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From the Fields

Q: What is the optimum pH for corn production?

A: The simple answer is a wide range of soil pH is suitable to produce corn. The key is to avoid significant acid condition - pH significantly below 6.0. Alkaline soil conditions - pH above 7.0 - can be quite productive for corn, but these soils can be susceptible to micronutrient deficiencies. Adjusting the pH of acid soils with lime is quite easy and reasonably affordable. Acidifying alkaline soils is possible, but expensive.

Robert Mullen, PhD., CCA, CPAg
Nutrien | Director of Agronomy

From the Fields

Q: How should a farmer sample for diagnostic purposes?

A: Like most production issues, nutrient deficiencies rarely affect an entire field. When there are areas that are exhibiting suspected nutrient issues, here is the best way to go about determining what the likely issue is.

Ideally, plant tissue and soil samples should be collected for comparison. Collect around 15 samples from the affected area and 15 samples from the unaffected area near the affected area. Sample the same plant parts from both areas. If the samples are collected early in the growing season, collect the entire plant for tissue analysis. Later season sampling should focus on specific plant parts (corn - ear leaf, soybean - newest most fully expanded trifoliate, etc.). Soil samples should be collected to a traditional soil sampling depth (typically 6-8 inches).

Compare the affected area against the unaffected area and see what differences there are. Interpreting the information can be a complicated exercise. Pay close attention to the details for each area that was sampled.

Robert Mullen, Ph.D., CCA, CPAg
Nutrien | Director of Agronomy