MSU Extension

This is a very exciting time in agriculture with advances in seed technology, new uses for corn and soybeans and soaring commodity prices. This is also a very risky time in agriculture with increasing costs for land, fuel, fertilizer, feed and other inputs. Part of a strategy to reduce your risk should include rigorous attention to the fertility and health of your soil.

It is basic to have your soil tested for pH, phosphorus and potassium at least once every three years. This will avoid problems with both yield losses due to deficiencies and money lost due to over applications. If your pH is high, then soil tests for zinc and manganese is recommended. Cleaner air emissions from industry have reduced sulfur in the rainfall and will likely be a bigger concern, especially on lighter sandier soils. Nitrate testing at sidedress time can also help fine-tune your nitrogen program. Getting your nutrient levels in order is very important to ensure good crop yields, but it does not stop there. For years we have over-looked possibly the most vital part of soil fertility and soil quality, which is the organic matter.

Organic matter is the vast assortment of carbon compounds in your soil. The compounds are the products of living organisms, like plants, animals and microbes. Nutrients are held in the soil by exchange sites on clays and organic particles. Organic matter can hold five times more nutrients than clay. As organic matter increases, a greater pool of nutrients can be held in the soil and be available for plants. Organic matter improves both water infiltration and water holding capacity of the soil. Acting like a sponge, it will absorb six times its weight in water. This is very valuable in years with dry summers like 2007.

Soil compaction can greatly reduce yields and increase tillage costs. Organic matter supports soil microbes that create substances that act as glues to form aggregates of smaller soil particles. These soil aggregates are what is important to provide good soil structure and soil tilth. With good soil structure, you get favorable pores for soil moisture and air. These pore spaces also provide an ideal conduit for plant roots to grow and thrive. The better the soil structure, the better the soil will hold up during adverse times with excessive soil moisture. A bonus effect would be reduced soil erosion. A couple of other benefits of organic matter include a quicker soil warm-up because of the darker soil color organic matter provides and the potential of supporting more beneficial organisms reducing plant pests and diseases.

Soil health cannot be improved over night, but the practices you do on your farm in regard to organic matter can have a dramatic effect on the future of your soil’s production capacity and resiliency. You can improve soil organic matter basically by two ways: adding more organic matter, and not losing the organic matter that you already have.

You can add organic matter by growing productive, healthy crops in a diverse rotation. Include in the rotation crops that produce a lot of roots, such as small grains and forages, and crops that produce lots of above ground residue, such as corn. Also include cover crops that will supply both, such as clover and rye. In all cases, limit the crop residue removal and leave it to add to the soil organic matter reservoir.

The loss of organic matter occurs primarily by two methods: tillage and erosion. Minimal tillage and no-till systems, cover crops, crop residues on the soil surface, filter strips and wind breaks are all examples that will reduce organic matter loss.

Not everything will fit into your farming operation. It is important to assess the condition of your farm’s soil and then consider those practices that make sense for you. Talk over ideas with others and gain from their experience. Put a plan together that you can follow, evaluate the practices that you change and fine tune your plan each year. Over time you can make a big difference in you soil’s production capacity and resiliency.

More information is available in two MSU Extension bulletins that discuss soil organic matter management. They are E-3137, Advanced Soil Organic Management and E-3144, Building Soils for Organic and Sustainable Farms. They can be ordered through the county MSU Extension office.