Soil nitrogen levels predicted to be low this spring

Soil nitrogen levels are predicted to be low this spring, prompting one agronomist to highlight the importance of soil sampling for 2013.

This is despite the difficult growing conditions last season leading to many crops failing to use all the nitrogen fertiliser applied last season, resulting in higher predictions of soil nitrogen than expected at the end of August.

Allison Grundy, arable agronomist at GrowHow UK, highlights the impact of the high rainfall in the months since harvest. “We’ve had an awful lot of rain since then,” she says.

“Looking at the figures up until mid-December, rainfall across England and Wales has been on average 150% of the norm, with some regions having more than 180% more rain than is usual over this period. Even the ‘driest’ region, the east, has had 125% of its usual rainfall and in the run-up to Christmas we saw even more rain,” she says.

“Leaching is bound to have been a problem on lighter soils, but where soils have been waterlogged, denitrification is likely to be the main problem. On all soil types the cold and wet will have meant very little mineralisation – every which way you look, nitrogen is being lost,” she warns.

Nitrogen levels are probably going to be low next spring, but she adds that N levels can be surprisingly variable, not only between years, but also between soil types, regions and even individual fields within the same year. “So soil sampling to measure the amount of nitrogen a crop will get from the soil over the entire growing season will be important in 2013.”

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