Ken plants green manures. They are crops grown to keep the soil covered and cool, they often add nutrients - like peas add nitrogen, and once tilled they add organic matter to the soil. Organic matter is key! For each percentage of organic matter in the soil the crops have the equivalent of 1" of rainfall. So, if you have five percent organic matter you could withstand a five week drought with minimum crop damage!
Like all gardening and farming, it is ongoing. Here is an example of Ken's process. He planted and grew peas and oats out in the field
A few weeks before he wanted to plant in that space, he mowed the peas and oats. In some situations he pastures animals like chickens or pigs where the green manure is planted and grown to size.
He tilled the space where the peas and oats had been. Next he prepares the bed for the crop - raking or trenching - it depends on what will be planted. Here he planted a late potato crop.