Seaweeds: Soil Health Boosters for Sustainable Agriculture

Abstract

Healthy soil is a key component to growing high quality crops, and it is essential that we manage our soils well. This would be majorly possible with intensive inputs of fertilizers, and irrigation as well as integrated soil management. Fertilization of soil with chemical-based inputs which has been practiced by farmers since several decades, has challenged the very existence of humankind. Intensive eco-friendly fertilization of soil is, therefore, a major challenge in face of synthetic fertilizers opening up the pandora box of environmental degradation and health hazards. Climate change, loss of biodiversity, and urbanization have also emerged as serious challenges to farmers. New innovations in fertilizer options for soil management need to be worked out. To lift agricultural productivity and food supply, fertilizer availability and affordability is prime concern of both farmers and stakeholders. Better still would be to adopt an integrated approach to soil management. It would not only address issues of environmental quality and land degradation but would potentially improve agricultural production and crop quality. Macro algae commonly referred to as seaweeds have fast emerged as promising candidates in soil management practices and “green” agriculture. Besides eliciting a growth-promoting effect on plants, seaweeds also affect the physical, chemical, and biological properties of soil which in turn influence plant growth. Seaweeds in fresh and dried form and seaweed concentrates enhance soil health by improving moisture-holding capacity and by promoting the growth of beneficial soil microbes, besides fertilizing it. Seaweeds offer a wide spectrum agri inputs in the form of biofertilizers, soil conditioners, amendments, enhancers and biostimulants. Seaweeds are preferred because of the high amounts of macronutrients, micronutrients, vitamins, amino acids, and growth regulators, e.g., auxins, cytokinins, and gibberellins, they contain besides phycocolloids of great commercial value. Seaweed extracts are known to enhance seed germination, increase root and plant growth, yield, protein and quality, increase resistance to insects and diseases, resistance to drought and frost and increase shelf life. They are one of the best soil supplements which improve tilth and other properties of soil. Macro algal effectiveness is due to the fact that it fulfils the basic needs of both—the soil and the plants, and can efficiently alter the physical and chemical properties of soil. The potential of seaweeds as biofertilizers, biostimulants, soil conditioners, and soil additives for soil health is discussed in this chapter.