Consider the strip-tillage alternative
Depending on tillage depth and speed, 20 to 30 horsepower per knife may be required to ensure satisfactory performance. Inadequate horsepower will compromise the efficiency and performance of the system.
The timing of strip-tillage is critical to achieve the system’s objectives. Traditionally, strip-tillage is conducted in the fall to maximize the benefits of creating the tilled zone before spring planting. Soils are generally drier after harvest than in the spring. Soil conditions are more suitable for strip tillage when soil moisture is at or below field capacity, minimizing soil compaction. Fall strip-tillage dries and warms the soil ahead of spring planting, preparing a more uniform seedbed and improving seed-to-soil contact.
Strip-tillage in the fall has its limitations, as well. This is particularly true now since fall application of nitrogen is being discouraged in many areas. If soils are wet under the heavy residue, tillage tools used to prepare a strip for seed placement can compact soil and forms clods. Wet soils in the spring can cling to the depth gauge wheels on the planter, inhibiting uniform seed depth. Labor needed to complete fall tillage may directly compete with labor required for harvest, so consider the number of hours available for fall tillage after harvest. Another challenge is the precision of planting in the tilled strips.
Strip-Tillage and Soil Environment
In general, tillage significantly affects soil environment by altering the soil’s physical properties such as soil structure, compaction, aggregate stability, hydraulic properties, and thermal properties. The degree to which the tillage affects or improves these properties depends on the intensity of the tillage system. The changes in soil properties will cause changes in the soil environment where crop production can be used as an indicator. Allowing soil to dry in the tilled zone before planting helps the planter’s soil-engaging components (seed opener, depth wheels, closing wheels) establish proper seed depth without excessively compacting soil.
Strip-tillage can have a significant impact on soil temperature, particularly in poorly drained soils and when soil moisture conditions remain relatively near field capacity. The improvement in soil temperature can be limited by excessive wet weather conditions. Studies show that strip-tillage improved soil temperature in the top 2 inches by more than 2° F over no-till in central Iowa.
Cool temperatures, soil-borne diseases such as Pythium damping-off, Fusarium root rot, Phomopsis seed decay, brown stem rot, and sudden death syndrome can cause problems for Iowa soybeans. Fungal pathogens of these diseases infect soybean seeds or seedlings when soil temperatures are low and moisture is high. These diseases are especially problematic in early planted soybean fields. Recent increases in soybean disease problems in Iowa are in part associated with the increased use of early planting. Strip-tillage warms soils in the seed zone or bed quickly and promotes fast germination and growth of seedlings, reducing disease risk.