Fertilizer application is a timely operation. There are different types of fertilizers; each type plays a different role and function in the growth of a crop. Most times, farmers apply fertilizers at the wrong time; thinking all fertilizers perform the same function in crops. NO.
This is not true. The type of crop grown also determines the type of fertilizers to be applied and the right time to apply them.
Time plays a prominent role in the effectiveness of fertilizer application. It is very possible you apply fertilizer and you do not get the desired result, even when the nutritional component of the fertilizer is guaranteed. This is because you have applied the fertilizer at the wrong time.
The knowledge of how fertilizers work will help farmers know the right time to apply and the methods of fertilizer application to enhance the yield and increase revenue.
Take a look at functions of fertilizers with the time of application in crop growth:
Firstly, fertilizers are classified into two:
Simple fertilizers contain only one nutrient element. A good example is Urea, which contains only one nutrient elements called Nitrogen. A compound fertilizer contains more than one nutrient elements. A good example is the NPK, which contains Nitrogen, Phosphorus, and Potassium respectively in different proportions.
There are 3 major nutrients needed by the plants for good growth and development; they are:
These nutrients are needed by plants in different quantities at different stages of their growth. Although, they are naturally present in the soil in varying proportions depending on the activities carried out on the soil. Deficiency of any of the above nutrients greatly impairs the growth and development of the crop.
Functions of Nitrogenous fertilizers in crop growth
Nitrogenous fertilizers are fertilizers that supply only nitrogen. Examples are urea, ammonium nitrate. Nitrogen is very important to crops at all stages of their growth but in varying quantity; Nitrogen is needed for growth, cell and tissues formation. Deficiency of nitrogen often causes retarded or abnormal growth and low yield.
Time to apply nitrogenous fertilizers
Nitrogen is required by all crops throughout the stages of their growth but in varying quantity at different stages of their growth and the phase of production (the purpose of producing the crop).
Leafy crops such as vegetables need Nitrogen throughout their production cycle. This is because Nitrogen helps in the formation of leaves. However, in fruit-bearing crops like cassava or maize; their Nitrogen requirement is reduced to a particular stage of their growth. This is the flowering stage.
From the point of planting to the flowering stage, Nitrogen is needed in higher quantity as compared to other nutrients. Deficiency of Nitrogen at this stage will lead to retarded growth; this is because nitrogen plays a prominent role in the formation of floral parts of a plant.
Once a fruit-bearing crop flower, the supply of Nitrogen is reduced and the supply of other nutrients: Phosphorus and Potassium; is increased to aid fruiting. Care must be taken when applying Nitrogenous fertilizers to fruit-bearing crops as excessive application leads to delay in maturity and fruiting of the crop.
This is why the supply of a large quantity of Nitrogen has to be limited to the flowering stage as the fruiting stage follows the flowering stage.
Excessive application of Nitrogen causes a high production of leaves and flowers leading to a delay in fruit formation. Hence, Nitrogenous fertilizers can be applied in large quantity to leafy crops like vegetables since the purpose of production is to produce leaves for consumption but should only be used up to the flowering stage of a fruiting crop.
Functions of Phosphatic and Potassic Fertilizers in crop growth
Phosphorus and Potassium are very important at advanced stages of plant growth. These nutrient elements play an active role in the fruit formation and structural development of a plant. They help in fruit formation and also determines the size of the fruits. They are support mechanisms for plants.
Potassium helps in the structural development of the plant. It helps build the tissues that support the plant; it strengthens and makes plants vigorous. It is needed at the early stage of growth alongside Nitrogen. Deficiency of Potassium leads to stunted growth, poor stem formation, and feeble plant stand.
Phosphorus is also very important at the fruiting stage and structural development of plants. The size of the fruit is a factor of the presence of Phosphorus. The quantity of Phosphorus should be increased when the flowers have fully developed; it will aid quick fruiting and also increases the size or number of the fruits.
It is very important I mention this; these nutrients are very important to plant’s growth and development but at varying quantities considering the age, stage of growth and purpose of the plant.
Nitrogen and Potassium are needed in relatively high quantities at the early stage of the plant’s growth; above the flowering stage, Nitrogen is still needed but in a relatively low quantity as compared to Potassium and Phosphorus.
Fertilizer application in plants becomes successful when it is highly utilized and observable changes are seen in the plants. The time and methods of applying fertilizers are also important and play prominent roles in the utilization of the fertilizer by the plants. Avoid excessive application of fertilizers; apply at a moderate rate and at the right time.