Necessary Plant Nutrients:
Did you know that plants need sixteen nutrients to grow and thrive? Thirteen
of the essential plant nutrients are absorbed from the soil by the plants'
roots. Plants will take up all the nutrients available and can show signs of toxicity
(too much) or deficiency (too little).
The levels of nutrients in the soil are controlled by the parent rock below
the soil, which weathered to become the mineral portion of the soil and by the
organic matter in the soil. The pH and the soil water level largely control
the availability of these nutrients.
The
Primary Macronutrients (N, P, & K) are needed in the greatest quantity by
plants, so they are included in most fertilizers. The three numbers on a
fertilizer container (both organic and inorganic) refer to the percent of these
nutrients in the fertilizer material. For example a bag marked 5 -10 - 10
contains 5% Nitrogen, 10% Phosphate (P2O5) and 10% Potassium (Potash or K2O).
Well composted cow manure might be marked 1 - 1 - 1 and contain 1% Nitrogen - 1%
Phosphate and 1% Potash. The organic fertilizer will contain organic matter that
will help improve the soil tilth (soil structure) as well as micronutrients.
As far as plants are concerned, they do not care if the nutrient source is
organic or inorganic since the nutrient is absorbed in its most basic form
through the plant roots.
Source: Soil and Plant Nutrition, Waldo County Office, University of Maine
Cooperative Extension, Belfast, ME.
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