Types of fertilizers and their deficiency symptoms in maize

Fertilizers can be broadly classified by application method and by nutrients found in the fertilizer. The classification can vary based on:

Application method

This method classifies fertilizers through the different methods it is applied in the farm. Under this there are foliar fertilizers that are applied by spraying the leaves.

Modern foliar fertilizers are liquid fertilizers that are highly concentrated with the required nutrients.

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Nutrients

This classification looks into the number of nutrients available in the fertilizer and sometimes the type of the primary macronutrient. Under this class we have Single nutrient fertilizers also known as straight fertilizers and Compound fertilizers or multi-nutrient fertilizers.

Single fertilizers

This class is further sub-divided based on the primary macro nutrient in the fertilizer. Macronutrients are essential nutrients used in large quantities by the plants for proper growth.  Major subdivisions are nitrogen, phosphate and potassium fertilizer as the three primary macro nutrients.

Nitrogen fertilizer

As the name indicates, this group contains nitrogen only. The percentage of nitrogen in the fertilizer differs based on the manufacturer and form like ammonia, urea or nitrate. Examples of this fertilizers include urea and C.A.N.  For maize production, nitrogenous fertilizers are important as they help in production of food for the maize plant which we in turn harvest.

It helps the leaves of the maize crop remain green for the maize to be able to make food. A healthy maize crop has dark green leaves. Any yellow colours on your maize crop is a sign that your crop has low nitrogen. To correct this, apply Urea using the right rates as advised by a soil test or a leaf analysis test which can be done at affordable costs in agricultural labs in the country.

Phosphate fertilizer

This class contains phosphorous as the main macronutrient. Examples of this would be Monoammonium Phosphate (MAP), Single Superphosphate (SSP), Double Superphosphate (DSP) and Triple Superphosphate (TSP). In this category some farmers use Minjingu which is a rock that is rich in phosphorous. Phosphorus in maize product is applied during planting as it is important in root formation and crop establishment. DAP is preferred as it releases the phosphorous slowly and also contains nitrogen. Maize plants with reddish colour on the tips of the leaves indicate phosphorous deficiency.

Potassium fertilizer

Potassium is important when it comes to the formation of the maize seeds and cobs. To avoid gaps, thin seeds and cobs, potassium is a key. Deficiency of this nutrient is similar to nitrogen deficiency where leaves yellow. The way to differentiate this is to closely inspect your crop. When yellowing starts with the bottom older leaves only, the plant lacks potassium.

Compound fertilizers

This category of fertilizers contains more than one primary macronutrient sometimes some manufacturers add trace nutrients. Trace nutrients are the nutrients that are used by the plant in small amounts such as Zinc, Boron, Copper among others.

Compound fertilizer example include NPK which contains all primary macronutrients that is Nitrogen (N), Phosphorous (P) and Potassium (K) either in equal ratios like 15:15:15 or have a higher nitrogen percentage 16:8:8. A fertilizer with all three macronutrients is sometimes called a complete fertilizer.

Compound fertilizers also includes fertilizer with two macronutrients like 18-46-0 (diammonium phosphate).

Farmers should always perform soil tests to understand the condition of their soils before application of any fertilizers. Use fertilizers wisely to avoid pollution.