Early Season Opportunities for Proactive Crop Tissue Sampling

Significant K deficiency in corn, photo courtesy of the University of Illinois Plant Clinic.

Most folks understand the saying, “If you don’t measure it, how in the world can you manage it?” I have always been a huge fan of utilizing sound, practical diagnostic tools to help understand if any given crop is either a “happy camper” or is struggling with some type of environmental, chemical, fertility, pest or other issue. There are many other factors besides soil fertility that can influence plant nutrient uptake efficiency of both soil and applied nutrients. Some of them are: soil compaction, root pruning with tillage, low soil temperature, soil moisture, drought, pathogens, nematodes, insects, tillage, herbicide stress and unfavorable soil pH. To maximize the probability of reaching the expected yield goal through balanced fertilization, these other factors must also be considered.

I believe one of the best “early-season” tools is a plant tissue test that measures the nutrient status at a given snapshot in time. Accurate nutrient status allows you to assess any nutrient shortages or imbalances in the plant’s early, formative vegetative stage, even though the plant looks like a “happy camper.” We refer to this event as “hidden hunger.” Helena’s tissue sampling program is called Extractor™ and provides some useful product solutions to correct nutritional deficiencies.

There are three parameters that validate a timely plant tissue test:

• Tissue testing complements a proven soil testing program.
• The two primary uses of a plant tissue analysis are diagnostic and monitoring.
• It’s critical to get the right plant part at the right growth stage.

For corn, I advocate a tissue test a V4 (4-leaf) to determine if any tweaks in nutrition are needed prior to the growing point emerging from the soil at V6 (in approximately 7-10 days). For example, if the young corn plant has struggled in obtaining adequate soil nitrogen, it is critical to quickly provide a supplemental dose, such as an application of CoRoN®.

Regarding soybeans, I generally recommend a plant tissue analysis at V4-V5 (4th to 5th trifoliate). This allows you to evaluate the soybean plants to see if nutrients such as Mg, K, Zn, S and B are “good-to-go” as the plant begins to bloom in late June. Having the correct balance of nutrients helps the soybean plant set and retain important raceme bloom clusters on the primary stem – more bloom retention usually equates to more pods, seeds and higher yields. Helena offers some great foliar nutritional products that provide cost-effective, timely treatments.

- Sam N. Bartee, West Central Division Agronomist