Nitrogen and Cover Crops

[cquick]

Evening all,
Drilling wheat today into a cover crop following OSR, I noticed this: (apologies for the blurry photos)

This patch is where wheat was topped off in June 2019 due to excessive sterile brome. The following OSR didn't really establish, so the N applied to this area hasn't been used. The cover crop is so much better where there is more N! The cover got a chance against the volunteers, and even the legumes are better.

The rest of the cover crop is rather stressed due to the lack of N. My question is whether it's worth sprinkling 50kg of N on to maximise the amount of biomass and light interception? Or, as Gabe Brown et.al say, is a stressed crop trying to make more associations with the soil biota, and that this is a necessary step in 'priming the pump' as they say? Is the N going to make it 'lazy' and not do a proper job? Of course if I could get hold of manure at this time of year then that would be ideal, but would bagged N be worthwhile?
Discuss.

 

[yellow belly]

If there is free n in the soil and crop will look better

applying n in the autumn never makes up on that already in the soil But adding some would increase the biomass but will not be efficient and probably not pay

availability is the important part

 

[Brisel]

NZ pea growers use DAP as starter fertiliser, whereas over here we're not really allowed it under RB209 and NVZ rules. It's a question of economics, I think. There was a long debate over carbon sequestration levels in pastures with & without bagged N fertiliser earlier this year with no clear conclusions.

 

[cows r us]

Personally I wouldn't be applying anything to a cover crop. The idea of them is to take up the excess soluble nutrients in the soil and convert them to om for the next crop. If the crop is struggling it will be putting on extra root mass to find more nutrients, it will also be trying to make assossiation with the many microbes in the soil to help make its own nutrients. Its not all about biomass with covers.
Nitrogen fert is terrible for the soil biota so a cover crop with no applied n salts is a nice holiday for them to multiple and build soil health. Remember much of the stable carbon stored in the soil has been broken down by the microbes, look after them.