Strip-till and sub-surface fertilizer placement has become a common conservation practice for both no-till and conventional tillage systems here in Ohio. Programs like H2Ohio support sub-surface nutrient placement since it can provide production and environmental benefits here in Ohio. Benefits for sub-surface placement of nutrients could be:
- Place fertilizer in a position readily available for crop uptake.
- Potentially reduce pre-plant field passes to a single operation, thereby conserving fuel and reducing compaction.
- Strip-till sub-surface placement equipment creates a more uniform seed bed with better seed-to-soil contact and less trash in the furrow, improving planter performance and emergence.
- Sub-surface placement can reduce fertilizer loads in overland runoff.
- Banded fertilizer increases the concentration gradient reducing soil absorption and improving P and K movement to crop roots through diffusion.
However, selecting the right tool and nutrient placement strategy is important for successful adoption. There exists a variety of implements to inject fertilizer and perform strip-till. When considering strip-till and subsurface fertilizer placement options, it is important to first determine the performance objective for the farm. Units vary in horsepower requirements, fertilizer placement depth, and the level of tillage. The correct unit will vary from farm to farm based on the differing management strategies.
To help identify which implement(s) is best suited for your farm, the Ohio State Digital Ag Team compiled a list of sub-surface equipment and published the information in a recently updated FACT SHEET: Opportunities for Sub-surface Nutrient Placement in Ohio, https://ohioline.osu.edu/factsheet/fabe-56401. This publication contains a listing of currently available equipment from different manufacturers. The equipment has been placed into one of four categories to help with selecting the correct unit for a farm and meet the farm’s performance objective for using this type of equipment. Here is an explanation and illustration for the four different categories.
- “Deep rip and placement” implements apply a fertilizer band (generally 3 to 8 inches) of liquid, dry, or anhydrous, prior to the growing season and usually involve some type of tillage or seedbed modification. These implements are generally able to operate 3 to 6 miles per hour in a minimal till to strip-till environment, producing more soil disturbance than “Zone Mixing” or “Injection” implements.
- “Zone mixing” type implements mix fertilizer and soil in a tilled zone generally around 8 inches wide and 6 inches deep. Typically uses a multiple coulter setup to induce a thorough mixing action on the soil while blending liquid, or dry fertilizer or manure. These implements are generally able to operate in the 7 to 12 mph range in a strip-till or similar environment, while producing more soil disturbance than “Injection” type implements.
- “Injection” type implements apply a shallow, narrow band of fertilizer (generally 3 to 5 inches), of liquid, dry, or anhydrous fertilizer. Typically, these implements utilize a single coulter or similar opener to inject the fertilizer product into a thin opening of the soil. These implements normally operate in the 7 to 12 mph range in a no-till or minimal till environment, while producing the least amount of soil disturbance compared to other implements.
- Broadcast then Incorporate application is typically conducted by a dual spinner-disc spreader, followed by incorporation through disc, field cultivator, or similar tillage tool. Incorporation can be done any time after the broadcast application, but preferably within 3 to 5 days.
Sub-surface placement tools offer many advantages through optimizing nutrient placement and seedbed preparation but often are more time-consuming than traditional (over-the-top) fertilizer spreading. Try to incorporate as many of the benefits as possible into your operation by selecting a tool that maximizes the value for that pass over the field.
