Keywords: Yield map, Soil map, Precision, Variable rate.
While it may be difficult to estimate exactly what improvement in financial returns may be generated as a consequence of implementing the first phase of PF, the benefits from management decisions taken as a result of the Direct Benefit Information gained from yield maps can be enormous. In my experience I have seen the range of in-field variability reduced from 10 tonnes per hectare to 4 tonnes per hectare in some fields. In other cases, where the reduction in in-field variability may not have been so great, the proportion of the field falling into the higher yielding bands has increased significantly with the consequence of considerably increased financial returns, providing a payback many times greater than the cost of installing a yield mapping system.
The case for adopting the second phase of PF, i.e. variable rate treatments, is less clear cut and whilst promising greater savings in terms of input costs, is difficult to justify in relation to the additional capital outlay necessary to make such applications, on a purely financial level.
Variable rate treatments do in theory offer benefits, though not yet quantified, to the environment and it is this aspect which may prove to be the driving force of PF in the future, not the financial aspect. If this is the case then a radically different approach to the support of agriculture will be necessary, with an assessment of the environmental impact of any application becoming necessary. My fear is that this is more likely to be driven by emotion rather than scientific fact.
John P Fenton, Yokefleet Farms Ltd, Hall Farm, Yokefleet, Goole, North Yorkshire, UK.
32 pages, 3 tables, 7 figures.