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Phillip B. McKenna, Natasha Ufer, Vanessa Glenn, Neil Dale, Tayla Carins, Trung h. Nguyen, Melody B. Thomson, Anthony J. Young, Stuart Buck, Paul Jones, Peter D. Erskine
Context. Pasture dieback has emerged as a significant threat to the health and productivity of sown pastures in eastern Queensland and northern New South Wales, Australia.
Aims. We aimed to address knowledge gaps on spatial spread patterns, recovery trajectories and floristic changes using remote sensing and ground surveys.
Methods. We used a time series of high-resolution (12–25 cm) aerial imagery to quantify and compare pasture dieback spread over 7 years in three land-use areas: ungrazed pasture, grazed pasture and rehabilitation following mining. The green leaf index was applied using supervised random forest algorithms to classify areas affected between 2015 and 2021. Flora surveys were conducted to compare impacted and unimpacted areas for the three land uses and validate classifications.
Key results. The first emergence of pasture dieback was in ungrazed pasture, and these areas recorded the highest rate of dieback spread at 1.88 ha month−1, compared with 0.54 and 0.19 ha month−1 in rehabilitated and grazed pastures respectively. Field validation showed that dieback-impacted pastures shifted from buffel grass (Cenchrus ciliaris L.), to forb-dominated communities with significantly different species mix, biomass and cover conditions. An analysis of local climate data showed that winter night-time temperatures and rainfall were notably higher than long-term means in the year preceding the first detection of pasture dieback.
Conclusions. High resolution aerial imagery and ground surveys can be used to monitor pasture health by employing vegetation indices and random forest classifiers.
Implications. Ungrazed pastures and roadside areas should be managed to protect the region from further outbreaks.
Lucas Mateus de Souza Mota, Bruno Henrique Martines Cezar, Odilene de Souza Teixeira, Raul Dirceu Pazdiora, Alice Munz Fernandes, Gleimiria Batista da Costa Matos, Ana Karina Dias Salman, Diego Soares Machado, Rangel Fernandes Pacheco, Isabelle Damé Veber Angelo
Context. The future of livestock farming is based on grazing management practices that balance using natural resources and forage technical efficiency for cattle.
Aims. This study aimed to investigate the bromatological characteristics and cattle performance under continuous and intermittent stocking systems in Panicum maximum cvv. Mombaça and Tanzania pastures, as well as identify the appropriate height for managing these forages.
Methods. A systematic review and meta-analysis were used from selecting studies available in scientific article format in electronic databases: Google Scholar, ISI Web of Science, and PubMed. We identified 4691 documents, of which 13 were submitted to meta-analysis.
Key results. Tanzania pasture presented 564.25 ± 38.56 g kg−1 of leaf biomass dry matter (DM) and 3.09 ± 0.34 of leaf stem−1 ratio in intermittent stocking system, which was higher than continuous system, with values of 313.10 ± 38.56 g kg−1 DM (P = 0.0380) and 1.04 ± 0.34 (P = 0.0216), respectively. Animals’ average daily gain was greater in continuous stocking system than intermittent system, with values of 0.91 kg day−1 and 0.67 kg day−1, respectively. Additionally, post-grazing height ≥31 cm for Tanzania increased average daily gain by 28.3% (P = 0.0263), and height ≥39 cm for Mombaça increased average daily gain by 38.1% (P = 0.0002).
Conclusions. Post-grazing residues from the intermittent method or constant pasture height from the continuous method are the main indicators for adapting pasture management. Therefore, grazing management at heights between ≥31 and 39 cm for Tanzania and Mombaça is promising for animal performance.
Implications. Results provide subsidies for decision making regarding grazing management to maximise animal productivity.
Context. Heat shock proteins play a vital role in cellular homeostasis by protecting proteins against various environmental stresses, which facilitates the survival of plants under unfavourable conditions.
Aims. We aimed to provide the first comprehensive genomic and expression analysis of the HSP70 gene family in betel palm (Areca catechu) to elucidate its role in heat stress response.
Methods. Genomic analysis revealed 34 putative HSP70 genes distributed across 13 chromosomes. These were renamed AcatHSP70 and classified into five subfamilies (A–E) based on phylogenetic analysis. These genes are mostly localised in the chloroplast, cytoplasm, and nucleus. Gene ontology revealed that these genes are mostly involved in heat stress. The gene duplication events of HSP70 genes involved only segmental duplications. We subjected betel palm seedlings (2 years old) to heat stress under controlled conditions for 30 days at high, low, and room temperatures for expression analyses of HSP70 genes.
Key results. Expression analysis revealed eight putative candidate genes (AcatHSP70-3, AcatHSP70-13, AcatHSP70-22, AcatHSP70-19, AcatHSP70-21, AcatHSP70-24, AcatHSP70-25, and AcatHSP70-26) that showed significantly higher expression under high-temperature stress. AcatHSP70-5 showed higher expression under low-temperature treatment, and AcatHSP70-16 was responsive at room temperature treatment.
Conclusion. We conclude that the majority of AcatHSP70 genes play a crucial role under thermal stress conditions, and respond to high-temperature stress as shown by the quantitative reverse transcription polymerase chain reaction analysis.
Implications. This comprehensive characterisation of the HSP70 gene family provides novel insights into the thermal protection mechanisms of betel palms in changing climates.
Context. Forage–livestock systems contribute to Brazilian greenhouse gas (GHG) emissions, harming the environment and reducing bioeconomic efficiency. Employing technologies like pasture management is crucial for sustainable mitigation.
Aims. Our objective was to measure greenhouse gas emissions of beef cattle in forage systems by exploring well-managed Brachiaria hybrid pastures in the Brazilian Amazon Biome.
Methods. The experimental design was a randomised complete block, with two cultivars: Ipyporã and Mulato II, in four replicates, totalling eight experimental units, and each experimental unit was 1.5 ha.
Key results. Ipyporã pastures had 88.5% greater herbage mass than Mulato II in January (8350 vs 4430 kg dry mass ha−1). There was no difference between cultivars for soil GHG emissions. The greatest enteric methane and carbon dioxide values were measured in February. In Ipyporã pastures, the average daily gain was 57% and 50% greater than in Mulato II, in February (837 vs 533 g day−1) and March (1054 vs 700 g day−1) respectively. Enteric methane and carbon dioxide were 34% and 48% less respectively in Ipyporã pastures in February.
Conclusions. Soil GHG emissions in fertilised pastures followed similar patterns across different cultivars, but those with greater production tended to produce more emissions (soil and enteric) due to fertilisation and increased stocking rates.
Implications. Forage–livestock production systems benefit from adequate grazing and pasture management of two Brachiaria cultivars, resulting in greater productivity compared to GHG emissions. This leads to reduced emissions per unit of product, contributing to the development of a more efficient and sustainable forage–livestock system.
Context. Chia (Salvia hispanica L.), a nutrient-rich crop with potential application in different industries, is sensitive to salinity. Halotolerant plant-growth promoting bacteria could be a biotechnological strategy to increase chia’s salinity tolerance.
Aims. The aim of this study was to determine the morphological and physiological response of chia plants inoculated with free-living halotolerant plant-growth promoting bacteria and grown in saline soils under greenhouse conditions.
Methods. A total of 15 bacterial treatments were inoculated to plants potted in soils with three electrical conductivity levels: 0.5, 4, and 6 dS m−1. Mortality and morphological and physiological parameters were evaluated. The measured variables were used to calculate a relative growth index.
Key results. Bacterial inoculation had a positive effect on plants at 4 dS m−1. Plants inoculated with Pseudomonas sp. AN23, Kushneria sp. T3.7, and C6 (Halomonas sp. 3R12 + Micrococcus luteus SA211) exhibited the best morphological and physiological performance (51% longer shoots, up to 90% heavier roots and up to 400% higher photosynthetic rate than control plants). Moreover, plants inoculated with Kushneria sp. T3.7 and C5 (Halomonas sp. 3R12 + Pseudomonas sp. AN23) showed significant increase in stomatal conductance and transpiration rate (up to 12 times) and in proline production (up to 345 μg g−1 leaf fresh weight) with respect to control plants (8 μg g−1 leaf fresh weight) under saline conditions.
Conclusions. The analysed extremophilic plant-growth promoting bacteria enhanced growth and stress tolerance in chia, a salt-sensitive crop.
Implications. Free-living plant-growth promoting bacteria isolated from hypersaline environments have potential for bioinoculant formulation for salinity-sensitive crops.
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