Plant Tissue / Petiole Analysis

Plant Tissue Analysis

The following elements are best determined with a plant tissue analysis since soil tests are not reliable for these elements: nitrogen, iron and copper.  Aluminum and sodium also are available but are not essential elements.

Soil tests are readily available for phosphorus, potassium, calcium, magnesium, sulfur, manganese, and zinc.  

The results of plant tissue analysis and a good soil test can furnish a guide to more efficient crop production.  The soil test provides a good estimate of lime and fertilizer needs.  The tissue analysis provides a picture of the plant nutrients, which will identify nutritional disorders, evaluate fertilizer efficiency and reveals unknown relationships among essential elements. Plant analysis also will point out the effect of lime on the availability of native and applied elements. 

Plant tissue analysis should be a routine part of every crop producer's nutrient management program. In addition, an AgSource Plant Tissue Analysis will alert you to

• Plant phosphorus uptake: Not all soil phosphorus is available to plants. The only way to accurately determine if plant needs are met is with a whole plant tissue analysis.
• Nitrogen requirements:  For many crops, nitrogen is the most expensive, out-of-pocket cost and also is the most critical nutrient for maximizing yields. Nitrogen recommendations are based on a number of factors; however, the best way to fine tune your crop needs is with a plant tissue analysis.
• Secondary nutrient and micro-nutrient deficiencies:  Soil tests can provide good information on these nutrients, but the gold standard of your soil's status is a plant tissue analysis.
• Very high or toxic levels of micro-nutrients: This is critical on land where municipal sewage is spread but can be an issue on all soils.
• Nutrient balance in the soil: AgSource's Plant Tissue Analysis Report provides a unique graphic that highlights nutrients that are deficient, in the proper range and those that are high.

Petiole Analysis

AgSource Petiole Analysis is primarily used for potatoes. Sampling potato petioles and analyzing them is a very effective way to refine and verify your potato fertility program. Petioles are commonly sampled as opposed to whole plant tissue. The petiole, the stem that connects the leaflets, acts like a straw for nutrients traveling to the leaves. Thus sampling the petioles provides information on flow rates of nutrients. 

A broad range of nutrients are monitored with petiole analysis. However, nitrogen is especially critical, and petioles are sampled at 60 days after planting, 70 days after planting, 90-100 days post planting and again at 100-120 days after planting. Correct petiole nitrate levels are dependent on the potato variety. If the nitrate levels are low, extra nitrogen can be applied, and if the levels are high, later applications may be reduced.

For laboratory specific information regarding plant tissue analysis, procedures, guidelines, test packages/supplies or analysis kits, please contact one of our laboratories nearest you listed below:

Laboratory Locations: