I planted a couple of plots this size last summer. One plot was a mixture of lablab and sunflower and the other was ICP/Buckwheat/sunflower. In one plot I used milorganite to try and keep the deer out for a few weeks as the plot matured and I did not use any Milorganite in the other. The plot with milorganite lasted almost until fall planting. The plants had a few more weeks to mature before getting browsed on too heavily and it really helped. Once the deer found the plot without Milorganite it was all ate up in about two weeks. This was problematic because it left the soil totally uncovered and the sun was drying it out quick.
Ill probably go back to the same plan this year but Will use Miorganite in all my small plots to let them get established before heavy grazing. Any plot that I had over 1.5 acres in size did awesome. In these larger plots we use WMS pea patch blend.

I planted all these right around the end of May/ beginning of June... worked out well