Tissue Samples Tell the Truth
Zinc deficiency in corn, photo courtesy of South Dakota University (left). Boron deficiency in soybeans, photo courtesy of the University of Illinois (right).
Soil samples can reveal many things. Sometimes, they can even provide valuable information tissue samples can’t, like the pH and percent of magnesium in the soil. But, unlike soil samples, tissue samples always tell the truth.
In some cases, soil tests will “lie.” For example, they may show the soil has enough potassium to grow a good crop, but as the crop grows, it develops a potassium deficiency. Here, something is preventing enough potassium from getting into the plants such as dry soil conditions or compaction. This is a common scenario. Although soil tests show adequate micronutrient levels, uptake can become inhibited as the crop grows due to a high pH soil, among other things.
Nutrient deficiencies are not always as easy to identify as in the previous examples. However, the tissue sample is the truth detector. It shows which nutrients are low and which nutrients are sufficient at the time of testing. Growers have already put a lot of time and money into a crop. Taking tissue samples is good insurance because it assures the farmer the crop has all the nutrients it needs.
The good thing about taking tissue samples and finding nutrient deficiencies is that most deficiencies can be rectified by a foliar application. Most nutrients can be foliar applied to supply the crop with the nutrient it is lacking, with the exception of sulfur. A small amount of ammonium thiosulfate can be applied foliarly if care is taken not to burn the crop. Because most crops require a fair amount of sulfur, soil application is best.
Helena offers a beneficial tissue sampling program called Extractor™. This program not only shows the level of each nutrient, but it also shows whether it is high, sufficient or low using easy-to-read color coding. Extractor will also suggest helpful foliar products from Helena's large selection of nutritional products to correct nutrient deficiencies in crops. The last page of the Extractor report gives information about each nutrient and why it is important.
- Dr. Randy Simonson, North Central Division Agronomist