how to handle last year sorghum before July brassicas mix

[NorthPotter]

...you're going from a crop that uses a lot of N to one that stores it to one that uses a lot again.

That is exactly for which i was looking to accomplish. Thanks.
The clover mix fixes the N. When we terminate the clover or "green manure" it will be released to the brassicas.

 

[scott44]

I kind of have the same thing, I planted a summer plot last year but it had clover and hairy vetch in the mix. My plans are to broadcast into it this year and mow it. I think your plan on oats and crimson should work with mowing or light disking then terminating that and planting brassicas. Watch your brassicas and if they are not dark green and are pale you might need to give them a shot of N.