N after set-aside likely to require a rethink
By Andrew Blake
THERE IS significantly less nitrogen left after set-aside this spring than DEFRA”s RB209 advisory booklet suggests, warns Farmacy.
The findings echo Kemira”s results and continue the trend of the two previous seasons, says Farmacy”s Pam Chambers.
Overall, in 169 soil tests by the firm”s agronomists, the tendency is for the results to show less residual N available to crops compared to RB209, she notes.
This contrasts with ADAS advice (Arable, Mar 25) that levels of soil N supply are above average this spring.
RB209 suggests that there could be an average of 200kg/ha (160 units/acre) remaining after set-aside, says Ms Chambers.
Farmacy puts the average at just 81kg/ha (65 units/acre) and Kemira 95kg/ha (76 units/acre).
Kemira says there is huge variability within regions and soil types.
“It would seem that on heavier soils the residual N levels are lower,” says the firm”s Allison Grundy. “But on lighter textured soils levels seem to be higher. However, this is by no means set in stone and there are specific examples of where the opposite is the case.”
With much nitrogen already applied there is a need for more work to determine the true picture after set-aside to permit increased applications to be justified in future, says Ms Chambers.
“I shall be talking to the Environment Agency about this. It now employs an independent agronomist which is quite a comfort factor.”
