Here is another picture of the trench technique. My mixes vary around the garden...there are so many factors to consider, acid or alkaline...cold or hot crop...or companion, or not to companion? But basically my mix is decomposed saw dust (to the black stage) about 20-30 pounds of black dirt per row and any kind of decomposed manure that I can find, and I am not picky. Also decomposed fish guts in saw dust does remarkable well for the corn and anything else that I have tried it on. I also top dress with manure (mixed or shredded) and put garden waste all around the rhubarb to decompose and keep away weeds and of course nourish the plants.