eChapters

Cryptosporidiosis is a protozoan disease.

Species

1. C. meleagridis: Infects small intestine.
2. C. baileyi: Infects digestive tract (bursa of Fabricius and cloaca), kidneys and respiratory tract.

Histomoniasis is a protozoan disease.

Etiology

Histomonas meleagridis.

Hosts

Mainly disease of turkey but has also been reported in chickens, peafowl, grouse, quail and gallinaceous birds.

Etiological Agent

Trichomonas gallinae, a flagellate protozoan. Strains vary in pathogenicity. The disease continues to be of significance in pigeons and doves. It has also been reported in raptors.

Introduction

Chickens are considered one of the most important hosts in the epidemiology of Toxoplasma gondii infection because they are an efficient source of infection for cats that excrete the environmentally resistant oocysts and because humans may become infected with this parasite after eating undercooked infected chicken meat.

Poultry meat is an important part of cuisine, consumed widely all over the world; therefore, consumption of uncooked or not properly cooked poultry meat may pose a risk factor for T. gondii infection in humans or animals.

Introduction

A. Common species of nematodes encountered in poultry are:

1. Syngamous trachea (in the respiratory tract) large 2.00cm size live in the trachea and larger bronchi. Many species of domestic and wild birds are affected. Dyspnea, gasping and head shaking are main clinical signs. Treatment is difficult.
2. Ascaridia galli (in the intestine) They parasitize chicken, turkey, pigeon, quail and guineas. In younger birds parasites cause enteritis. In heavily infected birds clinical signs are emaciation and diarrhea.

Introduction

1. Various genera of tapeworms are found in poultry. They are:
   1. Raillietina spp.
   2. Choanotaenia spp.
   3. Davainea spp.
   4. Amebotaenia spp. and
   5. Hymenolepis spp.
2. Tapeworms mainly parasitise the small intestine. Tape worms deprive the bird of its nutrition and cause weight loss and decreased egg production.
3. Out of 3 species of Raillitina, Raillietina echinobothrida is one of the pathogenic species as it produces granuloma at its attachment site (nodular disease).
4. They all require intermediate host for their development.
5. Intermediate hosts are common houseflies, ants, beetles and grasshoppers, which makes control of tapeworms difficult.

HAEMOPROTEUS

Host

Infection with Haemoproteus species is host specific.

H. meleagridis – domestic poultry and pet birds

H. olumbae in pigeons

H. nettionis in waterfowl.

Pododermatitis or bumble foot has many causes including excess weight bearing from obesity or unequal weight bearing between the two feet as a result of lameness of one foot, causing less weight to be placed on that foot and more on the contralateral foot, or from abnormal abrasions of the plantar surface from inappropriate substrate (too sharp or rough, wire, etc.), decreased blood supply to the foot (sometimes from lack of exercise), trauma, or standing for prolonged periods of time, especially in ducks that are not provided with adequate swimming opportunities.

Bumble foot is commonly seen in waterfowl under one or more of the following conditions; obesity, hard substrate, lack of access to water to swim in, malnutrition and underlying disease.

This is localized infection of the feet. It is seen as bulbous swelling of the footpad and surrounding tissues. It appears usually after an injury to the foot pad and causes lameness in one or both feet. Pododermatitis is divided into varying grades depending on the literature source used, but generally includes mild, moderate, and severe grades with the severe grades including osteomyelitis. Infection by various bacteria commonly occurs and superficial wounds may not be present. Sometimes ulcers are formed on the planter surface of the foot. The layers become lame and production lowers, sometimes completely stops. On opening the swelling a foul smelling thick pus is found. The condition is more common in heavy breeds. Early surgery and antibiotic therapy may control the condition. Removal of high roosts reduces the incidence.

Cage layer fatigue is a term used to describe leg weakness and acute deaths in chickens in cages, and is caused by inadequate calcium, phosphorus and Vitamin D levels in the blood stream. Calcium is required for muscle function, bone formation, and egg shell formation. This condition may be seen even in floor birds under certain conditions. It is seen most often in young hens early in production.

Introduction

Although the causative agent for the condition has not been identified, experimental studies indicate the association of parvovirus and or Astrovirus. Under experimental conditions, the virus induces clinical signs onlyin fast growing broiler chickens. The clinical signs, based on experimental inoculation of chickens, consist of watery or mucoid mustard yellow colour diarrhoea within 3-5 days after infection. Chickens become stunted, and a variable number of such chickens die during 10 and 20 days. Pronounced weight loss is in around four week’s age. The mortality is low (5 - 10%) however, the morbidity is very high (50 - 80%).

Introduction

1. The condition has been reported the world wide in growing broiler chickens.
2. The affected birds show clinical signs usually during 4 - 5 weeks of age. The clinically affected birds are smaller, listless with ruffled feathers, pale head and shrunken comb. Severely affected birds have distended abdomen, which restricts their normal movement. Death may occur suddenly, and not all the broilers which die of the condition have ascites. The incidence of the disease varies between 2 to 20%.

Introduction

Hypoglycemia Spiking mortality syndrome is a disease in broilers, characterized by low mortality with sudden onset of high mortality. The affected birds are clinically hypoglycemic.

There is no known aetiology.

The condition is characterized by proventriculitis and dilatation of proventriculus.

Etiology

The cause of transmissible viral proventriculitis (TVP) is a birnavirus referred as Chicken proventricular necrosis virus (CPNV). TVP is a disease of 3-8 week-old broiler.

Micropropagation through artificial seeds may be commercially exploited on a large scale, generating millions of plantlets within a few days, and this may become a profitable multibillion rupees industry in near future. This technology would be feasible and even competitive economically with the other seed production methods.

In the near future, the synthetic seed technology could be the key to overcome these problems, e.g., through automated procedures of artificial seed production (Aitken-Christie et al. 1995) followed by autotrophic micropropagation (Jeong et al. 1995). The synthetic seed systems coupled with artificial intelligence and microcomputer systems like the most advanced robots, which can mimic the motions, and functions of living beings (i.e. automated encapsulations). It would tremendously increase the efficiency of encapsulation and production of artificial seeds, and revolutionized the plant propagation method in the years ahead. This technology is gradually moving towards the commercial propagation of high value crops. However, there is a great need for refinement of this technology by tackling of certain technical problems such as the need to produce high quality and high fidelity somatic embryos and to avoid the genetic instability and variability of tissue culture derived plants. The somatic variation can be overcome if the process and regulation of somatic embryogenesis and origin of somaclonal variation are well understood. The understanding about the storage, transport, handling growth habit and harvest index of artificial seeds is essential. The efforts are also needed to increase the output of embryos or plants per gram of callus tissue and conversion frequency of artificial seeds are also needed.

Principle

Polyethylene glycol (PEG) is a high molecular weight compound which is inert to rumen fermentation. The concentration in the rumen liquor declines with the passage of digesta from rumen to lower G.I. tract and is proportional to time. Protein free filtrate of rumen liquor gives turbidity in the presence of trichloro acetic acid and barium chloride which is a measure of PEG concentration at different post feeding hours.

Various products of karanj (Pongamia glabra) are utilized for industrial, health and animal agricultural application in the Indian subcontinent. Despite a rich source of protein (CP 28 —34 %), karanj (honge) cake is found to be slightly bitter in taste and toxic owing to the presence of furanoflavonoid (Karanjin), restricting its safe inclusion in the livestock diets. Though a non polar solvent, soxhlet extraction of karanj seed cake with petroleum ether/ acetone drastically reduces karanjin content. The residual cake left after solvent extraction is proved to be safe as animal feed supplement.

Estimation of karanjin

The samples can be analysed for the toxin, karanjin as per the method of Prabhu et al. (2002).

Extraction of Karanjin from Raw and Processed Cake

Exactly 25 gm of ground and thoroughly mixed sample is weighed and transferred into the thimble and extracted for 12h using 200ml of freshly distilled methanol as solvent. Methanol extract is then cooled and filtered into preweighted round bottom flask using Whatman No.1 filter paper.The excess methanol is distilled off under vacuum. The flask containing the extract is weighed again to obtain the weight of extract by subtracting the empty flask’s weight. Sufficient amount of moisture free extract is transferred into vials for further analysis.

Body condition scoring (BCS), although subjective in nature, is the only practical method of evaluation of body energy stores in dairy cows. The method of body condition scoring, originally proposed by Edmonson et al. (1987) and recommended by the NRC (2001) is described here. This method uses a 5 point scale, with BCS of 1 being extremely thin and a score of 5 being extremely fat. This system includes a combination of both visual appraisal and manual palpation on 8 separate body locations. Figure 1 shows the suggested BCS chart based on these locations. The assessor can score the cows using this chart with a fair accuracy, without much previous experience of scoring the cows. The scoring method is recommended for HF and Holstein crossbred cows.

Loss of BCS is expected during early lactation when a cow is mobilizing body fat in support of energy needs for lactation. Typical observed changes in BCS range from 0.5 to 1.0 condition score units during the first 60 days postpartum. A 1-unit decrease in BCS for a cow weighing 650 kg at calving (BCS 4) would provide 698 MCal of ME.That amount of ME is sufficient to support 564 kg of 4 per cent fat corrected milk.

When dealing with the evaluation of the feeds and calculating the requirements of energy and protein for ruminants, it becomes necessary to inter convert values among different systems and units. Since the accuracy of conversions/equivalents and formulae used for calculating the requirements vary with different systems/constants used, the conversion factors and formulae given here can be used only as guidelines for routine purposes in laboratory or farms in feed formulation.

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).

In India many medicinal plants traditionally used by tribal and other sources have been recorded by different authors, workers and researchers. Many plants that can cause symptomatic relief for various ailments have also been established. Attempts have been made by different scientists to ascertain the active principles behind the herbal cure of certain diseases. Ayurvedic preparations from plant sources have been developed in our country to certain extent. Many Homeopathic medicines have also been procured from plants and herbs. Scientific conferences in State, National and International levels are being held on Traditional Asian Medicines to ascertain the scientific truth behind them. Council of Scientific and Industrial Research, New Delhi, Regional Research Laboratory, Bhubaneswar and many other Institutes of our country are doing creditable work to isolate the composition of medicinal plants. Many useful compounds have been isolated from different medicinal flora and their efficiency has been established scientifically. Good numbers of Allopathic medicines prepared on the basis of herbal cures are flooding in the market in different trade marks. Still the country is to find preventive and curative medicines for Cancer, AIDS, Thalsamia and other such deadly diseases. Recent International Conference on Cancer held at New Delhi came out with a suggestion that certain flora could be explored for the possibility of treating cancer without side effects. When we are starting to realize the importance of flora for a healthy living and scientists are in search of drugs from the vegetation to irradicate diseases deforestation is reampant in our country. Our environment has been contaminated due to various types of pollutants from industries and other anthropogenic sources. At this juncture man has to maintain a balance to achieve harmony of both the factors for our better living. The tribal dweller who is considered as the ‘Maa in the forest’ has to be recognized first so far his knowledge in medicinal plants is concerned. After ascertaining the utility of medicinal plants they are to be protected, propagated both by Government and Public. Scientific experiments are to be carried out to establish the active principles behind the herbal drugs. Herbal gardens are to be instituted at different places by adopting modern biotechnological methods. There is a need to make joint efforts by the workers from the fields of Allopathic, Ayurved and Homeopathic, as a step towards “the irradication of diseases”. Such an inter-disciplinary work on medicinal plants may throw a new light for achieving success, in finding out medicines without side effect. In this context, Pharmacologists have to play a vital role while preparing the doses of drugs from plant sources.

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.

The defined endocrine glands include the pituitary gland, the pineal gland, the adrenal glands, the thyroid gland and the parathyroid glands. The organs which contain groups of endocrine cells include the pancreas, the testis, ovary and placenta. The Hassall's corpuscles of thymus secrete hormone which contributes to the maturation of T-lymphocytes. Hence the thymus can be considered as having an endocrine function.

Pituitary : Refer to Part II, Chapter 2

Thyroid gland : Refer to Part II, Chapter 2

Pineal gland (Epiphysis cerebri) : Develops as a dorsal neuro epithelial diverticulum of the caudal part of the roof of the diencephalon. After its formation the gland remains attached to the diencephalon by a stalk. The neuroepithelial cells differentiate into pinealocytes and glial cells. The developing gland is surrounded by a thin layer of piamater.

Principle

In this method the estimation of pentose sugar is carried out. Acid hydrolysis of RNA releases ribose (a pentose sugar) which in the presence of strong acid undergoes dehydration to yield furfural. Orcinol, in the presence of ferric chloride as a catalyst, reacts with furfural producing a green colored compound which can be quantitatively estimated at A_{665 nm}. DNA gives a limited positive reaction with Orcinol test.

Materials and Reagents

1. Spectrophotometer
2. Boiling water bath
3. 5% chloroform (HClO₄)
4. Standard RNA solution : Dissolve yeast RNA (500ìg/ml) in 5% HClO₄ . make different dilutions to obtain solutions containing 100 – 500ìg RNA/ml with 5% HClO₄ .
5. Orcinol reagent : Dissolve 100mg of ferric chloride (FeCl₃.6H₂O) in 100 ml of concentration HCl and then add 3.5 ml of 6% solution of Orcinol prepared in alcohol.

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.

The essential plant nutrients, or essential elements, are listed in the Table 41. It enumerates 16 chemical elements of which the essentiality for plant growth and reproduction has been established according to the criteria formulated by D.I. Arnon and P.R. Stout, 1939. This listing has existed since 1954 with chlorine as the latest addition (cited by Hopkins 1999).

These plant nutrients are classified into various groups:

1.    Major elements and trace elements : Of the 16 listed, 9 are major elements or macronutrients and 7 are trace elements or micronutrients. Major elements are those which are needed by plants for their growth and reproduction in relatively large amounts while trace elements are needed in smaller amounts compared to the former. The major elements are further sub classified into structural elements (carbon, oxygen and hydrogen), primary macronutrients (nitrogen, phosphorus and potassium), and secondary macronutrients (calcium, sulfur, and magnesium). Micronutrients are Zn, Cu, Mn, Fe, Mo4 and boron (Table 41).

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.