No abstract

The aim of this review was to provide an update on the complex relationship between manure application, altered pathogen levels and antibiotic resistance. This is necessary to protect health and improve the sustainability of this major farming practice in agricultural systems based on high levels of manure production. It is important to consider soil health in relation to environment and land management practices in the context of the soil microflora and the introduction of pathogens on the health of the soil microbiome. Viable pathogens in manure spread on agricultural land may be distributed by leaching, surface run-off, water source contamination and contaminated crop removal. Thus it is important to understand how multiple pathogens can persist in manures and on soil at farm-scale and how crops produced under these conditions could be a potential transfer route for zoonotic pathogens. The management of pathogen load within livestock manure is a potential mechanism for the reduction and prevention of outbreaks infection with Escherichia coli, Listeria Salmonella, and Campylobacter. The ability of Campylobacter, E. coli, Listeria and Salmonella to combat environmental stress coupled with their survival on food crops and vegetables post-harvest emphasizes the need for further study of these pathogens along with the emerging pathogen Providencia given its link to disease in the immunocompromised and its’ high levels of antibiotic resistance. The management of pathogen load within livestock manure has been widely recognized as a potential mechanism for the reduction and prevention of outbreaks infection but any studies undertaken should be considered as region specific due to the variable nature of the factors influencing pathogen content and survival in manures and soil. Mediocre soils that require nutrients could be one template for research on manure inputs and their influence on soil health and on pathogen survival on grassland and in food crops.

Our immediate and future food security agenda requires sustainable phosphorus (P) management, and recovered P products such a struvite form part of the solution. Waste recovered struvite is generated from different waste streams and precipitation technologies. In this study, we compare P speciation and bioavailability of nine struvite products with traditional/granulated chemical fertilisers to investigate performance characteristics across soil types in the Irish ecoregion.Elemental-analysis/P-speciation of the struvites was examined by ICP-OES, 31 P solid state NMR, PXRD and P-solubility tests. The fertiliser dose effect and bioavailability of the different struvite products were tested in 4-week and 3-month rhizotron experiments with Lolium perenne. In addition to calculating plant-P offtake, bioavailability was assessed by Olsen-P and Diffusive-Gradients-in-Thin-Films (DGT). The struvites differed markedly in colour/appearance, texture, metal content and solubility. Struvites all had similar P-speciation, but minor impurity phases were detected. There was no significant difference between the struvite samples and triple-superphosphate (TSP) with respect to either plant growth performance or P-bioavailability. The struvite products are produced from different wastewater streams/processes, yet possess a uniformity in overall fertilising performance within our experiments. Encouragingly, no appreciable agronomic difference in terms of yield was observed between the struvite and chemical fertilisers, which provides further evidence in support of struvite as a sustainable alternative to mined rockphosphate derived products. Importantly the struvite samples analysed within this study contained both significantly fewer impurities than TSP and lower concentrations of toxic metals such as cadmium.

No abstract

Although Irish winter wheat yields are among the highest globally, increases in the profitability of this crop are required to maintain its economic viability. However, in order to determine if efforts to further increase Irish wheat yields are likely to be successful, an accurate estimation of the yield potential is required for different regions within Ireland. A winter wheat yield potential model (WWYPM) was developed, which estimates the maximum water-limited yield achievable, within the confines of current genetic resources and technologies, using parameters for winter wheat growth and development observed recently in Ireland and a minor amount of daily meteorological input (maximum and minimum daily temperature, total daily rainfall and total daily incident radiation). The WWYPM is composed of three processes: (i) an estimation of potential green area index, (ii) an estimation of light interception and biomass accumulation and (iii) an estimation of biomass partitioning to grain yield. Model validation indicated that WWYPM estimations of water-limited yield potential (YP w ) were significantly related to maximum yields recorded in variety evaluation trials as well as regional average and maximum farm yields, reflecting the model's sensitivity to alterations in the climatic environment with spatial and seasonal variations. Simulations of YP w for long-term average weather data at 12 sites located at spatially contrasting regions of Ireland indicated that the typical YP w varied between 15.6 and 17.9 t/ha, with a mean of 16.7 t/ha at 15% moisture content. These results indicate that the majority of sites in Ireland have the potential to grow high-yielding crops of winter wheat when the effects of very high rainfall and other stresses such as disease incidence and nutrient deficits are not considered.