Using Common Drills... Seed/Fertilizer Mixture

Making the Seed-Fertilizer Mixture (page 4 of 9)
The best way to mix seed and fertilizers is to have a fertilizer blending plant do it. Some plant managers can be rather irritable about that request, but most in our region now readily comply.

If you cannot have the mixture prepared for you, use a cement mixer (figure 1), which can be rented and holds 100 to 300 pounds of fertilizer. The machine takes one to three minutes to mix the materials well. Transfer the mix into the planter being used.

Figure 1. Using a portable cement mixer to field-mix bulky seed and dry fertilizer for planting with a common fluted feed grain drill

Figure 2. Hand mixing bulky seed & fertilizer in a trough

The most inefficient way to mix is by hand. Put the fertilizer in a container such as a no. 2 tub, calf trough, or barrel bottom, add the necessary seed, and stir with a tool (hoe) or by hand, but be sure to use gloves. Mixing 50 to 100 pounds of material at a time works well (figure 2). Pouring seed and fertilizer into the container simultaneously aids in mixing.

Besides bulky seeds, small grains and other crop seeds that flow readily can be planted in a seed-fertilizer mix. Hard seeds or less bulky seeds do not need to be mixed with the fertilizer: simply put in alternating layers of seed and fertilizer, starting with seed on the bottom of the hopper. Layers of 50 pounds each of wheat or other hard-seeded crops and fertilizer distribute very well. The seed and fertilizer mix as they move through the drill box in a funnel pattern and out of the feed openings (figure 3).

Because of their characteristics and bulk density, these mixtures flow differently than pure, hard seed. For example, to distribute a fifty-fifty mix of wheat and fertilizer, the calibration setting is usually near 175 percent that for wheat alone. The ratio of seed to fertilizer can be adjusted to the desired rates per acre, but the layering should be uniform and as consistent as feasible.

Figure 3. A schematic diagram of flow characteristics of a layered flowable seed and dry fertilizer combination coming out of a drill box or other planting equipment

Planting Management
Control planting depth according to crop requirements and field conditions.

When seed are broadcast planted in a row on top of a good seedbed and row openers are run above ground or shallowly, it is often necessary to disconnect the rod or other parts at the drill clutch and engage the clutch by hand to get seed flow. The boots may crimp when the row openers run above the soil line.