Cost of Ammonia Emission Abatement from Manure Spreading and Fertilizer Application

Abstract

Abatement of emissions following the application of manures to land has been identified as a priority to reduce emissions of ammonia (NH₃). However, the conventional method of spreading slurry, surface broadcasting by splash plate applicator, is rapid and inexpensive while application techniques which reduce emissions of NH₃ impose an additional cost on the farmer. We critically reviewed the methodology used to estimate the additional costs of spreading livestock manures to land by the use of reduced NH₃ emission (RAE) techniques. The input values used to calculate costs were as follows: purchase price of tractors and RAE spreading machines; depreciation, of both the tractor and the spreader; interest rates, on loan or expended capital; fuel consumption; repairs; labour costs. This approach is consistent with the method to estimate the cost of abatement techniques given in the BREF guidance document. As a result of revising the calculations with updated input costs the additional cost of spreading using reduced-emission spreading equipment was from £0.52 to £0.65 per m³ slurry applied by RAE techniques. The costs of spreading manure arise mainly from labour (27 %), Fuel (23 %), spreader costs (10 % from repairs and maintenance and 12 % from depreciation) and tractor costs (11 % from repairs and maintenance and 10 % from depreciation). Since most of the labour and fuel costs incurred during the spreading of slurry arise from travelling from the slurry store to the field, the reduced work rates of RAE machines, and greater fuel requirements for pulling injectors, incur only moderate additional costs. These cost estimates were within the range of additional costs reported by commercial farmers who had adopted RAE techniques in a pilot study. Estimates of the additional costs of applying livestock manures by RAE techniques will inevitably vary due to differences among farms and contracting operations with respect to the volumes of manure to be spread, differences in fuel and labour costs and in depreciation and interest rates. Nevertheless, we conclude that the estimates of £0.65 m⁻³ for slurry and £0.54 t⁻¹ for manures spread using farm equipment are broadly reliable. We also conclude that the costs of RAE techniques for manures applied by contractor will be substantially less than for manures applied by farm machinery.