The word ‘bio’ stands for ‘life’ and ‘fertilizer’ means ‘a product which provide nutrients in plant usable form’. Bio-fertilizers are those organic products which contain cells of living micro-organism that enhance the growth and productivity of crop through biological processes. Pakistan is an agro-based country, mainly dependent on agricultural foodstuffs for its economy.
Bio-fertilizers are used on farms at a limited scale which contributes less than 2.0% of the total fertilizers used by the farmers for crop productivity. However, there is a huge potential to increase the use of bio-fertilizers for sustainable agriculture. Currently, Pakistan is spending large amounts (i.e., 100 billion rupees) on the manufacturing and import of chemical fertilizers. Only 10% contribution by the bio-fertilizers to the total fertilizer consumption can save up to 10 billion rupees annually. Presently bio-fertilizers are getting very popular and the awareness of bio-fertilizer among farmers has been increased. Different bio-fertilizers are used for different crops in Pakistan and they are manufactured by all leading fertilizers groups and seed companies while some are imported from abroad.
Soil fertility is depleting due to wider gap between nutrient supplies and removal. Plant nutrients lost from soil in many ways, large quantities of nutrients are removed from soil due to the harvesting of crops, weeds obtain a significant amount of plant nutrients from the soil and nutrients also removed by leaching and erosion. Nitrogen is mostly lost through volatilization and de-nitrification. Generally, bio-fertilizers are categorized into four categories; (1) Nitrogen-fixing bio-fertilizers e.g. Rhizobium, Azospirillum, Azotobacter, Azolla and blue green algae. (2) Phosphorous solubilizing bio-fertilizer e.g. Bacillus, Pseudomonas, and Aspergillus. (3) Compost accelerator e.g. lignolytic and cellulolytic bacteria. (4) Plant growth promoting rhizobacteria (PGPR), promoting crop growth and yield through a variety of mechanisms.
For sustainable crop production biological soil fertility management is an ecological approach. It is necessary to maintain soil health and reduce nutrient losses and leaching. Bio-fertilizers help in fixing atmospheric nitrogen, dissolve soil phosphorus and accelerate plant growth through production of growth promoting agents. Bio-fertilizers provide both micro as well as macro nutrients required for healthy crop growth. Therefore, improves crop yields and the quality of agricultural produce, reduces cost of fertilizers and different types of pesticide sprays, based on yield. Use of bio-fertilizers is more preferable as compared to chemical fertilizers due to increasing cost of fertilizers. Bio-fertilizers are harmless and eco-friendly. Improve seed germination and thicker root growth. Have no adverse effect on plant growth and release antibiotic and anti-fungal substances in soil. Use of bio-fertilizes increase crop yield by 20-30%.
Now a day, bio-fertilizers are extensively used in many countries with admirable results in every kind of plants and crops. The studies on all aspects are still desirable in Pakistan, however, there is awful need to make easily availabilities of bio-fertilizers and transmission of technology to the famers at their door step, whatever done locally.