Gentry Sorenson, Field Agronomist
At the conclusion of harvest, decisions are made regarding what type and how much tillage is needed to prepare the seedbed for next year’s crop. Farmers consider different factors in their operation to make the best decisions for their farm. When considering what tillage practice is the best for your farm, consider topography, drainage, and field conditions. No-till, strip-tillage, chisel plow, and deep rip are tillage practices that we often see in preparation of planting soybeans. They are the initial passes of tillage performed after the corn crop has been removed from the field. Considering factors such as fuel use, machinery costs, and maintenance of the equipment are also important considerations.
Tillage operations or intensity of tillage should be adjusted based on the amount of crop residue remaining after harvest. Leaving residue on the surface to reduce windblown erosion is important to help hold soil in place. Higher residue tillage operations such as no-till and strip-till limit the amount of fine soil particles which can be carried away by wind and water. Smaller soil particles formed by aggressive tillage allow soil to be moved off target by wind and water and is lost from valuable farmland. Fields that have higher slopes can be prone to water erosion and windblown erosion. No-till or strip till may be a good fit for higher slope environments.
As tillage is performed, soil structure is affected as the soil is broken apart. When soil structure is altered by tillage operations that are performed at the same depth repeatedly, a compacted layer below the area of tillage can be formed. If tillage is reduced, natural soil structure can be preserved, and the soil will be more resistant to erosion from wind or water. Other benefits of good soil structure include increased soil organic matter, reduced nutrient loss from leaching, increased water infiltration, and greater retention of plant available water.
Long term tillage trials began in 2003 on seven research farms across the state of Iowa to evaluate tillage intensity. Through the trials, only limited differences in yield were observed. Tillage treatments studied in the trials included no-till, strip-tillage, chisel plowing, deep-rip, and moldboard plowing. Tillage of corn residue prior to planting soybeans did not show an economic increase in soybean yield. Reducing tillage intensity ahead of soybean production is not only good for the soil but maintains or increases profitability while reducing fuel and labor needs. An additional benefit of going to 100 percent no-till is soil strength which allows for faster return to the field after rainfall events.
Tillage practice decisions are important decisions for your farm. Weighing all factors is important. Consider wind and water movement of the soil and soil structure when making decisions. If you choose to make a change in your tillage practice, have patience. There may need to be changes made to your management to help the change in tillage practice succeed. Slight changes to fertilization methods or weed control methods may be needed. For instance, in reduced tillage operations, there may be an increase in perennial or bi-annual weed pressure.