Exploring the spatial relations between soil properties and electro-magnetic induction (EMI) and the implications for management

The relations between soil electrical conductivity (ECa) and top- and sub-soil physical properties were examined for an arable field in England. The correlation coefficients between ECa and the soil particle size fractions were large and their cross variograms showed that the coregionalization was also strong. The coregionalization was stronger for the subsoil properties than for the topsoil, the reverse to the correlation coefficients. The relations between ECa and some soil properties, such as clay and water content, appear complex and emphasize that a map of ECa cannot substitute for sampling the soil

Climatic, geographic and operational determinants of trihalomethanes (THMs) in drinking water systems

Trihalomethanes (THMs) are conditionally carcinogenic compounds formed during chlorine disinfection in water treatment processes around the world. THMs occur especially when source waters are subject to marine influences, high and-or regular precipitation, and elevated levels of organic matter. THMs formation is then rooted in geographic, operational and climatic factors, the relative importance of which can only be derived from large datasets and may change in the future. Ninety three full-scale Scottish water treatment plants (WTPs) were assessed from Jan 2011 to Jan 2013 to identify factors that promote THMs formation. Correlation analysis showed that ambient temperature was the primary THMs formation predictor in potable water (r2 = 0.66, p < 0.05) and water distribution systems (r2 = 0.43, p = 0.04), while dissolved organic carbon (r2 = 0.55, p < 0.001) and chloride (indicating marine influence; r2 = 0.41, p < 0.001) also affected THMs formation. GIS mapping of median THMs levels indicated brominated THMs were most prevalent in coastal areas and on islands. This real-world dataset confirms both geographic and climatic factors are key to THMs formation. If ambient temperatures increase, THMs control will become more challenging, substantiating concerns about the impact of global warming on water quality

Sampling to estimate soil nutrients for precision agriculture

Paper presented to the International Fertiliser Society held Cambridge (GB), 10 Dec 1998Available from British Library Document Supply Centre-DSC:6732.105(417) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

The impact of upland land management on flooding: insights from a multiscale experimental and modelling programme

A programme of field experiments at the Pontbren catchment in Wales has, since autumn 2004, been examining the effects of land use change on flooding. The Pontbren catchment possesses a long history of artificial drainage of its clay soils and intensification of sheep farming. Increased flood runoff has been noted within the last decades, as has the mitigating effect of trees at field scale. To examine the local and catchment-scale effects of land management within the catchment, including the potential advantages of planting additional trees, a multidimensional physically based model has been developed and conditioned on data from an intensely instrumented hillslope. The model is used to examine the effects of planting a small strip of trees within a hillslope. Results demonstrate that careful placement of such interventions can reduce magnitudes of flood peaks by 40% at the field scale. The challenges associated with upscaling these results to the Pontbren and Upper Severn catchments are discussed