Earth Day = Soil Health Day

Earth Day, a day to remind ourselves that the Earth’s health is fragile and must be taken care of.  For farmers, nothing is more “earthy” than the soil, which is the foundation of their livelihoods.  Soil health is delicate and farmers implement a variety of conservation practices to take care of it.  These practices can range from soil erosion control like terraces
and no till to nutrient management like soil tests and cover crops.

No till corn field

Another important aspect of nutrient management and soil health is application rate.  This is the amount of a nutrient such as nitrogen that is applied to a field and is usually measured in pounds of nutrient per acre.  When farmers harvest crops like corn and soybeans, they are removing nutrients that those crops have taken from the soil.  The soil’s health and continued productivity depend on those nutrients being replaced, which farmers do by applying manure or synthetic fertilizers.

Terraces

A recent study by Iowa State University researchers Laura Christianson, Michael Castellano, and Matthew Helmers looked at the nutrient balances in Iowa soils and factors that affect whether those nutrients are being replaced adequately to maintain proper soil health and productivity.  The results revealed positive correlations among nitrogen fertilizer application, corn yield, organic matter, and the nitrogen balance of the soil.  It also indicated that nitrogen rates that do not maximize crop yield and crop residue are likely to reduce organic matter and the nitrogen balance of the soil.  Nitrogen fertilizer application is important to replace the nitrogen removed by high yielding corn harvests.  High yields of corn also produce large amounts of crop residue (stalks, leaves, and cobs).  This residue is a source of organic matter for the soil.  Organic matter is the soil’s reservoir of stable nitrogen for future crops.

The State of Iowa is developing a Nutrient Reduction Strategy to reduce the loss of nitrogen and phosphorus to water bodies.  Nutrient application rate reduction is one potential practice outlined in the strategy to reduce nutrient loss.

In celebration of Earth Day every day, farmers will need to replace nutrients removed in grain harvest by applying manure or fertilizer and increase soil organic matter by managing crop residue, planting cover crops, and reducing tillage.  To read the Iowa State report, click here.

Ben Gleason is the Sustainable Program Manager at Iowa Corn where he works on a range of environmental projects affecting Iowa corn growers.  Soil and water conservation issues are a priority, and Ben works closely with government agencies and other organizations to address these issues.  Previously, Ben worked for the Iowa Department of Agriculture and Land Stewardship as a project coordinator for multiple watershed projects addressing sediment and nutrients in lakes and streams.  Ben grew up in Charles City, IA near his family’s farm on the Little Cedar River.  He resides in Ankeny and his hobbies include hunting, fishing, boating and attending Iowa State athletic events.