Will Bonsall of Khadigar Farm in Industry, Maine, grows barley for his own use and also conserves 62 varieties for the Seed Savers Exchange and his own Scatterseed Project.
His method of growing makes a lot of sense for small acreages. Will grows barley in 40 x 40 plots. He lays out the rows with string, about six inches apart, and does the planting with a Planet Jr. push seeder, about one seed per inch in the rows.
He cultivates between the rows with a hand hoe, and when the grain is a few inches tall he mulches the bed with ground-up leaves. These are stored dry the year before in bags. The mulching prevents weeds and water loss. The grain has no problems sending up tillers (shoots) through the mulch. Will minimizes weeds by rigorous cover cropping and never letting any weeds go to seed.
We've used a Planet Jr. to grow grain and the method works well. It's a lot slower than broadcasting, but the birds can't get to the seed (it's buried) and it all comes up. Germination is very consistent, because you get the kernels down into the moist earth. The cheaper Earthway seeder might also work, but none of the standard seed plates I've tried are suitable for barley. You would have to try modifying a plate (the spinach plate looks pretty promising) or else get the company to make you a barley plate.