In contrast to nitrogen (N) that moves freely through the soil system, phosphorus (P) and potassium (K) do not easily migrate distances in the application zone. This is a significant issue when applying fertilizer through broadcasting. Using the broadcast method, phosphorus and potassium nutrients remain at or near the soil surface, and generally do not effectively reach the root system.
To address this issue, fertilizer banding can be used as a more effective nutrient delivery system. Banding is the application of solid or liquid fertilizers in four-inch deep rows below seed level. The rows are then covered, after which seeds are planted, taking care that seeds are at least two inches from the nutrient source. The banding process reduces soil-to-fertilizer contact, reduces fixation and improves nutrient use efficiency.
Banding can be used effectively in both ridge-till and no-till planting systems. It has been widely observed that total nutrient application amounts (particularly P and K), using the banding method, can be decreased by one-third when compared with broadcast applications due to the concentration of nutrients in a smaller area. Therefore, while yields are similar, less fertilizer is used in banding.
Phosphorus banding can be particularly effective in acidic soils (when pH is less than 5.5), where increased soluble aluminum in the soil solution causes decreased nutrient uptake, root pruning (shortened roots that do not grow to their normal size/length) and toxicity to plants. In general, soluble aluminum and other elements such as manganese and iron react quickly with P fertilizer to produce a chemical reaction that separates the solid metals from the soil solution. As a result, toxicity near the seed can be temporarily reduced, creating a zone where germination and emergence of the plant is more favorable.
Ron Smith, senior technician of greenhouse services, demonstrates banding using nitrogen, phosphorus and potassium (NPK) granules in IFDC’s greenhouse.