphological differences, influencing the nutritive value of the forage. This study evaluated the histological arrangements of the leaves and stems of different elephant-grass genotypes, two tall-sized (Elephant B and IRI-381) and two dwarfs (Mott and Taiwan A-146 2.37), during a two-year trial. The grasses were harvested at 60-day intervals for two years. Biometric analyses of the stems and leaves were performed based on histological measurements. An </strong><strong><em>in vitro </em></strong><strong>dry matter digestibility (IVDMD) assay of the forage was performed. Among the elephant grass genotypes, the lignified cells and vascular bundles of the stems had higher variation than the leaves. Tall-sized genotypes displayed more lignified tissues in stems than the dwarfs. The transversal area occupied by vascular bundles and lignified cells were higher in Elephant B (44 911 μm² and 35 895 μm²) (</strong><strong><em>p </em></strong><strong>&lt; 0.05), compared to the dwarfs. Forage IVDMD was higher in leaves (699 g kg<sup>–1</sup></strong> <strong>of dry matter [DM]) than in the stems (678 g kg<sup>–1</sup></strong> <strong>of DM), considering all genotypes (</strong><strong><em>p </em></strong><strong>&lt; 0.05). We did not observe any direct influence of genotype on forage digestibility, despite some differences in the histological arrangements.</strong></p> 2024-01-04T00:00:00+00:00 Copyright (c) 2024 https://www.ajol.info/index.php/ajrfs/article/view/261719 Dynamics of tall fescue (<i>Festuca arundinacea</i>) and Kikuyu grass (<i>Cenchrus clandestinus</i>) pastures associated with white clover (<i>Trifolium repens</i>) in small-scale dairy systems in the highlands of central Mexico 2024-01-03T13:18:24+00:00 Dalia Andrea Plata-Reyes cmarriagaj@uaemex.mx Carlos Galdino Martínez-García cmarriagaj@uaemex.mx Omar Hernández-Mendo cmarriagaj@uaemex.mx Carlos Manuel Arriaga-Jordán cmarriagaj@uaemex.mx <p><strong>An on-farm participatory study was undertaken to assess changes over seasons on the availability, botanical and morphological composition, and nutritive value of herbage from two pastures in small-scale dairy systems in the highlands of central Mexico. One pasture (TF-33) was originally sown with tall fescue, while the second pasture (KY) was naturally invaded by Kikuyu grass; both associated with white clover and over-sown in winter with annual ryegrass. Sampling was every 28 days for a year. Variables were sward height, net herbage accumulation, soil cover, tiller density, chemical composition, and </strong><em>in vitro </em><strong>digestibility. A split-plot design was used. Sward height was greater for KY. There were no differences (</strong><em>p </em><strong>&gt; 0.05) for herbage accumulation. TF-33 was 53% live tissue, 30% dead tissue, and 17% other plant material, whilst KY was 50% live tissue, 30% dead tissue, and 18% other plant material. TF-33 showed a higher leaf to stem proportion, while stem was higher in KY. Kikuyu grass and annual ryegrass performed better when associated with TF-33 than in KY pasture. Seasonal changes significantly affected sward height, herbage mass and net herbage accumulation, whereby TF-33 performed better than KY in winter. The multispecies association of diverse grasses and legumes may be complementary at different times of the year due to plasticity among species, and is a feasible option for small-scale dairy systems.</strong></p> 2024-01-04T00:00:00+00:00 Copyright (c) 2024 https://www.ajol.info/index.php/ajrfs/article/view/261720 Quantifying the effect of chemical bush control of <i>Senegalia mellifera</i> on vegetation production in the Eastern Kalahari Bushveld, South Africa 2024-01-03T13:23:51+00:00 CJ Harmse cjj.harmse@gmail.com A De Ath cjj.harmse@gmail.com K Kellner cjj.harmse@gmail.com <p><strong>Bush encroachment is the invasion of whole landscapes by indigenous and alien woody species. An imbalance in the ratio of grasses to bushes is a consequence of bush encroachment due to competition for moisture, nutrients and sunlight. This imbalance results in a decrease in grass cover, plant biodiversity and grazing capacity, leading to severe economic losses. Several methods exist to reduce high woody plant densities, including mechanical, manual, biological or chemical control. In this study, we assessed the structural and compositional attributes of the grass layer and compared these to the woody vegetation structure for herbicide-controlled rangelands and the no chemical control. The main objective was to evaluate the potential of chemical control to restore an open savanna system dominated by perennial grasses. Woody-dominated vegetation resulting from long-term overgrazing was assessed and compared to chemically controlled sites. Results revealed that chemical control treatment increased forage production and maintained woody-patch conservation. After the treatment, the sites were characterised by more productive and desirable woody species. The re-encroachment of woody species at all bush-controlled sites is possible. A follow-up control programme to manage and mitigate encroachment needs to be implemented when mitigating bush encroachment.</strong></p> 2024-01-04T00:00:00+00:00 Copyright (c) 2024 https://www.ajol.info/index.php/ajrfs/article/view/261721 Grazing capacity change on a small Mediterranean-type South African offshore island following the control of invasive alien European rabbits (<i>Oryctolagus cuniculus</i>) 2024-01-03T13:27:18+00:00 Thabisisani Ndhlovu tsvuuraz@ukzn.ac.za Zivanai Tsvuura tsvuuraz@ukzn.ac.za Karen J Esler tsvuuraz@ukzn.ac.za <p><strong>Invasive alien species (IAS) are one of the most important factors driving extinction rates worldwide. Among the IAS, the impacts of introduced mammals on native biodiversity are most severe, with the European rabbit (</strong><strong><em>Oryctolagus cuniculus</em></strong><strong>) being the most problematic. Globally, European rabbits have been introduced to five continents and more than 800 islands or island groups where they are a threat to biodiversity and human livelihoods. The impacts of European rabbits on biodiversity and human livelihoods have been extensively studied across the globe. However, some regions of the world, such as the offshore islands along Africa’s southern coast, have been sparsely studied. In this study, we monitored change in grazing capacity on a South African offshore island, Robben Island, following an attempt to eradicate European rabbits between 2008 and 2009. Grazing capacity on the island increased following rabbit control, driven by the recovery of palatable plant species in response to release from herbivory. There was no change in grazing capacity at sites under Eucalyptus plantations because of the inhibitory effects of the alien trees on understory vegetation dynamics. We believe that grazing capacity changes on Robben Island are indicative of potential vegetation changes on other southern African offshore islands.</strong></p> 2024-01-04T00:00:00+00:00 Copyright (c) 2024 https://www.ajol.info/index.php/ajrfs/article/view/261722 Shepherding is not a shot in the dark: evidence of low predation losses from the Northern Cape province of South Africa 2024-01-03T13:30:33+00:00 Heidi-Jayne Hawkins hhawkins@conservation.org Liaan Minnie hhawkins@conservation.org HN (Walter) van Niekerk hhawkins@conservation.org HO de Waal hhawkins@conservation.org Dave Balfour hhawkins@conservation.org Graham IH Kerley hhawkins@conservation.org <p><strong>Predation threatens the viability of livestock farming, while lethal predator management can negatively influence wildlife ecology. There is renewed interest in non-lethal vs lethal methods of livestock protection, but a systematic comparison is lacking. Using multivariate models, we explored how predator management (shepherd, no shepherd), land tenure, flock characteristics, and environmental factors drive losses of small livestock across the Northern Cape, South Africa. Black-backed jackal and caracal were the dominant livestock predators in both management groups. Predation of small livestock was five-fold lower in the shepherd (1.29% ± 0.38) compared to the non-shepherd group (6.09% ± 0.51; </strong><strong><em>p </em></strong><strong>&lt; 0.0001), with a seven-fold lower-level of lamb predation (1.67% ± 0.51 vs. 11.52% ± 0.99; </strong><strong><em>p </em></strong><strong>&lt; 0.0001). Predator management, livestock type, and flock size (but not land tenure or environmental factors) were predictor variables in a best-fit linear mixed effects model describing small livestock losses (</strong><strong><em>p </em></strong><strong>&lt; 0.0001). We interpret our findings with caution because we could not control for predator and prey abundances, and the non-herder group could have inflated their predation estimates. While the efficacy of shepherding requires more research, we suggest that it is a viable predation management approach in South Africa and beyond.</strong></p> 2024-01-04T00:00:00+00:00 Copyright (c) 2024