19 January 1996



PINPOINTING the benefits of good fertiliser advice is easy for Suffolk farmer Roger Middleditch. With a range of hungry, light soils and crops ranging from feed wheat to punnet potatoes and vining peas, he knows the value of good fertiliser advice.

For him that means using an adviser approved under the Fertiliser Advisers Certification and Training Scheme (FACTS). Until recently that was John Pigg of J & A Bunns. Now Jim Holt, from the same company, has taken over.

"Fertiliser advice is all about trust – you need to trust your adviser and FACTS helps," says Mr Middleditch who farms 271ha (670 acres) at Priory Farm, Wrentham, near Beccles on the Suffolk coast and is chairman of the Wrentham Vegetables co-operative.

It is a sentiment echoed by Mr Holt. "As fertiliser suppliers we need to show we can provide sound, technical advice. FACTS helps give farmers the confidence that what we are telling them is the best."

40 years of advice

Advice at Priory Farm has come from Bunns for more than 40 years, ever since John Tooley first advised Mr Middleditchs grandfather. Now Mr Tooley is chairman of Bunns and president of the Fertiliser Manufacturers Association. There is a sound basis for trust.

But with new technology to exploit and ever greater environmental pressures Mr Middleditch demands top notch advice to maintain that relationship.

Key to the service he receives is a nutrient plan for the entire farm, which considers every factor that could influence crop need. Based on over 20 years of historical data, it is updated each summer by soil testing root fields for pH, P, K and Mg.

"The results are helpful, but need viewing in the context of prior cropping and fertiliser rates," notes Mr Holt. That sort of analysis reveals trends, such as unacceptably high phosphate levels in potato and beet fields.

"We were getting up to index five or six, because of the high rates of P needed for the root crops. That raised the risk of nutrient lock up, but through a policy of withholding P from intervening crops indices have been cut back to acceptable levels," says Mr Pigg.

For potash the problem is keeping it in the light soils long enough for the crop to benefit. Autumn applications are omitted, potash going onto cereals as a blend with the first spring N instead. That avoids winter leaching and exploits the synergism shown where N and K are applied together, says Mr Holt.

The N policy is based on a balance sheet approach, with full allowance for true yield potential, previous crop, soil type and muck.

Prior cropping can make a big difference, stresses Mr Holt. Rates are cut by 25kg/ha (20 units/acre) after vining peas, depending upon winter rainfall. Rape residue also justifies a cut, but not sugar beet.

Using realistic yields when planning is vital. This years budget is for 9.1t/ha (3.7t/acre) from feed wheats. The N rate will be cut if that looks unrealistic. "On these soils moisture is the key. Unirrigated beet gets 10 units/acre less N than irrigated crops, for example," says Mr Middleditch.

Full allowance is also made for manure – 10t/ha (4t/acre) of poultry muck is regularly used on beet land. After several years of checking N contents, it was found not to vary much beyond 87-100kg/ha (70-80 units/acre). Now just 50kg/ha (40 units/acre) of bagged N is used, resulting in low amino N levels and no wasted N.

Application accuracy is considered so important that Mr Middleditch uses calcium ammonium nitrate rather than ammonium nitrate. "It has a higher bulk density, at about 1070g/litre," notes Mr Holt. That helps the Amazone spreader remain accurate across the full 24m (80ft).

The spreader is calibrated and serviced by Amazone each year. Provided all fertilisers are of equal quality no re-calibration is needed in-season, says Mr Middleditch.

Bunns helps by using materials with a similar specification to prepare all Mr Middleditchs fertilisers. Those include a 27%N, 12%S spring blend for supplying sulphur to oilseed rape and cereals.

But the Amazone headland disc can still struggle to cope with different fertilisers when working across such a wide spread width – putting field margins at risk.

Mr Holt is keen to find a practical solution to better protect the environment. Small fields make buffer strips a non-starter, so liquid application is being considered for headlands.

However, change for technologys sake is resisted. "Mineral N testing is sure to find a role, but for now there isnt the knowledge to make the most of what is basically a snapshot of soil N status," notes Mr Pigg. Instead effort is directed to on-farm rate trials, particularly in the vegetables.

It is that commitment to continually enhance the fertiliser policy that convinces Mr Middleditch FACTS advice is worthwhile.

Bunns technical advisers are regularly updated by Mr Pigg. "It is an ongoing process, not just a case of passing the FACTS test," he says. &#42


&#8226 Soils range from blowing sand to Beccles sandy clays.

&#8226 271ha (670 acres), machinery pool with cousin, plus local contract farming.

&#8226 Key crops and N rates:


w wheat60200-225

w barley 41 137

s beet2850-137

potatoes 30 250

&#8226 Calcium ammonium nitrate bought in bulk and delivered in 20t lots to bins as needed helps cut costs.

&#8226 Amazone 24m disc spreader, with headland disc.

Advice must be based on trust and good local knowledge, says Suffolk farmer Roger Middleditch (centre). John Pigg (left) and Jim Holt of J & A Bunns work to FACTS standards to help meet that goal.