There are two nutrients — sulfur and calcium — that are coming up short in crop fields, but farmers may not know it.

“We get less and less sulfur from our rainfall every year,” says Kurt Grimm, founder and CEO of NutraDrip, “so we need to be addressing that, especially with our in-season fertility.”

The nutrients of a plant are found in the tissue, yet farmers can’t know their true value without taking a sample. Grimm has found the lack of sulfur and calcium because his family has been tissue-sampling on the farm for more than 15 years.

The importance of nutrient balance in the plant is key to increasing nutrient efficiency. Just trying to achieve a high nitrogen value will not necessarily result in higher yields.

“If you don't know where your numbers are, how do you know how to address your crop this coming year or the next year?” Grimm asks. “The things that we've learned on tissue sampling is helping us to make decisions maybe not for that exact week or that exact next management decision, but it helps us with our trajectory for next year.”

Know your nutrients

There are 11 nutrients identified in a tissue sample report. Understanding potential problems with these nutrients can help farmers create a plan for the 2024 crop growing season. Farmers who tissue-sampled in 2023 are off to a good start with the data. Those who did not should consider adding this crop management practice to next year’s growing season.

Ultimately, Grimm says tissue sampling allows farmers to use the plant as an indicator of health. “It will tell you what it needs to make it yield; then you can adjust your management to fit the need,” he says.

Often an imbalance in the tissue samples leads us to the imbalance in the soil. Here are the 11 nutrient values in a tissue sample report, how those nutrients help plants and problems farmers may face with each:

1. Nitrogen. It plays a critical role within the plant to make sure energy is available when and where the plant needs it in order to optimize yield. It is part of every living cell. It is present in roots as proteins and enzymes to help regulate water and nutrient uptake. Problem: Weather conditions can make it unavailable to the plant. But too much is a bad thing.

2. Phosphorus. It is involved in energy transfer, photosynthesis, transformation of sugars and starches, and nutrient movement through the plant. It enters the plant through the root hairs, root tips or outer layers of root cells. Problem: Plants require a lot of this nutrient; therefore, they are frequently deficient.

3. Potassium. It is most useful in movement of water, nutrients and carbohydrates in plant tissue. Potassium also helps regulate the exchange of water vapor, oxygen and carbon dioxide by regulating the opening and closing of the stomata. Problem: The soil provides some potassium for the crop, but not enough to sustain season-long plant growth.

4. Sulfur. It is used in the formation of amino acids, proteins and oils. Sulfur is necessary for chlorophyll formation. Problem: Sulfur is tied to nitrogen; therefore, crops with high nitrogen needs will usually have high sulfur needs.

5. Calcium. It is required for formation of cell walls and membranes. Young developing tissues need calcium. It can also protect the plant against heat stress by improving stomata function. Problem: Calcium mobility in plants is limited so calcium deficiency occurs in new growth; therefore, plants need a constant supply of calcium for continued growth.

6. Manganese. It helps with photosynthesis, converting sunlight energy. It affects chloroplast formation in leaves. It also plays a part in building carbohydrates and metabolizing nitrogen. Problem: Cold, wet conditions foster manganese deficiency. Without it, plants become weaker and more susceptible to drought and heat stress.

7. Boron. Part of the plant cell wall structure, it also helps seed set under stressful conditions. Problem: There is a fine line between deficiency and toxicity than with other nutrients. Farmers need to apply at the right rate and right placement.

8. Copper. It activates enzymes in the growth process and aids in protein synthesis. Only a small amount is needed for plant survival. Problem: Organic soils are most likely to demonstrate copper deficiency. In plants, copper is the most immobile of the micronutrients.

9. Magnesium. It plays a role in root formation, chlorophyll and photosynthesis. Problem: It is tied to soil pH. Low pH often signals a decrease in magnesium availability to the plant; therefore, farmers should test for soil acidity.

10. Zinc. It is key to chlorophyll production, carbohydrate metabolism and cell elongation, which affects leaf size and development. Although zinc is required in small amounts, it is needed for high yields. Problem: Deficiency happens with earlier planting into cool, moist soils — typically sandy soils low in organic matter and in organic soils.

11. Iron. It is a catalyst to chlorophyll formation and acts as an oxygen carrier. Because iron does not move within the plant, deficiency symptoms first appear on the younger leaves at the top of the plant. Problem: Iron can be toxic at too high of levels.

Here are some on how to collect a tissue sample: