This article is part of a 4-part feature on Untiedt's Vegetable Farm, one of our local Minnesota Grown farmers. Click here to read from the beginning.
Every farmer's harvest removes valuable and healthy nutrients from the soil. Consider the famous and particularly delicious Untiedt tomato. It's five percent potassium by weight, so for every ten tons of tomatoes harvested, at least 1,000 pounds of actual potassium is removed from the soil. Without soil amendment, nutrient depletion would render this most valuable of farm resources incapable of future production.
To counter this naturally occurring cycle, soil is continually rebuilt. Untiedt's Vegetable Farm implements about 10 natural soil rebuilding programs. A few key programs for soil amendment are as follows:
- Composted manure is gently worked into the top soil after the fall harvest, before the ground freezes or snow falls, to prevent losing nutrients from wind and water erosion and to allow nitrogen to work itself into the root zone, preventing it from escaping into the atmosphere.
- Green manure is also worked into soils on plots where early-maturing crops have already been harvested. Cover crops like sorghum, rye, and field peas are allowed to flourish until they are chopped and worked back into the land. Nitrogen-fixing legumes like beans, peas and clovers are grown only to be amended back into the soil, not harvested. This extensive cover crop menu naturally adds key nutrients (nitrogen, phosphorus and potassium) to the soil during their decomposition.
- Crop residue is an extremely important source of organic matter and nutrients for soils, too. It's chopped and spread on their fields to hasten decomposition and the release of nutrients back into the ground.
- Composting involves combining leaves, straw bales, old hay, etc., with a mixture of basalt and calcium plus bacteria and loam soils. Allowed to naturally ferment all summer, the end result is a nutrient-rich organic matter that looks similar to black dirt. When applied to the land, it adds soil microbes, bacteria and trace elements, all of which are necessary for healthy soil management.