- Amount of fertilizers applied;
Correct rate of fertilizers should be applied as too much/too little affects crop growth
- Fertility level of the soil;
If the soil is already fertile, then there’s no need to add fertilizers because the crops will not utilize it.
- Moisture content of the soil; Soil moisture dissolves fertilizer elements which will be taken in by plants in solution form.
- Soil temperature;
Some fertilizers especially N fertilizers are affected by high temperatures. They tend to escape into atmosphere by volatilization.
- Soil PH;
This affects the availability of some fertilizers elements in the soil. e.g. Under low PH (acidic) phosphorous becomes un available to plants.
- Type of crop;
Crops like legumes do not require N fertilizers application because they are able to fix their own N.
- Method of application;
Fertilizers should not be placed too close or too far as some may instead burn the crop when in direct contact.
- Stage of crop growth;
Fertilizers should be applied at right stage of crop growth e.g. N fertilizers should be top dressed at knee high stage of crop.
- Nature/form of the fertilizers;
Some fertilizers are less soluble e.g. SSP, this should be applied early enough to allow it to dissolve and be taken up by plants easily, While others dissolve early e.g. N (urea).
- Plant population;
Optimum plant population ensures that plants get adequate N while too high population, there will be competition.
- Weed infestation;
Too many weeds compete with crops for nutrients and response is going to be poor. Weed free crops respond well to fertilizer application