Foliar analysis : Primary macro elements

Foliar analysis : Primary macro elements

The realisation of foliar analysis laboratory tests are a perfect way to determine the nutritional deficiencies of your lawn. Each element of the plant composition has a function that can either be performed exclusively by that element or works in harmony with others. Let's look at the work of the primary macronutrients:

• Nitrogen (N)It is the most abundant and essential element among those that the plant does not have directly available in the air. Its main function is the construction not only of amino acids. It is also a component of nucleic acids, amino acids, proteins, chlorophyll and coenzymes. It affects shoot and root growth, density, colour, disease resistance and stress tolerance.

The deficiency is very easily noticeable, as the grass begins to losing greenery. As nitrogen is a very mobile element, it is translocated from older to newer blades. Nitrogen deficiency is very common in sports turf, as the mowing is always removed and the growth of the turf acts as a nitrogen pump. Nitrogen is extracted from the soil in the mowing residues and if not fertilised, this nitrogen is no longer available.

Nitrogen is a very leachable element, so much nitrogen can be lost if slow-dissolving fertilisers are not used.

• Phosphorus (P)It is the element in charge of the energy management for the metabolic processes of the plant. It is the main element of ATP (the molecule responsible for carrying out the vital processes of living beings). It allows the storage of carbohydrates in the roots and their maturation, which facilitates the stability of the grass throughout the year.

Phosphorus deficiency appears in the more mature leaves, usually first increasing their greenness. When the deficiency persists, the greens gradually turn purple and reddish. The most frequent reasons for deficiency can be due to several factors. Long periods of cold and wet conditions or soils with low infiltration capacity that do not allow the roots to search for new sources of phosphorus.

• Potassium (K)Potassium is related to the turgor of plants, their concentration of starch and sugars. Lack of turgor leads to loss of resistance to disease and drought.

Turgor is defined as the water balance within plant cells.

A plant with low access to potassium develops a yellowing of the older leaves which, if sustained over time, causes leaf curling and eventually forms necrotic spots on the leaf margins.

It is possible to determine nutritional deficiencies when the problem is already serious, but the interest of the analysis is never to reach such an extreme point of deficiency that the plant suffers the consequences.