Why are manure and fertilizers used in fields?

Deficiency of nutrients in the soil affects the physiological processes in plants including reproduction, growth and susceptibility to diseases. The use of manures and fertilizers in the fields helps in the enrichment of the soil with the required nutrients.

Manure:

Manure helps in enriching the soil with organic matter and nutrients and provides a lot of humus. It is prepared by the decomposition of animal excreta and plant waste. This increases the capacity of sandy soils to hold water. In clayey soils, the large quantities of organic matter help in drainage and in avoiding water logging. Manure is considered better than a fertilizer because it is made out of biological waste material, which increases soil health as it adds humus and improves fertility and overall soil quality.

Fertilizers:

Fertilizers are commercially produced plant nutrients. Fertilizers supply nitrogen, phosphorus, and potassium. They are used to ensure good vegetative growth (leaves, branches, and flowers), giving rise to healthy plants. Fertilizers are a factor in the higher yields of high-cost farming.

Even though they are quicker in action, fertilizers are bad for soil health in the long run because of their chemical nature. To get an optimum yield, it is advisable to use a balanced combination of manures and fertilizers in the soil.