Spring slurry applications will save on N

NITROGEN cost savings of £80 per hectare can be achieved where spring applications of slurry are made to growing crops growers attending a recent workshop were advised.

The workshop, held at JSR Farms, Driffield, was organised by Catchment Sensitive Farming officer, Derek Knight and consultant, Jim Lewis.

Mr Knight told the workshop that with fertiliser prices rising dramatically, manures were now a very valuable resource.

“However, to use them effectively you need to know what you are starting with,” he said.

Slurry could be sampled, to determine the level of N, P and K, for little cost compared to its potential value. An on farm meter could also be used to assess the available nitrogen in slurries.

Applications in the autumn, which was often the most convenient dry period, would be subject to leaching losses of more than half of the available nitrogen.

At current prices this could amount to losses of as much as £80/ha. However, application in spring to growing crops allowed most of the nitrogen to be utilised.

There was also advice on the economics of slurry storage. With such high fertiliser costs, storage might pay.

“But if you are to keep it until spring, ensure all rain water is excluded. Roofs on slurry tanks are worth considering to reduce the cost of spreading water. Covering solids is also desirable to reduce effluent run-off to groundwater or watercourses, which might be illegal,” said Mr Knight.

The workshop provided growers with an opportunity to look at two booms currently being used for spreading slurry on to growing crops.

One machine, an adapted sprayer, belonged to JSR Farms. The other was a state-of-the-art boom belonging to local contractor, Neil Buckton, adapted to fit on the back of a Unimog.

Independent consultant Jim Lewis explained the latest slurry could realistically be spread on growing crops was at growth stage 32 to ensure an even spread, with rapid infiltration and minimal emission loss.

When slurry was applied at this timing all available nitrogen was used for crop growth. Using slurry in this way could provide total cost savings in terms of NPK fertiliser of up to £244/ha, he said.

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