eChapters

OBSERVATION

The examination of the IRS - 1A imagery under raw and the digitally enhanced modes vividly display heavy concentration of suspended sediments in certain sectors along the east coast of Tamil Nadu. Such pockets of suspended sediments are seen as long and linear bodies trending parallel to the coast to the strike length of 20 - 30 km and width of 5 - 10 km. Such Phenomenon of suspended sediments concentration are strikingly observed in two sectors. One in between Tuticorin harbour and Vaippar river mouth and the other just at the mouth of Ponnaiyar river along Cuddalore-Pondicherry coast. Both of them are observed along conspicuous (Fig.1& 2) concave coasts.

The role of plant nutrients in crop production is well established. Estimation of nutrients contents and forms in materials, which are involved in nutrient supply and dynamics is a crucial step in scientific nutrient management and crop production. There are 16 essential plant nutrients. These are carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), sulphur (S), zinc (Zn), manganese (Mn), copper (Cu), boron (B), molybdenum (Mo) and chlorine (Cl). These nutrients have to be available to the crops in quantities as required for a yield target. Any limiting or deficient nutrient (s) will limit crop growth.

Agriculture is the most important sector in India in terms of the population dependent on it. Although agriculture now accounts for on 14 per cent of GDP, it is still main source of livelihood for the majority of the rural population. Rapid growth of agriculture is critical for development of rural economy and viable development of rural economy will leads to overall development of country. Diversification in agriculture is need of the hour, any cropping system comprising crops with varied maturity period, crop canopy and high yielding potential is need for an average farmer. Again cropping systems depending upon the soil type, total rainfall and arrival of monsoon in the region. Low cost technology is essential for reducing financial burden on farmers and to increase production on sustainable manner.

Synthesis of Zn Oxide Nanoparticle

Aim

To synthesize Zn oxide nanoparticle

Introduction

Zinc oxide nanoparticle are effective anti-bacterial and antiodur agent. They can be synthesized by number of techniques including hydrothermal methods. Their synthesis using solvothermal process is described, (Aneesh et al., 2007).

Aim

To synthesize iron (III) oxide (Fe₂O₃) nanoparticles

Introduction

Iron oxide nanoparticles have a number of applications in catalysis, sensors and high sensitive biomolecular magnetic resonance imaging (MRI) for medical diagnosis and therapeutics. They can be synthesize by the bottom-up approaches including the sol-gel technique.

Aim

To synthesize silver (Ag) nanoparticle.

Introduction

The Ag nanoparticles easily interact with other particles and increases their antibacterial efficiency. The Ag nanoparticles can be synthesized using various methods: biological, chemical electrochemical, γ-radiation, photochemical, laser ablation etc (Udapudi et al., 2012). The most popular preparation of Ag colloids is chemical reduction of Ag salts by sodium borohydride or sodium citrate (Udapudi et al., 2012).

Introduction

Hydrogels are loosely cross-linked, highly hydrophilic, organic polymers. They can absorb and retain aqueous fluids up to 500 times of their own weight (Singh et al., 2011). In the field application, such absorbents exhibited a limited swelling capacity within the soil matrix.

Aim

To synthesize Zero valent (Fe) (nZVIs) iron using tea leaf extract.

Introduction

In this approach extracts of natural products (in most cases green tea leaves) with high antioxidant capacities are used. The compounds present in these extracts react with Fe (III) in solution to form nZVIs (Nadagouda et al., 2010).

Agronomy is a branch of applied science deals with the principles and practices of field crops production and management of soil for higher productivity. The term Agronomy is derived from Greek word agros meaning field and nomos meaning to manage.

Norman (1980) defined Agronomy as the science of manipulating the crop environmental complex with dual aims of improving Agricultural productivity and gaining a degree of understanding of the process involved.

In recent times, Agronomy has assumed newer dimensions and can be defined as ‘A branch of Agricultural science that deals with the methods which provide favourable environment to the crops for higher productivity’.

1.1. Soil Resource Evaluation

Soil is the essence of life on the planet Earth. It has sustained humanity and human civilizations through five functions (Karlen et al. 1997) viz., i) sustaining biological activity, diversity and productivity; ii) regulating and partitioning water and solute flow; iii) filtering, buffering, degrading, immobilizing and detoxifying organic and inorganic materials, including industrial and municipal byproducts and atmospheric decomposition; iv) storing and cycling nutrients and other elements within the earth’s biosphere; and v) providing support to socioeconomic structures and protection for archaeological treasures associated with human habitation. Reeling under the pressure of increasing food, fodder, feed, fibre and fuel production, soil has been used as a medium of plant growth with considerable reliance on external supply of major nutrients, irrigation water, plant protection chemicals, etc. Although soil, a product of millions of years of weathering, has supported various forms of terrestrial life, its sustainable management holds the key for meeting the basic requirements of burgeoning population and development commitments. So intense has been the pressure of increasing food, fodder, feed, fibre and fuel production that the soil has been exploited often exceeding its carrying capacity. The soils are increasingly used for agricultural and non-agricultural uses, such as disposal of farm, urban and industrial wastes, ensuring environmental safety etc. This is possible by the judicious use of this resource.

A clear and intimate knowledge of the kinds of soils and their extent of distribution are essential prerequisites in developing rational land use plans for agriculture, forestry, irrigation, drainage, etc. soil resource inventory or mapping provides an insight about their potentials and limitations. It is therefore imperative to prepare an inventory of this resource for developing optimum land use plan and conservation plans.

Particle density of soil is the ratio of mass and volume of soil solids. Particle density of soil is an important physical characteristic because the interrelationships of porosity, bulk density and air space, and rates of sedimentation of particles in fluids depend on particle density.

Principle

The determination of particle density (ρ_p) requires the measurement of mass of the solid and its volume. The mass is obtained by weighing the oven- dry soil sample and volume by calculating from the mass and density of water displaced by the sample in a pycnometer. The pycnometer is a glass flask with a ground glass stopper having a capillary opening. The particle density can be calculated using the following equation:

Bulk density to which a soil can be compacted is dependent on water content and force of compaction. Adsorbed water on soil particles acts as lubricant and every addition of water increases ease of compaction to progressively a greater density. However, this increase in density will occur only to a certain value of water content beyond that it decreases with further addition of water in soil. The moisture content at which maximum dry density is obtained for a limited and fixed effort is called as proctor moisture and the density at that point is known as maximum or proctor density”.

Principle

A soil at varying water contents, compacted with a specific amount of compaction energy, would result in a bulk density-water content relationship. The maximum bulk density obtained at the proctor water content represents 100 % compaction. The test can be performed in laboratory on various soils using Abbot’s compactor

Breaking of soil aggregates and dispersion followed by a rapid drying leads to rearrangement and coherence of soil solids in the form of surface crust. The cohesion exhibited by soil upon drying is directly related to surface crusting and clod formation. The formation of soil crusts and hard clods is a major structural feature of soils. Seedling emergence of cereal crops is generally controlled by point resistance around the shoot tip (Richards, 1953). Penetrometer, which measures the resistance to vertical penetration in soil, is an effective instrument to evaluate the crust strength. A relationship between penetration resistance and seedling emergence would serve as a guide to ensure optimum soil condition for a desired plant density.

Apparatus and Accessories

Penetrometer, moisture box, trowel, electronic balance and oven.

Over most of the wetness range in which plant roots normally function, all the water in soil is controlled by matric forces. A relationship between water content and matric or soil water suction is referred to as water characteristics of the soil. Increase in matric suction is associated with decrease in water content in the soil and the process is known as desorption. On the other hand with decrease in suction soil moisture content increases and this process is known as sorption. The curves showing relationship during progressive intake and withdrawal of water are known as sorption and desorption curves respectively.

Tensiometer is suitable for finding out soil water characteristic at tension values below 2.0 kPa, whereas gas phase pressure is required for higher tensions. A pressure chamber containing a porous membrane or a ceramic plate with all its accessories to provide regulated compressed air is most convenient. A detailed methodology to determine water characteristic curve by pressure plate apparatus is described below.

The ratio of soil air-to-soil water permeability indicates the magnitude of breakdown of structure as a result of wetting. A value of one indicates no change in structure and a value greater than one reflects a deterioration of soil structure.

Principle

The permeability of soil to air can be obtained essentially in the same way as the permeability of soil to water. The measurement of permeability of soil to air involves the preparation and placement of the soil in a suitable container with provision for monitoring pressure differential across the sample and the rate of flow of air through it. For steady state case, this involves measurement of inlet and outlet pressures and the volume flux of air. The suitable form of the Darcy’s equation for calculating permeability of soil to air is:

Particle density determination is based on the measurements of weight of solids and their volume. The weight of solids is obtained by weighing a sample of oven dried soil. The volume of solids is determined is determined by immersion. The method outlined here is “Pycnometer method”.

Principle

A given amount of dry soil when immerses in a definitive volume of water, expels air and results in the displacement of equal volume of water. The volume of soil particles is determined by measuring the volume of water displaced in the pycnometer bottle.

Purpose

The determination of water holding capacity in soils is important as it gives an idea of the capacity of soil to hold water for the use by crops. The light soils which do not hold such water require more frequent irrigations than heavy clay soils; well decomposed organic matter increases the water holding capacity. Exchangeable sodium and type of clay mineral also have a marked effect on water holding capacity. Water holding capacity of soils is useful for selection of soils for irrigability classification. It also helps for comparing other properties of soils.

Soil Organic Matter (SOM) is the seat of nitrogen in soil and its determination is often carried out as an index of nitrogen availability. The top soil (surface soil) range from 0.5% to 3.0% organic carbon for most upland soils and less than 0.5% are limited to desert soils. Soil organic matter averages about 58% carbon, it follows that soils generally range from about 2 to 6 % organic matter (% O.M. = %C x 1.724, The factor 1.724 = 100/58). There is also a close relationship between carbon and nitrogen in soils. Most organic matter average about 5% nitrogen so that the N: C ratio is 1:11.6. Therefore by multiplying the soil organic matter percentage by 0.05 an approximate value for the soil nitrogen, percentage is obtained. In soil the chief source of some of the nutrients essential for plant growth is organic matter, such nutrients are N, S and boron is also largely derived from organic matter.

The total potassium content (K) of a soil varies from 0.05 to 2.5%. The total K is distributed in mineral form (90-98%), fixed non-exchangeable (1-10%) and exchangeable plus water soluble K(1-2). Exchangeable K represents an average of 2-15% of the sum of exchangeable bases and 1-3% of the total capacity of cationic exchange.

Principle

It is based on the principle of the equilibrium of the soils with an exchangeable cation mode of the solution of neutral ammonium acetate, in a given soil:solution ratio. During the equilibrium, ammonium ions exchange with the exchangeable K ions of soil.The K content in the equilibrium solution is estimated with a flame photometer.

Carbonate is a natural constituent of many soils occurring as sparingly soluble, alkaline earth carbonate, chiefly as calcite and dolomite. Most carbonate minerals found in local soils are calcite and account 90% of total soil carbonates. The determination of total carbonate such as CaCO₃in soil is of great interest on account of high useful ess for diagnosing soil status in terms of structure, texture, biological activity or nutrient content. In calcareous soils carbonates exert a major influence on the chemical properties. Also carbonate content is used as a differentiating criterion for some classes at the family level of soil taxonomy.

Principle

A qualitative rapid test for free calcium carbonate is made by adding 10 mL of diluted HCl(1:3) to about 5 g of air dry soil on a watch glass and observing the intensity of effervescence which results from the evolution of CO Based on the . degree of effervescence the amount of calcium carbonate present in the soil can be broadly categorized into “traces or negligible, low, medium, high and very high”. Soils having traces to low amounts of calcium carbonate do not pose any problem. But those showing medium to very high degree of effervescence, a separate quantitative analysis should be carried out using Puri’s rapid titration method.

Principle

Carbonate (CO₃) and bicarbonate(HCO₃) ions are species of the same acid, carbonic acid. Their proportionate content is a function of pH. The CO₃ starts to form as pH rises above 8.4. Carbonate and bicarbonate are generally determined in soil saturation extract by titration with 0.01 N H₂SO₄ to pH 8.3 and 4.5, respectively.

Apparatus Required

Burette, pipette, conical flask and mechanical shaker etc

Soluble chloride (Cl) concentration in the extract is determined by silver nitrate titration. This method quantifies the concentration of Cl (meq/L) in the saturation paste extract. Chloride may be determined using anion selective electrode (potentiometric). Plant tolerance to Cl can be related to its concentration in the soil saturation paste extract. The method detection limit is approximately 0.1 meq/L, dependent on the method of analysis, and is generally reproducible within ± 10 %.

Apparatus Required

Burette, pipette, conical flask and mechanical shaker etc

Principle

Pesticide residues are extracted from soil using a mixture of acetone/water in a soxhlet apparatus for 7-8 hours. This extract can be determined directly by GLC.

Scope: This method is suitable for most OPs, OCs, SPs, and herbicides residue analysis.

Principle

Pesticide residues in milk are derived from the intake of pesticide contaminated feed and fodder.

Scope

This method is suitable for most OPs, OCs, SPs, and herbicides residue analysis.

Horticultural plants present a kaleidoscopic scenario from small herbs to very big deep rooted perennial trees. The associated rhizospheres present variable conditions as to supply of nutrients, water and air. The principles governing their physical, chemical and biological properties along with their relationship with plants need to be understood clearly. The plants differ in their requirements at various stages of growth; hence their tissues require constant monitoring of nutrient status for better productivity and quality. As nutrient behavior in soils is governed by soil properties and environmental conditions, measurement of such properties is often required. These include pH, salinity, organic matter, CaCO₃ and texture in drier areas the presence of Na and gypsum (CaSO₄2H₂O) is also of concern.The irrigation water is a source of dissolved salts which are also nutrients and in excess impede water and nutrient relations of soil and plant. It requires a thorough understanding of the principles underlying methods of collection, characterization of water, air and nutrient relations of soil-plant system, monitoring of plant nutrient status, quality of irrigation water and soil and water pollution for effective management of nutrients avoiding pollution.

Soil and plant analysis is a diagnostic instrument for soil fertility and basis for fertilizer recommendation; to know where and where not fertilizer is to be applied. Obtaining accurate and precise values has always being the basis of soil analysis.

Family : Amaranthaceae

Flowering : October-December

Fruiting : December-January

Botanical description

The plant is an erect, straggling or subscandant herb. The leaves are ovate, elliptic, obtuse, acute and finely attached to the stem on both sides. The flowers are greenish white in colour, bracteolate having membranous blade and seeds are reddish brown in colour, sub-cylindric at apex and rounded at the base.

Family : Amaryllidaceae

Flowering: December-January

Fruiting: January-February

Botanical description: It is a herb. The leaves of the plants are cylindric, fistular and look like tubes. Flower of the plant is white or greenish white with a short pedicel.

Ecology: The plant is commonly cultivated along the river banks during winter season. The plant loves to grow in sandy and loamy soil.

Use: Young leaves and shoots are collected, fried then eaten. The leaves and the flowering stalks are used for various preparations and curries.

Family : Amaryllidaceae

Flowering: November-December

Fruiting: January-February

Botanical description: The plant is a herb. The leaves of the plants are flat, linear with sheaths, about half of their length. Flower of the plant is white or greenish white with a short pedicel. The plant is having bulbs with membranous outer scales in the axils of which do exist 10-12 lesser bulbs.

English Name: Node Flower Allmaina

Family: Amaranthaceae

Flowering: May-June

Fruiting: June-July

Botanical description: The plant is an annual herb. It is erect and rising, 10-50 cm tall. Stem is branched from or near the base. The Leaves are obovate, oblong, or linear with 1.5-6.5 mm long and 0.3-2.5 cm wide. Flowers of the plant are greenish or orange-red in colour with 3-7-flowered cymes. Seeds are single, black and shining with 1.5-2 mm in diam.

Ecology: The plant is a common weed widely distributed in forests and cultivated lands.

Family: Amaranthaceae

Flowering: July-October

Fruiting: November-January

Botanical description: The plant is a perennial herb. The plant is a much branched prostrate herb, branches often purplish, frequently rooting at the lower nodes. The leaves are simple, opposite, somewhat fleshy, lanceolate, obtuse or subacute, glabrous and shortly petiolate. The flowers of the plant are small, white and in axillary clusters. Fruits are compressed obcordate utricles, with suborbicular seeds.

Family : Amaranthaceae

Flowering: Most part of the year

Fruiting: Year round

Botanical description: The plant is an evergreen creeper, herbaceous and perennial, growing up to 15 – 30 cm in height and spreading to form a growth mat about 45cm wide or more. Stems are prostrate or erect and moderately branched, hairless below, generally hairy above and in leaf-axils. The leaves are inverted-lanceolate or narrowly elliptic, acute at apex, narrowed at the base into a poorly defined petiole, mostly 2-6 cm long and 0.6-2.0 cm wide. Round or short-cylindrical flower heads lie stalkless in leaf axils, 5-10 mm long and 5-7 mm wide.

Use: Young leaves and shoots are collected, fried and eaten as green vegetables

Family: Amaranthaceae

Flowering: November-December

Fruiting: January-March

Botanical description: The plant is a herb, reaches heights of over 1 meter tall with fleshy oval shaped leaves that are sometimes pointed at the tips. It is having a deep maroon colour in the center of the leaf with streaks of red, purple and green. The plant produces feathery purple, magenta or red flowers from the central stalk which is packed with edible seeds. The flower buds are edible, once they mature and become bushy.

Ecology: The plant is commonly used as leafy vegetables and cultivated throughout the country. The plant loves to grow in the sandy soil in winter season. It is also cultivated in left over potato fields.

Use: Leaves and young shoots are cut into small pieces, cooked with salt and chilly and then eaten. Sometimes the leaves and shoots are mixed with vegetables in cooking.

Family: Amaranthaceae

Flowering: June-August

Fruiting: September-November

Botanical description: The plant is an annual erect herb that grows upto 1 meter in height. The stem is grooved and often redish. The leaves are long-petioled, ovate or elliptic, acute or subacute with base shortly cuneate to attenuate. The flowers are in axillary and terminal red or green panicled spikes with up to 20 cm long. Seeds are black in colour, shining and compressed or subspherical with thick margin.

Ecology: The plant being commonly used as leafy vegetables, is cultivated throughout the country. The plant loves to grow in soil rich with organic materials. The plant is commonly cultivated in summer and it grows luxuriantly in rainy season.

Family: Amaranthaceae

Flowering: June-August

Fruiting: September-December

Botanical description: The plant is an annual herb with sometimes red tinged erect stems, sometimes ascending, 30-150 cm long, usually branched. The leaves are ovate to rhombic- ovate, elliptic, lanceolate-oblong, or lanceolate, blades 1-12 cm long, 0.89-6 cm wide and smooth. The stem and its branches carry spines. Flowers of the plant are green, and are in axillary clusters in the lower part of the plant and in unbranched or branched spikes in the upper part. The lower clusters are entirely without stamens as the lower flowers of the spikes, the upper flowers in the spikes are staminate. Seeds are dark brown or black in colour.

Family: Amaranthaceae

Flowering: June-August

Fruiting: September-December

Botanical descripion: The plant is an erect tropical annual herb with long-stalked leaves, growing up to 5 ft tall. The leaves grow up to 5 inch long, are notched or rounded at the tips. The flowers are whitish-green or red white, the seeds are very small, shining, black or red- brown in colour.

Family: Amaranthaceae

Flowering: Throughout the year

Fruiting: Throughout the year

Botanical description: The plant is an annual herb with erect stems growing upto 10-80 cm in height. The leaves are triangular-ovate to narrowly rhombic, 2-7 cm long, 1.5-5.5 cm wide, hairless, with a narrow and small narrow notch. The flowers of the plant are green, in slender, paniculate spikes, in leaf axils or at the end of branches. Fruit is nearly round, about 1.3-1.5 mm in size.

Ecology: The plant is a fairly common weed on waste ground and roadsides and distributed throughout India. The plant is also cultivated during summer season.

Use: Leaves and young shoots are collected, roasted and eaten

Family: Acanthaceae

Flowering: September-December

Fruiting: January-April

Botanical description: The plant is an erect annual herb extremely bitter in taste (all parts of the plant). It grows erect to a height of 1-4 ft. with dark stem. The leaves are glabrous, lanceolate, pinnate, with 8.0 cm long and 2.5 cm broad. Flowers of the plant are small, white-purple or spotted purple in colour, spreading axillary and terminal racemes or panicles and acute at both ends. Seeds numerous, sub quadrate and yellowish brown in colour.

Family: Araceae

Flowering: July-August

Fruiting: November

Botanical description: The plant is a herb, growing about 90 cm in height. It produces 2 - 3 leaves, 5 - 30cm or more in size with a flowering stem 30 - 50cm long. Leaflets are lanceolate, acuminate and oblique, uniting in an intramarginal nerve. Fruiting head 5 cm long, ovoid, berries are initially green clustered fruits finally ripening to bright red.

Family: Meliaceae

Flowering: February-May

Fruiting: June-July

Botanical description: The plant is a tree. The leaf of the plant is about 20-38 cm in length, leaflets 5-9 pairs and obliquely lanceolate. Flower is white in colour and fragrant. The plant bark, leaves and flowers are bitter in taste.

Family: Poaceae

Flowering & Fruiting: The plant flowers after about 90-100 years. Flowering and fruting occurs in wet season

Botanical description: The plant is a perennial tree growing up to 20-53 m in height and 8-18 cm in diameter. There are 1-3 spines at each branch node. Leaves are thin, linear, up to 20 cm long, 1-1.8 cm wide with a long pointed tip. The branches of the plant spread out from the base and areal roots reaching up to nodes. The length of the internodes is about 15-46 cm and is hollow.

Ecology: It is cultivated and naturalized throughout India. Plant loves to grow in moist soils.

Family: Basillaceae

Flowering: May-September

Fruiting: October-February

Botanical description: The plant is a twining succulent herb with green stem and petioles. Leaves of the plant are broadly ovate and green to purplish in colour. Flowers are pinkish or purple in colour. Fruits are berries, ovoid or depressed-globose, turns black after ripening with deep purple juice.

Family: Caesalpiniaceae

Flowering: September-February

Fruiting: February-March

Botanical description: The plant is a moderate sized tree with ashy or dark brown bark. Leaves are often oblong, about 5-18cm, deeply lobed from one third way down to nearly the base with scarcely overlapping. Flowers are purple and large on terminal panicled racemes. Pods are 15-30×18-25 cm long, narrow below, somewhat broadening upwards.

Family: Caesalpiniaceae

Flowering: April-June

Fruiting: December-March

Botanical description: The plant is a climber growing up to 10-30 m long. The woody stem can get as thick as 20 cm. The spreading tout branches are covered with rusty fine hairs. The stout tendrils are coiling and occur in pairs. Large leaves are 10-45 cm, 2-lobed with a broad cut. The flowers are white, 2-3 cm across, turn yellow when old and borne in rounded clusters. Fruit is a flat woody pod with fine rusty hairs, 20-30 cm long.

Family: Caesalpiniaceae

Flowering: February-March

Fruiting: April-May

Botanical description: The plant is a moderate sized tree growing up to 20-40 ft tall and 10-20 ft wide with a spreading crown of briefly deciduous leaves which are 10-15 cm across and rounded with lobed ends and heart shaped bases. The leaves are shaped like a cow’s hoof. The flowers are white or purple in colour with one petal variegated yellow, 5-10 cm across and carried in clusters at the branch tips. The flowers often make their first appearance in late winter while the tree is bare of leaves. Seeds of the plant are sub-orbicular in shape.

Family: Cucurbitaceae

Flowering: October-November

Fruiting: December-January

Botanical description: The plant is a annual climbing herb, having stems up to 6 metres long that scramble over the ground or climb on other plants, supporting themselves by means of tendrils. Leaves are roundish, kidney-shaped, base deeply heart-shaped. Upper surface is rough, lower surface shortly bristly, 5-7-lobed, with long and hairy stalk. Tendrils are slender and rarely simple. Flowers are yellow in colour, calyx tube 10-15 mm long with spreading petals ending in a short point. Fruits large, succulent, densely hairy when young, with a thick waxy deposit when mature.

Family: Nyctaginaceae

Flowering & Fruiting: Most parts of the year, mostly dry winter season

Botanical description: The plant is a prostrate herb with diffuse inflorescences. The stem of the plant is glabrous or minutely pubescent and often purplish. The leaves are in unequal pairs, broadly ovate with obtuse or rounded apex. Flowers are very small, purplish red to reddish pink or nearly white, bell-shaped beyond the constriction.

Ecology: It is a common weed found near dry and warm river valleys; along roadsides, near habitations, in and along cultivated fields and in open cleared patches in forests. It is distributed throughout India.