16 February 1996


THIS weeks T-sum map shows that south-west England, south Wales, Dyfed, Anglesey and the Lleyn, Isle of Man and Northern Ireland are all now at T-sum 200.

Once conditions in these areas are suitable, fertiliser application for early grass can proceed with confidence. Much of England, up to a line from the Ribble to the Humber is currently shown in yellow and is not forecast to reach T-sum 200 until the first week of March., says Kemira.

Producers here should be in no hurry to apply nitrogen to grass and must wait at least a fortnight, possibly three weeks before spreading.

Once in the soil, fertiliser nitrogen behaves just like soil nitrogen, and of the two chemical forms nitrate will leach easily but ammonium is stable, loosely bound to holding sites in the soil.

In the spring, plants show a preference for ammonium N which is the form that resists leaching. The best fertilisers for early grass reflect this by being rich in ammonium.

Kemira recommends first applications of about N62-75kg/ha N (50-60 units/acre), applied as a compound with appropriate levels of phosphate and potash. Where grass staggers is a risk avoid applying any potash in early spring. In contrast, there are clear benefits to spring phosphate… as explained next week.

More information is available on the farmers weekly/Kemira Hotline on 0151 357-5631.