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Title: Alternative Farming Methods A Study of the Effects of an Integrated Arable Mgment System on Levels of Herbicide and Nutrients Reaching 'Controlled Waters'
Author: V W L Jordan
Author: Environment Agency
Author: J A Hutcheson
Document Type: Monograph
Annotation: Environment Agency Project ID:EAPRJOUT_234, Representation ID: 34, Object ID: 1581
This document sumarises the data gained, results and conclusions of a research project investigating the influence and impact of conventional and integrated arable crop production systems on herbicide and nutrient emissions and water pollution from diffuse sources during the period September 1994 - August 1996. The main purpose of the project was to monitor levels of total oxidised nitrogen and soluble phosphate, and of selected autumn-applied herbicides, isoproturon, diflufenican, mecoprop-P, pendimethalin, propyzamide, triallate and trifluralin, and two spring-applied herbicides, fenoxaprop ethyl and fluroxypyr, in stream waters bordering on, or within, agricultural catchments from conventionally farmed crop areas and those farmed under the guidelines for integrated production (IFS Farmlets), at two commercial farms (Trerulefoot, Cornwall and Harnhill, Gloucestershire) in south-west England. Additional monitoring was done of drain water discharges, surface run-off, soil erosion and the loss of sediment-associated total-P, from fields farmed conventionally and under the guidelines for integrated production (IFS) within the IACR-Long Ashton LIFE Project near Bristol. The project found that concentrations for fluroxypyr, mecoprop-P, pendimethalin, propyzamide, triallate, trifluralin and fluroxpyr in streamwater were below detection limits throughout the sampling periods in both years. Concentrations of diflufenican ranged from below detection limits to maximum levels 8.5 ~kg/l, and for the spring-applied fenoxaprop-ethyl to maximum levels of 46.5 ~kg/l in 1994/95, but neither herbicide exceeded detection limits in 1995/96. Only isoproturon exceeded detection limits in both years. Although levels of herbicides detected were variable at both sites they were, in general, lower from integrated (IFS) production systems than those conventionally farmed. Isoproturon was the most commonly detected herbicide, and was generally detected within three days of application in all catchments. Significant rainfall events two or three months after application tended to produce further positive samples. Similar concentration levels were found in all samples. Data from monitoring surface run-off, erosion and the loss of sediment-associated total-P, on land with Soil P-Index 2, showed that run-off was reduced by 48%, total sediment loss(erosion) by 68% and total-P loss by 81% in the integrated production system compared to the conventional production system. These responses are mainly attributed to the differences in crop structure and function resulting from the different tillage systems used for crop establishment over the past six years. Crops grown in the integrated production system Field Units have been established using soil conservation tillage (a one-pass non-inversion tillage system) whereas crops grown in conventional production Field Units have been sown following ploughing and subsequent springtine cultivations.
Publisher: Environment Agency
Subject Keywords: RiversEstuariesCoastal watersPhosphorusFertilizersNutrientsAgricultural pollutionRunoffBrackishwater environment
Extent: 66
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