After the introduction of chemical fertilizers in the last century, farmers were happy of getting increased yield in agriculture in the beginning.
However, slowly chemical fertilizers started displaying their ill effects such as leaching out and polluting water basins, destroying microorganisms and friendly insects, making the crop more susceptible to diseases, reducing the soil fertility and thus causing irreparable damage to the overall system.
A number of intellectuals found that biofertilizers can help in increasing the yield without causing the damage associated with chemical fertilizers.
What is Bio Fertilizer?
Biofertilizers are preparations containing microorganisms, with capability of mobilizing nutritive elements from non-usable form to usable form through biological processes.
The name itself is self-explanatory. The fertilizers are used to improve the fertility of the land using biological wastes, hence the term bio fertilizers, and biological wastes do not contain any chemicals, which are detrimental to the living soil.
They are extremely beneficial in enriching the soil with those microorganisms, which produce organic nutrients for the soil and help combat diseases. The farm produce does not contain traces of hazardous and poisonous materials.
Thus, those products are accepted across the world as organic ones. Hence, for organic farming the use of bio fertilizers is mandatory.
Organic fertilizers differ from chemicals fertilizers in that they feed your plants while adding organic material to the soil. Soils with lots of organic matter remain loose and airy, hold more moisture and nutrients, foster growth of soil organisms, and promote healthier plant root development.
If only chemicals are added, the soil gradually loses its organic matter and micro biotic activity. As organic matter is used up, the soil structure deteriorates, becoming compact, lifeless and less able to hold water and nutrients. This result in increased amounts of chemical fertilizers needed to feed plants.
Organic fertilizer offers these benefits:
- Easy Product Application
- Completely Non-Toxic: Safe for your children or pets
- Extremely Universal: Apply it to any plant in your yard
- Immediate Observable Results: You'll see that it's working
- Tremendous Drought Resistance: Enhances root systems
- Excellent Pest & Disease Tolerance: Protect your plants
- Unbeatably Cost Effective: You don't spend a fortune for a beautiful lawn and garden
Galaxy of Biofertilizers
- Phosphate Solubilizing Bacteria (PSB)
- Abuscular Mycorrhizal Fungi
- Potassium Solubilizing Bacteria (KSB)
- Most common biofertilizers used in legume crops g. pea
- Fixes atmospheric N by symbiotic association with the root hairs of the legumes
- Results in the formation of root nodules that fix atmospheric N successfully
- Azotobacter is free-living nitrogen-fixing bacteria, fixing nitrogen equivalent to 25-30kg N/ha. It also produces hormones like Indole Acetic Acid (IAA) and Gibberellins. Vitamins like biotin, folic acid and different B-group are also produced. The application of Azotobacter, supported by judicious use of organic matter, ensures good seed germination, increasing productivity.
- It colonies the root mass and fixes N in loose association with plants
- It has positive interaction with cereal crops
- Saves 15-20 Kg N/ha
Phosphate Solubilizing Biofertilizers (PSB)
- These biofertilizers play a significant role in solubilizing insoluble phosphate.
- Around 95-99% of the total soil, phosphorus is insoluble which is directly not available to plants.
- The P-solubilizes containing bacteria or fungi may convert isolable form of phosphate to soluble form by producing organic acids in general.
- About 15-25% of insoluble phosphate can be solubilized, saving chemical fertilizers significantly.
Potassium solubilizing bacteria (KSB):
It is a latest technique introduced in biofertilizers its release insoluble potassium in soil and fixes this potassium, which is of great significance in vegetable production. e.g. Bacillus mucilegins.
How do these biofertilizers work?
- These microbial cultures fix atmospheric nitrogen, helps in phosphate and potassium solubilization or producing hormones, vitamins and other growth factors required for plant growth.
- Biofertlzers are called biological instruments and play a very significant role in the augmenting of the productivity.
- It can improve health and hardiness in a wide variety of plants. It does this by supplying the plant root zone beneficial microorganisms, humic acid and organic fungi and actinomyces, humic and fulvic acids, and organic fertilizer nutrients.
- Increased mineral uptake from the soil and into the plants leaves.
- Improved seed germination and thicker root development.
- Increased bloom set, size of flowers and fruit.
- Increases and stabilizes chlorophyll in plants, which remits in photosynthesis, darker green leaves and increased sugar content in plants.
- Relieves stress in plants caused by extreme weather conditions.
- Increased plant vigor and a greater resistance to disease, insect attack and frost due to increased protein, found within the plant.
- Increases the storage life of fruits and vegetables by retarding the loss of protein, chlorophyll and RNA in produce.
- Retards the aging process in plants (senescence), keeping them producing longer.
- It also produces vitamins like biotin; folic acid and different B-group are also produced.
- Biofertilizers contains completely fermented organic matters, which will improve the physical properties of all soils, enrich air aeration, water and nutrients retention capacity and reduce acidity as well.
How to apply biofertilizers in crops ?
There are four methods for applying biofertilizers in vegetables:
- Seed treatment,
- Cut piece/set treatment,
- Seedling treatment and
- Soil application
- About 200g of bio-fertilizers is required to treat 10-14 kg of seed.
- Suspend one packet of 200g in approximately 400ml water and mix it thoroughly.
- Pour this mixture on seeds and mix with hands to obtain uniform coating on each seed.
- Spread the seeds in shade for drying for 10-15 minutes then sow them immediately.
- Prepare a culture suspension by mixing 1 kg of culture in 50-60 liters water.
- The cut pieces of planting material required for 1 acre are kept immersed in the suspension for 10-15 minutes.
- Then bring out these cut pieces and allow to dry for sometimes before planting.
- Cut pieces method is applicable for crops like potato.
- Seedling treatment is recommended for tomato, chilli, onion and transplanted crops.
- Prepare the suspension by mixing 1 kg of culture in 10-15 liters of water.
- Get seedlings required for 1 acre and make small bundles of seedlings.
- Dip the seedlings in the suspension for 15-20 minutes.
- Transplant these immediately.
- Generally the ratio of inoculants and water should be 1:10 approximately, i.e., 1 kg packet in 10 liters of water.
- Prepare the mixture of 2-3 kg of bio-fertilizer in 40-60 kg of soil/compost.
- Broadcast the mixture in one acre of land at either sowing time or 24 hr. before sowing. The application of phosphate-solubilizes is very common.
New technique in Biofertilizers
Generally, biofertilizers are carrier based and always-in powder form. The carrier is mostly lignite, which has high organic matter content, and it holds more than 200% water, which enhances the growth of the microorganisms. Before use, slurry is made which is applied to seed. This method is universal unless it has some difficulty in application to seed no other method is used.
Recently University of Agricultural Sciences, Bangalore has developed a method. Dry complex fertilizer for direct soil application this method consists of granules (1-2 mm) made from tank bed clay (TBC). These granules are baked at 200ºC in a muffle furnace, which helps to sterilize the material and gives porosity to granules.
The baked granules are soaked in a suspension of nitrogen fixing bacteria grown in a suitable medium overnight. The clay granules are air-dried at room temperature under aseptic conditions. The granules contain more than a billion of bacteria per gram of granules.
These granules are suitable for field application along with seeds and fertilizers in furrows. However, quantity of biofertilizers to be applied will be slightly higher than seed application.
Constraints in the use of biofertilizers
- Region wise unavailability of soil specific strains, which limit the use of bio-inoculants
- Shelf life is the major constraints in the development of adequate market
- Demand is limited because of the unawareness of farmers to advantages of Biofertilizers
- Unavailability of proper transportation and storage facilities is also a major constraint for development of effective market
- Lack of publicity is one of major constraint in popularizing biofertilizers among the farming community
- Raw material may not be available in sufficient quantities and desirable quality
- Microbial strains which can compete with indigenous ones and work over a range of soils and agro-climate conditions need to be isolated, multiplied and made available to farmers
- Ideal, cheaper and easily available carriers for increasing longevity of biofertilizers should be developed
- Research should be done with regard to suitability of biofertilizers against adverse conditions
- N fixation by different legumes under different agro-climate situations needs to be estimated
- Intensive promotional activities need to be undertaken by extension services so that farmer develop confidence in the use of biofertilizers
- Encouragement to private industries, state governments volunteers organizations for production, distribution and marketing of biofertilizers
- Organization of training for farmers, extension workers, producers and traders on various aspects of technology
- Publicity programme through mass media and other media.
Biofertilizers are low cost eco-friendly inputs which improve the nutrient availability to many vegetable crops. It increase the growth and yield attributes of vegetable crops. Although it cannot replace the chemical fertilizers, but certainly are capable of reducing their input.
Demand for biofertilizers in India surpasses its production, so it is necessary to increase its production. Thus to improve the productivity and farm income it becomes necessary to use biofertilizers. Quality produce is the need of present scenario of agriculture or higher demand by people then biofertilizers play important role as a tool of organic production
Shweta, Navjot Singh Brar and Manu Malik
Department of Agronomy , CCSHAU, Hisar