GOOD PRACTICE & OPTIMUM PROFITS
A fertiliser policy to optimise yield and profit while protecting the environment is the goal of one Norfolk grower.
Edward Long reports on the strategy he works to
MORE precise use of fertilisers on cereals, with inputs targeted to crop need, is likely to pay dividends by optimising yields, minimising costs and reducing environmental risks.
So says a Norfolk farm manager who is committed to improving accuracy of rates and applications to ensure wasteful luxury amounts are not given.
"In the past we, like everyone else, were probably over-doing fertilisers for cereals by adopting a rigid programme without taking much notice of the conditions or the crop," says Andrew Elton, who manages 445ha (1100 acres) of arable on Lord Walpoles Mannington and Wolterton Estates near Aylsham.
"But farming by the calendar using fixed rates was inflexible and meant money was wasted. Now, with tightening economic pressures and more dry seasons, those ideas have to change."
The estate is moving to a system where individual fields, or blocks of small ones, are treated according to their potential. Soils range from light sandy loam at Mannington to more fertile medium loam at Wolterton, and cereals have more potential at the eastern end of the estate.
Cropping is varied (see table). The wheat, which is mostly grown on the better soil, is all Hussar for feeding. Winter barley is drilled with Halcyon, Puffin, and Fanfare for malting. The spring barley is Optic and Chariot.
"On our land wheat has the potential to yield just over 3t/acre, the winter barleys are capable of doing 2.5-3t, and the spring barleys give 2-2.5t/acre. We have tried to cut back fertiliser rates as far as we can to achieve the economic optimum, and I think we are about there."
Regular soil sampling ahead of the beet, and increasingly before cereals, has revealed a lack of sulphur and a fluctuation in levels of residual N.
"We apply the first N to wheats in early February with 34 units/acre as ammonium nitrate, or if tests reveal a shortage of sulphur 30 units/acre as Sulphur Gold. A month later 3.3 bags of straight ammonium N is put on. Top-dressings take the total to between 150 and 160 units/acre. We adopt a one-hit approach for barley with the winter crop getting 80 units of Sulphur Gold before mid-March and the spring crop slightly less at emergence."
Information about residual N levels from soil tests could, in theory, be exploited when determining rates. But Mr Elton is concerned that not all which is left behind in the soil after the winter will be readily available soon enough for following crops in the spring.
"Early last year soil tests showed supposedly high levels and cereal growers were advised to hold off as there was less need for early applied N. In retrospect it is obvious this advice was flawed, as the residual N was not readily available, so plants were starved at a critical time in their early development. There must have been a knock-on effect on final yield.
"We combine information from soil tests with data from tissue analysis, which we have done for the past two years, to provide a guide to help us improve precision of fertiliser use."
Product choice is considered important. Ammonium nitrate or a locally blended P and K mix is used. Urea is not an option, as the risk of scorch is considered too high, which compromises the flexibility of application timings.
The two 12m spreaders, a Horstine Farmery Cascade and a Overum Tive are particularly accurate and provide the placement needed. Each is carefully calibrated for each blend every year.
"Last spring we were just 1cwt out across the whole of our wheat and barley acreage."
"An estate-wide environmental project is geared to encouraging wildlife and maintaining habitats by improving hedgerows and banks. "We leave a headland strip around the field boundary unploughed and have a 21m wide strip of permanent set-aside bordering main watercourses," concludes Mr Elton.n
Matching nutrient input to crop potential is key to optimising profits on the Mannington and Wolterton Estates in Norfolk, which Andrew Elton (right) manages for Lord Walpole. Careful calibration is also practised.
Soil analysis of N and S levels can be misleading, warns Andrew Elton. The amount of nutrient available to the plant is what really counts.
• Treat each field separately.
• Match rates to potential.
• Sample soil for N and S.
• Treat N figures as guide – may not be available to plant.
• Tissue analysis helps.
• Choose products with care.
• Calibrate spreader for each product and re-check mid-season.