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To understand the production and flow of effluent within silage and to develop a model - WA0109

Description
WA0109. Non-polluting strategies for forage treatment and silage production

Silage effluent causes substantial environmental damage by polluting water courses and flow of nutrients from silage in effluents represents a substantial financial loss to UK agriculture. This study will aim to develop outline models of the following: production of effluent from forage per se, considering factors ranging from the degree of cell breakdown to the effects of different fertiliser application rates; the flow of effluent through the matrix of forage within the silo, including properties such as porosity and hydraulic conductivity, together with factors likely to affect these properties (e.g. dry matter, density and chop length); and changes in the matrix as fermentation proceeds and consolidation occurs, including macro-properties of the forage, such as density, as well as properties of individual fragments that contribute to the whole (e.g. compressibility and lignification). An experimental programme, using new techniques where necessary, will be used to characterise conditions in experimental silos on a laboratory and a farm scale and provide inputs for the models. In addition, the Cornell University silage fermentation model will be assessed for its ability to predict the composition of silage effluent. Physical properties of typical absorbents will be characterised in isolation from silage and linked to the models, which will then be refined and extended to predict flow patterns in silos with non-uniform properties, such as those which would occur in drained silos and silos in which absorbents were added in layers. The models will also be used to make predictions of effluent arisings in silos with and without drains, and the predictions will be compared with experimental data. Results of the study will be used to recommend modifications to the Code of Good Agricultural Practice for the Protection of Water. It is anticipated that this study will lead to an improved understanding of the mechanisms of moisture release, migration and retention in forage matrices after ensiling, together with changes in the matrices themselves.
Objective
To produce outline models of: (a)the production of effluent from forage per se (b)the flow of effluent through the matrix of forage found within the silo (c)the changes in the matrix as fermentation proceeds and consolidation occurs. The first model will be developed in close collaboration with IGER and it is intended that it will consider factors ranging from the degree of cell breakdown to the effect of different fertilizer application rates. (ii)To conduct experiments that will provide inputs for and test the three outline models. To characterise the physical properties of typical absorbents (recommended by IGER) in isolation from silage and link these to the models. To make predictions from the models of effluent arisings in silos with and without absorbents and drains, and these predictions will be compared with experiments.
Time-Scale and Cost
From: 1993

To: 1994

Cost: £100,000
Contractor / Funded Organisations
Silsoe Research Institute (BBSRC)
Keywords
              
Fields of Study
Environmental Protection - Agriculture