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Measurement of water used in irrigation ensures the application of required amount of water in crops. Knowing the rate of flow the adjustment to period of control at gates, etc. can be done to regulate the water at different branches of canals. To get the total control over the supply of water there should have the provision of water measurement at the critical points in irrigation systems.

Units of Measurement

Water is measured at rest or in motion. The water of reservoir, ponds, tanks, etc. at rest is measured in volumetric unit as liter, cubic meter, hectare-meter and hectare-centimeter. Water flowing in rivers, canals, channel, etc. is measured in litre/sec , liter per hour, meter per sec and hectare-meter per hour or day.

Water Quantity and Measurement: The amount of water to be applied and its measurement are crucial aspects of irrigation management. There are various methods and tools used to measure and control the flow of water, including:
1. Parshall flume
2. Orifice
3. Weirs
4. Water meter
5. Float method
6. V-Notch
Methods of Soil Moisture Measurement
The measurement of soil moisture is essential to determine when to irrigate, the amount of water needed, to evaluate evapotranspiration, and to monitor soil matric potential. Soil moisture is measured in two ways: direct and indirect methods.
Direct Methods
1. Gravimetric method: The gravimetric method is a standard method for measuring soil water content directly. It involves collecting soil samples from the field and determining their moist and dry weights. The mass water content is then calculated as the ratio of the weight loss in drying to the dry weight of the soil sample. This method is accurate but time-consuming and requires laboratory equipment.
2. Spirit burning method: The spirit burning method is a direct method for measuring soil moisture in the field. Soil moisture is evaporated by adding alcohol and igniting it. The time taken for the soil to dry is then used to calculate the soil moisture content. This method is quick and easy but can be affected by soil temperature and organic matter content.

Measurement of water used in irrigation ensures the application of required amount of water in crops. Knowing the rate of flow the adjustment to period of control at gates, etc. can be done to regulate the water at different branches of canals. To get the total control over the supply of water there should have the provision of water measurement at the critical points in irrigation systems.

Units of Measurement

Water is measured at rest or in motion. The water of reservoir, ponds, tanks, etc. at rest is measured in volumetric unit as liter, cubic meter, hectare-meter and hectare-centimeter. Water flowing in rivers, canals, channel, etc. is measured in liter/s, liter per hour, meter per second and hectare-meter per hour or day.

Object: Measurement of leaf area by graph paper method.

Material required: leaves, graph paper and pencil or pen.

Leaf area is an important attribute in bio-productivity studies, as it bears an important and direct relationship to photosynthesis and transpiration. Leaf area is also important in determining the percentage of solar radiation intercepted by an individual plant or crop canopy. Photosynthesis centers on individual leaf. However, productivity depends not only on individual leaves but on stand of vegetation and canopy structure. The photosynthetic productivity of a canopy depends on both the amount of leaves present and the configuration of the leaves making up the canopy. Thus, leaf area has direct bearing on plant growth and final yield.

Aim: To know the actual length of a Thomas splint & measurement for an animal.

Procedure

Animal is kept in lateral recumbancy with affected limb upward.

After padding & medical bending of Thomas splint, it is fitted upon the fractured limb.

At the time of measurement, the limb should be kept vertical to body for accurate measurement, otherwise the length of Thomas splint may be shorteror longer if the limb is kept forward or backward respectively.

The ring of the Thomas splint is kept close to the axilla (forelimb), groin (hind limb).

Limb is put downward & Thomas splint is pushed upward keeping both the extension bamboo of Thomas splint in crossed manner, measurement of length of Thomas splint is taken up to the bulb of the heel & mark is recorded.

The excess length is trimmed short (figure-1). Two nicks are made on the distal end for retaining the thread in position.

Both the distal ends are tied together with thread, soft padding is placed at the site where hoof is to be kept & retained in position with bandage (figure-3).

Introduction

The major biogenic gases, which contribute to global warming, are carbon dioxide, methane and nitrous oxide. Out of these, methane is the most important gas because its thermal absorption is 30 times greater than carbon dioxide, though its atmospheric concentration is about 200 times less than carbon dioxide. Atmospheric measurements of greenhouse gases indicate that methane concentration had increased by 1 per cent annually to 1.7 ppm (by volume) during the last decade. The steady increase of atmospheric methane concentration in the past 200 years has attracted much attention.

Flooded rice soils provide an optimum environment for methane production and emission. Flooding a soil creates essential redox potential, anaerobic decomposition of organic matter and stabilizes the soil pH near neutral, thus makes the congenial environment for methane emission.

Rice is the world’s most important food crop

Introduction

The soil microbial biomass is an important component of the soil organic matter that regulates the transformation and storage of nutrients. It is a labile component of the soil organic fraction containing 1 to 3% of the soil carbon and up to 5% of the total soil N. The microbiologically mediated processes affect ecosystem functions associated with nutrient cycling, soil fertility, global C change and soil organic matter turnover. The size and activity of the soil microbial biomass must be assessed to fully understand nutrient flux in managed and natural ecosystems.

Soil microbial biomass estimations are useful in investigations that compare temporal nutrient fluctuations along natural and perturbed gradients. The effect of tillage, crop rotations and soil type on organic carbon and nutrient turnover can be assessed by following nutrient pools and activity associated with the soil microbial biomass.

Measurement of soil aeration

Oxygen Diffusion Rate (ODR) - the rate at which O₂ in soil air is replenished. ODR decreases with soil depth.

Measurement of ODR in soil

Lemon and Erickson (1952) devised a method for measuring oxygen diffusion in the soil system with the help of platinum micro electrode

Principle

When a certain potential is applied across the platinum electrode and a reference electrode inserted in the soil, oxygen is reduced at the platinum surface. The electric current flowing between two electrodes is proportional to the rate of oxygen reduction. The later, in turn, is related to the rate of oxygen diffusion to the electrode. The oxygen diffusion rate (ODR) is calculated from the measured electric current with the following equation.

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:

Introduction

Measurement of pH of a solution and preparation of different types/strength of buffers are common practices in a laboratory, particularly in the Biochemistry and Molecular Biology laboratories. Therefore, in this chapter you will be acquainted with the procedures of measuring pH of a solution as well as preparation of some of the commonly used buffers in a laboratory.

Potential or Power of Hydrogen Ion (pH)

Measurement of pH of a solution is measuring the molar concentration of hydrogen ion [H+] in the solution, which is an indication of the acidity or basicity of the solution. The symbol pH stands for “power of hydrogen” and numerical value for pH is just the negative logarithm of the molar concentration of hydrogen ions [H+]. The ionic product of water (Kw ) is the basis for the pH scale. The total hydrogen ion concentration from all the sources and it can be experimentally measured.

The pH scale designates the concentration of H+ (and thus of OH−) in an aqueous solution, which ranges between 1.0 M H+ and 1.0 M OH−. The term pH is defined by the expression

Thus, the ionic product of water makes it possible to calculate the concentration of H+, with given concentration of OH−, and vice versa. The value of 7 for pH of a neutral solution is not an arbitrarily chosen figure; it is derived from the absolute value of the ionic product of water. A solution having pH greater than 7 is basic, and the concentration of OH− is greater than that of H+. A solution having a pH less than 7 is acidic.

Introduction

Various organic orthophosphoric mono-and di-esters in soils are hydrolyzed when incubated with toluene-treated or irradiated soils, indicative of phosphatase activity. Assays have been identified, based on the rates of release of orthophosphate. Phosphatase activities of field soils showed little or no variation with season but were influenced by the cropping system and nature of the plant cover. Activities generally increased after the addition of inorganic and organic fertilizers to soils. However, inhibition of phosphatase by phosphatic fertilizers and by liming of soils (application of ca and Mg) has been reported. Phosphatase activities were directly related to the organic-P of soils but were not consistently related to available-P contents.

Phosphatases have been used to describe a broad group of enzymes that catalyze the hydrolysis of both esters and anhydrides. These are classified into five categories

Photosynthesis is an important physiological process associated with plant growth and productivity. During the process of photosynthesis, the solar energy is trapped and converted into chemical potential which is later used for the reduction of CO₂ into carbohydrates. The powerful reductant, NADPH that is needed for carbon reduction is generated by the light driven reactions of the chloroplast lamellar system. Photosynthesis can be summarized as follows.

Photosynthetically active radiation (PAR) is the radiation in the 400-700 nm wave band. For plants, 400-700 nm wave band of the light spectrum is very useful because of photosynthesis activity in this band. A simple integral relationship exists between the number of molecules changed photo-chemically and the photons absorbed within the requisite wave bands regardless of photon energy. Net photosynthesis rates are found to be almost linearly proportional to the radiation intercepted, which can be measured by line quantum sensor.

Pressure of air at a given place is the force exerted against a surface by continuous collision of gas molecules. Pressure may be defined as the force per unit surface area.

Rainfall is precipitation (falling of any type of condensed moisture to the ground) in the form of liquid drops larger than 0.5 mm in diameter falling on the earth surface. Ordinary rain drop size varies from 0.5-4.0 mm in diameter. Rainfall is measured in term of depth of rain water (millimeters) on a solid surface provided that rain water is neither allowed to percolate nor runoff or loss in any form.

In previous section, we discussed about the concept of the reliability and its importance. In this section, we will discuss about different types of reliability and procedures for estimation of the reliability. We already discussed that one cannot measure the reliability but of course it can be estimated.

Aim:- To know the measurement for preparation of an appropriate size of ring of Thomas splint for a large animal.

Objective: Measurement of an appropriate size Thomas splint essential to avoid complications like tight fitting which may affect bone healing.

Materials required: 6mm G.l. wire, jute thread

The moisture content is the amount of water in the seed and is usually expressed as a percentage. It can he expressed on either a wet weight basis (where it is expressed as a percentage of the fresh weight of the seed) or on a dry weight basis (where it is expressed as a percentage of the dry weight of the seed). The seed moisture content is the most vital parameter, which influence the seed quality and storage life of the seed. Seed moisture content is closely associated with several aspects of physiological seed quality. For example, it is related to seed maturity, optimum harvest time, mechanical damage, economics of artificial seed drying, seed longevity and insect & pathogen infestation.

Introduction
• A cell is the most basic structural and functional unit of life. These are of two types:
i) Prokaryotic cells– Prokaryotes are those cells which lack a membrane bound nucleus and other membrane bound cell organelles. These cells are primitive cells. Examples, bacterial cells, archaeal cells.
ii) Eukaryotic cells– Eukaryotes are those cells which have distinct membrane bound organelles. These are advanced cells. Example, animal cells, plant cells, fungi.
• A microorganisms (from the Greek: mikros, “small” and organism’s, “organism”) are those small living organisms which cannot be seen with naked eyes. These are of two types:
i) Single cell– Organism made up of a single cell.
ii) Multi-cellular– Organism made up of multiple cells.
Shape and Arrangement of Bacterial Cells
• Prokaryotes display following shapes
• Spherical cells called Cocci
• Cylinders called rods or Bacilli
• Coma shaped called Vibrio