Phosphorus (P) transfer in surface runoff from field plots receiving either no P, triplesuperphoshate (TSP), liquid cattle manure (LCS), liquid anaerobically digested sludge (LDS), or dewatered sludge cake (DSC) was compared over a 2-yr period. Dissolved inorganic P concentrations in runoff increased from 0.1 to 0.2 mg L(-1) on control and sludge-treated plots to 3.8 and 6.5 mg L(-1) following application of LCS and TSP, respectively, to a cereal crop in spring. When incorporated into the soil in autumn, runoff dissolved P concentrations were typically < 0.5 mg L(-1) across all plots, and particulate P remained the dominant P form. When surface-applied in autumn to a consolidated seedbed, direct loss of LCS and LDS increased both runoff volume and P transfers, but release of dissolved P occurred only from LCS. The largest P concentrations (>70 mg L(-1)) were recorded following TSP application without any increase in runoff volume, while application of bulky DSC significantly reduced total P transfers by 70% compared with the control due to a reduced runoff volume. Treatment effects in each monitoring period were most pronounced in the first runoff event. Differences in the release of P from the different P sources were related to the amounts of P extracted by either water or sodium bicarbonate in the order TSP > LCS > LDS > DSC. The results suggest there is a lower risk of P transfer in land runoff following application of sludge compared with other agricultural P amendments at similar P rates.

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This survey examined 306 samples of farm-stored wheat, barley and oats as received at, or tested by, central grain depots in the UK. Samples were taken from lorries or from stored grain using the existing in-house procedures used for quality checking and examined for ochratoxin A using a fully validated analytical HPLC method with a detection limit of 0.1 microgram/kg. Ochratoxin A was detected in 21% of the samples examined, with barley more frequently contaminated than wheat. Mean concentrations of ochratoxin A found for all samples were 0.69 microgram/kg in barley, 0.29 microgram/kg in wheat and 0.15 microgram/kg in oats. The highest concentration found was 17.8 micrograms/kg in a barley feed although concentrations of 81 and 30 micrograms/kg were found in 'reject-grade' wheat samples whose results were excluded from the main survey. In summary, 2.7 and 0.3% of samples exceeded concentrations of 5 and 10 micrograms/kg respectively. There appeared to be significant relationships between ochratoxin A concentrations and moisture content, storage time and geographical area. Although conditions at harvest in 1997 were quite variable countrywide and often wet, results were similar to those found in earlier surveys carried out in the UK.

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