Jayanta K. Saha

Effect of distillery effluent on seed germination in some vegetable crops.

A laboratory experiment was conducted to study the effect of different concentrations (0%, 5%, 10%, 15%, 20%, 25%, 50%, 75% and 100%) of distillery effluent (raw spent wash) on seed germination (%), speed of germination, peak value and germination value in some vegetable crops: tomato, chilli, bottle gourd, cucumber and onion. The distillery effluent did not show any inhibitory effect on seed germination at low concentration except in tomato, but in onion the germination was significantly higher (84%) at 10% concentration as against 63% in the control. Irrespective of the crop species, at highest concentrations (75% and 100%), complete failure of germination was observed. The speed of germination, peak value and germination value also followed a similar trend. We found that a concentration of 5% was critical for seed germination in tomato and bottle gourd, and 25% in the rest of the crops. Based on the tolerance to distillery effluent, the crops studied have been arranged in the following order: cucumber > chilli > onion > bottle gourd > tomato. We conclude that the effect of the distillery effluent is crop-specific and due care should be taken before using the distillery effluent for pre-sowing irrigation purposes.

Relationship between C addition and storage in a Vertisol under soybean-wheat cropping system in sub-tropical central India

Kinetic relationship between addition of organic carbon (through unharvested crop biomass and externally applied farmyard manure) and storage in a Vertisol (Typic Haplustert) was studied in a seven-year soybean-wheat rotation experiment. We investigated 16 treatments comprised of combinations of four annual rates of farmyard manure (0, 4, 8 and 16 t ha—1 on dry weight basis) and four annual rates of fertilizer N (0, 72.5, 145, and 230 kg N ha—1). Average annual contribution of C input from soybean was 21.65% and from wheat was 32.32% of the harvestable above ground biomass. Net increases in the contents of soil organic C (Corg) at 0—15 and 15—30 cm depth were observed in all treatments. The annual rate of Corg enrichments ranged from 85 to 739 kg C ha—1 at 0—15 cm and 54 to 149 kg C ha—1 at 15—30 cm soil depth. The observed annual rate of change in Corg (δCs/δt, kg C ha—1 yr—1) at 0-30 cm was positively correlated with the gross annual C input (A, kg C ha—1 yr—1) to the 0—30 cm soil horizon, as described by a linear equation (δCs/δt = 0.1806 × A — 160.34; r = 0.978, P < 0.01). This indicates that 18.06% of the annual gross C input was incorporated in soil organic matter.

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.

Cadmium Phytotoxicity in Spinach with or without Spent Wash in a Vertisol

Abstract The phytotoxicity due to cadmium (Cd) and its likely contamination of the food chain—resulting from its addition from low to very high levels to a swell‐shrink clayey soil (Haplustert) in spinach (Spinacia oleracea L.)—was studied in a pot culture experiment. Twelve levels of Cd (0, 2, 4, 8, 10, 20, 40, 60, 80, 120, 160, 200 mg kg−1 soil) were applied singly and in combination with two doses (0 and 2.5 cm) of spent wash. Above 80 mg Cd kg−1 soil, there was very slow growth of spinach after germination. Spinach crop suffering from severe Cd toxicity had small roots and narrow yellowish leaves, covered in small necrotic spots. Higher levels of Cd inhibited the growth and biomass of the crop. However, application of spent wash alleviated the toxic effect of Cd to some extent. The concentration of Cd in plant parts increased when Cd was applied singly but decreased considerably when used in combination with spent wash. Cd concentration in spinach root ranged from traces (control) to 120 mg kg−1 dry matter and was directly related to soil Cd concentration. At 40 mg kg−1 soil, yield of spinach was reduced to 38% of control plants. A laboratory study was also conducted in the soils collected from treated pots after harvest in order to know the different operationally defined fractions of Cd that control the availability of Cd to spinach and that were correlated with dry‐matter yield of spinach crop.

Sulfur accumulation in Vertisols due to continuous gypsum application for six years and its effect on yield and biochemical constituents of soybean (Glycine Max L. Merrill)

Application of S through inorganic sources is recommended to the crops in the cropping system in S deficient soils of India. However, transformations of S in the soil profile following continuous gypsum application are not known. The accumulation of S into different fractions due to application of a total of 180—540 kg S ha—1 over a six-year-period in soybean — wheat cropping system and its effect on the yield and quality of soybean produce were investigated in a vertisol area. About 25—38% of the S added was retained in the 90 cm depth of profile. Significant changes in the total S content in soil layers were recorded wherein a total of 360 kg S ha—1 or more S was applied. Maximum increase in total S content was recorded in upper layers. Soluble S accumulated more in the 30—75 cm depth; whereas, proportion of sorbed fraction of S increased with depth. Build up of S in the surface layer of the profile was mostly related to the increase in organic fraction. The S accumulation in lower layers of the profile was mostly due to increase in soluble and sorbed fractions of S. Such an increase of the S content in the soil caused an increase in seed yield, uptake of S as well as content of oil and S containing amino acids, cystine, and methionine in seed of soybean crop. Schwefelakkumulation in Vertisolen infolge sechsjahriger Gipsapplikation und Einflusse auf Ertrag und biochemische Bestandteile von Soja (Glycine Max L. Merrill) In Boden mit Schwefel (S)-Mangel in Indien wird eine mineralische S-Dungung der Pflanzen empfohlen. Die Umsetzungen des S in Bodenprofilen nach Gipsapplikation sind nicht bekannt. Die Tiefenverteilung von S-Fraktionen nach einer Dungung von insgesamt 180—540 kg S ha—1 zu einer Soja-Weizen-Fruchtfolge wurde in Vertisol-Profilen untersucht. Etwa 25—38% des zugefuhrten S verblieben in den Bodenprofilen bis 90 cm Tiefe. Signifikante Anderungen der Gesamt-S-Gehalte wurden erst ab Zufuhren von 360 kg S ha—1 nachgewiesen. In den obersten Bodenschichten stiegen die Gesamt-S-Gehalte am starksten an. Diese Anreicherungen waren insbesondere durch Erhohungen der Gehalte an organisch gebundenem S verursacht. Loslicher S wurde besonders in 30—75 cm Profiltiefe angereichert. Die Anteile an sorbiertem S stiegen mit zunehmender Profiltiefe. Erhohte S-Gehalte in den unteren Profilteilen waren vor allem auf die losliche und sorbierte Fraktion des S zuruckzufuhren. Die erhohten S-Gehalte der Boden bedingten hohere Ertrage, S-Aufnahme, Olgehalte und Gehalte der S-haltigen Aminosauren Cystin und Methionin in den Sojabohnen.

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.

Comparison between fertilizers and untreated sewage effluent as sources for nutrient recovery by wheat (Triticum aestivum)-soybean (Glycine max) cropping system

ABSTRACT Recovery and recycling of plant nutrients from municipal sewage effluent (SE) can reduce consumption of costly chemical fertilizers, besides reducing eutrophication of water bodies. Field experiment was conducted on Vertisol of central India for six years with the objective of quantifying recovery of major plant nutrients by aboveground biomass of wheat-soybean cropping system from untreated SE. Wheat crop was grown with irrigation (groundwater and sewage effluent) and fertilizer treatments; while soybean was grown without any treatments. Recoveries of nitrogen (N), phosphorus P) and potassium (K) by the aboveground biomass were considerably more from SE than from fertilizers and manures. Recovery of nutrients from SE was the highest by wheat grain for N and by soybean straw for P and K. Straw biomass of both the crops recovered about 31% N, 22% P and 69% K from SE, which can be recycled back into agricultural land of groundwater (GW) irrigated as well as rainfed area.

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.