Sidedressing

Sidedressing is an agricultural practice in which fertilizer is applied to the side of a crop row after the plant has emerged, aiming to deliver nutrients closer to the active root zone during periods of high demand. It is most commonly used for nitrogen in row-crop systems such as corn, though it can apply to other crops as well. It differs from preplant or starter fertilization and from broadcast topdressing, which spreads nutrients over the entire field surface.

Placement and timing: Sidedressing places fertilizer near the developing roots after emergence, usually several weeks into the growing season when the crop’s nutrient uptake accelerates. It is commonly applied as a liquid injection or a granular band, either in-furrow, beside the row, or as a shallow trench along the plant row.

Materials and methods: Nitrogen is the primary nutrient targeted, but sulfur or potassium may be included where needed. Equipment includes liquid injectors, knifing or coulter devices, and side-dressers that apply a narrow band of fertilizer alongside the row. The choice of method depends on crop, soil, weather, and access to irrigation.

Management and considerations: Rates are expressed as pounds of nitrogen per acre and are adjusted based on soil tests, yield goals, crop growth stage, and residual soil N. In corn, sidedress nitrogen rates commonly range roughly from 30 to 120 lb N per acre, sometimes split as a portion of total planned N. Sidedressing can improve nitrogen use efficiency and reduce leaching, but excessive application can cause crop burn and environmental loss, particularly with heavy rainfall or drought conditions.