After reading this article you will learn about the Use of Biofertilizer:- 1. Merits of Biofertilizer Use 2. Constraints to the Use of Biofertilizers 3. Precautions.
Merits of Biofertilizer Use:
Biofertilizers have now been recognised as the essential component of Integrated Plant Nutrition System (INPS). This system ensures nutrient supply from various sources including chemical fertilizers, organic manures, green manures, crop residues etc. The concept of INPS is to adjust the plant nutrient supply at optimum level by maximising benefits from all sources of plant nutrients in an integrated manner.
Supply of nutrients from chemical fertilizers is an energy intensive process and utilizes fast depleting non-renewable source of energy. Organic manures and biofertilizers have been universally identified as two important renewable sources of plant nutrients. Organic manures being bulky in nature required in large quantities and are costly, also not available to that extent.
Therefore, for augmentation of plant nutrition at cheaper rate yet effective way, the biofertilizers are the ultimate renewable sources and have played potential role in evolving judicious combinations with chemical fertilizers to further supplement the nutrient requirements of crops.
Its merits are as follows:
(i) A biofertilizer is a natural product carrying living microorganisms derived from the plant root or cultivated soil. As such no harmful effect on soil fertility is generally seen.
(ii) Biofertilizer is required in smaller dose. A dose of 350- 500 gm. of material per hectare is often sufficient to give desirable effect. This is because each gram of carrier of biofertilizer contains at least 10 million viable cells of a specific strain.
(iii) Wide variety of biofertilizers with proven utility for large number of crop species are now available in the market. Effect of biofertilizers in increasing the yield of different crops under irrigated and rainfed conditions has been proved.
(iv) Besides their direct effect on current crop, use of a biofertilizer also leaves considerable beneficial residual effect on sod fertility.
(v) Biofertilizers may exert favourable effect on root growth and crop stand by affecting general growth and development of plant. For example, Azospirillum and Phosphobacterin produce growth promoting substances.
(vi) It may hasten flowering and crop maturity to a certain extent.
(vii) Rhizobium culture possesses better tolerance to salt and pH under various ecological conditions, therefore, possess better adaptability to different agro- climatic situations.
(viii) Use of biofertilizers is economical with a high cost: benefit ratio, without risk.
(ix) Some biofertilizers may work as bio pesticide. For example, Azotobacterin strain has shown potential to inhibit seed borne pathogen in some cereals.
(x) Biofertilizers are renewable and pollution free.
Constraints to the Use of Biofertilizers:
In-spite of the usefulness of biofertilizers, the farmers acceptance of this practice has been found far from satisfactory, because the crop response to organic and biofertilizers is not as spectacular as with mineral fertilizers.
Constraints are as follows:
(A) Production Constraints:
(a) Raw material:
Peat and lignite are regarded as ideal carriers for biofertilizers. However, it is not available in India in sufficient quantities and in desirable quality.
(b) Specificity of Strains:
Most of the biological strains of biofertilizers are soil and agro-climatic specific. This limits their widespread and foolproof use with expected performance. Therefore, region wise inadequate availability of specific strains limits their popular use.
(c) Biological Constraints:
Presence of ineffective or antagonistic strains in the bio- inoculant, which cannot be displaced easily, mars the overall efficiency of friendly microorganism in the biofertilizer.
(d) Technical Constraints:
Mutation is the problem which arises during fermentation, resulting reduction in effectiveness of bio-inoculants.
(e) Economics of Production:
For the production of quality product, use of high-tech instruments and equipment is discernible. In the absence of these facilities, it is difficult to ensure the production of truly contamination free product.
(B) Marketing Constraints:
(a) The life span of biofertilizers is short. The self-life of biofertilizers produced by using the common carriers like peat or lignite is often less than six months. The best results are rather possible if the material is used in 3-4 months time, provided the material is not subjected to very high temperature (about 40-C) during transportation and storage.
(b) Unavailability of proper transportation and storage facilities.
(c) Demand is limited because of the unawareness of farmers to advantages of biofertilizers.
(d) Lack of adequate promotional and publicity support because of being a low turnover product with limited demand and profitability.
(e) Lack of interest on the part of dealers because of slow disposal rate of the product, nominal profit margin and extremely low turnover.
(f) Lack of proper supply push, the demand generation is extremely low and slow.
(C) Field Level Constraints:
(a) Existing soil conditions such as acidity, alkalinity, pesticides application and high nitrate level limit the nitrogen-fixing capacity of the inoculants resulting in poor results of inoculants.
(b) Presence of certain toxic elements and deficiency of P, Cu, Co and Mo is unfavorable for bacterial fertilizers.
(c) Use of sub-standard inoculants or faulty inoculation techniques, any adverse effect of agro-chemicals and unfavorable conditions such as water-logging or drought reduces the effectiveness of biofertilizers.
Precautions for the Use of Biofertilizers:
(i) Keep the packet of the culture at a cool and shady place, till their use.
(ii) Use of material before the date of expiry.
(iii) Use a biofertilizer only for the crop specified on the packet, especially in the case of Rhizobium culture.
(iv) Open the packet containing the culture just before use and inoculate only that much seed which could be sown immediately.
(v) Do not put culture in warm or hot water which would destroy the living bacteria contained in the biofertilizer.
(vi) For seed treatment, if besides a biofertilizer, the seed is also to be treated with a fungicide or insecticide, treat the seed first with a fungicide followed by the insecticide and finally with the biofertilizer.
(vii) While using a biofertilizer in strongly acidic or saline- alkali soils, it would be desirable to use some soil amendment along with bio-inoculant.
(viii) Adequate nutrition, for instance, with phosphorus, calcium, potassium etc., for the normal growth and activity of Rhizobium is a must and should be restored.