Keywords

1.1 Agriculture in Indian Economy

The economy of India is the seventh-largest in the world by nominal GDP with an average growth rate of approximately 7% over the last two decades. Sources contributing to Indian economy is normally categorized in three sectors—Agriculture (also includes livestock, forestry, fishing and related activities), Industry and Services. While contribution of agriculture and allied sector to GDP of the country was 51.81% in 1950–1951 at current prices, the same has declined gradually to 18.20% by the year 2013–2014 which is still higher than similar figures from most of the developed and developing countries (Table 1.1). Although contribution of agriculture & allied sector in Indian economy is smaller as compared to industry and service sector, it engages about 50% of the total workforce which is the highest among major developed and developing countries. This emphasizes the role of agriculture & allied sector in maintaining socioeconomic and sociopolitical stability of the country. Due to integrated efforts through genetic manipulation of crop varieties as well as nutrient, water and pest management during the last 30 years, India’s food grains production nearly doubled from 102 megatonne (Mt) in 1973 to nearly 200 Mt in 1999. In 2013–2014, India achieved a record food grains production of 264 Mt in spite of continuous shrink in cultivated area due to its diversion for non-agricultural use. However during the same period, Indian population increased by about 3.4 times and is projected to be growing at 1.25% rate (Economic Survey 2014–2015 of Union Budget, Government of India). The massive increase in population poses a challenge before the farmers and government to produce about 2.5 Mt of food grains extra each year; besides increasing supply of livestock, fish and horticultural products. Being a source of livelihood and food for a vast majority of low income, poor and vulnerable sections of society, performance of agriculture assumes greater significance in view of the government’s target for ensuring food security. In the last two 5-year plans, it has been clearly indicated that for the economy to grow at the rate of 9%, it is important that agriculture should grow at least by 4% per annum. In spite of the considerable emphasis given by government in the agriculture sector, productivities of most of the crops are considerably lower as compared to major countries of the world. This indicates that there is still a considerable scope of increasing per-unit-area productivity in the country, provided soil and water quality is maintained for achieving the targeted potential.

Table 1.1 Status of India agriculture and economy among the major countries in the world in 2014
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In this context, important issue that needs to be addressed is whether soil resources of the country are adequate to meet the food demands for rapidly increasing human population. Due to development of high yielding fertilizer responsive cultivars and increased use of fertilizer nutrients and agrochemicals in the post green revolution period in tandem with the enhanced availability of irrigation water, agriculture witnessed major transformation in terms of increased crop intensity and productivity per unit area during post 80s. However, sharply declining partial factor productivity (yield response per unit quantity of NPK applied) of fertilizer over the years (Fig. 1.1) has been attributed to rising concerns for decreasing profitability and unsustainability of Indian agriculture, which is also one of the major reasons for migration of human force from agriculture to other sectors and causing the former a more vulnerable sector of Indian economy.

Fig. 1.1
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Partial factor productivity of fertilizer NPK (Yadav et al. 1998)

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1.2 Role of Soil in Sustainability of Agriculture in India

An earlier estimate indicated that 89.5% of land area in the country was considered threatened due to human activity (Eswaran et al. 1999). In broader context of environment management, Wackernagel et al. (2002) defined sustainability as living within the regenerative capacity of the biosphere. Within micro-environment also, regenerative capacity of the soil contributes towards sustainability of agro-ecosystem. Thus, enhancement and maintenance of soil regenerative capacity is essential for the sustainability of agriculture and for meeting basic needs of rising population of country. Wackernagel et al. (2002) also indicated that human demands for goods and services have exceeded the biosphere regenerative capacity since the 1980s and quantified this analysis by suggesting that humanity’s load corresponded to 70% of the global biosphere in 1961 and this ballooned to 120% in 1999. Although quantitative estimate is not available, contribution of soil in agricultural production during pre-green revolution period was assumed to be higher than during later period when seed, water, fertilizers and agrochemicals played larger role (Yadav et al. 1998). As majority of essential nutrient elements are taken up by plant roots, quality of rhizospheric environment is important for higher fertilizer nutrient use efficiency and agricultural profitability. Optimum root proliferation, proper vertical air diffusion and absence of any adverse interactions among soil constituents are some of the soil criteria which determine rhizosphere quality for higher nutrient use efficiency. Beside several inappropriate agricultural management practices, excessive build-up of several elements/compounds has been attributed to declining soil quality in and around the root zone. Hence, resilience (i.e. regenerative capacity) of soil resources to the degrading forces is an emerging area of investigation due to emergence of such forces caused by increased anthropogenic activities.

1.3 Threat to Soil and Environment

India has been identified by World Conservation Monitoring Centre under UNEP in 1988 as one of the 17 megadiverse countries that harbor the majority of the Earth's species and high numbers of endemic species. Wide variation in climates, land topography, soil types are some of the major drivers responsible for such large biodiversity. Soil is by far the most biologically diverse part of Earth and has been evolved in the nature to perform several ecosystem services critical for life and performs as filter for water; acts as medium and nutrient reserve for plant growth; provides habitat for billions of organisms contributing to biodiversity; supplies most of the antibiotics used to fight diseases and regulates the Earth's temperature as well as many of the important greenhouse gases. However, with the progress of modern civilization, humans additionally use land as a dumping site for solid wastes, filter for wastewater, and foundation for our cities and towns. Except in forest ecosystem at far away from pollution activities, positive balances of heavy metals have been estimated during computation of trace elements budget (Kabata-Pendias and Pendias 1992). This is due to their higher rate of inputs through fertilizers, sludges, manures, residue recycling, atmospheric inputs etc. as compared to the removal through crop uptake and infiltrating water, which indicates gradual build-up of heavy metals in soils under agro-ecosystem.

In the quest of rapid growth in the national economy, India is increasingly pushing forth for rapid urbanization, industrialization and transportation; all of which are competing for agriculturally important natural resources like land and water. From 2001 to 2010, it was observed that each state lost about 1% of its total geographical area due to diversion of agricultural land for urban expansion and magnitude of such diversion has been increasing steadily (Pandey and Seto 2015). Large scale urbanization, industrialization and associated environmental alteration and their impact on soil quality pose a threat to biodiversity as evident from the extensive studies conducted at several developed countries. Although industry has several adverse impacts on agriculture, their influential & dependency relationship is many a times quite complex because of the unlimited human need. Different agricultural and industrial requirements and activities affecting environment and human life and their relationships are depicted below in Fig. 1.2.

Fig. 1.2
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Different agricultural and industrial requirements and activities affecting environment and human life and their relationships

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Above complex relationships among different economic and social sectors and associated activities indicate that most of the anthropogenic activities are essential for meeting expectations and need of increasing population and socio-economic development of the country; and any such developmental activities leaves irreparable damage to the environment including its natural resources. This is a transition period for many developing economies like India to strike a balance between industrial development and environmental protection so as to feed the bulging population adequately with quality food as well as to improve the comfort and quality of lifestyle. Although considerable researches are being conducted by different institutes under Indian Council of Agricultural Research as well as by State Agricultural Universities to address the issues of declining soil quality due to faulty agricultural practices, insufficient research efforts have been put to address the issue of soil and water pollution arising from high inputs of contaminated fertilizers, soil amendments and agro-chemicals. Although long-term fertilizer experiments at different agro-ecosystems across the country have conclusively indicated that integrated and balanced fertilizer management systems in crop production do not leave any adverse effect on soil quality (Swarup 1998), a study conducted by ICAR-Indian Institute of Soil Science indicated groundwater contamination with nitrate beyond permissible level at several places in high fertilizer using districts of the country (Biswas et al. 2013).

In the early Anthropocene, rural population dominated but in the last 70–80 years, urban centers expanded rapidly with higher concentrations of people. These urban centers and their encompassing ecosystems initiated a new set of environmental problems mostly related to land surface sealing, water use, waste management, and an insatiable appetite for food, fiber and energy needs. Widespread development of infrastructure such as housing, roads and railways have contributed to environmental degradation by changing the general hydrology and energy fluxes of the area. Apart from the threat of land consumption by non-agricultural activities like urbanization, transport and industrialization, soil contamination by different pollutants has become a major cause for deterioration of its health; and in the long run the polluted soil may not be fit to grow food which in turn may affect Indian economy directly or indirectly through reduction in raw material supply to industries and emergence of several socio-economic problems. Urbanization and industrialization exploited natural resources and damaged the environment through their activities at every phases and processes of operation. It is evident from several environmental tragedies that pollution from various sources particularly from industries and mining had negative impact on environment which was mostly irreversible in nature, and cause extinction of species resulting in loss of unique genetic resources of valuable use. In agro-ecosystem, soil pollution is caused by the presence of xenobiotic chemicals or other alteration in the natural soil environment by industrial activity, agricultural chemicals, or improper disposal of waste. The most common chemicals involved are petroleum hydrocarbons, aromatic hydrocarbons, pharmaceutical products, solvents, pesticides, lead, and other heavy metals. Impact of pollution on soil is quite alarming and introduction of these hazardous chemicals into the soil environment results in huge disturbances to the ecological balance of soil and injures health of living creatures on earth.

1.4 Addressing the Issue of Soil Pollution

To address issues related to land degradation, different countries have formulated action plan and strategies to identify and combat soil pollution for the purpose of protecting environment and organisms. United States Environmental Protection Agency has taken up ‘Superfund’ program for cleaning up of some of the nation’s most contaminated land and responding to anticipated environmental emergencies, oil spills and natural disasters. The European Commission has established a framework based on common principles and objectives to address the different facets of soil degradation, where member countries identified the issues and location of problems and devised their own strategies to address those problems. In India, attention has been given to protect environment from different types of pollution in the country through environmental laws and act like ‘Environment Protection Act, 1986’, as well as through awareness program and education. However, almost all the emphasis has been given to air and water pollution, probably due to higher mobility of toxicants towards organisms through these matrices. Unlike many developed countries, the information and awareness on pollution of land resource and it impact is lacking in the country. In most of the Environmental Impact Assessment (EIA) of different industrial/mining/infrastructural projects, impact on land resources and agroecosystems are largely ignored.

In India, information on extent of soil pollution, its impacts on other functional area, plant and human health is not complete. About 60% of the geographical area of the country is occupied by agricultural land, most of which is facing one or more kind degradation stresses. The data given by different agencies on soil degradation mainly focus on physical aspects of soil deterioration like erosion, waterlogging etc. and in case of chemical degradation not much attention was given except on soil salinity problems (Table 1.2).

Table 1.2 Degraded land areas of India
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In many developed countries like in North America and Western Europe, extent of contaminated land been estimated with many of these having a legal framework to identify and deal with the environmental problems. However, information on magnitude of different developmental activities like mining, industries, urbanization, transportation and others, and their impact on land/soil quality are meager in India. Instances of soil pollution or chemical degradation are cited to be very sporadic and region specific; and hence assessment of soil pollution, locating their sources and impact across the country is specifically required for devising suitable action plan for its protection and remediation. In India, each area is unique in respect of nature and extent of anthropogenic interventions, climate, land morphology, geology, hydrology and biodiversity. For precise EIA focusing land degradation or soil pollution, one needs to have comprehensive knowledge on the soil resources and its interaction with other environmental components as well as pollutants so that protective/remedial soil management can be planned effectively. To keep in view of the above, an attempt has been made to review the status of soil pollution in India under the background of ongoing anthropogenic activities with appropriate interpretation using scientific knowledges generated on the subject and to suggest future course of action.