A Modified SIR Model Equivalent to a Generalized Logistic Model, with Standard Logistic Approximations

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Use of phosphorus fertiliser for increased productivity of legume-based sown pastures in the Brigalow Belt region – a review

The Brigalow Belt bioregion of southern and central Queensland supports a large percentage of northern Australia's sown pastures and beef herd. The Brigalow soils were widely thought to have adequate phosphorus (P) for cropping, sown pastures and grazing animals, which has led to almost no use of P fertiliser on sown pastures. The majority of pastures established in the region were sown with tropical grasses only (i.e. no legumes were sown). Under grass-only pastures, nitrogen (N) mineralisation rates decline with time since establishment as N is 'tied-up' in soil organic matter. This process leads to a significant decline in pasture and animal productivity and is commonly called 'pasture rundown'. Incorporating pasture legumes has been identified as the best long-term solution to improve the productivity of rundown sown grass pastures. Pasture legumes require adequate P to grow well and fix large amounts of N to increase the productivity of rundown sown grass pastures. Producers and farm advisors have traditionally thought that P fertiliser is not cost-effective for legume-based improved pastures growing on inland areas of Queensland despite there being little, if any, data on production responses or their economic outcomes. Recent studies show large and increasing areas of low plant available soil P and large responses by pasture legumes to P fertiliser on Brigalow soils. The economic analysis in this scoping study indicates potential returns of 9–15% on extra funds invested from the application of P fertiliser, when establishing legumes into grass pastures on low P soils (i.e. lower than the critical P requirement of the legume grown). Higher returns of 12–24% may be possible when adding P fertiliser to already established grass/legume pastures on such soils. As these results suggest potential for significant returns from applying P fertiliser on legume pastures, it is recommended that research be conducted to better quantify the impacts of P fertiliser on productivity and profit. Research priorities include: quantifying the animal production and economic impact of fertilising legume-based pastures in the sub-tropics for currently used legumes; quantifying the comparative P requirements and responses of available legume varieties; understanding clay soil responses to applied P fertiliser; testing the P status of herds grazing in the Brigalow Belt; and quantifying the extent of other nutrient deficiencies (e.g. sulphur and potassium) for legume based pastures. Development and extension activities are required to demonstrate the commercial impacts of applying P fertiliser to legume based pastures

Use of phosphorus fertiliser for increased productivity of legume-based sown pastures in the Brigalow Belt region – a review

The Brigalow Belt bioregion of southern and central Queensland supports a large percentage of northern Australia's sown pastures and beef herd. The Brigalow soils were widely thought to have adequate phosphorus (P) for cropping, sown pastures and grazing animals, which has led to almost no use of P fertiliser on sown pastures. The majority of pastures established in the region were sown with tropical grasses only (i.e. no legumes were sown). Under grass-only pastures, nitrogen (N) mineralisation rates decline with time since establishment as N is 'tied-up' in soil organic matter. This process leads to a significant decline in pasture and animal productivity and is commonly called 'pasture rundown'. Incorporating pasture legumes has been identified as the best long-term solution to improve the productivity of rundown sown grass pastures. Pasture legumes require adequate P to grow well and fix large amounts of N to increase the productivity of rundown sown grass pastures. Producers and farm advisors have traditionally thought that P fertiliser is not cost-effective for legume-based improved pastures growing on inland areas of Queensland despite there being little, if any, data on production responses or their economic outcomes. Recent studies show large and increasing areas of low plant available soil P and large responses by pasture legumes to P fertiliser on Brigalow soils. The economic analysis in this scoping study indicates potential returns of 9–15% on extra funds invested from the application of P fertiliser, when establishing legumes into grass pastures on low P soils (i.e. lower than the critical P requirement of the legume grown). Higher returns of 12–24% may be possible when adding P fertiliser to already established grass/legume pastures on such soils. As these results suggest potential for significant returns from applying P fertiliser on legume pastures, it is recommended that research be conducted to better quantify the impacts of P fertiliser on productivity and profit. Research priorities include: quantifying the animal production and economic impact of fertilising legume-based pastures in the sub-tropics for currently used legumes; quantifying the comparative P requirements and responses of available legume varieties; understanding clay soil responses to applied P fertiliser; testing the P status of herds grazing in the Brigalow Belt; and quantifying the extent of other nutrient deficiencies (e.g. sulphur and potassium) for legume based pastures. Development and extension activities are required to demonstrate the commercial impacts of applying P fertiliser to legume based pastures

Mixed farming diversification may be costly: southern Queensland case study

Many farmers in Australia and in other countries have a choice of crop or livestock production, and many choose a mixture of both, based on risk preference, personal interests, markets, land resources and local climate. Mixed farming can be a risk-spreading strategy, especially in highly variable climates, but the right scales of each enterprise within the mix may be critical to farm profitability.To investigate expected farm profits, the probability of breaking even, as well as the worst and best case scenarios, we used farm data and APSIM (Agricultural Production Systems Simulator) to simulate the production of a typical, semi-arid, mixed-farm in southern Queensland. Three farming system scenarios were investigated: I, livestock and more intensive cropping; II, current production system of livestock and minimal cropping; and III, livestock only. We found that the expected profits were in the order system I > system III > system II. The key reason for the lower profits of system II was the high overhead cost of capital to continue some cropping, with low annual cropping income. Under the worst case scenario, in years with low rainfall, system I had the greatest downside risk with far greater financial losses. Systems I and III had similar probabilities of breaking even, and higher than system II, which incurs cropping overheads and limited cropping returns. Therefore, system II was less desirable than either system I or III. This case study helps farmers and advisors of semi-arid mixed farming enterprises to be better informed when making decisions at the paddock and whole-farm level, in both the short and long term, with respect to profit and risk. The method used in this paper can be applied to other mixed farms, in Australia and elsewhere

Review of productivity decline in sown grass pastures

Productivity decline in sown grass pastures is widespread in northern Australia and reduces production by approximately 50%, a farm gate cost to industry of > $17B over the next 30 years. Buffel grass is the most widely established sown species (>75% of plantings) and has been estimated to be “dominant” on 5.8 M hectares and “common” on a further 25.9 M hectares of Queensland. Legumes are the most cost effective mitigation option and can reclaim 30-50% of lost production. Commercial use of legumes has achieved mixed results with notable successes but many failures. There is significant opportunity to improve commercial results from legumes using existing technologies, however there is a need for targeted research to improve the reliability of establishment and productivity of legumes. This review recommends the grazing industry invest in targeted R,D&E to assist industry in improving production and sustainability of rundown pastures

FcγRI-Deficient Mice Show Multiple Alterations to Inflammatory and Immune Responses

AbstractThe inactivation of the mouse high-affinity IgG Fc receptor FcγRI resulted in a wide range of defects in antibody Fc-dependent functions. These studies showed the primary importance of FcγRI in endocytosis of monomeric IgG, kinetics, and extent of phagocytosis of immune complexes, in macrophage-based ADCC, and in immune complex-dependent antigen presentation to primed T cells. In the absence of FcγRI, antibody responses were elevated, implying the removal of a control point by the deletion of FcγRI. In addition, FcR-γ chain-deficient mice were found to express partially functional FcγRI. Thus, FcγRI is an early participant in Fc-dependent cell activation and in the development of immune responses

Stocktake and analysis of legume evaluation for tropical pastures in Australia

There has been a large effort dedicated to the evaluation of a wide variety of sub-tropical and tropical pasture legumes in the past. This large body of information is very valuable for guiding any future legume development activities, yet much of this information was at risk of being lost. This project aimed to collate and store this tropical legume evaluation data and use this and knowledge from past researchers to recommend priority R&D approaches and activities for future pasture legume development. Together with retired pasture researchers, legume evaluation datasets were identified, prioritised, and collated into a database which captured over 180 000 data records collected from 567 sites across northern Australia. Using this large integrated dataset, high power statistical approaches were used to identify legume species which performed well across this large range of evaluation sites. Several species and genera were identified which warrant further investigation and further in-depth analysis of the database in species or genera of interest would be valuable. A gap analysis of commercially proven, underused and prospective legumes was conducted across the key production regions of northern Australia. A range of material was identified which could offer potential improvements in seed production, cold, drought or grazing tolerance compared to the current released varieties