Natural fertilizers are those which are made from living beings without the need for synthetic processing. They are best suited for crops and also useful to uphold soil properties.
Types of Natural Fertilizers
They are of the following types like
- Farm Yard Manure
- Compost
- Sheep and Goat Manure
- Green Manure
- Biofertilizers
- Vermicompost
- Poultry Manure
- Concentrated organic manures
- Oil cakes
Farm Yard Manure
Farmyard manure is a mixture of cattle dung, litter or bedding material, urine, a portion of fodder not consumed by cattle, and domestic wastes like ashes, etc. collected; these collected materials are dumped like a heap or a pit which is located in the corner of the backyard, until unless complete rotting and final application to the soil it was allowed to remain at that same place. The nutritional composition of farmyard manure is O.5 percent N., 0.2 percent P2 O5 and 0.5 percent K2 O.
Compost
The rotten plant and animal waste or residue are called compost.
In simple terms, composting can be defined as the rotting of animal and plant residues.
Optimum levels of moisture, air, and temperatures are essential prerequisites to ensure good composting. Microorganisms are involved in this composting activity; by adding some beneficial microorganisms, we can increase the fertility status of compost.
Sheep and Goat Manure
Manure made from sheep and goat manure is rich in nutrients compared to farmyard manure and compost. The manure has 3 % of Nitrogen, 1 % phosphate as P2O5, and 2 % potassium as K2O. This manure is applied to the soil after collecting it from the pit near the sheds of these sheep and goats. But, it is observed that there is a loss of urine nutrients by this method. In another method of application, sheep, and goats are allowed to gaze and excrete in the field, where their excreta and urine are directly applied to the soil. By doing so, there is minimal loss of nutrients.
Green Manure
Green manure crops are grown in the field itself either as an intercrop or as a pure crop with the main crop and buried in the same field before flowering.
Dhaincha, sunn hemp, and guar are most used as green manure crops. Leaves from the forests and wastelands are collected and applied to the soil as it serves as a source of organic matter and source of nutrients. Ex: Sesban, Millettia pinnata, and sometimes trees are also used after cutting.
Biofertilizers
These biofertilizers contain nitrogen-fixing biological organisms that are of utmost importance in agriculture.
Advantages of Biofertilizer
- Helps in the establishment, and growth of crop plants
- They increase biomass production and grain yields by 10-20 percent.
- Sustainable agriculture can be achieved by using biofertilizers.
- These are suitable for organic farming.
Types of different Biofertilizers
Rhizobium
It is the most known biofertilizer among all biofertilizers. It harbors the roots of legume species and forms pink color nodules. These nodules are termed root nodules. Ammonia production in legumes occurs through these nodules. It can fix up to 100-300 Kg/N in one crop season.
Azotobacter
Azotobacter application was found to increase the yield of up to 30 percent in crops like maize and rice. Azotobactor also produces anti-fungal and anti-bacterial compounds in addition to regular nitrogen fixation.
Azospirillum
Microbes like blue and green algae have the ability to take up atmospheric nitrogen and fix them in the soil. Nowadays, it is widely used in many field crops. It is said to enhance the yield of up to 20 percent in cereals and 30 percent in millets using azospirillum.
Blue-green algae
Nowadays, the use of blue, green algae is gaining popularity. Proper application of these microorganisms as bio-fertilizers in rice fields can increase yields to a great extent. Using these blue, green algae would also result in lowering the alkalinity of the soil.
Azolla
We can observe this Azolla (a fern) in freshwater bodies. Generally, it floats on water and is small in size.
Mycorrhizae
It is an association between fungi and the roots of vascular plants, which are symbiotic in nature. It elevated the uptake of phosphorous in many fruit crops.
Vermicompost
Here, composting earthworms are used for the composting process. Earth is fed up with various farm and animal wastes, and after digestion, earthworms will excrete. This is called vermin compost. For 1 square foot of land, around 1800 earthworms are enough.
Concentrated organic manures
Blood meal, oil cake, fish manure, etc., are grouped under this concentrated organic manure. These manures have higher concentrations of nitrogen compared to the others. Concentrated manures are also known as organic nitrogen fertilizers. The nitrogen present in the manure is converted into ammoniacal and nitrate form by the action of bacteria. These types of manures supply nitrogen for longer time periods but are a little slower in action.
Oil cakes
These are prepared from oilseeds. After the extraction of oil from them, the pulp is dried and used as a source of manure.
Types of oil cakes
There are two types of oil cakes:
Edible oil cakes
These cakes can be used to feed cattle.
e.g., Coconut cake, Groundnut cake, etc.,
Non-edible oil cakes
These cakes are suitable for feeding cattle.
e.g., Neem cake, Castor cake, etc.,
Both the Non-edible and edible oil cakes can be used as manures.
- But ]edible ones are used as cattle feed, while non-edible ones are used as a source of manure for crops.
- These cakes should be applied in the form of powder for better utilization by the plants.
Other Concentrated Organic Manures
Blood meal and bone meal can also be used as manures. These are rich in nitrogen.
Natural Fertilizers Advantages and Disadvantages
Natural fertilizers help in
- Giving complete nutrition to the plant.
- They help retain water in the soil for a longer period.
- The crop gains disease resistance.
But they are hard to prepare and cumbersome.