April 2, 2013

Soil Moisture & Planting Population Decisions​

As a kid growing up I thought it was so much fun pulling the field cultivator with the dust rolling behind me (Figure 1). I have a different perspective now, especially after last year. I think we can all agree you can’t predict the weather so you need to develop a solid strategy for the year. Tillage and planting population are a couple of big decisions to make when developing that strategy.

spring tillage moisture loss

Figure 1. Spring tillage moisture loss

The cost of soil moisture loss by type of tillage equipment varies. Soil moisture loss per tillage pass can range from 0.15 inch of water to 0.50 inch of water.1 Tillage does have benefits, but recognize it may come at a cost. With adequate rainfall the cost may not be obvious, but with low rainfall the cost is definitely realized.

34,000 plants per acre

Figure 2. 34,000 plants per acre

Having a management plan in place for each farm/field is essential for success; tillage is just part of the plan. Plant population can also be a game changer. I was in a field this past year that had two planting populations: 34,000 and 30,000 seeds per acre. The difference between 34,000 to 30,000 plants per acre was easily recognizable by looking at the ear size (Figures 2 and 3). This demonstrates how critical plant population can be for each field because of the impact different yield environments can have, especially in a dry year. I’m not the only one who noticed the differences in planting population this past year, and the interest in variable rate planting is increasing. The technology offers the ability to match plant populations by yield environment. Keep in mind there are differences between equipment manufacturers on the speed of changing populations. Precision Planting® has the ability to change populations within 24 inches while other manufacturers may take 30 feet to change populations.

30,000 plants per acre

Figure 3. 30,000 plants per acre

In some fields, yield environments change quickly and often, while in others they don’t. It is important to recognize the capability of your equipment and your expectations. By working closely with your Channel Seedsman you can have a solid plan in place for this growing season.


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Sources: Croissant, R.L., G.A. Peterson, & D.G. Westfall. 10/2012 Update. Dryland cropping systems. no. 0.516. Colorado State University. http://www.ext.colostate.edu (verified 2/8/2013)