This document discusses different types of fertilizers including organic manures, chemical fertilizers, and biofertilizers. Organic manures include farm yard manure, compost, green manure, and vermicompost. Chemical fertilizers can be simple or complex. Biofertilizers contain nitrogen-fixing organisms that help crop growth. Common biofertilizers include Rhizobium, Azotobacter, Azospirillum, Azolla, and mycorrhizae fungi.

1. Fertilizer Classification
 Fertilizers- Organic manures (natural)
Chemical fertilizers (synthetic)
Biofertilizers
A.Organic manures(natural)
Compost
Farm yard manure
Green manure
Vermicompost
B. Chemical fertilizers(synthetic)
Simple fertilizer (Straight fertilizer)
Complex fertilizer (multinutrient fertilizer)
C.Biofertilizers

2. Manures:-
Manures are organic materials added to the soil to
increase crop production.
They are biological in origin.
The organic matter content is bulky and large and the
nutrient content is small. They have the following effect on
the soil.
1. They supply nutrients to the soil. Since the manures
contain nutrients in small quantities they have to be used in
bulk quantities.
2. Since the manure contains a lot of organic matter, it
increases the water holding capacity in sandy soils and
drainage in clayey soils.
3. Organic manures provide food for soil organisms like
earthworms which are responsible for improving soil quality.
Organic manures include (i) Farmyard manure (FYM), (ii)
Compost, (iii)Green manure, (iv) Vermi compost.

3. Compost:-
This consists of a variety of farm wastes such as farm
weeds, straw, sugarcane refuse, rotting vegetables, kitchen
wastes, crop stubble, groundnut and rice husk.
Composting is a biological process in which aerobic and
anaerobic microorganisms decompose organic matter.
A trench of suitable size 4-5 m long, 1.5 to 1.8 m broad
and 1.0 to 1.8 m deep is dug. A layer of well mixed refuse of
about 30 cm thickness is spread in the pit. A slurry of cow
dung, earth and water is poured over this layer to keep it
moist. Another layer of the mixed refuse is spread in the pit
till the heap rises to a height of 45 to 60 cm above ground
level. Finally the top is covered with a thin layer of mud.
Three months later of decomposition the layers are well
mixed and covered again. After three months the compost is
ready to be used in the fields.

4. Green manure:-
Green manuring is the practice of growing and ploughing
in, the green crops, into the soil.
It is a cheap and effective method that increases soil
fertility as it can supplement farmyard and other organic
manures and is more cost effective.
Green manures add nitrogen and organic matter to the
soil for improving crop productivity.
They also improve soil aeration and drainage conditions.
Both leguminous and non-leguminous plants are grown
for making green manure.

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This type of manuring is used in fields in which crops like
rice, maize, sugarcane, cotton, wheat etc., which require high
nutrient input are raised. There is 30 - 50% increase in the
crop yield by using green manure.
The green manure crops are grown in the field for about 6 -
8 weeks and ploughed into the soil during the flowering
stage. The plants are allowed to remain buried for about 1 - 2
months. During this period, the plant gets totally
decomposed. The soil is then tilled and the next food crop is
sowed. By alternating the green manure crop with food crop
the nitrogen and organic content of the soil is maintained.

7. Vermicompost:-
Vermicompost is a type of compost made by
earthworms and microorganisms as they feed on organic
wastes.
The compost thus produced is mainly worm excreta and
finely ground soil.
Organic wastes can be collected and fed on by worms so
that the end product is the broken down version of the
original organic wastes.
Worm castings (excreta) in the vermicompost have
nutrients that are 97% utilizable by plants. Besides providing
nutrients to plants, worms also upturn the soil thus making
the soil lighter.

8. Biofertilizers:-
The biofertilizers containing biological nitrogen fixing
organisms are of utmost importance in agriculture
Advantages Of Biofertilizer
i) They help in the establishment and growth of crop plants
and trees.
ii) They enhance biomass production and grain yields by 10-
20 percent.
iii) They are useful in sustainable agriculture.
iv) They are suitable in organic farming.
v) They play an important role inAgrotorestry/ Silvipastaural
system.

9. Types of Biofertilizers:
Rhizobium:- Most widely used biofertilizer is
Rhizobium which colonizes the roots of specific legumes to
form tumour like growths called root nodules. These nodules
act as factories of ammonia production. The Rhizobium –
legume association can fix up to 100-300 KG/N. in one crop
season.
Azotobacter:-Application of azotobacter has been
found to increase yield of wheat, rice, maize, pearl-millet and
sorghum by 0-30 p.c. over control. Apart from nitrogen this
organism is also capable of producing antifungal and
antibacterial compounds, hormones.
.
Azospirillum:-Certain micro-organisms like bacteria
and blue green algae have the ability to use atmospheric
nitrogen and transport this nutrient to the crop plants.
Azospirillum is inoculated to maize, barley, oats, and
sorghum, pearlmillet and forage crops. It increases grain
productivity of cereals by 5-20%, of millets by 30% and
fodder by over 50%.

10. Azolla:-A small floating water form Azolla is commonly
seen in low land fields and in shallow fresh water bodies. a
live floating nitrogen factory using energy from
photosynthesis to fix atmospheric nitrogen accounting to
100-150 kg N/ ha / year from about 40 – 60 tones of biomass.
Mycorrhizae:-It is the symbiotic association of fungi
with roots of vascular plants. It is useful in increasing
phosphorus uptake e.g. in fruit crops like citrus, papaya.
Blue-green algae:-The utilization of blue green algae
as a biofertilizer for rice is very promising. A judicious use of
these algae could provide to the country’s entire rice acreage
as much nitrogen as obtained from 15-17 lakh tones of urea.
Algae also helps to reduce soil alkalinity.