BS says no need for extra N after heavy rain

1 May 1998

BS says no need for extra N after heavy rain

NO EXTRA nitrogen fertiliser will be needed on most sugar beet crops after recent heavy rain, says British Sugar.

Soil nitrogen tests by the company show that unless beet growers, against advice, applied all their crops N needs before or at drilling, standard fertiliser recommendations should not be amended.

Findings from 10 sites ranging from sandy loam to fen peat show available N levels in April differed little from those in March. Biggest apparent loss was on sandy loam at Garboldisham, Norfolk, where levels on undressed land fell from 79kg/ha (63 units/acre) to 43kg/ha (34 units/ acre). But at four sites, including two on similar soil, amounts available rose over the period, albeit by at most 13kg/ha (10 units/acre).

In general this means that where crops are given split N applications, total dressings should remain as normal (see box), says BS.

Sand land crop risk

But some sand land crops may be at risk where all the N went on before or at drilling and heavy rain followed. In these cases soil sampling for available N may be prudent, says Holmewood Hall researcher Stephen Brown.

Crops benefit from timely applications, he adds. For those still unsown 30-40kg/ha (24-32 units/acre) should be applied immediately after drilling, and all crops should get the rest of their requirements at full emergence as soon as conditions allow, he advises. &#42

British Sugar nitrogen recommendations

kg/ha (units/acre)

Sandy loam, loamy sand

and very light silt 120 (96)

Calcareous loam 90 (72)

Very fertile silt and clay loam 60 (48)

Fen peat 30 (24)

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