Making the most of henpen to cut input costs at Banff and Buchan Monitor Farm

With arable financials under close scrutiny this year, using henpen can be a valuable option to reduce costs, but making the most of it requires analysis, planning and prompt action.

Banff and Buchan Monitor Farm host Bruce Irvine has used henpen in the past but having recently added two laying hen units to his business, he will be making greater use of it this year. “I used to buy-in about 700t a year before, but now we are producing about 1,200t a year from our two flocks.”

This spring, he plans to apply it to stubbles before drilling spring barley, to grass and to swede and kale ground. His farm, Sauchentree, is in a Nitrate Vulnerable Zone (NVZ) and on mixed soil types which impacts spreading dates and rates.

Bruce has already had his henpen analysed, a critical step in making best use of it, says Zach Reilly from Grounded Agronomy. “If you know what you’ve got, you can put a value on it and reduce artificial fertiliser application.”

Analysis also highlights that henpen nutrient values vary widely – it is not a standard product, he warns. This is particularly the case for nitrogen (N) availability, which has a big impact on its value. N availability is affected by factors such where and how long it has been stored for, or even the place the analysis sample was taken from and whether it is representative.

Henpen can also be high in phosphate which, with repeat applications, can quickly build up in soil as it isn’t much depleted by crops. “Too much phosphate can lead to induced phosphate deficiency – there is so much that it isn’t plant available, particularly when the soil is acidic, which means crops need a small amount of phosphate to get the plants up and away. It’s a surprisingly common issue on intensive livestock units applying a lot of henpen.”

Bruce will use a local contractor to apply his henpen at a rate of about 5t/ha using a 24m rear-discharge Bunning spreader. With his own henpen to spread now, he has costed out buying a spreader with weigh cells, but it’s expensive. “I’d need to spread about 20,500t to pay for it.”

Zach adds that working out spreading costs is crucial, including haulage, storage, loading and spreading. “I do a lot of valuations for growers wanting to buy henpen. If you can haul and spread it cheaply, it’s a good option – but a lot comes down to the distance it is being hauled.”

Getting the best nutrient – and financial - value means applying it to a growing crop. “The second-best option is applying it to stubbles – it should be incorporated as soon as possible to reduce N losses and crops sown within four to six weeks.

“From a legislative point of view, you can spread henpen after 1 February, after the end of any closed period, but unless you incorporate it very quickly you will lose N. It’s better holding off. It’s a brilliant fertiliser with very little cost, but you do need to use the manure.”

At Sauchentree, he says applying henpen in March at 5t/ha and ploughing down immediately will capture all the available N (27kg/ha based on analysis of the Sauchentree sample) and supply 36kg/ha phosphate and 54.5kg/ha potash. With spring barley needing 130kgN/ha, Bruce can reduce bagged N to just over 100kg/ha.

Bruce says he finds henpen valuable on grass, particularly clover-rich swards. “Red clover really likes the phosphate and it’s not too rich in N compared with ammonium nitrate.

“It’s good to have more henpen to use if we want to, and it will save us money. I think people often don’t realise what’s in muck in terms of nutrients.”

Making the most of hen pen

• Sample the manure - the standard analysis isn't standard
• Be aware of P levels - repeat applications will see P indices rising in a typical rotation
• Calculate the spreading costs (haulage, storage, loading, spreading) - particularly important if buying-in
• Maximise nutrient utilisation to increase value - N optimisation is key