Consequences of Bioinoculants and Intercropping Approach to Alleviate Plant Drought and Salinity Stress for Sustainable Agriculture

Saline conditions have created severe negative influence on agricultural productivity and salt accumulation in soil leading to significant yield losses. According to an estimate, approximately 5.2 billion hectares (ha) of agricultural land is subject to soil degradation, erosion, and salinity. The salt-affected soil in India is about 8.1 million ha, with 3.1 million ha coastal saline soil, 2.8 million ha sodic soil, and the remaining 2.2 million ha saline soil located inland. Even though salinity has already significantly affected the fertile lands, the land area under salinity is still increasing due to various anthropogenic activities as artificial irrigation, improper water management, blocking of natural drainage system, and similar human interferences with the environment. In saline-affected soils, the rhizosphere environment becomes unfavorable and inhospitable for growth of plants and microbes, although there may be sufficient amount of water and nutrients in soils. Overuse of artificial fertilizers and chemical pesticides causes long-term degradation of natural soil fertility and creates environmental pollutions. The degradation of soil fertility, in combination with an estimated rise of the world population to 8.5 billion over the next 25 years, calls for additional strategies to ensure the worldwide requirement of food supply. The development of sustainable and safe means for agriculture production will be necessary, which includes enhancing the output on arid and saline areas to avoid further loss of cultivable land. The application of bioinoculants like plant growth-promoting rhizobacteria (PGPRs) and arbuscular mycorrhizal fungi (AMF) has the potential to enhance plant growth under abiotic stress conditions and to avoid soil degradation at the same time. This kind of plant-microbe interaction is based on biological processes and has the potential to change conventional agricultural practices to a vital and sustainable agriculture. In such a world, microbes take over an important role as an ecological actor to resolve environmental stress problems. Another natural way to enhance plant growth and marginal land use is in planting different species simultaneously at the same space (intercropping), as, e.g., intercropping of legumes and cereals. Highly promising are techniques where plants with different root systems are grown together, which do not compete for the same space in the soil. The different abilities of intercropping plant species to use ephemeral or permanent water sources strongly affect physiological performance and species coexistence in water-limited ecosystems. Therefore, the present chapter highlights the various techniques to counteract crop loss in marginal soil and explore various beneficial biofertilizers and their modes of action in terms of abiotic stress tolerance and reduction to enhance agricultural production in a sustainable way.