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Mass cultivation of Azolla

1. Microplots (20m2) are prepared in nurseries in which sufficient water (5-

10 cm) is added.

2. For good growth of Azolla, 4-20 Kg P2O5/ha is also amended.

3. Optimum pH (8.0) and temperature (14-30C) should be maintained.

4. Finally, microplots are inoculated with freshAzolla (0.5 to 0.4 Kg/ m2).

5. An insecticide (furadon) is used to check the attack of insects.

After three, week of growth mat formed by

Azolla is harvested and the same microplot is inoculated with freshAzol

to repeat the cultivation.

6. After the 3week period of growth, mat formed by Azolla is harvested and

the same microplot is inoculated with fresh Azolla to repeat thecultivation.

7. Azolla mat is harvested and dried to use as green manure.

There are two methods for its application in field:

(a) incorporation ofAzolla in soil prior to rice plantation, and

(b) transplantation of rice followed by water draining and incorporation

ofAzolla.

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(d)Phosphate solubilising bacteria

1.(i) Phosphate solubilising bacteria (PSB) e.g. Thiobacillus, Bacillus spp., etc.

and (ii)plant growth promoting rhizobacteria (PGPR), includingPseudomonas fluorescens and .P.putida are important new biofertilizers.

2. SBs convert non-available inorganic phosphates into soluble organic

phosphates, which can be utilized by crop plants.

3. PGPRs produce siderophores (iron chelating substances, e.g. pseudobactin

which chelate with iron and' make it unavailable to harmful fungi (e.g.

Eriwinia) in rhizosphere, leading to their death.

4. These biofertilizers are yet to be commercially utilized in our country.

(e) Mycorrhiza as Biofertilizers

1. Mycorrhiza (fungus roots) is a distinct morphological structure which

develops as a result of mutualistic symbiosis between some specific root -

inhabiting fungi and plant roots. So that the nutrients absorbed

from soil by the fungus are released which is utilized by host cells and inturn,the fungi takes its food requirements from the host.

2. Plants which suffer from nutrient scarcity, especially P and N, develop

mycorrhiza.

3.In most of the cases plant seedling fails to grow if the soil does not contain

inoculum of mycorrhizal fungi.

Types of Mycorrhizas

By earlier mycologists the mycorrhizas were divided into the following thregroups :

(i)Ectomycorrhiza.

(ii) Endomycorrhiza.

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(iii) Ectendomycorrhiza.

(f)Organic Fertilizers

Green Manuring

1. Ghai and Thomas (1989) have defined green manuring as"a farming practice where a leguminous plant which h

derived enough benefits from its association with appropriate speciesRhizobium is ploughed into the soil and then a non legume is grown anallowed to take the benefits of the already fixed nitrogen".

2. List of various leguminous plants to be used as green manure.

Some of them are:I.Cultivated annual legumesII.Crotalaria juncea,II.C. striata,V.Cassia mimosoides,V. Cyamopsis pamas,

Other Organic Fertilizers

1. India has vast potential of manorial resources and major resources a

listed below:I. Animal dung,II. animal urine,III. bone meals,IV. slaughter house waste,V. crop residues ,VI. oil cakes ,VII. urban garbage,VIII. sewage,etc. --These wastes can be profitably used as fertilizerts.