NVZ proposals leave host of unanswered queries

Last week’s Nitrate Vulnerable Zone proposals will have left many farmers with more questions than answers. Issues such as what qualifies as a high trajectory, high pressure application technique for spreading organic manure will leave many scratching their heads.

Even ADAS principal scientist Peter Dampney is unsure of what some terms in the DEFRA consultation document mean, particularly high trajectory application techniques. “It’s unlikely to include dirty water systems when true dirty water collected from yards is being applied. However, when water is separated out of slurry storage that could be an issue. But there is no definition of what constitutes these systems splash plate tankers shouldn’t be included, but some equipment may be restricted.”

Furthermore, Mr Dampney says there is an issue over what constitutes incorporation of high available nitrogen manures. “It may be that ploughing or discing is the minimum standard applicable.”

But Northumberland-based beef and sheep producer Charles Armstrong says simply harrowing may be sufficient. “We’ve applied sewage sludge in the past and harrowing has been enough of a cultivation to suffice for those requirements.”

The proposals also require increased storage requirements, with minimum storage of 26 weeks required for pig and poultry units and 22 weeks the minimum for cattle and other slurry. Mr Armstrong says this shouldn’t be an issue for his unit as he only needs to clean buildings once a year, avoiding the need for separate storage.

Farmers will also be required, should these proposals be enacted, to have a written risk assessment to identify suitable locations for organic manure applications. This, says Mr Dampney, should be in the form of a traffic light system map.

“Areas completely unsuitable for spreading, such as river and ditch banks, should be marked red. Areas where spreading is allowable for only part of the year should be marked orange and those where spreading is safe at all times outside the closed periods should be coloured green.”

But the area which is likely to create the biggest problem for many units is the reduction in the whole-farm livestock manure nitrogen loading limit to 170kg/ha from 250kg/ha. “DEFRA is considering applying for a derogation to keep the limit at 250kg/ha, but if it does fall to 170kg/ha farmers, and particularly those with intensive dairy units, will need to find alternative ways of coping with excess manure,” explains Mr Dampney.

“It may be that manure needs to be exported to units with lower stocking rates or to arable units with no livestock to reduce nitrogen loading on intensive livestock units.”

Alongside these requirements, DEFRA is proposing to extend the closed spreading season to five months from three months and to include all soil types in this, rather than just sandy and shallow soils as in the last set of NVZ rules. “This is simply because all water running out of all soils carries some surplus nitrate with it, potentially causing polution,” says Mr Dampney.

Together with this will be a requirement for farmers to balance crop nitrogen requirement with nitrogen supply from soil and from applications of organic manures and manufactured fertilisers. “This will mean taking full account of organic manures, something many farmers fail to do adequately at the monent.”


  • Whole farm livestock manure limit of 170kg/ha
  • Increased closed periods on all soil types
  • Minimum storage requirements of 26 weeks (pig and poultry) and 22 weeks (cattle and other slurry)
  • High trajectory, high pressure application techniques prohibited
  • Written risk assesment required to identify suitablee sites for organic manure applications