Sampled Soil Lately? Findings Could Change Seed Decisions


When selecting hybrids and varieties for the upcoming season, soil sampling should be a critical consideration – with pH being especially important. That’s why Golden Harvest breeders have tested corn and soybean response to pH for nearly 20 years. pH measures relative acidity or alkalinity of the soil, and soils typically range on a scale from 3.5 to 10, with the optimum target being from 6 to 7.

A pH test plot is pictured above, with a Golden Harvest pH-tolerant hybrid on the left, versus a competitor hybrid at right.

Nutrients such as phosphorus, manganese and zinc become less available when pH exceeds 7.5. Here are the 3 different pH levels and what you can do about your test results:

  • Low pH: Soil acidity increases as pH drops below 7, or neutral pH. So if you see field results below 5.5, consider a lime application.
  • High pH: Soil alkalinity increases as pH rises above 7, so in instances of field results above 7.8, using the proper combination and placement nutrients is important to aid in plant uptake. Varietal selection tolerant to high pH in both corn and soybeans is key to a successful crop.
  • Ideal pH: Levels between 6 and 7 are optimum, so when your fields test within this window, you’re right where you should be.
Before Golden Harvest corn and soybeans are released with a high pH tolerance rating, uniform testing is conducted in Nebraska, with observations 4 times a year on a 10-acre plot. No Golden Harvest hybrids or varieties go untested, and competitor products such as DeKalb and Pioneer undergo standardized testing. Hybrids and varieties are measured for pH levels at 4 stages: emergence, V5–V6 and twice during the reproductive stages.
Taking a closer look at pH levels on your farm, collect soil samples from a depth of 6 to 8 inches every 2 to 4 years. Sampling soil 3 to 6 months before planting the next crop allows enough time to develop a nutrient plan to address the needs your pH might demand. Late fall or early winter is the perfect time to discover what is going on in your fields. As a guideline, obtain 15 to 20 soil cores for an area of 20 acres or less, and make sure to clean your sampling instruments to avoid contamination from one area to another.
Knowing how a variety or hybrid responds to pH helps ensure proper product placement so you can maximize plant health and yield. Once you have a clear understanding of your fields’ pH levels, you are several steps ahead of starting off on the right foot at planting. For more help determining field soil solutions, contact Golden Harvest Seed Advisor with questions or for additional agronomic insights.
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