Soil science is the scientific examination of soil as a natural asset found on the Earth's surface. It encompasses the study of soil formation, classification, and mapping, as well as the physical, chemical, biological, and fertility characteristics of soils. The former process primarily entails the physical fragmentation into smaller particles, whereas the later process is responsible for chemical degradation, eventually resulting in the creation of new substances. Soil serves as a foundation for plant roots, allowing them to stand upright. It also serves as a reservoir for water and nutrients, which are essential for plant growth. Furthermore, soil allows for the circulation of air, creating a favorable environment for the biological processes of soil organisms.
Soil science is a discipline of science that focuses on studying the different aspects of soil and its interactions with living and non-living entities. Therefore, Soil Science is a scientific discipline that focuses on the study of soil formation, mapping, classification, and the features of soil, including its physical, chemical, and biological characteristics. Soil is a complex and ever-changing natural substance that forms through the breakdown of rocks and the action of various processes. It is made up of both inorganic and organic materials, with distinct chemical, physical, mineralogical, and biological characteristics. Soil depth varies across the Earth's surface and serves as a vital medium for the growth of land plants. Soil is an important component of the pedosphere, which covers the earth's crust. The fundamental fields of soil science include edaphology and pedology, which deal with the physical, chemical, and biological characteristics of soil.
Various schemes for categorizing soils and soil materials have been developed, each serving distinct purposes. Among these, morpho-genetic systems with an agricultural implication, such as World Reference Base for Soil Resources (WRB) and Soil Taxonomy, have become widely accepted globally. This chapter delivers an outline of the fundamental principles of soil classification, focusing on Soil Taxonomy, WRB, and select national soil classifications (Australia, New Zealand, Brazil, and Canada). The WRB classification system was designed not to replace national taxonomies but to facilitate soil correlation internationally, enabling specialists from different countries to communicate more effectively. This chapter explores how these systems contribute to understanding soil diversity and supporting sustainable land management practices worldwide.
Regarding physical composition, soils consist of mineral and organic particles of different sizes. The particles form a matrix with roughly 50 percent pore space, which is filled with both water and air. This results in a tripartite system consisting of solids (mineral and organic matter), liquids (water), and gases (air). In essence, the physical properties of soils greatly impact all of their uses. Soil's physical properties are characteristics, processes, or reactions resulting from physical forces and can be explained using physical terms or equations. The physical properties of soil, such as texture, structure, density, porosity, consistency, colour, temperature, and water content, are connected to plant support, root penetration, drainage, permeability, aeration, moisture retention, and nutrient availability in soil. The chemical and biological characteristics of all soils are also affected by the physical properties of soil. The physical characteristics of soil are influenced by the quantity, dimensions, configuration, and mineral components of its particles. The amount of organic matter and pore spaces in soil also plays a role.
Soil which is considered as a finite and non-renewable resource, through its critical function supports numerous terrestrial forms. Soil quality and its management depend on the close relationship of soil, environment and society. Soil health represents the fertility of soil. A fertile soil is the one that produces ample crops under satisfactory environmental conditions. The word soil fertility is related to supply of nutrients and soil productivity is about the production or yield with the proper attainment of nutrients. Basically, the fertility of soil can be inherent or by the application of fertilizer and manure. The nutrients in soil i.e macro (N, P & K) and micro (Fe, Mn, Zn etc.) nutrients represent the fertility and under specific management when this nutrient gives ample production it is considered as crop productivity. The essentiality of nutrients for crop production is very much important as it effects the crop growth and development and deficiency causes a great loss in productivity. In this era where sustainability is major issue soil fertility should be managed properly and so as soil productivity, which is very much essential for development in agriculture sector, food production and agriculture sustainability.
In spite of modern agricultural advancements, soil nutrient depletion and food contamination hazards remain a critical challenge, necessitating sustainable solutions like integrated nutrient management (INM). This approach harmonizes the use of chemical fertilizers, organic amendments, and biofertilizers, ensuring a balanced nutrient supply and improving soil health over time. By incorporating crop residues, green manures, and the adoption of intercropping or crop rotation, INM fosters beneficial soil microbial activity, enhancing nutrient availability and uptake. This comprehensive strategy not only reduces dependency on synthetic fertilizers but also mitigates adverse environmental impacts such as soil degradation and water and air contamination. Recent studies highlight the effectiveness of INM in optimizing crop yields, improving nutrient use efficiency, and promoting agro-ecosystem resilience. As global food security concerns rise, adopting INM practices offers a viable path toward sustainable agriculture, emphasizing the critical need for integrated approaches in nutrient management to maintain agricultural productivity and environmental health.
Nutrient management involves the strategic management of nutrients and soil amendments to optimize economic benefits while minimizing environmental impacts. It focuses on factors like the right rate, timing, source, and placement of nutrients to enhance crop yields and quality while reducing off-site specific nutrient transport that can harm the environment. Key practices include selecting the appropriate fertilizer type, applying the correct amount at the right time and place.
Soil microbes are fundamental to soil health, fertility, and ecosystem functionality. These microorganisms, including bacteria, fungi, archaea, and protozoa, perform critical roles in nutrient cycling, organic matter decomposition, soil structure maintenance, and plant health. They facilitate the transformation and mobilization of essential nutrients such as nitrogen, phosphorus, and sulfur, enhancing plant nutrient availability and promoting growth. Soil microbes also contribute to the formation of soil aggregates, improving soil structure, water infiltration, and retention. Additionally, they play a pivotal role in carbon sequestration, aiding in climate change mitigation by stabilizing organic carbon in soil matrices. Understanding the diversity, functions, and interactions of soil microbes is essential for developing sustainable agricultural practices and managing soil health. This chapter highlights the vital contributions of soil microbes to ecosystem services and their benefits for soil management and environmental sustainability.
Soil is the prime global carbon (C) sink, contributing almost two-third of the carbon under terrestrial ecosystem. Soil organic carbon positively affects soil fertility and productivity, as it is an important resource that offers essential ecosystem services including food, fibre, habitats for biodiversity, climate regulation, water filtration and purification and human heritage. But, improper land management techniques, soil erosion and climate change have resulted in the loss of a significant quantity of SOC. However, appropriate management based on scientific data can not only prevent SOC loss but also restore additional SOC and directly solve major global concerns such as nutritional security, environmental sustainability and mitigating and adaption to climate change. Increasing SOC storage can greatly enhance our capacity to meet the objectives of numerous international and national policies, such as the UNCCD, FAO, and IPCC goals as well as the Sustainable Development Goals. To attain the stated aims of increasing SOC stocks, an efficient integrated solution that can combine existing national and intergovernmental policies is required. SOC is a crucial natural resource that is needed to achieve these objectives, which include improved soil health, sustainable agricultural practices and environmental services, as well as boosting soil carbon storage.
In recent decades, both inevitable natural activities and impetuous human activities have caused significant heavy metal contamination, resulting in immense human misery. Elevated levels of these heavy metals are detrimental to plants, animals, and humans, leading to the acute risk of bioaccumulation. This chapter explores various sources and fundamental chemical properties of heavy metals, the impact of contamination on the soil-plant system, critical contamination limits, and the effects of exposure on human health. It also discusses available management strategies, including soil amendments, phytoremediation, bioremediation, and future research directions such as soil washing. By considering these aspects, the chapter aims to offer a detail understanding of the issue and effective solutions for mitigating heavy metal contamination.
Micronutrients are essential for plant and animal health, influencing key physiological processes and overall productivity. Despite their presence in soils, availability to plants is often limited, leading to widespread deficiencies that impact agricultural yield and food security. Understanding and managing micronutrient availability in different soil types is critical for sustainable agriculture, improved crop yields, and ensuring nutritional adequacy. The transformation and mobility of micronutrients in soil are regulated by processes such as adsorption and desorption, complexation and chelation, redox reactions, microbial mediation, and the influence of soil pH. These processes determine nutrient availability, which in turn affects plant uptake, growth, and metabolic functions. Plant roots absorb micronutrients through mechanisms including passive diffusion, active transport, facilitated diffusion, chelation, and root exudates. Once absorbed, nutrients are transported into the plant's vascular system, where they undergo translocation, redistribution, and remobilization to maintain homeostasis and optimal nutrition. Each micronutrient plays a unique role in plant physiology. Iron is crucial for chlorophyll synthesis and enzyme activation, while manganese supports photosynthesis and antioxidant mechanisms. Zinc is essential for enzyme activity and DNA synthesis, copper aids in electron transport, and boron maintains cell wall structure and reproductive development. Molybdenum (Mo) facilitates nitrogen and sulfur metabolism and enhances stress tolerance. Recognizing the visual symptoms of micronutrient deficiencies is vital for timely intervention. Effective management strategies include optimizing soil pH, using organic amendments, applying micronutrient fertilizers strategically, and employing biofortification techniques. These practices ensure sustained nutrient availability, promoting crop health, productivity, and global nutrition security.
ISBN : 978-81-973154-9-7
