Cranfield University at Silsoe (1975-2008)
Permanent URI for this community
Browse
Browsing Cranfield University at Silsoe (1975-2008) by Type "Postprint"
Now showing 1 - 6 of 6
Results Per Page
Sort Options
Item Open Access The effect of incorporating slurries on the transport of faecal coliforms in overland flow.(Blackwell Publishing Ltd., 2003) Quinton, John Norman; Tyrrel, Sean F.; Ramos, María C.Rainfall simulation experiments on a laboratory soil flume were conducted to test the hypothesis that the incorporation of slurry into the soil would reduce bacterial transport in overland flow. Presumptive faecal coliform (PFCs) concentrations were higher in the runoff from the surface applied treatment than from the incorporated treatments. The transport of PFCs and organic sediment were strongly correlated, with values of r ranging from 0.72 to 0.91.Item Open Access Effects of cattle manure on erosion rates and runoff water pollution by faecal coliforms.(Elsevier, 2006-01) Ramos, María C.; Quinton, John Norman; Tyrrel, Sean F.The large quantities of slurry and manure that are produced annually in many areas in which cattle are raised could be an important source of organic matter and nutrients for agriculture. However, the benefits of waste recycling may be partially offset by the risk of water pollution associated with runoff from the fields to which slurry or manure has been applied. In this paper, the effects of cattle manure application on soil erosion rates and runoff and on surface water pollution by faecal coliforms are analysed. Rainfall simulations at a rate of 70 mm h−1 were conducted in a sandy loam soil packed into soil flumes (2.5 m long×1 m wide) at a bulk density of 1400 kg m−3, with and without cattle slurry manure applied on the surface. For each simulation, sediment and runoff rates were analysed and in those simulations with applied slurry, presumptive faecal coliform (PFC) concentrations in the runoff were evaluated. The application of slurry on the soil surface appeared to have a protective effect on the soils, reducing soil detachment by up to 70% but increasing runoff volume by up to 30%. This practice implies an important source of pollution for surface waters especially if rainfall takes place within a short period after application. The concentrations of micro-organisms (presumptive faecal coliforms (PFCs)) found in water runoff ranged from 1.9×104 to 1.1×106 PFC 100 mL−1, depending on the initial concentration in the slurry, and they were particularly high during the first phases of the rainfall event. The result indicates a strong relationship between the faecal coliforms transported by runoff and the organic matter in the sediment.Item Open Access Effects of soil compaction and mechanical damage at harvest on growth and biomass production of short rotation coppice willow(Springer Science + Business Media, 2004-06) Souch, C. A.; Martin, Peter J.; Stephens, William; Spoor, G.The effects of soil compaction and mechanical damage to stools at harvesting on the growth and biomass production of short rotation coppice (SRC) of willow (Salix viminalis L.) were monitored on clay loam (CL) and sandy loam (SL) soils. Moderate compaction, more typical of current harvesting situations did not reduce biomass yields significantly. Even heavy compaction only reduced stem biomass production by about 12% overall; effects were statistically significant only in the first year of the experiment on sandy loam. Heavy compaction increased soil strength and bulk density down to 0.4 m depth and reduced soil available water and root growth locally. Soil loosening treatments designed to alleviate the effects of heavy compaction did not markedly improve the growth of willow on compacted plots. Hence the focus fell on harvesting. Extensive mechanical damage to stools caused a 9% and 21% reduction in stem dry mass on the clay loam and sandy loam soils as a result of fewer stems being produced. The particularly severe effect on the sandy loam soil probably resulted from a combination of dry conditions in the year of treatment, root damage and soil compaction under stools and might have been aggravated by the young age of the plants (1 year) at the time of treatment.Item Open Access Estimating organic carbon in the soils of Europe for policy support.(Blackwell, 2005-10) Jones, Robert J. A.; Hiederer, Roland; Rusco, E.; Montanarella, LucaThe estimation of soil carbon content is of pressing concern for soil protection and in mitigation strategies for global warming. This paper describes the methodology developed and the results obtained in a study aimed at estimating organic carbon contents (%) in topsoils across Europe. The information presented in map form provides policy-makers with estimates of current topsoil organic carbon contents for developing strategies for soil protection at regional level. Such baseline data are also of importance in global change modelling and may be used to estimate regional differences in soil organic carbon (SOC) stocks and projected changes therein, as required for example under the Kyoto Protocol to the United Nations Framework Convention on Climate Change, after having taken into account regional differences in bulk density.Item Open Access Modeling sediment yields in Italian catchments.(Elsevier, 2005-02-01) van Rompaey, Anton; Bazzoffi, Paolo; Jones, Robert J. A.; Montanarella, LucaSediment yield observations, derived from 40 long-term sedimentation records in Italian reservoirs, were used to calibrate and validate the spatially distributed sediment delivery model WaTEM/SEDEM using the best data available at national scale. The sediment yield data set includes records from semi-natural catchments in northern Italy as well as agricultural and semi-natural basins in central and southern Italy. The average size of the catchments is 150 km2 with mean annual sediment yields ranging from 0.20 to 20 t ha−1 year−1. WaTEM/SEDEM estimates mean annual sediment fluxes to permanent river channels. Depending on the local transport capacity, the sediment flux is detachment-limited or transport-limited. The optimal transport capacity parameters for Italian conditions were derived via automatic calibration procedures. A global model calibration procedure taking into account all catchments in the dataset led to an overestimation of the sediment yield for the mountain catchments and an underestimation for the non-mountain catchments. Sediment yield estimates are more reliable when calibration procedures are applied separately for mountain and non-mountain catchments. The model performance of WaTEM/SEDEM is rather poor in the mountain catchments (R=0.25), which suggests that the model structure is too simplified to come to an adequate description of the sediment fluxes. The model performance for the non-mountain catchments, which are more important from a management point of view, is significantly better (R=0.51). Considering the fact that data layers with a 75×75 m resolution were used, the results are encouraging the further development and application of spatially distributed sediment yield models at regional and national scale levels.Item Open Access Vulnerability of subsoils in Europe to compaction: a preliminary analysis.(Elsevier, 2003-10) Jones, Robert J. A.; Spoor, G.; Thomasson, A. J.Identifying the vulnerability of subsoils to compaction damage is an increasingly important issue both in the planning and execution of farming operations and in planning environmental protection measures. Ideally, subsoil vulnerability to compaction should be assessed by direct measurement of soil bearing capacity but currently no direct practical tests are available. Similarly, soil mechanics principles are not suitably far enough advanced to allow extrapolation of likely compaction damage from experimental sites to situations in general. This paper, therefore, proposes a simple classification system for subsoil vulnerability to compaction based for field use on local soil and wetness data at the time of critical trafficking, and, at European level, on related soil and climatic information. Soil data are readily available ‘in Country’ or from the European Soil Database and climatic data are stored in the agrometeorological database of the MARS Project. The vulnerability to compaction is assessed using a two-stage process. First, the inherent susceptibility of the soil to compaction is estimated on the basis of the relatively stable soil properties of texture and packing density. Second, the susceptibility class is then converted into a vulnerability class through consideration of the likely soil moisture status at the time of critical loadings. For use at local level, adjustments are suggested to take account of possible differences in the support strength of the topsoil and specific subsoil structural conditions. The vulnerability classes proposed are based on profile pit observations, on a wide range of soils examined mainly in intensively farmed areas where large-scale field equipment is employed. A map of soil susceptibility to compaction in Europe has been produced, as the first stage in developing a more rigorous quantitative approach to assessing overall vulnerability than has been possible hitherto.