Biofertilizers

Biofertilizers - Biofertilizers are defined as biologically active products or microbial inoculants of bacteria, algae and fungi (separately or in combination), which may help biological nitrogen fixation for the benefit of plants.Biofertilizers also include organic fertilizers (manure, etc.), which are rendered in an available form due to the interaction of micro-organisms or due to their association with plants. Biofertilizers thus include the following:(i) symbiotic nitrogen fixers Rhizobium spp.;(ii) asymbiotic free nitrogen fixers (Azotobacter, Azospirillum, etc.); (iii) algae biofertilizers (blue green algae or BGA in association with Azolla);(iv) phosphate solubilising bacteria;(v) mycorrhizae;(vi) organic fertilizers.

Name of bio-fertilizer            

Contribution  Beneficiaries

A)  Nitrogen1)   Rhizobium {Symbiotic}

a)      Fixes 50-30 kg N/hab)      Leaves residual nitrogenc)      Increase yield by 10 –30%d)      Maintains soil fertility

Pulses legumes: Cowpea, Green gram, Black gram, Pea, GramOil legumes: Groundnut, SoyabeanFodderlegumes: Berseem, lucerneFodderlegumes:Subabul,Shisan,Wheat,Jowar,Bajra, Maize

2)   Azotobacter a) Supplies 20-40mg N/g of carbon sourceb) Promotion of growth substances like vitamins, B Group, IAA and Gibberellic acidc)10-15% increase in yieldd)Maintains soil fertilitye)Biological control ofplant disease, suppresses plant pathogens

Mustard, sunflower, banana, sugarcane, grapes,papaya,watermelon, tomato, chillyladyfinger,coconut,spices,flower,plantation crops, forest sp.  

3. Azospirillum a) Fixes 20-40 kg Nitrogenb) Results in increase mineral and water uptake.c) Root developmentd) Vegetative growth and crop yield.

Rice, sugarcane, fingermillet, wheat, sorghum bajra etc.; 

4.   Blue Green Algae {bga}

a) 20-30 kg N/ha in submerged rice fields.b) Production of growth substances like auxins, IAA, giberellic acid 

Rice

5.   Azolla a) Fixes 40-80 kg N/hab) Used as green manure because of large bio-mass

Rice 

SOME IMPORTANT POINTS to REMEMBER:-

*Contain live or latent cells of microbes.*Ready to use formulations.*Efficient strains of microbes.*Applied to seed/seed material/seedling/soil/waste material/crop residue in order to increase their population.

*Accelerate some biochemical processes.*Make more nutrient available to the crops.

ROLE OF BIOFERTILIZERS:-*Makes availability of nutrients. *Make the root rhizosphere more lively.*Growth Promoting Substances are produced.*More root proliferation.*Better germination.*Improve quality and quantity of produce.*Improve fertilizer use efficiency.*More biotic and abiotic stress tolerance.*Improve soil health.*Residual Effect.*Make the system more sustainable.

First, because increase in the use of fertilizers leads to increased crop productivity, second, because increased usage of chemical fertilizer leads to damage in soil texture and raises other environmental problems. Therefore, the use of biofertilizers is both economical and environment friendly. The pragmatic approach will be to develop the integrated nutrient supply system involving a combination of the use of chemical fertilizers and biofertilizers. Moreover, India is not self sufficient in fertilizer production. Realizing the  importance of biofertilizers in supplementing the use of chemical fertilizers, the Government of India had launched the 'National Project on Development and use of biofertilizers during the sixth year plan.

Biofertilizers like Rhizabium, azotobacter, Azospirillum and blue green algae (BGA) are in use since long. These organisms fix atmospheric nitrogen and supply it to plants. Hence, bio fertilizers to some extent. The bacterial biofertilizers contribute 20-30 kg N/ha/season. Rhizobium inoculant is used for leguminous crops. Azotobacter can be used with crops like wheat, maize, mustard, cotton, potato and other vegetable crops. Azospirillum inoculants are recommended mainly for sorghum, millets, maize, sugarcane and wheat. Blue green algae belonging to genera Nostoc, Anabaena, tolypothrix and Aulosira fix atmospheric nitrogen and are used as inoculants for paddy crop grown both under upland and low land conditions. However, the inoculants are most effective under low land rice cultivation and contribute 20-30 kg N per ha per season with better quality of grains. Anabaena in association with water fern Azolla contributes nitrogen up to 60 Kg/ha/season and also enriches soils with organic matter.

Phosphate solubilizing microorganisms (PSM) are a group of microbes capable of solubilizing inorganic phosphorus from insoluble sources. In alkaline and acidic soils, the availability to phosphorus is low. These microbes can be useful to reverse this process. PSM when used with rock phosphate can save about 50% of the crop requirement of phosphatic fertilizer like single super phosphate. Simple inoculation of seeds with PSM gives crop yield responses equivalent to 30 kg P2O5/ha of phosphatic fertilizers.Vesicular-Arbuscular Mycorrhizae (VAM) fungi are found to be associated with a majority of agricultural crops. VAM have been associated with increased plant growth and enhanced accumulation of plant nutrients, mainly phosphorus, zinc, copper and sulphur through greater soil exploitation by mycorrhizal hyphae. Maximum root colonization and sporulation occurs in soils with low phosphorus.

A schematic diagram of Vesicular arbuscular mycorrhiza

FOR FREE LIVING ORGANISMS:

Small quantity of inoculum of BGA and azolla can be obtained from laboratories and they can be multiplied in the farmers’ field for subsequent application.

BGA inoculum is multiplied in iron trays of 2m*2m*0.25m size. Each tray is filled with 20kg soil and 400gms superphosphate. BGA inoculum is sprinkled on it standing water of 5-10cm is maintained. A thick algal scum is formed within a week. Then, water is drained out and soil is allowed to dry. Then the flakes are ready for application.

Same procedure is followed in case of azolla except that it is multiplied in 4m*2m nursery beds. Moreover azolla can be used as a green manure crop.

COMPOSTINGComposting is a process of biological decomposition of organic waste that is carried out by a group of active micro-organisms which break down the cellulolytic material and hasten the process of composting under aerobic condition at an elevated temperature.Factors influencing composting are Number and species of micro-organisms, Oxygen levels, Particle size, Nutrient levels, Temperature, pH etc.

Advantages of composting :-•Reduction of volume and weight•Soil conditioner•Means of land reclamation•Quality of soil making it more productive•Compost increases soil aeration•It makes heavier soils easier to till•Reduces soil erosion•Buffer effect as a protection against that of chemical fertilizer.

Methods of Application:-BGA(Rice)Soil Application @4kg algal culture/ac at 7DATAzolla(Rice)As Green Manure (4t/ac) at plantingAs Dual Crop/inter crop (400-500kg/ac) at 7DATRhizobium (all legumes)1.Treatment Seed2.Soil ApplicationAzotobacter and Azospirillum (all non legumes)1.seed treatment2.Seed material treatments (potato/sugarcane/sweet potato etc.)3.Seedling Root dipping (vegetables/flowers those are transplanted)4.Soil application

PSM (all legumes and non-legumes)1.seed treatment2.Seed material treatment(potato/sugarcane/sweetpotato etc.)

3.Seedling Root dipping (vegetables/flowers those are transplanted)

4.Soil application

VAM (Vescicular Arbuscular Mycorrhiza) 1.Inoculation of seedlings on the seedbed2.Inoculation of potted soil

Waste Decomposers1.Compost pit decomposition2.Field(in situ) decomposition

RegionRegion ChemicalChemical(NPK (NPK kg/ha.)kg/ha.)

Cropped Cropped area(%)area(%)

ChemicalChemical

(NP)(NP)(kg/ha.)(kg/ha.)

Bio-Bio-fertilizersfertilizers(kg/ha.)(kg/ha.)

SouthSouth 125.21125.21 18.4618.46 107.06107.06 0.050.05

NorthNorth 130.43130.43 22.3222.32 127.65127.65 0.010.01

WestWest 60.8260.82 40.9140.91 57.0757.07 0.060.06

EastEast 70.6370.63 18.3218.32 61.7361.73 0.010.01

TotalTotal 90.0490.04 100.00100.00 82.9082.90 0.040.04

Table : Use intensity of Biofertilizers (BF) and Chemical fertilizers in Indian Agriculture

To attain production targets, the Government of India implemented a central sector scheme called National Project on Development and use of Biofertilizers (NPDB) during the Ninth Plan for the production, distribution and promotion of biofertilizers.The government also plays a dominant part in marketing biofertilizers in three possible channels:(a) State government via District level Officers and Village level workers to farmers, (b) State Marketing federation via cooperative bodies to farmers and (c) State Agro-industries Corporations via Agro service Center to farmers.

SOME OF BIO-FERTILIZERS IN THE MARKET

Biofertilisers are live products and require care in Biofertilisers are live products and require care in storage ,transport,,application and maintaining field condition.storage ,transport,,application and maintaining field condition.

For best results use both nitrogenous and phosphatic For best results use both nitrogenous and phosphatic biofertilisers biofertilisers

Use of biofertilizers is being empasized along with chemical Use of biofertilizers is being empasized along with chemical fertilizers and organic manures. This makes INTEGRATED fertilizers and organic manures. This makes INTEGRATED NUTRIENT MANAGEMENTNUTRIENT MANAGEMENT

Biofertilizers are not replacement of fertlizers but can Biofertilizers are not replacement of fertlizers but can supplement their requirement. supplement their requirement.