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Orissa state(81o 27’ E, 17

o 49’ N to 87o 39’

E,29o 34’ N)is one among the few principal rice

growing states of India. Based on soil type, climatic

water balance, intensity and duration of rain fall and

topography Orissa is divided into 9 agro climatic

zones. Out of these 9th agro climatic zone, Western

and mid central table land comprises major rice grow-

ing areas of Orissa. Bargarh and adjoining regions

harvest rice crop twice a year and serve as a rice

bowl for Orissa and its neighboring state. As, rice is

a staple food for all most all people of this region,

study on the modern rice cultivation practice and

specifically soil nutrient study have made tremen-

dous interest for agricultural scientists, officials, work-

ers and farmers of this region.

Nitrogen is one of the most essential fertiliz-

ers for crop plants. Though it constitutes over 70%

of our atmosphere, the crop plants are unable to

exploit it directly from the nature. To support crop

production the fertilizer consumption has increased

to many folds. Several thousands tones of chemical

fertilizers consumed per year(two cropping seasons)

alone in Bargarh and adjoining regions of Western

Orissa .Increasing cost of chemical fertilizers, reduc-

tion/abolition of subsidy, widening gap between sup-

ply and demand together with low level of purchas-

ing power of majority farmers of this region have

indeed created an embarrassing problem. Also the

chemical based system of rising crop has degraded

the soil environment (altered C/N ratio) which has

cumulated in reduced agrochemical utilizing effi-

ciency of crop plants. Chemical characteristics of soil

samples of many places of Western Orissa also

Dr.Jayanta Kumar Sahu

Blue Green Algae Biofertilizer Technologyfor rice based cropping system of Western Orissa

shows this trend(Sahu,Naik and Adhikary,1996).It is

therefore time to think for some of the alternative natu-

ral resources to meet part of our demand and to re-

lieve the pressure on the chemical fertilizer nitrogen

required.

Under water logged conditions of rice fields,

Blue Green algae plays a vital role in maintaining soil

fertility and crop yield even in the absence of any

added agrochemicals. In recent years, algalisation has

been recognized as an important input in rice cultiva-

tion as its form a per-

petually renewable

source of nutrients

and improve soil

health (Venkatraman,

1981; Goyal,1993)

C y a n o b a c t e r i a l

biofertilizer for rice

cultivation is an eco friendly, easily manageable in-

put forming a self generating system contributing to

about 25 Kg N/ha per season and also they add or-

ganic matter and growth promoting substances to

the soil (Roger and Kulasooriya,1980).

A survey on the distributional pattern of Blue

Green algae on all nine agro climatic zones of Orissa

was studied. Rich diversity of Blue Green algae com-

prising specie of Nostoc, Anabaena

,Aulosira,Calothrix,Tolypothrix and Cylindro spermum

was observed in the several rice fields of Western

Orissa (Naik, Sahu and Adhikary, 1996) .Out

of the eight different strains of Nitrogen fixing Blue

62

Blue-green algae (BGA) are primitivemicroscopic plants that live in fresh water. Theirscientific name is cyanobacteria but they are more com-monly known as pond scum. Normally blue-greenalgae are barely visible, but, during warm weather,populations can rapidly increase to form a large masscalled a bloom. Blooms most commonly occur duringthe late summer and early fall.Blue-green algae thrivein areas where the water is shallow, slow moving, andwarm, but they may also be present below the surfacein deeper, cooler water. One key factor affecting growthrates is the level of available nutrients such as phos-phorus and nitrogen

Some blue-green algae produce toxins

that could pose a health risk to people and

animals when they are exposed to them in large

enough quantities. Health effects could occur

when surface scums or water containing high

levels of blue-green algal toxins are swallowed,

through contact with the skin or when airborne

droplets con-taining toxins are inhaled while

swimming, bathing or showering.

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Green algae suggested for biofertilizer production in

Orissa, one efficient Nitrogen fixer Nostoc carneum

UU 29130 belong to Western part of Orissa,

Padampur. Also this strain has been deposited in BGA

germplasm conservation centre at Indian Agricultural

Research Institute, New Delhi .This strain is a region

specific stress compatible strain, therefore, this spe-

cies can be recommended for biofertilizer production

by farmers in this region.A tested (rural oriented)

method is described below which is recommended

for setting up large scale algal production farm in this

region.

Mass production in cemented tanks

Out of the different method recommended for the pro-

duction of BGA, open air cement tank method is con-

sidered to be easy and cost effective. The cement

tanks are permanent structures and can be cleaned

easily. On the other hand galvanized iron trays are

very expensive, prone to rusting and difficult to clean.

Similarly polythene lined pits don’t last for more than

3-4 harvests and thus become costly.

Production of BGA inoculum can be done in

the following steps

• Construct cement tanks of size5m length,1.5m

width and 0.3m depth in an open space. The inner

walls and floor of the tank should be glazed smooth.

Provide a water tap at about 25 cm height at one of

the broad sides and a drainage pipe fitted on the op-

posite wall at the bottom. An overflow outlet is pro-

vided at about 20 cm height above the drainage out-

let. The length of the tanks can be manipulated but

width should not be increased. Provide a space of

about 1.0 m between the tanks for operational con-

venience.

• The four corners of the tank should be round.

• Spread 10 kg of soil and add 200 g of single super

phosphate per tank. The soil should be loam and

sandy loam and heavy type like clay. Light soil facili-

tates formation of algal flakes which easily separate

out from the soil. The soil should be preferably taken

from a fallow land since it is low in Nitrogen and mi-

crobial flora.

• Fill the tanks with water up to a height of about 15

cm and add insecticide(10-15ml malathion, 50% EC

or endosulphan 30% EC) to prevent breeding of

mosquitoes and other insects. Mix the contents thor-

oughly and allow to stand till the supernatant be-

comes clear.

•Sprinkle 200 g of BGA culture on the water

surface(mother starter region specific BGA cultures

are available at Utkal university BGA germplasm

conservation centre, Bhubaneswar)

• Under favorable conditions (temperature 300 C

and above), the growth of blue-green algae will be

rapid and a thick algal mat is formed on the surface of

the water in about 10-15 days. At this stage, forma-

tion of another BGA layer can be seen on the surface

of the soil. During this period, add water periodically

to maintain the water level around 10 cm.

• Closely monitor the BGA coming up in the tanks

by periodically examining the algal growth using a

microscope. One can alternatively use the iodine test

to differentiate between green and blue-green algae.

The green algae turn dark violet or black in colour

with iodine.

• Alkaline conditions with pH around 8, appreciable

prevent contamination with green algae.

• Stop adding water to the tanks only after a thick

BGA mat is formed and allow the contents to dry

without draining the water.

• When completely dry, the algal mat will form

flakes which will separate out from rest of the soil.

These flakes are collected, sun dried and packed in

polythene bags.

• Fill the tanks again with water, put fresh soil,

starter culture and super phosphate and repeat the

process. Single harvest from a tank yields about 7-

10 kgs of soil based algal flakes.

63

Avoiding exposure toblue-green algae

Never drink untreated surface water, whether

or not algae blooms are present. Untreated

surface water may contain other bacteria, para-

sites or viruses, as well as algal toxins, that all

could cause illness if consumed. People not on

public water supplies should not drink surface

water, even if it is treated, during an algal bloom

because in-home treatments such as boiling

and disinfecting water with chlorine or UV and

water filtration units do not protect people from

blue-green algal toxins. If washing dishes in untreated

surface water is unavoidable, rinsing with bottled wa-

ter may reduce possible residues. While we don’t know

if water containing low levels of blue-green algal tox-

ins could leave residues on dishes, taking this pre-

caution may help reduce possible exposures. People,

pets and livestock should avoid contact with water that

is discolored or has scums on the surface. Colors can

include shades of green, blue-green, yellow, brown or

red. If contact does occur, wash with soap and water

or rinse thoroughly with clean water to remove algae.

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• Instead of using the soil based starter culture,

one can use laboratory grown liquid culture of rice

fields BGA to inoculate the tanks. Even the dominat-

ing native BGA, directly collected from rice field can

also be used. Recommendation for Field Applica-

tion

• Broadcast the dried algal flakes on standing water

at the rate of 10 to 20 kg per hectare ,one week after

transplantation. The field should be kept water logged

for about ten days after inoculation to allow good

growth of BGA.

• If nitrogen fertilizers are not being used, apply BGA

in order to gain a benefit of 15-25 kg N/ha. Where

the nitrogenous fertilizers are used, keep the basal

dose unchanged and reduce the subsequent two ap-

plications by half. This will save on the chemical fer-

tilizers without affecting the yield.

• Apply BGA at least for 3-4 consecutive seasons to

have the advantage of cumulative effect.

• The sun dried BGA inoculums packed in polythene

bags can be stored at room temperature for at least

3 years without loss in the viability.

• Recommended pest control measures and other

crop management practices generally do not inter-

fere with the establishment and activity of the BGA in

the field.

microscopic structure

of

Blue Green Algae

• Application of small quantity of phosphatic fertilizer

after BGA inoculation accelerates the algal establish-

ment.

The above algal biofertilizer technology is rural

oriented technology for farmers resulting in low cost

production of rice. This is of particular significant to

the farmers of this region who are economically weak

to invest on chemical Nitrogen fertilizer. Fields experi-

ment using algal inoculations at various location

showed promising results with respect to nitrogen

saving and increased yield. Large scale production

of the soil based BGA biofertilizer has an income gen-

erating potential and can be taken as a profession for

the unemployed youths of this region.

REFERENCES

Goyal,S.K.1993.Algal Biofertilizer for vital soil and free

Nitrogen.Proc.Indian Natl.Sci.Acad.B.59:295-302.

Naik,H.K.;Sahu,J.K.and Adhikary,S.P.1996.Blue Green algae of

rice fields of Orissa state 11.Growth and Nitrogen fixing

potential.Phykos, 35(1&2):111-118.

Roger,P.A.and Kulasooriya.S.A.1980.Blue Green algae and

rice,I.R.R.I..,Los Banos,Manila,Phillipines.pp.1-112.

Sahu,J.K.;Naik,H.K.and Adhikary,S.P. Blue Green algae of rice

fields of Orissa state 1.Distributional pattern in different

agroclimatic zones. Phykos ,35(1&2):93-110.

Venkataraman,G.S.1981.Blue Green algae for rice production,a

manual for its promotion:FAO field documentation no.2(RAS/75/

004),FAO, Rome.pp.102.

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64

Despite their name, blue-green algae are not algae at all. They are a type of photo-synthetic bacteria, called ‘cyanobacteria’, that rely onsunlight for energy.Blue-green algae are present inalmost all aquatic ecosystems, including creeks, riv-ers, lakes and wetlands. Individual cells are quite small,so bluegreen algae can be present in a water bodywithout being visible. However, as environmental con-ditions become just right, algae numbers can start toincrease rapidlyand blooms, or scums, become easilyvisible across the water surface. The blooms range incolour from dark green to yellowish–brown and de-velop a paintlike consistency as they dry out aroundthe water’s edge. A blue pigment may also be seen asthey dry.

Cyanobacterial toxins are the naturally produced poisons stored in the cells ofcertain species of cyanobacteria. These toxinsfall into various categories. Some are known toattack the liver (hepatotoxins) or the nervoussystem (neurotoxins); others simply irritate theskin. These toxins are usually released into waterwhen the cells rupture or die. scientists are moreconcerned about hepatotoxins than neurotoxins,because neurotoxins are not considered to beas widespread as hepatotoxins in water supplies.Very few cyanobacterial toxins have actually beenisolated and characterized to date. Bettermethods of detection are being developed tohelp us learn more about them,