Corn populations have increased on average around 300 plants per acre/year since the 1920s. Why? Better genetics and more innovative planting practices are two reasons, but the realization that higher planting populations equate to higher yields is what started it all. And this definitely applies to corn.
Planting populations nowadays depend on a number of factors — environment, row spacing, tillage and hybrid placement, to name a few. On productive soils, many growers opt for planting pops ranging from 34,000 to 36,000 for corn and 140,000 to 160,000 for soybeans. Now, we’re seeing more growers choose narrow-rows and even higher-population planting. If you make this switch, understand that choosing the right genetics, appropriate population for your fields’ unique growing conditions and following optimum management practices all play a role in the success of higher populations.
Stine Corn Breeding Program and our Unique Genetics
Since 2012, Stine has been marketing unique HP hybrids derived from our one-of-a-kind corn breeding program. We’ve spent considerable time developing genetics that perform in higher populations and have the characteristics to maximize yields when planted at increased populations. Some of the characteristics include:
- Shorter plant height with less biomass without compromising ear height (ideally 40 to 45”).
- More efficient utilization of water and nutrient uptake. Ideal for drought or water-logged soils.
- Superior standability and disease tolerance because they’ve been thoroughly tested at high populations.
- Upright leaf structure and greater leaf area index for maximum sunlight interception, which helps with plant photosynthesis. Striving for at least 97 percent.
- Most all of our hybrids respond best to higher final stand populations.
After you’ve selected the right high-population hybrid for your fields, it’s time to brush up on best management practices for higher populations. Here are some tips to remember and recommendations to ensure you’re prepped and ready for higher populations this planting season.
Understand Your Soil’s Cation Exchange Capacity (CEC) and Organic Matter
Soil sampling is key to determining your soil’s CEC and organic matter levels. Consider this when reviewing your sample results.
- CEC is capacity of a negative charged soil to retain positively (+) charged nutrients. That’s why nitrates and sulfates are negatively charged and are known to leach in the soil profile or be released through denitrification.
- CEC directly affects the amount and frequency of fertilizer applications.
- Higher CEC soils don’t leach as much mainly because of the percentage of clay particles and organic matter content.
- Roughly every one percent of CEC gives you 10 pounds per acre of nitrogen.
- Knowing CEC and organic matter is especially important to know when and how often nitrogen and potassium fertilizers can be applied in a given year.
- Soil organic matter provides between 20 to 80 percent of the CEC in the mineralized soil, and the rest comes from the amount of sand, silt and clay in the soil.
- Organic matter can release 20 to 30 pounds of nitrogen per acre each year for every one percent of CEC.
Other Soil Nutrient Considerations
- Nutrient application and proper timing is critical, especially for leachable nutrients like nitrogen and sulfur.
- Nitrogen credits from a previous crop of soybeans is limited based on the soils productive yield potential (20 to 40 pounds/acre nitrogen credit).
- Adding sulfur to your program may be better money spent (one pound for every five to 10 pounds of nitrogen). Ammonium sulfate or ammonium thiosulfate forms are preferred.
- Different soil properties have different water-holding capacity. Whether you have sand, silt or clay, populations will need to be adjusted accordingly.
- Potash is key to late-season plant health and having good base saturation levels so nutrients are readily available to the plant.
- Phosphorus yearly crop removal is 0.4 to 0.6 pounds per bushel, and potassium is 0.29 to 1.33 pounds per bushel.
- A 240 bu/acre corn crop removes 60 pounds per acre of potash while a 60 bu/acre soybean crop removes 68 pounds per acre of potash. A rule of thumb to remember — big crop yields have big nutrient removal.
Technology Considerations
- Updated planters with the best row unit options (99 percent singulation) are critical for proper seed placement and depth for uniform plant emergence. Higher plant populations and plant spacing are more easily obtained when moving to 22-inch or narrower rows.
- There’s more technology available such as satellite imagery or drones to detect in-season problems, including nutrient shortages such as nitrogen.
- There are a number of companies that employ precision technology to offer data-driven management recommendations for your farm. For example, Stine works with Farmers Edge — a company that offers customers on-farm hardware, software, digital agronomy and AI-driven analytics. These companies take the data from your field and compile best management recommendations to help you maximize returns.
For more tips and recommendations on high-population planting, contact your local Stine sales representative.