The generic term that addresses both accurate seed population and in-row seed spacing is “picket fence stands”. Picket fence stands are a combination of accurate seed population and seed spacing so that the plants appear to be uniform, according to Bill Hoeg, Case IH Planter Marketing Manager.
How do you achieve picket fence stands?
University studies have shown that picket fence stands can impact yield from 2 to 4 percent. There are several factors that influence accurate seed population and in-row spacing. Hoeg explains that accurate seed populations are more important than spacing.
Hoeg suggests that farmers adjust their planting populations based on seeds’ germination rates, which can be found on the seed bag or by germination test. This will allow producers to be better informed about what their final stand counts should be.
“For example, if you’re aiming for a final stand count of 34,000 plants per acre, and your seed has a germination rate of 97 percent, then you need to plant 35,000 seeds per acre to get the desired stand count,” says Hoeg. He adds that growers’ final stand counts will vary on a field by field basis. Geography, soil type, amount of moisture, and other factors all figure into determining final stand counts.
Hoeg recommends attaining accurate seed populations before analyzing in-row spacing issues. New planting monitors have formulas that calculate skips and doubles which may or may not match up with the grower’s perception of a skip or double. Therefore, a skip or double may not be truly affecting population. A skip should not be accepted visually until one digs to ensure that the skip wasn’t caused by a seed that didn’t germinate. Depending on the way farmers’ display calculations work, the seed population may be accurate, but may show a skip or double because of a small distance variation between seeds; even though that small variation would not create an agronomic yield impact.
Research shows that on a 30-inch row, if seed population is correct, then a 2.8 standard deviation spacing or less optimizes yield. With today’s technology, everybody can do that if you stay within the meter’s rules. Therefore, spending lots of money to improve spacing won’t yield an economic return on investment. However, you also don’t want to live on the edge where any variability could cause a 2.8 standard deviation or higher, which does start to impact yield.
The Case IH Early Riser® Advanced Seed Meter generally delivers a 1 to 1.5 standard deviation performance at 5 to 7 mph. “If you start from a lower standard deviation rate, you have more flexibility in adverse conditions when operating your planter,” says Hoeg. “For example, at 1.5 standard deviation spacing, if the weather looks bad, you can pick up speed without affecting yield, as long as seeds are being planted at the proper depth.”
Early Riser planters are designed to not only help farmers achieve picket fence stands, but more importantly, photocopy plants. Photocopy plants have a 9 to 22 percent impact on yields. When you add photocopy plants to accurate populations and proper spacing, then the total yield impact could range from 11 to 26 percent. Basically, getting all of your seeds to emerge within eight hours of each other so they look like photocopies has a greater yield impact than anything else you can do.
By placing seeds in the correct temperature and moisture, with the right soil density, and at the proper depth using a Case IH Early Riser planter, producers can better influence the factors that work together to impact yield, including seed population and in-row spacing. All of these factors can result in photocopy plants: plants that emerge at the same time, have the same stalk thickness, are at the same leaf stage as neighboring plants, and most importantly, have uniform ear length.
“Just three extra kernels per ear means one extra bushel per acre,” says Hoeg, “So, growers who focus on photocopy plants can start to see strong increases in yields. And those extra bushels are where farmers can see a greater return on investment, which becomes even more important in times of falling commodity prices.”
Find out more:
To learn more about agronomic considerations at planting and photocopy plants, click here to request a new Agronomic Design Insights report on seed bed conditions.