Chapter 12 - Biofertilizers: Mechanisms and application

Abstract

A large amount of chemical fertilizers are used because of intensive agriculture and high yielding varieties. Synthetic fertilizers are expensive and harmful to soil health and nutrition. High dose of chemical fertilizers decreases the soil fertility and soil biodiversity and also add a spillover issue that prompts numerous nutrients downstream. This is conceivably a major challenging ecological issue. Biofertilizers are alternative to chemical fertilizers. Biofertilizers reestablish typical soil fertility and improve the soil structure and function. Biofertilizers are preparation of living microbial cells that improve the nutritional level of soils. In India, Fertilizer Control Order (FCO) 1985 has recommended only five fertilizers, viz., Rhizobium, Azotobacter, Azospirillum, phosphate-solubilizing bacteria (PSB), and arbuscular mycorrhiza (AM) for commercialization. Biofertilizers enhance the plant growth and yield through various mechanisms like atmospheric nitrogen fixation, phosphorus solubilization and mobilization, composting, phytohormones production and disease suppression. First four mechanisms are involved in the supply of plant nutrients. Phytohormones have a crucial role to play in the development and differentiation of different plant tissue and also increase the micronutrients (especially Fe) uptake and translocation. Plant growth-promoting microbes suppress the plant pathogens through antibiotic production, hydrolytic enzyme (β-1,3-glucanase and chitinase) production, siderophore production, HCN, and ammonia production induce the plant defense system and competition for nutrients and habitat regions. Application of biofertilizers may increase the crop yield by 20%–35% over the control and may also reduce the application of N, P, and K fertilizers up to 60%. Hence, the practical application of biofertilizers is expanding around the world. We should try to use a multitasking strain for biofertilizers production. Use of multitasking strain absolutely improves the advancement of biofertilizer innovation for the future of agriculture.