It may be the beginning of the year, but planning for the coming planting season is likely already underway. Taking soil samples is one of those tasks to be completed at this time of year so there is time to make adjustments prior to planting.
Each year, it seems Extension agents note that soil pH problems often take growers by surprise. A soil pH below 6.0, which is the target pH for peanuts, can cause zinc toxicity and will kill peanut plants. For corn and cotton, the target pH is even higher at 6.5. Liming is the practice needed to adjust soil acidity levels.
University of Florida assistant professor and cropping system specialist Hardeep Singh has some helpful information about liming in his article, “Considerations When Liming Your Fields.”
Singh says, “The frequency and quantity of liming depends on the soil’s traits and how it’s managed. Factors like nitrogen fertilization and organic material decomposition decrease soil pH. Regular soil testing becomes crucial to monitor pH levels and fertility status accurately. These routine tests offer insights into soil pH and suggest appropriate lime application rates.
“The timing of lime application is crucial for its effectiveness. While lime can be applied throughout the year, incorporating it during periods when there’s less rainfall allows for better absorption and distribution within the soil. Fall and early spring are often preferred times for liming, enabling the lime to gradually neutralize acidity before planting season begins.”
Since calcium is needed for peanut production, a calcite lime is the preferred soil amendment over the magnesium-rich dolomitic lime.
There are areas, such as North Carolina, where zinc levels will be so high that an increased soil pH is not enough to tie up the element, making it safe to grow peanuts. On a yearly basis, according to recent data, 7% to 10% of soil samples in the Tar Heel State may have a zinc index of 250 or above, which is not advisable for peanut planting.
It all comes down to testing to make sure you know what’s going on in the soil.
As Singh says, “Remember, each field is unique, and consulting with your local agricultural Extension agent or crop agronomists can provide invaluable guidance tailored to specific needs and conditions.”