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Eyesight important plant diagnostic tool

One of the best tools to detect crop nutrient deficiencies in crops could be the farmer’s eyes.

One of the best tools to detect crop nutrient deficiencies in crops could be the farmer’s eyes.

Visual clues may tell a producer what nutrient a crop may need, says PotashCorp Director of Agronomy and eKonomics contributor, Dr. Robert Mullen.

A sharp eye, Mullen says, is especially important in soils that have not had recent lab soil tests.

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Soil tests are helpful in identifying potential nutrient deficiencies, he adds, but monitoring visual cues given by crops is also important.

Those cures include:

  • Upper vs. Lower Canopy – Determine if the abnormality is in the upper (newer growth) or lower (older growth) part of the plant. Problems in the upper canopy typically signify a micronutrient deficiency, while the lower canopy will show macronutrient issues, which can be fixed by applying potassium, nitrogen, phosphorus or magnesium.  
  • Discoloration – Most healthy plants should have evenly colored, deep green leaves. Reddish or purplish leaves usually indicate a phosphorus deficiency, while yellowing leaves often signal a shortage of nitrogen or potassium. The latter can be differentiated by how the yellowing progresses – if it is along the edge, it indicates a potassium shortage, but if it is down the middle of the leaf, the plant is likely deficient in nitrogen.
  • Plant height – Stunted growth is often a sign of a nutrient deficiency. Plants with extremely slow, stunted growth usually represent a potassium or phosphorus shortage, while spindly stalks signify a nitrogen deficiency. A plant with an abnormally small height is a simple way of diagnosing a nutrient deficiency, but this recognition should be used in combination with additional information (plant analysis/soil testing) to identify the particular deficiency and the best course of action. 

Mullen says nutrient deficiencies can result from a number of reasons, but should be diagnosed and fixed as soon as possible, regardless of the cause. “Identifying deficiencies early allows you to take corrective action to minimize damage.”




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