6 December 1996

Analyse grassland in autumn/winter

GRASSLAND is best sampled over the autumn and winter to assess nutrient status.

So says Boxworth, Cambs-based ADAS soil scientist Peter Dampney. "Soils should be analysed every four years, and more often where fertiliser applications are likely to lead to a rapid change in nutrient status."

Producers should avoid sampling soil within three months of applying fertiliser or organic fertiliser, he warns. "That means late autumn and winter sampling is the best option on grassland. Winter sampling is also likely to be easier as soils are moist."

In addition, lack of grass growth during colder weather will give a more accurate picture of soil nutrient status, says Mr Dampney. "Nutrient levels fluctuate far more when grass is growing rapidly, which can give an inaccurate analysis."

But producers suspecting sodium deficiency should sample actively growing herbage rather than relying on soil analysis. That means waiting until spring to analyse grass samples.

"Soil samples are less useful than sampling herbage for sodium deficiency.