Use poultry manure with great care, warns ADAS
IGNORE the nutrient content of poultry manure at your peril, warns soil scientist Ken Smith of ADAS Wolverhampton. "No more than 8-10t/ha (3-4t/acre) is the rule," he advises.
"This complies with the Code of Good Agricultural Practice and also means that lodging and other crop quality problems are avoided. Farmyard manure may be worth £3.50/t but laying hen manure is worth up to £9/t and broiler litter as much as £17/t off the annual fertiliser bill. Therefore, it pays to make best use of it."
Heavy applications to stubbles or fallow ground prior to ploughing and drilling in the autumn or winter is not the best way to utilise the nitrogen content, he stresses. "In a wet winter, a large amount of nitrogen will be lost by leaching. But because poultry manures contain six to 10 times the concentration of readily available nitrogen normally present in FYM, significant amounts of nitrogen may still remain in the soil in the spring.
"This is often ignored and full-rate inorganic fertiliser N top dressing applied to the crop. The inevitable crop lodging problems may well be followed by further nitrate leaching during the next winter."
Poultry manure should be applied carefully, using machinery that is capable of spreading accurately at a low rate, advises Mr Smith.
The extra amounts of phosphate and potash contribute to soil reserves for use by later crops.
"Of course, it is better if autumn and winter spreading is avoided because of the nitrogen losses, but, on heavy land, this may be the only practical option. And advice is available to help farmers decide how much manure nitrogen they need to allow for when deciding on appropriate top dressings in the following spring."
But more of the nitrogen in poultry manure can be used by delaying treatment. "Top dressings of poultry can be used successfully on cereal crops in the early spring where crop, soil type and conditions allow," comments Mr Smith.
• More information in MAFF Fertiliser Recommendations (RB209) from HMSO at £8.50. *
Consider the nutrient content of poultry manure – or risk lodged crops.
• 8-10t/ha maximum rate.
• Hen muck worth £9/t, broiler muck £17/t.
• 6-10 times more N than FYM.
• High leaching and lodging risk.
• Apply with care.
• Allow for when planning spring top dressing.