अजोला की खेती- हरे चारे की कमी को कम करने के लिए वैकल्पिक समाधान

About 50–75 percent of the overall cost of producing milk, meat, and other livestock products goes toward feed and fodder, making them the most significant inputs. Grazing cattle in India are typically not supplemented with anything to satisfy their requirement for protein and minerals.

Grazing lands are continuously degrading as a result of exploitative strain and are contracting as a result of conflicting demands for food and forage brought on by the pressure of an expanding population, urbanization, and industrialization. Due to the rising need for food and commercial crops, it is difficult to expand the area used for the production of fodder in India.

Due to this, it is crucial to look for and use feed supplies that can help provide more nutrients with less input. Azolla a free-floating aquatic fern seems to hold the solution for this situation. Azolla is an excellent source of protein for animals since it fixes atmospheric nitrogen in association with the nitrogen-fixing blue-green alga Anabaena azollae.

It belongs to the Pteridophyta order and family Azollaceae. Azolla pinnata is the most prevalent species of Azolla in India. In comparison to lucerne and hybrid Napier, it generates more than 4 to 5 times the amount of excellent quality protein.

Additionally, compared to hybrid Napier and lucerne, biomass production is almost 4 to 10 times higher, respectively. The plant has a high rate of productivity and can double in weight in seven days. Per pond hectare, it can generate 9 tones of protein per year.

India is the world's largest milk producer, however there is a severe lack of feed and fodder for dairy animals. According to estimates, there is a 12-14 %, 25-30 %, and and 30-35 %shortage of dry fodder, green fodder, and concentrate, respectively.

The shortage of fodder is, therefore, compensated with the use of readymade commercial feed resulting in increased cost of milk production. The search for alternatives to green fodder and concentrates led to the wonderful plant Azolla, which holds the promise of providing sustainable feed for livestock.

The plant is popular as ‘super-plant’ because of its great speed of growing and doubling its biomass within 2 or 3 days. Azolla leaves are roughly 1-2 cm long and have a similar width.This can be used as a part of feed or as a supplemental source of protein and minerals in the cattle ration.

Nutrient & Chemical composition of Azolla

Azolla was found to contain 78-80 % organic matter, 25-35% protein content, 10-15% mineral content, and 7-10% comprising a combination of amino acids, bio-active substances, and biopolymers, 4.8–6.7% dry weight crude fat, with 6.1–7.7% and 12.8– 26.4% total fat for the polyunsaturated acids omega 3 and omega 6 and 12-15% crude fiber on a dry matter basis.

The percent Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF) of Azolla recorded was 45-47 and 30-33 respectively. Azolla is also very rich in vitamins (vitamin A, vitamin B12, Beta Carotene), growth promoter intermediaries, and minerals including Sodium, potassium, calcium (%) was 0.60, 0.73, 0.11 while Copper, zinc and Iron (ppm) were 16.12, 71.47 and 73.0 respectively indicating Azolla as a good source of macro as well as micro minerals.

Azolla’s carbohydrate and oil content are very low. The in vitro dry matter digestibility was 78-80% while organic matter digestibility was 80-83%.Azolla meal contains 25.78% crude protein, 15.71% crude fiber, 3.47% ether extract, 15.76% ash, and 30.08% nitrogen-free extract on an air-dry basis. Azolla can be applied as organic fertilizer in fresh, dried or composted form.

If composted alone, decomposition takes about two weeks. It contains about 4.5% Nitrogen, 1.5% Phosphorous and 2-3% Potassium. It also can be used for Azolla-Vermi bio-wash. Besides Azolla Vermi cast the Azolla Vermi wash can be sprayed as a foliar nutrient. It can be even be consumed by humans either directly or as azolla omelettes and burgers.

In addition to their farming activity, small and marginal farmers are generally capable of rearing 2 to 3units of cow/ buffaloes. Azolla fodder plot, if set up by these small farmers can cater to the fodder requirements of remaining part of the year. Azolla can be supplemented with regular feed of the animal @ 2-2.5 kg of Azolla per animal.

Azolla Cultivation Technology

Azolla can be easily produced by individual farmers on a small scale and on a commercial basis. It can be grown in nurseries, ponds, canals, cemented tanks and pits lined with polythene sheets, depending on need and availability or affordability.

Any water bodies to be used for Azolla cultivation preferably should be in a shady place like under shade of a tree. A place of direct sunlight should be avoided. For low input production of Azolla, a pit covered with polythene sheet is advisable.

Cultivation process of Azolla

The establishment of Azolla forage plots does not require any expertise and the farmers themselves can easily take care of it. When setting up in the backyard, the area should be leveled and lined with bricks. The side of the plots should be raised to enable the water to stand. Alternatively, the fodder plot can be in a pit with depth of 0.2 m.

A polythene sheet is spread over the bed in such a way that 10 cm of standing water can be maintained. Width of the bed is maintained at 1.5 m to enable the cultural operation from both sides.

Length may be varied depending upon the fodder requirement of the unit. For two cows, two beds with a length of 2.5 m each with an area of ​​approximately 8 m² can meet 50% of the green forage requirement.     

Once the 2.5m x 1.5m bed is ready, approximately 15kg of fine sieved soilis spread over the bed to provide nutrients to the Azolla plant. About 5 kg of pre-decomposed cow manure (2 days old) is mixed with water, which is a carbon source for the Azolla.

About 40 g of nutrient mixture (prepared by mixing 10 kg of rock phosphate, 1.5 kg of magnesium salt and 500 g of Murate of potash) is added to the Azolla bed. The solution is fortified with micronutrient of desired quantity.

This not only takes care of the micronutrient requirement of Azolla but also the cattle when it is fed with the Azolla. Sufficient water is added to make the water level of the bed to 10 cm.

Production of Azolla scientifically and on a continuous basis requires cement concrete tanks of size 2 m long, 1 m wide and 0.5 m deep. Care must be taken to ensure that water can remain in the tank.

It is possible to build ten or more tanks in one place with an area of ​​25 m². Arrangements for water to each tank should be made by laying pipe and tap from the overhead tank.

The soil is evenly distributed on the bottom of the tank. The depth of the soil layer should be about 10 cm. Cow manure must be added in a proportion of 1 to 1.5 kg per m2 of tank area (2 to 3 kg of cow manure per tank).

Single Super Phosphate (SSP) is to be added at the rate of 5 g per sq m of the tank area every week. (10 g SSP per tank).Fill the water tank until the water accumulates at a height of 10 to 15 cm from the ground. Allow soil particles to settle down. Prepare fresh Azolla inoculum by adding 2 g of carbofuran to prevent pest infestation.

Remove the layer of foam and scum that forms on the surface of the water. The foam impedes the growth and root penetration of Azolla. Allow the tank to stand overnight. On the following day, spread around 200 g of fresh Azolla inoculum over the surface of the water. It takes about 2 weeks for Azolla to form a mat over the water surface.

The water level in the tank should be kept constant, especially during the summer months. To reduce excessive ambient light, a shade made out of coconut leaves may be laid above the tank. This also prevents dew formation on the growing Azolla during winter.

About 1.5 kg of mother culture of Azolla seed material, which comes from Azolla mother nursery, is evenly distributed on the bed after agitating the water in the Azolla bed. Care should be taken about the source of the Azolla seed.

Initially, Azolla will spread over the entire bed and will take the shape of thick mat within seven days. Ideally it will give 10 kg of Azolla within seven days. During the initial seven days azolla is not harvested. Water level is maintained by applying water every day. After the seventh day, 1.5 kg of azolla can be harvested every day.

Azolla should be harvested in plastic trays with sieve. Harvested Azolla should be washed in fresh water before being fed to livestock. Washing is necessary to remove the smell of cow dung. Azolla wash can be used as organic fertilizer for crops grown nearby. Harvested Azolla can be mixed with commercial feed in a 1:1 ratio.Cow dung and mineral mixture removed by Azolla mass has to be supplemented at least once in seven days after harvest.

A mixture of cow dung, mineral mixture, earth and water should be added once every seven days. After every 60 days, the soil is removed from the bed and another 15 kg of fresh fertile soil is added to the bed to prevent nitrogen build-up and also to provide nutrients to the Azolla.

Fresh inoculation of Azolla after the removal of soil and water should be done at least once every six months and repeat the whole process again.

Cost of Azolla Production Unit

The cost involved in setting up fodder plot varies between Rs 2500 to Rs 3000.The primary cost is in the form of manual labour, which can be contributed by the family labour.

While estimating the cost of fodder plot, two units of fodder beds have been considered to maintain regular yield of azolla fodder. The number of units can be increased depending on the number of cattle and feed requirements. The cost details are as follows:

Profit: (Excluding the uses as fodder cost)

• Sale price of Azolla leaves per kg: Rs. 300/-
• After 20 days Azolla is harvested : 1.5 kg/day
• So the monthly income from harvesting Azolla is estimated to be: 13500/-

Benefits for Growing of Azolla

Potential fertilizer for its:

• High N-fixing ability
• High biomass due to rapid growth
• Scavenger of K
• Sollubilise Zn, Fe,Mu.
• Improves soil physico-chemical properties.
• If applied together, the utilization efficiency of urea increases.
• Thick Azolla mat control weed growth.
• Produce compost with a rich, more constantly releasable supply of plant available N. narrow down C: N ratio for better decomposition.
• Extract P from eutrophicated water (average P content of soil should be 25 pm to support growth).
• It releases plant hormones and vitamins which enhance the growth of the riceplant.

From other uses

• Check evaporation loss of water from rice field 45000 lit/crop/ha.
• Absorbing heavy metals from polluted water
• Feeding livestock’s, poultry, birds and fishes.
• As carrier for microbial cultures (bio fertilizers ).
• The oxygen released due to oxygenic photosynthesis, helps the respiration of root system ofthe crops as well as other soil microorganisms.
• Source of biogas.
• Known as the mosquito control breeding populations by more than 95%. Azolla helps by covering the surface of standing water, freshwater bodies, stops adult mosquitoes from laying eggs in freshwater and also reducing the development of mosquito larvae.

Environmental factors affecting Azolla production

Temperature: Optimum temperature for Azolla growth is 25-300C, but most of the species can survive between15-350 In peak summer or peak winter growth of Azolla gets reduced.

pH of water: Azolla can grow in the pH range of 4.5-8.0 however optimum pH is 5.0-7.0. It can also grow in alkaline pH.

Light: Growth under field condition is maximum at 50K lux.In summer season also the Azolla growth is affected highly because of the bright sunlight. A simple thatching by coconut palm/ Palmyra palm leaf can save the Azolla in the hot summer.

Phosphorus: Phosphorus plays an important role in the growth and multiplication of Azolla. Some phosphorus sources like Single superphosphate should be added at a regular interval in the pond water for rapid growth. The concentration of 25ppm of phosphorus in the soil can support the growth of Azolla well.

Limitations of Azolla production

Harsh weather conditions like extreme summer and winter seriously affect the growth and production of Azolla similar to other crops. Azolla is sensitive to dryness, so the optimum water level in the pond should be maintained for the free-floating of Azolla.

 After 6-8 months of Azolla production from a pond replacement of soil bed, water along with fresh Azolla culture is required for optimum production of Azolla.

Measures to be taken for pests & diseases

Conclusion

Azolla can be used as an ideal feed substitute for cattle, fish, pigs and poultry, in addition to its usefulness as an organic fertilizer for wetland rice. Azolla cultivation helps the farmer reduce the cost of animal feed supplementation. The Azolla technology will be widely adopted by dairy farmers, especially those suffering from a lack of land for forage production.

Authors:

Sanjib Kumar Parida

Agriculture Assistant, Government of India

Ministry of Fisheries, Animal Husbandry and Dairying

Department of Animal Husbandry and Dairying

Central Cattle Breeding Farm, Po. Sunabeda -763002, Koraput (Odisha)

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