32 research outputs found

    N, P and K budgets for crop rotations on nine organic farms in the UK

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    On organic farms, where the importation of materials to build/maintain soil fertility is restricted, it is important that a balance between inputs and outputs of nutrients is achieved to ensure both short-term productivity and long-term sustainability. This paper considers different approaches to nutrient budgeting on organic farms and evaluates the sources of bias in the measurements and/or estimates of the nutrient inputs and outputs. The paper collates 88 nutrient budgets compiled at the farm scale in 9 temperate countries. All the nitrogen (N) budgets showed an N surplus (average 83.2 kg N ha-1 year-1). The efficiency of N use, defined as outputs/inputs, was highest (0.9) and lowest (0.2) in arable and beef systems respectively. The phosphorus (P) and potassium (K) budgets showed both surpluses and deficits (average 3.6 kg P ha-1 year-1, 14.2 kg K ha-1 year-1) with horticultural systems showing large surpluses resulting from purchased manure. The estimation of N fixation and quantities of nutrients in purchased manures may introduce significant errors in nutrient budgets. Overall, the data illustrate the diversity of management systems in place on organic farms, and suggest that used together with soil analysis, nutrient budgets are a useful tool for improving the long-term sustainability of organic systems

    Formal thought disorder in autism spectrum disorder predicts future symptom severity, but not psychosis prodrome

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    Formal thought disorder (FTD) is a disruption in the flow of thought, which is inferred from disorganisation of spoken language. FTD in autism spectrum disorders (ASD) might be a precursor of psychotic disorders or a manifestation of ASD symptom severity. The current longitudinal study is a seven-year follow-up of 91 individuals aged 5-12 years with ASD. We tested (1) whether childhood FTD predicted prodromal symptoms of psychosis in adolescence and (2) whether childhood FTD was associated with greater ASD symptom severity in adolescence. ASD symptom severity was assessed in childhood (T1) and 7 years later (T2), using the autism diagnostic observation schedule (ADOS). At T1, the Kiddie-Formal Thought Disorder Rating Scale (KFTDS) was used to measure symptoms of FTD. At T2, the prodromal questionnaire (PQ) was used to assess prodromal symptoms of psychosis. FTD at T1 did not predict prodromal symptoms of psychosis at T2 in children with ASD. FTD symptoms at T1, namely illogical thinking, predicted ASD symptom severity at T2 and this effect remained significant after controlling for T1 ASD symptom severity. In children with ASD, illogical thinking predicts severity of ASD symptoms in adolescence, but FTD does not predict prodromal symptoms of psychosis

    Improving mechanical seagrass transplantation

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    Until recently seagrass transplantation efforts have met with limited success in areas with high wave energies. Survival in Western Australia has been markedly improved by the deployment of large, mechanically transplanted units which provide sufficient anchorage to overcome water motion. ECOSUB1 was an underwater seagrass harvesting and planting machine designed to extract and plant large seagrass units with minimal disturbance. Over 2000 sods have been planted, with an average survival of approximately 70% over 3 years. New machines (ECOSUB2) have now been constructed to improve efficiency; these are located semi-permanently on the seafloor and allow for concurrent seagrass harvesting and planting
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