Manures And Fertilizers

 

The deficiency of plant nutrients and organic matter in the soil is made up by adding manures and fertilizers to the soil of crop-fields.

Manures:

  • Manures are natural fertilizers. They are bulky sources of organic matter which supply nutrients in small quantities but organic matter in large quantities.
  • Manures are prepared by the decomposition of animal excreta and plant waste. Manures include farmyard manure (FYM), compost, green manure etc.

Functions or advantages of manure:

  1. Manure helps in enriching the soil with nutrients and organic matter and increasing soil fertility.
  2. The bulk of organic matter in manure helps in improving the soil structure. This involves increasing the water holding capacity in sandy soil.
  3. Manures provide food to soil organisms (like bacteria, fungi, etc.) which help in making nutrient available to plants.
  4. In using manure we use the biological waste material, which is advantageous in protecting our environment from the excessive use of fertilizers.
  5. Manures contain substances which act as stimulants for seed germination and plant growth.

Types of manures:

Based on the kind of biological waste material used, the manures are classified as:

  1. Farmyard manure (FYM): It is the decomposed mixture of cattle excreta (dung) and urine along with litter and leftover organic matter such as roughage or fodder. The waste materials are collected daily from the cattle shed and stored in a pit for decomposition by the microorganisms (bacteria and fungi etc.). FYM contains nitrogen, phosphorous and potassium.
  2. Compost: It is a mixture of decomposed organic matter derived from garbage, sewage, vegetable waste etc. the mixture is decomposed in pits and the process is known as composting.
  3. Vermicompost: The degradation of organic waste through the consumption by the earthworms is called vermicomposting. Earthworms used in vermicomposting are Dichogaster bolani and Drawida willisi.
  4. Green manure: It is prepared by cultivating fast growing green manure crops like Sunhemp, Horse gram, Guar, Cowpea before sowing of seeds. The fast-growing crop is then ploughed back under the soil. Green manure enriches the soil with nitrogen, phosphorous as well as organic matter and provides protection against erosion and leaching.

Fertilizers:

Fertilizers are commonly produced from plant nutrients. Fertilizers supply nitrogen, phosphorous and potassium. They are used to ensure good vegetative growth, giving rise to healthy plants.

 

Type of Fertilizers

Availability of nutrient

Example

Nitrogenous fertilizers

Nitrogen

Urea CO(NH2)2, Ammonium sulphate (NH4)2SO4, Sodium nitrate NaNO3

Phosphatic fertilizers

Phosphorous

Single superphosphate, Dicalcium phosphate

Potassic fertilizers

Potassium

Potassium chloride KCl, Potassium nitrate KNO3

Complex fertilizers

Two or more nutrients (N, P2O5, K2O)

Nitrophosphate, Ammonium phosphate

 

Fertilizers should be applied scientifically in terms of proper dose, pre- and post-application precautions for their utilization. These should not get washed away due to excessive irrigation.