How Low Can You Go?... Corn populations and drought prone soils.

2021 has brought abundant rainfall to Eastern NC and most of the folks I know are gearing up for an exciting (and maybe their all-time best) corn yields. In some instances everything has gone right this year and there's 200+ Bu/A in some areas.

It's time for a reality check. The North Carolina statewide average corn yield was 113 Bu/A in 2020. The year before that it was 111 Bu/A.

If we are honest with ourselves, it is probably more important to implement strategies that help maintain profitability on years where things go wrong, rather than plan for years like 2021. Water is most often the yield limiting factor affecting North Carolina corn. Here are some strategies that make corn more viable on the toughest, least productive acres, while still maintaining some yield upside if conditions are ideal.

1. LOWER YOUR POPULATION: On less productive soils we are dropping too many seed. Often I see people planting between 25 to 28 thousand seeds/A. That is fine on productive soils, but don't be afraid of dropping it WAYYY back on less productive ground. Consider dropping 20 to 22 thousand seeds/A but be cautious. You need the right hybrid if you're going to be successful with this strategy. A flex-ear hybrid with excellent drought tolerance is the key. If you get plenty of rainfall then that flex-hybrid will put on a larger ear, allowing you to still capture top-end yield potential. All the while, you've reduced some risk if growing conditions aren't ideal. With decreased seeding rates you are looking at costs savings of $15 to $25 per acre. While that is only equal to a few bushels, by shaving a few thousand seeds off of your population, you are dramatically reducing corn stress if rainfall becomes limited. The goal here isn't maximum yield if everything goes right. It's about reducing risk of failure in a year with poor growing conditions.
   

2. BE EFFICIENT AND DON'T OVERDO IT ON NITROGEN: Everyone asks "how many units of nitrogen should I put?" That's a loaded question and the answer is probably "it depends." If a farm typically only produces 115 bu/A, you don't need 150 units of N. I often find we are being unrealistic with ourselves about yield potential. If nitrogen is being split-applied (it should be on sandy soil), don't be afraid of reducing N rates; nitrogen use will be much more efficient with split applications. Another benefit of split applications is the ability to make rainfall adjustments to N rates. Nitrogen management is often discussed in the context of increasing corn yield in high-yielding environments, but it is as important or more important on marginally productive soils.
   

3. DON'T SKIMP ON THE OTHER NUTRIENTS: Nitrogen gets all of the attention but we can't neglect the other leachable nutrients on our sandy soils. Applying potassium, sulfur and boron are important too. In some cases, split applying these nutrients may be helpful. Especially in the case of potassium and sulfur, which are demanded in large quantities. Potassium is critical for defending against plant stressors, such as drought. Maintaining soil potassium levels can be difficult on very sandy soils, and applying at least a portion of the potassium at sidedress timing can be beneficial.

I'll wrap up this blog post with a few pictures I snapped last week. The photos below are of a full-flex hybrid planted at 22,000 seeds/A on a Wagram sand. That's a soil type not known for being particularly productive, yet you can see this hybrid is putting on massive ears. With ideal conditions as we have experienced in 2021, low planting populations coupled with efficient fertilization can still produce excellent yields. It may not be as showy or win a contest, but it can be highly productive and profitable.