Grow your soil first, your food second. This is a piece of advice many ecological growers are familiar with.
So how exactly does one grow a mass of brownish black dirt? Soil is a living and thriving thing. It is a substrate hosting microbes, bacteria, and a multitude of nutrients, the most important for plant growth being Calcium, Potassium, Nitrogen, Magnesium, and Phosphorus. The soil feeds living microbes. Healthy soil is teeming with living matter from microscopic material to slimy earthworms. The things we put into or take out of the soil in agriculture can either improve the health of this living system or severely deplete it of nutrients.
For example, chemical based agriculture pumps alien sources of synthetic chemicals into soil to feed crops rather than relying on the natural occurring substances to do so. Intensive farming of one crop, monocropping, sucks too much out of the soil substrate. Soon farmers are left with a dead brown mass that once was home to millions of thriving microbes. In order to continue growing crops, farmers must pump more external, synthetic substances into the depleted soil, essentially just using the dirt as a place to put plants who then eat these synthetic fertilizers.
The alternative to this model is feeding the soil so it grows and in turn provides nutrients to support the growth of healthy crops in a more natural way. This can only be done by harnessing the power of nature and working with, not controlling or depleting, ecological nutrient cycles. AASD and many other ecological growers grow the soil through natural fertility building techniques such as compost and bocashi. These materials restore the nutrients we took out of the soil with the previous crops. And most importantly, we rotate crops.
Different types of crops take different nutrients out of the soil and put other ones back in during their growing cycle. In order to ensure the balance of nutrients is restored, we can rotate crops based on the ratio of nutrients they give and take. For example, lettuce feeds heavily on nitrogen. So we don’t want to plant kale after lettuce which because both are what we call heavy feeders. Instead, we want to balance this nutrient load out. We use the above chart to help plan this rotation. This is a simplified version to help one remember which plants usually give, take, or lightly feed on nitrogen. Of course, other nutrients are restored through this balance too. Normally we rotate our crops by fruiting varieties (tomatoes) to leafing varieties (lettuce) to rooting varieties (onions) to leguminous varieties ( beans). With this rotation, we can help restore the nutrient balance, growing our soil, and in turn growing healthy plants. ~Kat