Rajendiran Selladurai

Soil Pollution - An Emerging Threat to Agriculture

Agriculture has always remained backbone of economy and sociopolitical stability of low and middle income countries, and employs largest work force in India. Maintenance of soil quality has been pointed out as one of the major contributing factors for sustainability of agricultural production. Rising contribution of industry to India’s GDP has been speculated to cause adverse impact on the precious land resources; though the issue has received less attention among the policy makers. There is a complex relationship of Indian economy with industry and agriculture, both of which competing for same natural resources with differential impact on land resources. This chapter highlights the need for reviewing different developmental activities having direct or indirect impact on agricultural productivity and the need for accelarating soil research to investigate upon migration of pollutants from source of generation and their impact on soil so as to devise strategies for protection and remediation of precious non-renewable soil resources.

Effect of humic acid multinutrient fertilizers on yield and nutrient use efficiency of potato

ABSTRACT A field experiment was conducted to study the effect of humic acid multinutrient fertilizers like Grow Flow 45H and HA-NPK complex on crop yield, nutrient content and uptake, and nutrient use efficiency of potato. Application of Grow Flow 45H (humic acid multinutrient liquid fertilizer) at recommended dose increased the tuber yield by 9.3% as compared to chemical fertilizer. Nitrogen (N), phosphorus (P) and potassium (K) content of the Grow Flow 45H treated plants were 2.89, 0.33 and 1.58% in shoots and 1.89, 0.21 and 1.03% in tubers, respectively which were significantly higher than the other treatments. Grow Flow 45H increased the N, P and K use efficiencies by 16.4%, 9.3% and 18.3% respectively over chemical fertilizer. Though HA-NPK complex fertilizer (developed in the laboratory) was not significantly different from chemical fertilizer in respect of yield, the contents and uptake, and use efficiencies of N, P and K; however the former was found better than the latter.

Impacts of Soil Pollution and Their Assessment

Impact assessment of pollution is important step towards initiating appropriate remedial measures. However impact of soil pollution may not necessarily be uniform across the agro-ecological regions due to complex relationship among soil types, climate, crop types, nature and level of contamination as well as soil and crop management methodologies adopted. Moreover land resources are habitat of numerous organisms having varying degree of sensitivity towards contaminants. Hence, choosing right approach for assessing impact of pollution becomes important for satisfying various stakeholders affected by soil pollution. This chapter covers different types of impact of pollution on soil quality, economic yield of crop, food quality, biodiversity, fertilizer nutrient use efficiency, economy of the country etc. Pollution has already made adverse impacts on environment including soil in different countries. Widely cited instances of different types of pollution across the world and their impacts on soil and crop has also been discussed in this chapter.

Urban Activities in India Leading to Soil Pollution

Due to rapid growth in industry and service sectors, urbanization has seen phenomenon increase in many countries across the world with consequent rise in solid and liquid wastes. Per capita generation and nature of such urban wastes has been found highly related to level of economic activities of a country. Due to insufficient treatment facilities for these wastes, urbanization has been found polluting agricultural land considerably, particularly in lower and middle income countries. Unscientific processing of solid wastes as well as release of sewage effluents in environment and their use for benefit to crop production have been found an important route for contamination of agricultural land with toxic trace metals and organic pollutants. Safe and beneficial recycling of municipal solid wastes in agricultural land after appropriate processing and treatment is facing obstacles due to lack of appropriate quality and hazardousness of the end products. Widely prevalent marginal quality sewage water use for irrigation in agriculture in urban and peri-urban areas in developing countries like India has also been discussed in details through different perspectives like carbon sequestration, crop productivity, plant nutrient supply as well as risks from various pollutants and pathogens.

Remediation and Management of Polluted Sites

Soils perform several important ecosystem functions and therefore polluted land requires remediation and appropriate management for restoration of its life sustaining functions. Several technologies have been developed for their remediation based on clean-up, detoxification and risk minimization approaches. All of these technologies have both advantages and disadvantages in respect of the extent of applicability, side-effects on other components of environment, cost & ease of adoption, speed & effectiveness of remediation etc. While removal of contaminants and the risk minimization are the major approaches for heavy metal polluted soil, degradation to non toxic or less toxic compounds is the most common approach for soils polluted with organic pollutants. Plants, microorganisms, nanotechnology have also been used for remediation of polluted sites with varying degree of success. Waste products from agriculture, industries, city etc. have also exhibited their potential in minimizing risk from pollutants. Growers may minimize risks from polluted land through modification of soil, crop and nutrient managements. This chapter also discusses examples of a remediation approaches followed in case of different polluted sites worldwide.

Soil and Its Role in the Ecosystem

Soil is highly heterogeneous body in the terrestrial ecosystem that has evolved through thousands of years of natural processes and has remained habitat for enormous biodiversity. Due variability in seasonal temperature, rainfall, parent materials and vegetation, different types of soils have been found in India; and each of these soils have distinct mineralogical compositions, physical and chemical properties. Such heterogeneity has resulted wide variations in the response of soils to polluting activities which causes differential location specific impacts. To understand the interaction of pollutants with soil constituents and their impact on agroecosystems, basic knowledge on various aspects of soil resources and its functions are essential. This chapter describes in brief, the major soil types of India and their properties, role of soil constituents on its quality, different soil forming processes, inhabiting organisms and their role in different soil nutrient cycling processes affecting crop productivity.

Assessment of Heavy Metals Contamination in Soil

Several heavy metals are toxic to organisms including human and therefore their entry into food chain from polluted agricultural land is required to be controlled. Management and remedial measures of metal contaminated sites depend on the level and distribution of contamination. In view of high heterogeneity of soils in respect of heavy metals concentration, mere analysis of a sample may not confirm contamination due to polluting activities. This chapter describes various approaches for assessing heavy metals contamination of soil and expected degree of threat it may pose to the environment. Importance of baseline concentration in areas with high polluting activity is thoroughly discussed along with statistical significance. Degree of contamination and its threat has also been estimated by researchers through various models. Methods of assessment of risks to organisms due to heavy metals contamination in soil involving critical analysis of their translocation within plants and to human through various routes have also been described. Different countries have adopted regulatory limits to protect the land from contamination based on different approaches which resulted wide variations in their limiting values. Soil testing methods for rapid assessment of contaminated site has also been described in this chapter.

Agriculture, Soil and Environment

Agriculture has always remained backbone of economy and socio-political stability of low and middle income countries, and employs largest work force in India. Maintenance of soil quality has been pointed out as one of the major contributing factors for sustainability of agricultural production. Rising contribution of industry to Indias GDP has been speculated to cause adverse impact on the precious land resources; though the issue has received less attention among the policy makers. There is a complex relationship of Indian economy with industry and agriculture, both of which competing for same natural resources with differential impact on land resources. This chapter highlights the need for reviewing different developmental activities having direct or indirect impact on agricultural productivity and the need for accelarating soil research to investigate upon migration of pollutants from source of generation and their impact on soil so as to devise strategies for protection and remediation of precious non-renewable soil resources.

Impact of Different Developmental Projects on Soil Fertility

Soil fertility is highly important for countries where economy is dependent considerably on agriculture and animal husbandry. With the ambition of boosting economic growth many countries like India tap their vast mineral and human resources and expand industrial sector which also have considerable impact on soil fertility and agriculture. In order to have sustainable economy of a country, a harmony between industry and agriculture is highly essential. Though the cost involving protective and remedial measures appears to cut away the profit of industrial sector, these are extremely essential for shielding non-renewable soil resources which anchor the food producing agriculture sector. In order to formulate effective policies on protective and remedial measures, knowledge on the impact of different industries is required. This chapter reviews the research carried out worldwide to study the impact of major industries on soil quality and its consequences on quality of life including human. While some of the industries like thermal power plants, mining and associated ore beneficiation processes have direct impact on soil resources, other industries like textiles, paper & pulp, chemical & petrochemical, distillery etc. affect soil quality via polluted water used for irrigation.

Soil Protection Policy

Since independence, agriculture and food security has received considerable importance in policy documents of Planning Commission of Indian government. Although issue of land protection has been raised and addressed in the Five Yearly Plan documents, focus remained mainly on rational use of land by different sectors of economic activity and on prevention of soil erosion from agricultural land. Protection of land from chemicals & radionuclides pollution and prevention of toxic contaminants entry into soil have received less reference in environmental acts and rules as compared to that received by air and water pollution. Therefore, the need for soil protection policy has been felt by environmentalists that can regulate anthropogenic activities responsible for land pollution and put forward guidelines on remedial measures of already contaminated land. This chapter identifies key considerations for soil protection policy after analyzing basic functions of soil and types of threats perceived from human activities.