One way to maintain soil quality is to avoid fall tillage, according to, Dr. Corey Brubaker, state agronomist for the Natural Resources Conservation Service.
"Eliminating fall tillage reduces wear on farm machinery, saves fuel, provides better erosion control, improves soil quality, provides wildlife habitat, and enhances water quality," Brubaker says.
Leaving this year's crop residue on the soil surface over the winter can help provide erosion protection and capture winter precipitation. The moisture captured by the residue enters the soil rather than losing it to runoff, adds Brubaker.
Tillage reduces soil quality by destroying soil structure, which reduces infiltration rates and increases runoff. Tillage speeds up decomposition of crop residues resulting in less organic material being returned to the soil. All of these factors reduce soil quality, according to Brubaker.
Even the application of fertilizer in the fall can have a negative impact on soil quality if it is not timed appropriately. The University of Nebraska Extension guidelines indicate anhydrous ammonia should not be applied until soil temperatures are at a constant low temperature. The mid-day temperatures at a four-inch soil depth should be below 50 degrees Fahrenheit.
Applying nitrogen to warm soils creates a higher potential for losses to occur making nitrogen unavailable next year for a corn crop. Part of the nitrogen lost can leach into the groundwater.
Recent crop planting survey data released by NRCS shows a 12% increase in the amount of corn and soybeans being planted using "no-till" between 2004 and 2006. Sorghum and wheat planted using no-till also showed an increase. No-till planting means the soil is left undisturbed from the previous year and the new crop is planted directly through the residue into the soil in the spring.