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Plant analysis benefits producers

by Wyoming Livestock Roundup

Ward Laboratories, Inc. hosted a webinar on Feb. 21 featuring Dr. Ray Ward and Dr. Nick Ward discussing plant analysis and its benefit to producers. 

“Plant analysis is simply taking a plant part or a whole plant and digesting it to analyze mineral content and using the information as a decision tool to diagnose a problem,” Nick says.

Producers utilizing plant analysis are able to measure nutrients within the soil and plants. 

“Plant analysis can be used to monitor plants to see if the plants are using the nutrients being applied in fertilizer and diagnose problems in the field,” Ray adds. “If abnormal growth or discoloring of plants is seen in the field, plant analysis can determine if there’s a deficiency or toxicity.”

Sap analysis versus tissue analysis

Sap analysis and tissue analysis are two types of sampling systems currently being used to identify nutrient levels within plants.

Nick mentions the biggest difference between sap testing and tissue testing is tissue testing produces total mineral content, while sap testing produces a soluble, extractable type of nutrient.

“Sap analysis is when something is used to squeeze or press the plant to analyze the liquid coming out of the plant,” says Nick. “Tissue analysis is where we take the plant, dry it down and digest it so we get the total mineral content.”

He says tissue testing results are easier to interpret than sap testing results. There is much more open-sourced information on how to interpret tissue testing results, allowing for analyzers to better understand the results and offer recommendations to producers.

“Some of the sap analysis might be less open-sourced and less available for people to use and interpret,” Nick adds.

When to sample

The correct plant sampling time depends on the crop, according to Nick. He recommends sampling when plants are old enough to be influenced by the soil they grow in.

“If producers were to sample corn at a very early stage, a lot of fertility is still coming from the seed,” Nick shares. “Therefore, producers may get results not necessarily indicative of what the plant is seeing in the soil.”

He says environmental conditions often determine how good a plant looks in the first stage of its life.

“Wait to sample until you know the plant is feeding off the soil it’s in,” Nick adds. Ray agrees, suggesting producers wait to sample until corn is about 10 to 14 inches tall.

Ray says wheat can be sampled early in the season, once there’s full tiller development. Continuing to monitor growing plants and sampling throughout the season has added benefits for all plant species as well.

Sampling throughout the growing season helps producers “track nutrient content and make sure it’s at a level sufficient for proper growth,” says Nick.

Ray explains nutrient levels in plants change as the plant ages. 

“As plants develop, they get more carbon in the plant and the sufficient nutrient levels go down, so a nutrient level seen at stage V5 of corn will be different than stage V18,” says Ray.

Ray recommends sampling soybeans “early-bloom” and again at the R3 stage.

“This way, producers measure nutrients for the developing plant as it’s blooming and can then see if they have nutrients left to fill out the pods as they develop,” he says.

How to sample

In order for producers to receive accurate results, they must conduct proper sampling.

“To take a soybean plant sample, take the trifoliate at the top of the plant – the most recently matured trifoliate,” Ray says. “Grab the trifoliate and pull – don’t include the petiole – and take samples from about 15 plants.”

“When sampling wheat in the early stages, use scissors to clip the plants off an inch above the soil surface, making sure not to include any soil,” Nick says. “Young wheat plants have high moisture content, so a larger sample size of tissue is needed so there is still an adequate amount to analyze after drying it down.”

He mentions to place the samples in a paper bag and send off to the lab. It typically takes about four days for producers to receive results.

Plant analysis results

Producers often wonder if plant analysis results are tied to the yield of their field. 

“Yield is somewhat independent of the plant analysis we are performing,” says Nick. “Our goal is to identify and evaluate the nutrient status of the plant, and the yield is based off of other factors.”

The number of kernels per ear of corn and ears per field determines the yield for corn, and the number of beans per pod, pods per plant and plants per field determines the yield for soybeans, says Nick.

“The amount of fertility in a plant at a higher yielding environment should be the same in a plant at a lower yielding environment,” Nick concludes.

Kaitlyn Root is an editor for the Wyoming Livestock Roundup. Send comments on this article to

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