Bio Fertilizers

The fertilizers are used to improve the fertility of the land using biological wastes, hence the term biofertilizers, 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 micro-organisms, 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 biofertilizers is mandatory.

Biofertilizers are Eco-friendly organic agro-input and more cost effective than chemical fertilizers. Biofertilizers like Rhizobium, Azetobacter, Azospirillum and blue green algae (BGA) are in use since long time ago. Rhizobiuminoculant is used for leguminous crops. Azetobacter 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. Anabaena in association with water fern Azolla contributes nitrogen up to 60 kg/ha/season and also enriches soils with organic matter other types of bacteria, so-called phosphate solubilizing bacteria like Pantoea agglomerans strain P5, and Pseudomonas putida strain P13 are able to solubilize the insoluble phosphate from organic and inorganic phosphate source. In fact, due to immobilization of phosphate by mineral ions such as Fe, Al and Ca or organic acids, the rate of available phosphate (Pi) in soil is well below plant needs.

Plants have a number of relationships with fungi, bacteria, and algae, the most common of which are with mycorrhiza, rhizobium, and cyanophyceae. These are known to deliver a number of benefits including plant nutrition, disease resistance, and tolerance to adverse soil and climatic conditions. These techniques have proved to be successful biofertilizers that form a health relationship with the roots. 

Biofertilizers will help solve such problems as increased salinity of the soil and chemical run-offs from the agricultural fields. Thus, biofertilizers are important if we are to ensure a healthy future for the generations to come.

Mycorrhiza:

Mycorrhizae are a group of fungi that include a number of types based on the different structures formed inside or outside the root. These are specific fungi that match with a number of favourable parameters of the the host plant on which it grows. This includes soil type, the presence of particular chemicals in the soil types, and other conditions.

These fungi grow on the roots of these plants. In fact, seedlings that have mycorrhizal fungi growing on their roots survive better after transplantation and grow faster. The fungal symbiont gets shelter and food from the plant which, in turn, acquires an array of benefits such as better uptake of phosphorus, salinity and drought tolerance, maintenance of water balance, and overall increase in plant growth and development.

While selecting fungi, the right fungi have to be matched with the plant. There are specific fungi for vegetables, fodder crops, flowers, trees, etc.

Mycorrhizal fungi can increase the yield of a plot of land by 30%-40%. It can absorb phosphorus from the soil and pass it on to the plant. Mycorrhizal plants show higher tolerance to high soil temperatures, various soil- and root-borne pathogens, and heavy metal toxicity.

Cyanobacteria:

Both free-living as well as symbiotic cyanobacteria (blue green algae) have been harnessed in rice cultivation in India. A composite culture of BGA having heterocystous Nostoc, Anabaena, Aulosira etc. is given as primary inoculum in trays, polythene lined pots and later mass multiplied in the field for application as soil based flakes to the rice growing field at the rate of 10 kg/ha. The final product is not free from extraneous contaminants and not very often monitored for checking the presence of desiredalgal flora.

Once so much publicized as a biofertilizer for the rice crop, it has not presently attracted the attention of rice growers all over India except pockets in the Southern States, notably Tamil Nadu. The benefits due to algalization could be to the extent of 20-30 kg N/ha under ideal conditions but the labour oriented methodology for the preparation of BGA biofertilizer is in itself a limitation. Quality control measures are not usually followed except perhaps for random checking for the presence of desired species qualitatively.

Liquid Bio-Fertilizers:

Leguminous plants require high quantities of nitrogen compared to other plants. Nitrogen is
an inert gas and its uptake is possible only in fixed form, which is facilitated by the rhizobium bacteria present in the nodules of the root system. The bacterium lives in the soil to form root nodules (i.e. outgrowth on roots) in plants such as beans, gram, groundnut, and soybean. 

Liquid Bio-Fertilizers:

Nitrogen & Phosphorous are two major nutrients for plant growth which are provided through Chemical Fertilizers or Organic Manure. Certain soil microorganisms have an ability to fix part of elementary form of atmospheric nitrogen to the available form for the plants and / or solubilize part of the bound phosphates of the soil and thereby make them available to the plant which increases fertility of the soil and yield. These characteristics make them useful as Biofertilizers.

Benefits of Bio-fertilizers:

• ·         Increase crop yield by 20-30%.
• ·         Replace chemical nitrogen and phosphorus by 25%.
• ·         Stimulate plant growth.
• ·         Activate the soil biologically.
• ·         Restore natural soil fertility.
• ·         Provide protection against drought and some soil borne diseases.

Advantages of Bio-fertilizers:

Cost effective relative to chemical fertilizer and reduces the costs towards fertilizers use, especially regarding nitrogen and phosphorus. It is environmentally friendly fertilizer that not only prevents damaging the natural source but helps to some extend clean the nature from precipitated chemical fertilizer.And can provide better nourishment to plants.