eChapters

14.1. PPVFR Act

TRIPS (Trade Related Aspects of Intellectual Property Rights) agreement of WTO (World Trade Organization) was signed.

Enacted PPVFR act in 2001.

Regulation formulated in 2003.

13.1. Germplasm

Also known as genetic resources or gene pool or genetic stock.

Sum total of hereditary material i.e. all the allele of various genes, present in a crop species and its wild relatives

12.1. Variety release

Superior cultivars are to be purified by breeder and tested for genuiness in 7 generations.

Then, they are forwarded to MLT after RYT, RRYT, PYT and CYT in respective research station.

Based on results of the MLT, strain is forwarded to Adaptive Research Trials (ART).

Crop production is challenged by abiotic and biotic stresses results in low yield and high production costs.

Magnitude and intensity of stresses are increasing dramatically due to climate change causing recurrent droughts, increased temperature (heat) and emergence of new diseases and pests.

10.1. Heterosis

Occurrence of a genetically superior offspring from mixing the genes of its parents.

Superiority of F₁ hybrids over its both parents in terms of yield and vigour.

9.1. Molecular breeding and marker assisted selection

Using conventional breeding, developing new varieties takes atleast 15-20 years.

Molecular breeding shortened the time to 7-10 years.

One of the tools for faster variety development is Marker Assisted Selection (MAS).

MAS-refers to use of DNA markers to assist phenotypic screening.

Plants that possess particular genes or quantitative trait loci (QTL) may be identified based on their genotype rather than their phenotype.

Refers to induced chromosome manipulation

Aneuploidy-One or few chromosomes extra or missing from 2n.

Autoploidy-Genomes identical with each other.

Refers to entire operation of the induction and isolation of mutants.

Term mutation was introduced by Hugo de vries in 1900 in connection with sudden heritable changes observed by him in Oenothera.

Done for both biotic and abiotic stresses.

Biotic stresses are disease and insect pests.

Abiotic stresses are drought, salt, flood, heat, cold, etc.

Aim

To estimate the soil loss using universal soil loss equation

Universal soil loss equation

Wischmeir and Smith (1962) has been developed a predictive equation for estimating the soil loss taking into account following factors: Climatic characteristics, soil characteristics, crop management and conservation practices. It is called Universal soil-loss equation (USLE).

Aim

To design bench terrace

1. Components of bench terrace

The bench terrace essentially consists of the four components namely: riser, outlet channel, platform and shoulder bund

Aim

To design a graded bunds

The procedure in design of contour bund is followed while design a graded bund. A stability of 10-25%, should be given to contour bund. This is called graded bund.

Example: Design a graded bund length of 500 m with an average land slope of 3.5% in a sandy loam soil. Vertical distance between consecutive bund is 2.5 m. Rainfall intensity for the time of concentration and for the recurrence interval is 18.5 cm/hr. The runoff coefficient is 0.3. For stability, the grade provided for first 100 m is 0.1%, for next 200 m is 0.15% and for last 200 m is 0.18%. For the sandy loam soil, side slope of the bund and slope of seepage line are 1.5:1 and 5:1 respectively is assumed.

Aim

• To design the contour bunds

Design parameters

The design of contour bund includes determination of following parameters:

• Choice of bund
• Spacing of bunds
• Size of bund
• Alignment of bund

1. Choice of bund

The choice of bund should be selected weather the contour bund or graded bund depends on the annual rainfall, soil condition and types of outlets used.

Aim

To design the grassed water ways or open channel

Geometric characteristics of different waterways

The shape of open channel is dependent upon the field conditions and types of the construction equipments used.

The common shapes of open channels generally used are (i) Parabolic or semi circular (ii) Triangular (iii) Rectangular and (iv) Trapezoidal section.

The parabolic shape approximates a natural channel. The reason is that in natural course of channel flow, the trapezoidal and triangular sections tend to become in parabolic shape due to deposition of sediments and bank erosion.

Aim

To measure the irrigation water flowing through a pipe by using Venturimeter

Theory

A venturimeter is a device used to measure the rate of flow of a fluid through a pipe and is often fixed permanently at different sections of the pipeline to know the discharge there. Venturimeter consists of three parts: (i) a short converging part (ii) a throat (iii) a diverging part (Fig.62.1). In the venturimeter, the fluid is accelerated through a converging cone of angle 15-20° and the pressure difference between the upstream side of the cone and the throat is measured, and provides the signal for the rate of flow. Due to the constriction there is an increase in the flow velocity and hence an increase in the kinetic energy. The fluid slows down in a cone with smaller angle (5-7°) where most of the kinetic energy is converted back to pressure energy. Because of the cone and the gradual reduction in the area there is no “vena contracta”. The flow area is at minimum at the throat.

Aim

To measure the irrigation water by using parshall flume

Construction of Parshall flume

Parshall flume is a water measuring device that can be used to measure water flowing in an open channel and intended primarily for use in irrigation. The flume consists of a converging inlet section, a throat section with straight parallel sides, and a diverging outlet section (Fig.61.1). The floor of the converging section is level with walls which converge in the direction of flow, towards the throat. The throat section constitutes the middle portion of the Parshall flume. The floor of the throat section is dips downward in the direction of flow, but the walls are parallel. The throat width specifies the dimensions of the parshall flume. The diverging outlet section of the flume has a floor which rises in the direction of flow. The walls become further separated in the direction of flow (diverge).The parshall flume can be constructed by G.I. sheet, aluminum sheet, M.S. sheet, brick masonry, reinforced concrete or timber. Flumes made of G.I. or aluminum sheets are easily portable. Brick masonry and concrete flumes are permanently constructed in the channels. Stilling wells should be constructed at the side to take measurements.

Aim

To measure the irrigation water by using orifice

Orifices

An orifice is an opening in a bulk head with closed perimeter usually circular or rectangular cross-section through which water flows. For measurement of water, orifices are fabricated by making an accurate cut of proper size and shape in a mild steel sheet, aluminum plate etc. Proper machining is done to have a sharp edge through which water flows (Fig.60.1).

Free discharge

If the downstream water level is lower than the bottom of the orifice opening, the water jet discharges freely into the air and then it is said to be free discharge. The depth of water on the upstream side of the orifice that causes the flow is called the head. The orifice flow formulae can be applied only when the orifice flows fully.

Aim

To measure the irrigation water by using weirs

a) Weirs

A weir is a notch or opening of some definite shape installed on a channel or a stream through which waterfalls (Fig.59.1). Materials like wood, concrete, mild steel, rigid PVC etc. can be used for construction of a weir. Mainly a cut on a sheet metal is used for fabrication of weirs, to be installed at various locations in a channel. Advantages of weirs are (i) capable of accurately measuring a wide range of flows (ii) easy to construct, portable and adjustable (iii) tends to provide more accurate discharge rating than flumes and orifices.

Aim

To measure irrigation water by area-velocity method by using (i) float and (ii) current meter

Apparatus required

Float

Current meter

Theory

The rate of flow of water in open channel can be determined by multiplying the cross sectional area of the flow section at right angles to the direction of flow by the average velocity of water. In area-velocity method, the water can be measured at motion. The water is measured in motion by means of rate of flow or discharge and is expressed in litre per second (lps), litre per minute (lpm), cubic metre per second (m³/s), etc. Litre per second: A continuous flow amounting to 1 litre passing through a point each second. Cubic metre per second: A flow of water equivalent to a stream of 1 m long, 1 m wide and 1 m deep flowing at a velocity of 1 metre per second. In area-velocity method, the velocity of water is measured either by float or current-meter

Aim

To measure irrigation water by volumetric method

Apparatus required

Siphon tube

Stop watch

Measuring bucket

Aim

To determine the contours by radial line method using dumpy level.

Materials required

Dumpy level
Leveling staff
Measuring tape
Wooden pegs/chain pins
Field book

Aim

To determine the contours by cross-section method using dumpy level.

Materials required

Dumpy level

Leveling staff

Measuring tape

Wooden pegs/chain pins

Field book

Aim

To determine the contours by grid method using dumpy level.

Materials required

Dumpy level

Leveling staff

Measuring tape

Wooden pegs/chain pins

Field book

Aim

To prepare a contour map by direct method using dumpy level.

Materials required

Dumpy level

Leveling staff

Measuring tape

Wooden pegs/chain pins

Field book

Theory

For locating a point on the ground on a contour, its position and elevation in a horizontal plane should be known. In direct method, the contours to be plotted are located on the ground with a level by making various points on each contour, and these points are surveyed and plotted on plan. This method is more accurate but slow and tedious, and is suitable for contouring small areas where great accuracy is required. For locating the points of the same elevation, the instrument is set in such a commanding position from where maximum number of points can be covered. The bench mark is established near the site of survey. The height of the instrument (H.I) is determined after taking a back sight (B.S) on the established bench mark.

Aim

To determine the reduced levels on various points on the road

To plot the profile of the road

Materials required

Dumpy level

Levelling staff

Theory

Profile leveling is the process of leveling along a fixed line to determine the elevations of the ground surface along that line. The fixed line is generally the centre line of a highway, railway, canal, sewer, etc. The profile leveling is done to determine the undulations of the ground surface. Cross-sectioning is required to determine the levels across the line along which profile leveling is done. Profile leveling should be commenced from a bench mark and should end at a bench mark, as far as possible. When the ground surface does not have many undulations, the intermediate points are fixed at a uniform interval. If the ground surface is irregular and there are abrupt changes in the ground surface, the interval may be non-uniform.

Aim

To determine the reduced level of various points

To find out difference of elevations of two points

Materials required

Dumpy level

Levelling staff

Aim

To study the levelling instruments

To practice the simple leveling

Leveling

Leveling is a method of surveying used for determination of the difference of elevations or levels of various points on the surface of the earth. The elevation of a point is its vertical distance above or below a reference level, called datum. Most commonly used datum is the mean sea level (M.S.L). Leveling is required to determine the undulations of the earth’s surface for topographic mapping. Leveling is needed for the design of highways, railways, canals, sewers, etc. Leveling is essential for the layout of construction projects, locating the excavation levels and for the control of various elevations in buildings, bridges, dams etc. The results of the leveling can be used to determine the catchment area, volume of the reservoir and the area submerged by a reservoir.

Aim

To determine the area of given field by intersection method of plane table survey.

Materials required

Tripod

Plane table

Plumbing fork

Level tube

Magnetic compass

Alidade

Measuring tape

Ranging rods

Drawing sheet

Pins, pencil and eraser

Aim

To determine the area of given field by intersection method of plane table survey.

Materials required

Tripod

Plane table

Plumbing fork

Level tube

Magnetic compass

Alidade

Measuring tape

Ranging rods

Drawing sheet

Pins, pencil and eraser

Aim

Studies on plane table survey instruments

To determine the area of given open field by radiation method of plane table survey.

Plane table survey

Plane table surveying is a simple method of surveying for determination of area of field. The plane table survey is quite suitable for plotting small-scale and medium scale mappings directly in the field where great accuracy is not required. It is also used for plotting the topographical maps in the field. The plane table survey is generally more rapid and less costly than other types of survey.

In this survey, a plane table is used for taking the measurements and for plotting the plan in the field. Plane table surveying is a method in which the field observations and plotting of the plan proceed simultaneously. The plotted map can be compared with the actual features in the field. Errors in measurements and plotting can be easily detected in the field by taking suitable check lines.

Aim

To determine the area of the field by intersection method using a prismatic compass.

To determine the included angle of the closed polygon.

Materials required

Prismatic Compass

Tripod

Measuring tape

Arrows

Ranging Rods

Aim

To determine the area of the given field by radiation method using a prismatic compass.

Materials required

Prismatic Compass

Tripod

Measuring tape

Arrows

Ranging Rods

Aim

To identify different parts of prismatic compass and to know their functions.

To practice of taking the angular measurement.

Compass survey principle

Compass surveying is a branch of surveying in which directions of survey lines are determined with a compass and the lengths of the lines are measured with a chain or tape. In practice, the compass is generally used to run a traverse. In compass surveying, a traverse consists of a series of straight lines connected together to form an open or closed polygon as shown in Fig.44.1. The points A, B, C, D and E defining the ends of the traverse lines are called traverse station or traverse points. The lengths of the traverse lines are measured with a chain or tape. At each traverse station, where the traverse lines meet, the angle is measured with a compass.

Theory

Area computation is an important part of surveying. The term ‘Area’ is meant the projected area on a horizontal plane. The area is computed from the following methods: (i) Graphical method (ii) Instrumental method and (iii) Use of formulae. In graphical method, the area can be computed by dividing the whole area either into triangles or squares. The area of individual triangle is computed from base and the altitude and summation of individual area gives the total area. A tracing paper is divided into number of small squares is placed over the plan. The number of complete squares within the boundary is counted. The squares more than half are counted as full squares and those less than half are neglected. The total number of squares multiplied by the area of each square gives the total area of the field. In instrumental method, the planimeter is used to measure the area of a plotted plan. In use of formulae, computation of area by formulae depends on the shape of the field.

Aim

To find out the area of given field by cross-staff survey method

Materials required

Cross-staff

Metric chain

Measuring tape

Ranging rods

Chain pins

Aim

To determine the area of given field by triangulation method of chain survey

Materials required

Metric chain

Measuring tape

Ranging rods

Chain pins

Aim

To measure horizontal distance on the level ground using chain

Materials required

Chain

Ranging rods

Chain pins

Field note book

Aim

To study the different materials used for chain survey

Theory

Chain surveying is the method of land surveying in which only linear measurements are made. This method of surveying quit simple and it requires only a chain, a tape, few ranging rods and few arrows. It is used for securing data for exact description, marking the boundaries of land and preparing the maps of the area to show various details. The term details mean a natural or man-made feature at the ground surface.

Aim

To design of greenhouse cooling system

To determine the rate of air exchange in an active summer and winter cooling system.

Theory

Elevation factor (F_elev)

Elevation factor is directly proportional to the elevation. The values of elevation factors, used to correct the rate of air removal for a particular elevation. The rate of air removal from the greenhouse increase as the elevation of the greenhouse site increases.

Theory

Heat required for heating greenhouses is based on the quantity of heat lost through different structural components of greenhouses per unit time. Shapes of greenhouse (A-frame and quonset) and structural components (roof, wall, gable, curtain wall, curved covering and end) are mainly influencing the calculation of heat requirement. The amount of heat lost from a greenhouse depends on glazing materials, exposed surface area of the house, inside desired temperature, outside existing temperature, wind speed, and condition of house (old, new, tight or loose). The outside temperature should be based on the lowest average expected temperature during the heating season.

Greenhouse selection

Selection of greenhouse to be constructed is important as each type has its own merits and demerits. There are two common types of commercial greenhouses namely; (i) Freestanding (single span) and (ii) Ridge and furrow (gutter connected or multi-span). Multi-span structure permits economy in construction, heating and cooling but the single span gives flexibility as far as microclimate inside the greenhouse in concerned. The freestanding Quonset type is usually accommodates many growing situations but there height restrictions near the side walls. Another freestanding type is single gable greenhouse and its many variations. The ridge and furrow or gutter connected greenhouse are joined at the eave by a common gutter.

Aim

To determine cost of operation of processing machineries with available data.

Total operation cost

For calculation of cost of operation of processing machineries, two types of cost viz., fixed cost and variable cost to be estimated.

Description

Bucket elevator is one of the equipments used in the material handling to convey the material vertically. The lab model bucket elevator (Fig.34.1) consists of number of buckets/cups arranged to an endless flat belt. The belt with cups run vertically and cups are placed at a particular interval in the belt. The belt is wrapped over two pulleys, one at the top is called head pulley which receives power from an electrical motor 0.5 hp through suitable power concentration and rotates at required rpm. The belts, cups and pulleys are mounted on a steel frame. The grain from the hopper is reaches to the bottom pulley. The bucket is filled with grains during upward movement and is discharged at the top due to the centrifugal force. An outlet is provided at the top to collect the discharge grain. The capacity depends on the bucket size and seed of operation. For proper discharge of the material, the weight of the material in each cup should be equal to the centrifugal force created due to rotation.

Description

Screw conveyor is one of the equipment used in material handling to convey the material horizontally. The screw conveyor consists of screw blade, screw shaft, coupling, tubular trough, cover, inlet and outlet gates, bearings and drive mechanism. A shaft with spiral screw revolves in the tubular trough. The screw shaft is supported by end and hanger bearings. The rotation of screw pushes the grain along the trough. The pitch of a stranded screw which is the distance from the center of one thread to the center of the next thread is equal to its diameter

Aim

To design a belt conveying system

Theory

The design of belt conveying system is based on available space, horizontal conveying length, conveying lift, characteristics of the materials to be conveyed and capacity requirement.

On the basis of overall requirement and information, the belt width, belt speed, required horsepower, maximum belt tension and breaking strength of the belt, diameter of the pulleys and idlers and quantity of belt (thickness) are determined to design a belt conveyor (Fig.32.1).

Aim

To design a bucket elevator

Theory

The bucket elevator’s capacity mainly depends on bucket size, conveying speed, bucket design and spacing, the way of loading and unloading, the bucket and the characteristic of bulk material.

Bucket elevators with a belt carrier can be used at fairly speeds of 2.5 to 4 m/s. The speed of the belt depends on the head pulley.

If the belt speed is too low, the discharge of the grains become more difficult, with too high speed the buckets are not fed well.

Aim

To design a screw conveyor

Theory

The screw conveyor consists of screw blade, screw shaft, coupling, tubular trough, cover, inlet and outlet gates, bearings and drive mechanism.

A shaft with spiral screw revolves in the tubular trough. The screw shaft is supported by end and hanger bearings. The rotation of screw pushes the grain along the trough.

The screw blade or flight is a continuous one-piece helix, shaped from a flat strip of steel welded on to the shaft.

The screw shaft is usually a joint less tube with thick sides and a high tensile strength to reduce the weight.

Aim

To design shallow and deep bins

Theory

The structure behaves as a deep or shallow bin depending upon its relative dimensions such as depth and diameter or width. It is decided from the concept of the plane of rupture.

Plane of rupture: The plane of rupture is that surface down which a wedge of material bounded by one wall face, the free surface, and the plane of rupture would start sliding if bounding wall were to move.

Specifications

These structures are generally used for the storing grain in the bags. The length of the structure is about twice the width or greater than that. Special care should be taken to make the side walls, floor and roof in constructing the structure. The walls are made of bricks or stones laid either in lime mortar (1:2) or cement mortar (1:6). The thickness is restricted to a minimum of 37.5 cm or maximum of 45 cm. The height of the walls on which the trusses are placed is kept about 5.5 m. Each of the structures is provided with two large size doors of 2.4 × 2.4 m and top ventilators.

Rubber-roll Sheller consists of two rubber rolls rotating in opposite direction at different speeds. One of the roll is fixed while the other is adjustable to obtain desired clearance between them. The rolls are driven by mechanically. The adjustable roll normally runs about 25% slower than the fixed one. A feeder feeds paddy uniformly to the machine (Fig.27.1). Paddy is fed in thin layer through the clearance between two rubber rolls, rotating in opposite directions at different speed. Difference in speeds of the rolls develops a shearing force on grain surface results in the splitting, breaking and separating the husk from the grains. One part of the husk is subjected to shearing forces whereas the other part in contact with the slower roll is under compression and is thus subjected to breaking forces. Husking is done by the action of these forces. The clearance between them should be smaller than the mean thickness of paddy and may be adjusted subsequently by judging the shelling efficiency. If the gap between rolls is properly adjusted, it can shell up to 95% of paddy fed to it. At decreased gap excess pressure results more breakage of grain and can also cause coloring of shelled rice. During shelling the faster roll should have a peripheral speed of 10 -13 m/ s, while the slower roll 8-10 m/s.