Suchergebnisse

ABSTRACTA review was undertaken of (a) the levels and prevalence of Salmonella spp., Campylobacter spp., Listeria monocytogenes, Escherichia coli 0157. Cryptosporidium parvum and Giardia intestinalis in livestock manure, and (b) factors which affect their survival during storage and following land application. Pathogens are commonly present in livestock manures and can survive in soil for several months or years after spreading or excretion onto land. Temperature was identified as being the most important factor influencing pathogen survival, although pH, UV light and drying were also important. Various practical measures to minimise the risk of pathogen transfer into the food chain were identified, including treatment, extended storage and no/harvest periods following land spreading. Guidelines are being developed on managing farm manures to minimise the risks of microbiological contamination of ready‐to‐eat crops.

ABSTRACTResearch in the UK on the beneficial aspects of biosolids additions to land has primarily concentrated on nitrogen and phosphorus supply. Biosolids have other beneficial effects on soil through the addition of organic matter and other plant nutrients such as sulphur, magnesium and sodium. This study evaluates the effects of biosolids additions on soil quality and fertility at seven established field experimental sites where biosolids have been applied for at least four years. These additions influenced several physical properties of the soil, increasing topsoil water‐infiltration rates, plant‐available water supply on a light sandy soil, soil porosity and bearing strength. There were also increases in the level of plant‐available sulphur, magnesium, copper and boron. Liquid digested biosolids applications also increased the concentrations of major nutrients in grass.

AbstractHeavy metal inputs to agricultural soils in England and Wales were estimated from major sources, including atmospheric deposition, biosolids, livestock manures, inorganic fertilisers and lime, industrial by‐product 'wastes' and composts (year 2000). Across the whole agricultural land area, atmospheric deposition was the main source of most metals ranging from 25 to 85% of total inputs. Livestock manures and biosolids were also important sources representing 37 and 8% of total zinc (Zn) inputs, 40 and 17% for copper (Cu), and 10 and 4% for cadmium, respectively. The highest heavy metal input rates on a field basis were generally from biosolids, although Zn and Cu inputs from pig manures were equivalent to 46–52% of biosolids inputs (both applied at a rate of 250 kg/ha total N). The study provided baseline information to develop and focus policies limiting heavy metal inputs to and accumulation in topsoils.