Fertilizers are always needed when growing a crop. In order to be sure of a correct amount of each nutritional element or fertilizer, it is believed to be crucial to carefully put together a nutritional feeding schedule. Besides calculating the amount of all nutritional elements needed, it should not be forgotten that all different elements for which we use the collective term fertilizers, could possibly counteract.

When different elements counteract, the term ‘antagonism’ is used. Antagonism is defined as for example substances that do not go together, leading to an opposite functioning. When making use of fertilizers, antagonism could occur.

The prevention of the counteraction of fertilizers is not always easy. What is the best way to deal with this? First of all, the reactions of different fertilizers should be known.

Unintended contamination should not be confused with the counteraction of fertilizers. Unintended contamination is defined as an undesired, but logical reaction between several elements that can be found in fertilizers. 

An antagonistic effects of fertilizers is explained as the competition between two elements. Below, Mulders’ Chart is seen, in which an explanation on the reaction of several elements is given. 

Regarding the image below; by means of the blue lines, insight is given into which elements counteract with each other. The dominant element is indicated by the arrow’s direction. 

• Copper is dominated by manganese (not vice versa)
• Phosphorus and magnesium counteract
• Copper and nitrogen are dominated by molybdenum (not vice versa)
• Magnesium is dominated by nitrogen (not vice versa)
• Iron is dominated by potassium (not vice versa)

In the first example, the counteraction of manganese and copper is shown. 

When copper is already present within the plant, and manganese is added, this element will ‘overpower’ copper. This will result in the plant only taking in manganese, and could increase the risk for a deficiency to occur. 

Phosphorus and magnesium are proven to be equal. In this case, equal is defined as equally powerful, which means that both will ‘loose’ when competing with each other. The plant will not take in these elements. 

Luckily most nutritional elements within the ‘fertilizer world’ can be combined. The majority of the elements start a collaboration, in which all positive effects on the plant of each element is ensured. The fact that calcium and manganese can be mixed, does not always have to be the same vice versa. It strongly depends on the amounts that are added of both nutritional elements. 

As shown in Mulders’ Chart, some elements are not recommended to use simultaneously. But how do you ensure the right elements to be taken in by the plant? 

A stable basis is very important. This basis is formed by the soil or the substrate in/on which the crop is grown. If the structure, pH and soil life are in order, the chance for the right intake of all elements is higher. Eventually, a good balance of all separate nutritional elements is the essential in fertilizing. This is why a well-considered nutritional feeding schedule is recommended. 

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