The decision for one Gloucestershire arable farmer to switch from a granular to liquid fertiliser system was based on better accuracy, a timely and professional delivery service   coupled with improved logistics.

With seven farms to manage as part of a contract farming arrangement that covers 1,295 ha’s and is spread over 10 miles, Martin Parkinson who is arable farm manager of the Cotswold Farm Park based near Stow-on-the-Wold has his work cut out. With only three full time skilled operatives to assist him, workload pressure required a change in management strategy.

Each enterprise runs its own accounts but the general day to day running of the operation is managed through the Cotswold Farming Partnership. Cropping is based on combinable crops including spring barley, winter wheat, oilseed rape, spring oats and winter barley.  Average yields for Group 1 winter wheat are 8.7t/ha and oilseed rape yields 3.7t/ha.

Soils are mostly Costwold brash with high stone content, lack nutrients and have a poor water holding capacity. Annual rainfall is only 750mm. Much of the land lies 1000 feet above sea level and many of the fields are small, with several under 2ha.

The decision to go liquid coincided with changing the sprayer, which at the time was a 24m 3000l Sands self-propelled machine and was replaced this year with a 36m 8000l Horsch self-propelled sprayer. The farm’s 36m Amazone ZAM Ultra granular applicator has been retained to apply P:K and compound to grassland.

“One of our biggest challenges has always been labour,” he says. “With only three skilled operatives in the business I have too many days where everyone is either in the yard or everyone is out of the yard. We were spread too thinly at peak workload periods and we needed to make better use of available spray days.

“Fertilising was always a two man operation and still is, but the difference now is that it’s by choice,” he says. “Output on the granular system was between 300-400acres/day compared to 550acres/day with the Horsch. Being high up means it’s often windy which can be a problem when spreading granules.

“On a liquid system we can select our spraying days rather than being beholden to the weather. To save time we employ a Unimog and mixer tank which only takes ten minutes to pump off mixed chemicals or liquid fertiliser direct into the sprayer.”

In Mr Parkinson’s experience it is the smaller and odd shaped fields where applying granular at 36m is not as good as a liquid system.  “We know this is the case because we can see by the yield difference between granular and liquid fertiliser on the headlands,” he says. “Our own study comparing granular and liquid fertiliser in a 100 acre trial across several fields last year showed a yield difference of 2-2.5t/ha between the headland and the rest of the field in favour of liquids.

“This demonstrates the limited capabilities of a granular application because it just can’t apply accurately on the headlands compared to a liquid system which is accurate right up to the edge of the field.

“There are other factors to take into account of course such as overhanging trees, rabbit and slug damage, but if we could get 70% of the yield back on a liquid system that would otherwise be lost on a granular system on the headland, it makes economic sense.

“Environmentally we were compromised using granular fertiliser even spreading in ideal conditions,” says Mr Parkinson. “All our farms are in the ELS/HLS scheme so it’s imperative that we do not spread onto any margins.”

For ease of management the farm only uses one mix of liquid fertiliser based on 24N:7.5SO3. This year it took delivery of 1,000,000 litres of OMEX liquid fertiliser which is all applied in the spring between February 10th and early May.

“We could have ordered two different mixes with one of them containing more sulphur for the oilseed rape, but logistically it’s impractical with distances between farms and the individual farm rotations,” explains Mr Parkinson.

In the past managing granular fertiliser deliveries has been a problem. “Frequently it would be delivered when we were at our busiest – often during autumn drilling – leading to additional workload pressure,” he says. “It wouldn’t be unusual to have three deliveries turning up at the same time in three different locations and all wanting the same forklift.

“On a liquid system all we have to do is apply a bit of careful planning and pre-ordering. The liquid fertiliser turns up and is pumped directly into one of nine 50t OMEX static horizontal tanks. No on-farm labour is needed. It’s all very simple and straight forward,” explains Mr Parkinson.

Also, the undercover storage that was required for the bagged fertiliser can now be utilised for storing grain, seed or machines, he says.

“OMEX literature claims potential cost benefits upwards of £100 per ha by using its fertiliser, but in reality we should get much more than this based on our experiences so far with small irregular shaped fields. Having got the end of our first season I can honestly say I am very happy with the decision to move to liquid fertiliser.”