Nutrient interactions and deficiencies

Nutrient uptake by plants is not an isolated process – there are interactions between the 19 essential elements (antagonistic or synergistic) that affect the ratio of nutrients taken up by plants. This is demonstrated by Mulder’s Chart below (Figure 6).

Figure 6 Mulder’s Chart of Nutrient Interactions showing elements with antagonistic and synergistic relationships (From http://www.msue.msu.edu)

The uptake of some nutrients antagonises (blocks) the uptake of others for example, Phosphate (P) and Calcium (Ca); or Potassium (K) and Nitrogen (N). Other nutrient pairs have synergistic relationships where the uptake of one nutrient increases the availability of the other. For example, Nitrogen (N) and Molybdenum (Mo); or Boron (B) and Magnesium (Mg).

Deficiencies of different essential nutrients may show up as symptoms on plant leaves. Some show up on young tissue, whereas others will first be seen on older tissue (Figure 7).

Figure 7 Diagram showing where deficiency symptoms are first observed. (From 4R Plant Nutrition Manual, IPNI 2012)

There is a variety of online resources you can use to help identify nutrient deficiencies in your crops. Yara’s “CheckIT” app allows you to scroll through a library of photos of nutrient deficiencies in a variety of vegetable crops.