The Timing is Right: Flexibility in Strip-Till Timing and Nutrient Application

Considering the adoption or current use of strip-till in your farming operations often raises the question: when is the optimal strip-till timing—fall or spring? This decision depends on factors such as equipment and labor availability, as well as annually varying weather and field conditions. A three-year study (2016-2018) at Iowa State University focused on this very question, examining the effects of strip-till timing and nutrient application.

The study involved annual commercial-scale tests on at least 50 acres, with field sites rotating each year to encompass diverse production conditions. All fields maintained a corn-on-corn rotation. The primary objective was to assess the impact of different strip-till timing strategies combined with nutrient applications.

Researchers implemented three treatments across each field, replicated in side-by-side strips to minimize spatial variability:

• Fall strip-till with phosphorus and potassium (P&K) application.
• Spring strip-till with P&K application.
• Both fall and spring strip-till passes, with P&K applied during the fall pass.

A coulter-type strip-till machine featuring wavy coulter blades was utilized to create 10-inch-wide tilled zones, incorporating dry fertilizer evenly throughout the depth. Configured for 30-inch rows, the zones shifted 15 inches each season to align between previous crop rows. P&K replacement rates were calculated based on prior crop removal and target soil fertility levels, using monoammonium phosphate (MAP) and potash as nutrient sources.

Despite yield variations among the three test fields due to inherent soil productivity and seasonal weather differences, no statistical differences were observed between treatments within the same field. This outcome suggests that growers have flexibility in scheduling strip-till operations based on labor and equipment availability. Additionally, it allows for annual adjustments in strip-till timing in response to changing weather and operational factors. For instance, if the fall season is unusually wet or an early freeze occurs, performing strip-till and nutrient application in the spring remains a viable option without significant yield penalties.

Beyond flexibility, strip-till provides additional benefits such as reduced soil erosion, improved water infiltration, and enhanced root development. By limiting full-width tillage, strip-till helps retain soil structure and organic matter, leading to long-term soil health improvements. Additionally, targeted nutrient placement in the strip can improve fertilizer efficiency, reducing costs and minimizing runoff into waterways.

The inherent flexibility in the timing of strip-till and nutrient application is crucial for integrating this system successfully into any farming operation. It enables growers to adapt strip-till timing to their specific operational needs and to adjust annually based on weather patterns and other influencing factors.

For more detailed information, refer to the original article: The Timing is Right: Flexibility in Strip-Till Timing and Nutrient Application.