A third of the UK’s arable crop needs no phosphate (P) fertiliser this year and one in four hectares can take a potash (K) holiday, according to soil analysis figures from precision-farming leaders SOYL. The company’s new Planning with Precision (PWP) programme, now being rolled out to customers, is helping them save an average £60 per hectare on compound fertiliser without compromising crop yield.
SOYL has analysed more than three-quarters of a million soil samples on its database, drawn from almost a million hectares of land it has sampled – around 15% of the UK’s cropped area. The figures reveal a startling potential for growers to save substantially on compound fertiliser applications, provided they target their inputs effectively, notes SOYL general manager Simon Parrington.
"The temptation over the last 12 months has been to cut back on P and K as a knee-jerk reaction to prices that have climbed by up to five times previous levels. Our figures show there are plenty of growers out there who can afford the luxury of a P and K holiday on parts of their fields, without compromising yield. But equally there are a similar number for whom indices are worryingly low."
The UK’s leading and best known precision-farming specialist, SOYL has taken, analysed and mapped soil samples using GPS equipment since 1993, and has a current client base that covers over half-a-million hectares. Analysis of these samples show that 36% of the cropped area surveyed was index 3 or above for P and 26% of samples index 3 or higher for K. But 35% and 22.5% of samples were at index 0 or 1 for P and K respectively.
Using the data generated by SOYL, growers have been able to variably apply inputs, building up areas where indices are low to maximise crop potential, while cutting down rates where indices are high. Massive price rises for P and K fertiliser mean that average savings have leapt from around £12/ha to £60/ha.
"If you want to save fertiliser sustainably this year, the first step to take is to carry out some detailed soil sampling of each field. That will give you an indication of the variability and the potential to save – the practice of taking one sample for each field or each soil type belongs in the past and can be very misleading" advises Mr Parrington.
After sampling a set of fertiliser recommendations are made. For 2009, SOYL has developed a new Planning with Precision (PWP) programme – a choice of recommendations that ensures growers maximise the potential to cut P and K without compromising crop yield:
1. Normal SOYL calculation – this is the standard calculation, based on the SOYL map, local conditions, straw off-take, crop type and predicted yield.
2. Manure/biosolid base – apply a flat rate of farmyard manure or biosolids to give a base covering and variably apply a top-up of P and K to meet crop requirements.
3. Budget application – set a total farm fertiliser budget and apply according to need until the budget is spent.
4. Remedy application – use the SOYL map to apply fertiliser only to areas at index 0 or 1. Although a cheap short-term solution, this practice is not advised for more than one season. This allows efficient use of fertiliser where budget is limited.
5. P and K holiday – use your sampling maps to justify no application at all on fields or parts of fields.
Advice should always be taken before any change to P and K strategy, notes Mr Parrington. "Our area managers work through recommendations with customers, taking account of local soil conditions, expected yield and cropping history."
GPS soil-sampling is carried out one year in every four and a set of recommendations is created for each year over the four-year life of the maps. The full nutrient management service includes all initial sampling, lab costs and maps, and 4 years advice and support, including annual fertiliser plans, application maps and files for a GPS spreader. It costs £20/ha flat fee or £5.50/ha per year on SOYL’s finance scheme. For more information call SOYL on 01635 204190, www.soyl.co.uk.
