What's an ideal GAI for osr at this time of year?

[Charlie--chalk]

Just wondered on the question above. Cheers

 

[franklin]

1 ish about fine.

 

[Brisel]

Who cares? There's nothing you can do about it right now though the 50 kg/ha N per GAI unit to get to 3.5 by flowering still applies. Less than 0.5 with a poor root structure ought to have its inputs cut back and take what comes but at today's money there is lots of work for an even bigger net loss if you grub it up for something as daft as a spring osr crop instead. The first loss is the best. If you've used residuals like Astrokerb you may as well not bother trying anything else.

Mine vary from 0.6 for a crop with a massive root system that was knee high in November to 1.2 for the thicker crops. Both have the potential to do a decent yield.

 

[Charlie--chalk]

It's the first time growing winter osr for me so I've not had any experience with it hence the question. My index's range from 1.7 to 2.6. Seeing the agronomist next week so wanted half an idea. Cheers, Charlie

 

[Feldspar]

Went out and cut and weighed a few m2 yesterday and have between 55 and 75 kg/ha of N in the crop. According to the formula in the Strategies 3 NIAB document, that means applied spring nitrogen requirements of between 105 and 155 kg/ha. Then again we bought our Nitram at £170/t which equates to 50 p/kg which, combined with OSR where it is now, would mandate, according to RB209, roughly another 50 kg/ha of N. I'm not sure though whether that formula is that sensitive to N vs OSR price though.

 

[franklin]

It's the first time growing winter osr for me so I've not had any experience with it hence the question. My index's range from 1.7 to 2.6. Seeing the agronomist next week so wanted half an idea. Cheers, Charlie

Just means less on the first dose.

 

[Hindsight]

Went out and cut and weighed a few m2 yesterday and have between 55 and 75 kg/ha of N in the crop. According to the formula in the Strategies 3 NIAB document, that means applied spring nitrogen requirements of between 105 and 155 kg/ha. Then again we bought our Nitram at £170/t which equates to 50 p/kg which, combined with OSR where it is now, would mandate, according to RB209, roughly another 50 kg/ha of N. I'm not sure though whether that formula is that sensitive to N vs OSR price though.

I note the strategy document say 160 kg/ha for exceptionally large canopies and 200kg/ha for large (average) canopies. So my view would be you should just aim to apply the 155kg/ha or somewhere between that and 200 kg/ha (that would get you to the RB209 amount) - not more complicated than that, but split the timings to put more of it on towards the later usual timing - ie green bud / latest time spreader will get through crop. But you do need some sulphur on early and thus your choice of S N fert will drive the decision process as well. Examining the dose response curves can be 50 kg/ha either side of the optimum and be correct. Hey ho

 

[Brisel]

I wouldn't be too worried about getting all the sulphur on this early, just enough to see it through for now. Sulphur demand is strongly related to biomass growth so plenty is needed later on.

 

[Feldspar]

I note the strategy document say 160 kg/ha for exceptionally large canopies and 200kg/ha for large (average) canopies. So my view would be you should just aim to apply the 155kg/ha or somewhere between that and 200 kg/ha (that would get you to the RB209 amount) - not more complicated than that, but split the timings to put more of it on towards the later usual timing - ie green bud / latest time spreader will get through crop. But you do need some sulphur on early and thus your choice of S N fert will drive the decision process as well. Examining the dose response curves can be 50 kg/ha either side of the optimum and be correct. Hey ho

We have only Double Top to use. So will need 250 kg/ha of that to get us up to 75 kg/ha of SO3, which will give 68 kg/ha N. Just need to work out when exactly to apply it. Looking at the weather the earliest is going to be very end of Feb / very beginning of March which may end up being about right.

 

[Brisel]

So your timing of the second dose will be determined by the canopy size? Are you using liquid or solid?

 

[Feldspar]

So your timing of the second dose will be determined by the canopy size? Are you using liquid or solid?

I'm not sure really. Crop is pretty big at the moment and it had plenty of N in the autumn so I don't think there's too much rush. Just worried about getting the S there in time, but from what you said there isn't a desperate rush. Using solid.

 

[franklin]

GAI 1.2. 40cm rows. Going to get 80kgN and 75kg SO3 this week. That will do until its at green bud.