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Chapter 5.1

Fertilizer Placement

The primary difference among fertilizer application techniques is where fertilizer is placed relative to the developing crop and its roots (Figure 5.1.1). This has implications for how effective the crop will be able to utilize certain nutrients.

Broadcast and Broadcast and Incorporation

Broadcasting spreads fertilizer across the soil surface. Broadcast fertilizer can be left on the soil surface or incorporated by a tillage operation after application. With incorporation, these nutrients are mixed into the surface layer of the soil where root interception is more likely to occur.

Broadcasting is generally the fastest and least costly fertilizer application method. On established crops it is usually the only practical way to apply fertilizer without damaging the crop. Elemental sulphur is particularly suited to broadcast applications because the granules

are left on the soil surface and exposed to weathering processes, which oxidizes the sulphur to plant available forms.

Broadcast fertilization has some limitations. Without adequate incorporation a portion of broadcast nitrogen fertilizers may volatilize and be lost to the atmosphere. Immobile nutrients (e.g., P, K, Cu) broadcast on the soil surface could be stranded above plant roots. These nutrients are inaccessible for root uptake or crop production and susceptible to loss through wind and water erosion, possibly ending up in environmentally

Figure 5.1.1 Placement of Fertilizer Using Different Application Techniques

Broadcast (not incorporated)

Broadcast (incorporated)

Banding

Side band Seed-placed

Fertilizer placement

Seed placement