The issue is that grain stubble is not garbage. If you remove it from the field, you will have to replace the nutrients that you remove with it. Farmers learned that long ago. So instead of making bricks from topsoil, why not stick with making bricks from clay?
Its not like we are running out of clay.
I was merley pointing out two things, one the bricks the article discusses are not made from bio-waste as intimated by posters and two, that the idea of bricks made from waste products, ie. trash has been around for 40 years.