Browsing by Author "Pullen, D. W. M."

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    Injecting bio solids into grass and arable crops. Part I: Design and evaluation of a shallow injector
    (Elsevier, 2004-03) Pullen, D. W. M.; Godwin, R. J.; Grundon, P.; Moseley, P. J.
    Shallow injection of liquid bio solids at depths of 50–70 mm into grass and arable crops offers many advantages over existing application methods. However, current shallow injection equipment only places the sludge or slurry into slots leaving it exposed with a high runoff risk. The objective of this study was to determine the benefits and limitations of injecting digested sewage sludge into land growing arable crops using shallow injection techniques. It is documented in two parts. One part describes the agronomic trials undertaken to determine the effect of application technique and timing on combinable crops. This part describes the work undertaken to understand the mechanics of shallow injection and develop an improved injector design. Here, laboratory and field studies were undertaken to compare both existing and new winged shallow injector designs. These showed that a winged injector penetrated better with an equal or lower draught than existing designs. The design also incorporated the sludge into the soil with minimal crop damage at rates of at least of 50 m3 ha−1 when working 50 mm deep.
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    Injecting bio solids into grass and arable crops. Part II: Development of a shallow application technique
    (Elsevier, 2004-04) Pullen, D. W. M.; Godwin, R. J.; Grundon, P.; Hann, Michael J.
    Digested sludge contains valuable crop nutrients but these are largely lost because current application techniques limit where and when it can be applied. Soil injection to depths in excess of 150 mm to reduce odour problems can only be used on fallow land or grass because of the damage it can cause. This leads to applications at high rates being applied with increased environmental risk. The aim of this study was to determine the benefits and limitations of injecting digested sewage sludge into land growing arable crops using shallow, less than 100 mm deep, injection techniques. Agronomic trials conducted over 2 years with winter wheat and rape showed that the crops were surprisingly resistant to mechanical damage during the growing season. Crop yields were not effected by injecting sludge into the crop up to March, equivalent to growth stage 30 in winter wheat, using a conventional tractor-based system working. Injection is possible later in the growing season based on systems with the tractor operating along "tramlines" for field traffic control.