Farm Machinery and Power – FMP 211 PDF

FMP 211 - FARM MACHINERY AND POWER (1+1) THEORY Tillage - objectives - furrow terminology - methods of ploughing - field capacity and working out problems. Primary tillage implements - components and functions of indigenous ploughs - mould board, disc, ro...

FMP 211 - FARM MACHINERY AND POWER (1+1) THEORY Tillage - objectives - furrow terminology - methods of ploughing - field capacity and working out problems. Primary tillage implements - components and functions of indigenous ploughs - mould board, disc, rotary and chisel ploughs. Secondary tillage implements - components and functions of tillers, harrows, ridger, bund former, puddler, leveller and green manure trampler. Sowing methods - equipment used - seed cum fertilizer drills and planters - components - functions. Plant protection equipment - sprayers - classification and uses, dusters - types and uses. Intercultural implements - sweep - junior hoe - weeders - types and uses. Harvesting equipment - principles - components - function. Threshers - types - principle of operation, combine - functions - advantages. Farm power sources - IC engines - non conventional energy sources - solar, wind, biogas and biomass - merits and demerits. Farm mechanization benefits and constraints - cost of operation of farm machinery and implements. PRACTICAL Identification of components of primary and secondary tillage implements. Identification of components of seed drill and calibration. Identification of components of intercultural implements. Identification of components of plant protection equipment. Identification of components of paddy harvester, thresher and combine. Implements for dryland, garden land and wetland under different cropping systems. Cost of operation of farm machinery and implements. REFERENCE Jagadishwar Sahay, 1992. Elements of agricultural engineering. Agro book agency, Patna–20. Michael and T.P.Ojha, 1996. Principles of agricultural engineering. Jain brothers, New Delhi. Bindra, O.S. and Harcharan Singh, 1971. Pesticide application equipment. Oxford and IBH pub Co., New Delhi. Srivastava, A.C., 1990. Elements of farm machinery. Oxford IBH pub Co., New Delhi. THEORY SCHEDULE Tillage - objectives and types. Furrow terminology and methods of ploughing. Field capacity and field efficiency. Primary tillage - objectives, mould board plough - types - components and functions. Disc plough - components and functions - advantages and disadvantages. Rotary tiller, chisel plough and sub - soilers - operation - uses and advantages. Secondary tillage - objectives, cultivator - components and functions. Harrows - types - components and functions. Problems on field capacity and field efficiency of tillage implements. Sowing methods, seed and fertilizer drills - components and functions. Planter - problems related to seed drills and planters. Mid - semester examination. Intercultural tools and implements - sweep, junior hoe, manual and power operated weeder - components and functions. Plant protection equipment - sprayers and their classification - manually operated sprayers. Knapsack power operated sprayer - ULV sprayer - dusters - types and uses. Harvesting equipment - paddy harvester - principles - components and functions. Thresher - components - types of threshing cylinders - threshing efficiency. Combine - functions and uses. Farm power sources - internal combustion engine - petrol and diesel engines - comparison. Introduction to non conventional energy sources - solar, wind, biogas and biomass - merits and demerits Farm mechanization - benefits and constraints. Cost of operation of farm machinery by straight line method. Scope Agricultural field operations involve tillage, seedbed preparation, sowing, intercultural, plant protection and harvesting. Presently the cultivation of crops is predominantly depended upon human labors. When commercial cultivation has started, the equipment used for agricultural crops gain importance. This will depend upon level of adoption of mechanization technology by the farmers for different crops. Tractors and power tillers are gaining momentum in rural sectors for agriculture-oriented operations. Tractors are recommended for big farms and power tillers for small and medium farms. Attachments of implements for different power sources are available for different operations like land preparation, sowing, intercultural, plant protection and harvesting. Selection of suitable implements for different operations is very much importance based on power, land holding size, time, agronomical practices and investment cost. Basic knowledge of functioning of power tiller, tractor and implements is very much required for successful mechanization of the country. Acquiring skills on operation and maintenance of these power sources and implements results in maximizing the utilization efficiency and reduce cultivation costs. Objectives: To expose the basic farm machinery and equipment on cropwiseand operation sequence To impart skills on usage of different farm machinery To know the cost of operation and work out problems on farm machinery  Lecture -1 Tillage It is a mechanical manipulation of soil to provide favourable condition for crop production. Soil tillage consists of breaking the compact surface of earth to a certain depth and to loosen the soil mass, so as to enable the roots of the crops to penetrate and spread into the soil. Objective of Tillage to obtain deep seed bed, suitable for different type of crops. to add more humus and fertility to soil by covering the vegetation. to destroy and prevent weeds. to aerate the soil for proper growth of crops. to increase water absorbing capacity of the soil. to destroy the insects, pests and their breeding places and to reduce the soil erosion. Classification and types of Tillage Tillage is divided into two classes: i) Primary tillage, ii) Secondary tillage. Primary tillage It constitutes the initial major soil working operation. It is normally designed to reduce soil strength, cover plant materials and rearrange aggregates. The operations performed to open up any cultivable land with a view to prepare a seed bed for growing crops is known as primary tillage. Implements may be tractor drawn or animal drawn implements. Animal drawn implements mostly include indigenous plough and mould-board plough. Tractor drawn implements include mould-board plough, disc plough, subsoil plough, chisel plough and other similar implements. Secondary tillage Tillage operations following primary tillage which are performed to create proper soil tilth for seeding and planting are secondary tillage. These are lighter and finer operations, performed on the soil after primary tillage operations. Secondary tillage consists of conditioning the soil to meet the different tillage objectives of the farm. The implements used for secondary tillage operations are called secondary tillage implements. They include different types of harrow, cultivators, levellers, clod crushers and similar implements. These operations are generally done on the surface soil of the farm. Secondary tillage operations do not cause much soil inversion and shifting of soil from one place to other. These operations consume less power per unit area compared to primary tillage operations. The main objectives of secondary tillage operations are  To pulverize the soil of the seedbeds in the field.  To destroy grasses and seeds in the field.  To cut crop residues and mix them with top soil of the field and  To break the big clods and to make the field surface uniform and levelled. Secondary tillage implements may be tractor drawn or bullock drawn implements. Bullock drawn implements include harrows, cultivators, hoes etc. Types of Tillage There are various types of tillage. Minimum Tillage - It is the minimum soil manipulation necessary to meet tillage requirements for crop production. Strip Tillage - It is a tillage system in which only isolated bands of soil are tilled. Rotary Tillage -It is the tillage operations employing rotary action to cut, break and mix the soil. Mulch Tillage -It is the preparation of soil in such a way that plant residues or other mulching materials are specially left on or near the surface. Combined Tillage -Operations simultaneously utilizing two or more different types of tillage tools or implements to simplify, control or reduce the number of operations over a field are called combined tillage. Tillage is performed by tool, implement or machine. Tool - It is an individual working element such as disc or shovel. Implement - It is an equipment generally having no driven moving parts, such as harrow or having only simple mechanism such as plough. Machine -It is a combination of rigid or resistant bodies having definite motions and capable of performing useful work. Plough - The main implement for primary tillage is plough used for ploughing operations. Ploughing is the primary tillage operations, which is performed to cut, break and invert the soil partially or completely. Ploughing essentially means opening the upper crust of the soil, breaking the clods and making the soil suitable for sowing seeds. The purpose of ploughing can be summarized as below To obtain a deep seed bed of good texture. To increase the water holding capacity of the soil. To improve soil aeration. To destroy weeds and grasses. To destroy insects and pests. To prevent soil erosion and To add fertility to the soil by covering vegetation. Normal Ploughing: It is the ploughing up to a depth of about 15 cm. Contour Ploughing: It is the method of ploughing in which the soil broken and turned along the contours. Ploughing of Land The ploughing of land separate the top layer of soil into furrow slices. The furrows are turned sideways and inverted to a varying degree, depending upon the type of plough being used. It is a primary tillage operation, which is performed to shatter soil uniformly with partial or complete soil inversion. There are a few important terms frequently used in connection with ploughing of land. Fig.1. Plough furrow (i) Furrow -It is a trench formed by an implement in the soil during the field operation (Fig.1a ). (ii) Furrow slice - The mass of soil cut, lifted and thrown to one side is called furrow slice. (iii) Furrow wall - It is an undisturbed soil surface by the side of a furrow. (iv) Crown - The top portion of the turned furrow slice is called crown. (v) Back furrow - A raised ridge left at the centre of the strip of land when ploughing is started from centre to side is called back furrow. When the ploughing is started in the middle of a field, furrow is collected across the field and while returning trip another furrow slice is lapped over the first furrow. This is the raised ridge which is named as back furrow (Fig.1b ). (vi) Dead furrow - An open trench left in between two adjacent strips of land after finishing the ploughing is called dead furrow (Fig.1c). (vii) Head land - While ploughing with a tractor to turn, a strip of un ploughed land is left at each end of the field for the tractor to turn, that is called head land. At the end of each trop, the plough is lifted until the tractor and the plough have turned and are in position to start the return trip. The head land is about 6 metres for two or three bottom tractor plough and one metre more for each additional furrow. Methods of ploughing In order to provide furrows at all times on the right hand side of the plough two method of working are used a) Gathering b) Casting. Fig 2a. Gathering b. Castering a) Gathering - Whenever a plough works round a strip of ploughed land, it is said to be gathering (Fig.2a). b) Casting - Whenever a plough works round a strip of un ploughed land, it is said to be casting (Fig.2b). Ploughing of a field by casting or gathering alone is normally uneconomical. The following are a few important methods used in tractor ploughing. i) Continuous ploughing method and ii) Round and round ploughing Continous ploughing method In normal conditions, the continuous ploughing method is considered very convenient and economical. This is a method usually used in which the tractor and plough never run idle for more than three quarter land width along the headland and never turn in a space narrower than a quarter land width. In this method, first the headland is marked and the first ridge is set up at three quarter of a land width from the side (Fig. a). The other ridges are set at full width over the field. The operator starts ploughing between the first ridge and the side land. The operator continues to turn left and cast in the three quarter land until a quarter land width of ploughing is completer on each side (Fig. b). At this stage, it is important to lift the plough to half depth for last trip down the side land of the field. This leaves a shallow furrow where the finish comes. Fig.3 Continuous ploughing method After this, the driver turns right and gathers round the land already ploughed on the first ridge. Gathering is continued till the un ploughed strip in first three-quarter land has been ploughed and completed. This gathering reduces the first full land by a quarter (Fig. c). The remaining three quarter land can be treated in exactly the same manner as the original three quarter land. This process is repeated for all other lands in the field. (ii) Round and round ploughing In this method, the plough moves round and round a field. This system is adopted under conditions where ridges and furrows interfere with cultivation work. The field can be started in two ways. a) Starting at the centre A small plot of land is marked in the middle of the field and it is ploughed first. After that, the plough works round this small plot and the entire plot is completed. This is not a very economical method. b) Starting at the outer end Tractor starts ploughing at one end of the field and then moves on all the sides of the plot and comes gradually from the sides to the centre of the field. Wide diagonals are left unploughed to avoid turning with the plough. There are no back furrows in this method. Conventional ploughing is usually done by this method. One way ploughing This system requires the use of a special type of plough known as reversible plough or one way plough. Such a plough turns furrows to the left or right. After the headland has been marked, the operator plough along a straight side land mark. At the end of the first trip, he turns his tractor in a loop and returns down the same furrow. No dead and back furrows are left in the field. In gently sloping fields, this method is suitable. Theoretical field capacity It is the rate of field coverage of the implement, based on 100 per cent of time at the rated speed and covering 100 per cent of its rated width. w idth (cm) x speed (metre / sec) x 36 Theoretical field capacity in hectares / hr = 10000 Effective field capacity It is the actual area covered by the implement based on its total time consumed and its width. Field efficiency It is the ratio of effective field capacity and theoretical field capacity expressed in percent. Effectifive field capacity x 100 Field efficiency = Theoretica l field capacity Effective field capacity is calculated as follows Sx W E x C= 10 100 Where C = effective field capacity, hectare per hr. S = speed of travel in km per hour. W = theoretical width of cut of the machine in metre, and E = field efficiency in per cent. No. of weeds before ploughing in a fixed area -  No.of w eeds after ploughing in the same area x 100 Soil inversion = No.of w eeds before ploughing in the same area Soil pulverization It is the quality of work in terms of soil aggregates and clod size. This is measured by penetrometer. Model questions: i. List the animal drawn primary tillage implements and mention its advantages. ii. Mention the advantages of iron plough over country plough. iii. Define Theoretical field capacity. iv. Define Effective field capacity. v. Define field efficiency List Objectives of Tillage Differentiate casting and gathering. Mention furrow terminologies What do you mean by soil pulverization. Lecture - 2. Primary tillage - objectives, mould board plough - types - components and functions. Primary tillage It constitutes the initial major soil working operation. It is normally designed to reduce soil strength, cover plant materials and rearrange aggregates. The operations performed to open up any cultivable land with a view to prepare a seed bed for growing crops is known as primary tillage. Implements may be tractor drawn or animal drawn implements. Animal drawn implements mostly include indigenous plough and mould-board plough. Tractor drawn implements include mould-board plough, disc plough, subsoil plough, chisel plough and other similar implements. Plough The main implement for primary tillage is plough used for ploughing operations. Ploughing is the primary tillage operations, which is performed to cut, break and invert the soil partially or completely. Ploughing essentially means opening the upper crust of the soil, breaking the clods and making the soil suitable for sowing seeds. The purpose of ploughing can be summarized as below  To obtain a deep seed bed of good texture.  To increase the water holding capacity of the soil.  To improve soil aeration.  To destroy weeds and grasses.  To destroy insects and pests.  To prevent soil erosion and  To add fertility to the soil by covering vegetation. Country plough It penetrates into the soil and breaks it open. The functional components include share, body, shoe, handle and beam (Fig.1). It can be used for dry land, garden land and wetland ploughing operations. Fig.1. Country plough Share - It is the working part of the plough attached to the shoe with which it penetrates into the soil and breaks it open. Shoe - It supports and stabilizes the plough at the required depth. Body - It is main part of the plough to which the shoe, beam and handle are generally attached. In country plough body and shoe are integral part. Beam - It is generally a long wooden piece, which connects the main body of the plough to the yoke.  Handle - A wooden piece vertically attached to the body to enable the operator to control the plough. Operational adjustments a. Lowering or raising the beam with respect to the plough body, resulting in a change in the angle of the share with the horizontal plane to increase or decrease the depth of operation. b. Changing the length of the beam (body to yoke on the beam) to increase or decrease the depth of operation. The size of the plough is represented by the width of the body and the field capacity is 0.4 ha per day of 8 hours. The approximate cost is Rs. 300/-. Mould board plough Function: 1) cutting the furrow slice 2) lifting the soil 3) turning the furrow slice and 4) pulverising the soil. Components M.B. plough consists of (Fig.2 ) Fig.2. Components of Mould Board plough Share b) Mould board c) Land side d) Frog and e) Tail piece. Share It is that part of the plough bottom which penetrates into the soil and makes a horizontal cut below the surface. Mould board -It is the curved part which lifts and turns the furrow slice. Land side - It is the flat plate which bears against and transmits the rear side lateral thrust of the plough bottom to the furrow wall. Frog - It is the part to which other components of the plough bottom are attached. Tail piece - It is an adjustable extension, which can be fastened to the rear of a mould board to help in turning a furrow slice. A) Share - It penetrates into the soil and makes a horizontal cut below the soil surface (Fig.3 ). It is a sharp, well polished and pointed component. Different portions of the share are called by different names such as Share point 2) Cutting edge 3) Wing of share 4) Gunnel 5) Cleavage edge and 6) Wing bearing. Fig.3. Share 1. Share point : It is the forward end of the cutting edge which actually penetrates into the soil 2. Cutting edge: It is the front edge of the share which makes horizontal cut in the soil. It is beveled to some distance. 3. Wing of share: It is the outer end of the cutting edge of the share. It supports the plough bottom 4. Gunnel: It is the vertical face of the share which slides along the furrow wall. It takes the side thrust of the soil and supports the plough bottom against the furrow wall. 5. Cleavage edge: It is the edge of the share which forms joint between moulboard and share on the frog. 6. Wing bearing: It is the level portion of the wing of the share, providing a bearing for the outer corner of the plough bottom. Material of share: The shares are made of chilled cast iron or steel. The steel mainly contains about 0.70 to 0.80% carbon and about 0.50 to 0.80% manganese besides other minor elements. Type of Share Share is of different types such as i) Slip share ii) Slip nose share iii) Shin share and iv) Bar point share.  Fig.4. Types of share i) Slip share - It is one piece share with curved cutting edge, having no additional part. It is a common type of share, mostly used by the farmers. It is simple in design, but it has got the disadvantage that the entire share has to be replaced if it is worn out due to constant use (Fig. 4a). ii) Slipnose share - It is a share in which the point of share is provided by a small detachable piece. It has the advantage that share point can be replaced as and when required. If the point is worn out, it can be changed without replacing the entire share, effecting considerable economy (Fig. 4 b). iii) Shin share - It is the share having a shin as an additional part. It is similar to the slip share with the difference that an extension is provided to it by the side of the mouldboard (Fig. 4c). iv) Bar point share - It is the share in which the point of the share is provided by an adjustable and replaceable bar. This bar serves the purpose of point of the share and land side of the plough (Fig. 4d). B) Mouldboard - The mouldboard is that part of the plough which receives the furrow slice from the share. If lifts, turns and breaks the furrow slice. To suit different soil conditions and crop requirements, mouldboard has been designed in different shapes. The mouldboard is of following types: a) General purpose b) Stubble c) Sod or Breaker and d) Slat. Fig.5. Types of mould board a) General purpose - It is a mouldboard having medium curvature lying between stubble and sod. The sloing of the surface is gradual (Fig. 5a). It turns the well defined furrow slice and pulverises the soil thoroughly. It has a fairly long mouldboard with a gradual twist, the surface being slightly convex. b) Stubble type -It is short but broader mouldboard with a relatively abrupt curvature which lifts breaks and turns the furrow slice used in stubble soils. Its curvature is not gradual but it is abrupt along the top edge. (Fig. 5b). This causes the furrow slice to be thrown off quickly, pulverising it much better than other types of mouldboard. This is best suited to work in stubble soil that is under cultivation for years together. Stubble soil is that soil in which stubble of the plants from the previous crop is still left on the land cat the time of ploughing. This type of mouldboard is not suitable for lands full of grasses. c) Sod or Breaker type - It is a long mouldboard with gentle curvature which lifts and inverts the unbroken furrow slice (Fig.5c). It is used in tough soil of grasses. It turns over thickly covered soil. This is very useful where complete inversion of soil is required by the farmer. This type has been designed for used in sod soils. d) Slat type - It is a mouldboard whose surface is made of slats placed along the length of the mouldboard, so that there are gaps between the slats (Fig. 5d). This type of mouldboard is often used, where the soil is sticky, because the solid mouldboard does not scour well in sticky soils. C) Land side - It is the flat plate which bears against and transmits lateral thrust of the plough bottom to the furrow wall (Fig.6 ). It helps to resist the side pressure exerted by the furrow slice on the mouldboard. It also helps in stabilizing the plough while it is in operations. Land side is fastened to the frog with the help of plough bolts. The rear bottom end of the land side is known as heel which rubs against the furrow sole. Fig.6. Mould board bottom D) Frog -Frog is that part of the plough bottom to which the other components of the plough bottom are attached (Fig.6 ). It is an irregular piece of metal. It may be made of cast iron for cast iron ploughs or it may be welded steel for steel ploughs. E) Tail piece -It is an important extension of mouldboard which helps in turning a furrow slice. Plough accessories There are a few accessories necessary for plough such as (i) Jointer (ii) Coulter (iii) Gauge wheel (iv) Land wheel and (v) Furrow wheel. Jointer It is a small irregular piece of metal having a shape similar to an ordinary plough bottom. It looks like a miniature plough. Its purpose is to turn over a small ribbon like furrow slice directly in front of the main plough bottom. This small furrow slice is cut from the left and upper side of the main furrow slice and is inverted so that all trashes on the top of the soil are completely turned down and buried under the right hand corner of the furrow. Coulter It is a device used to cut the furrow slice vertically from the land ahead of the plough bottom. It cuts the furrow slice from the land and leaves a clear wall. It also cuts trashes which are covered under the soil by the plough. The coulter may be (a) Rolling type disc coulter or (b) Sliding type knife coulter. Rolling type disc coulter It is a round steel disk which has been sharpened on the edge and suspended on a shank and yoke from the beam. The edge of the coulter may be either smooth or notched. It is so fitted that it can be adjusted up-down and side ways. The up-down adjustment takes care of depth and sideways adjustment is meant for taking care of width of cut. Sliding type knife coulter It is a stationary knife fixed downward in a vertical position on the beam. The knife does not roll over the ground but slides on the ground. The knife may be of different shapes and sizes. Gauge wheel It is an auxiliary wheel of an implement to maintain an uniform depth of working. Gauge wheel helps to maintain uniformity in respect of depth of ploughing in different soil conditions. It is usually placed in hanging position. Landwheel - It is the wheel of the plough which runs on the ploughed land. Front furrow wheel - It is the front wheel of the plough which runs in the furrow. Rear furrow wheel - It is the rear wheel of the plough which runs in the furrow. Adjustment of mouldboard plough For proper penetration and efficient work by the mouldboard plough, some clearance is provided in the plough. This clearance is called suction of the plough. Suction in mouldboard plough is of two types (i) Vertical suction and (ii) Horizontal suction. Vertical suction (Vertical clearance) It is the maximum clearance under the land side and the horizontal surface when the plough is resting on a horizontal surface in the working position. It is the vertical distance from the ground, measured at the joining point of share and land side. (Fig.7a). It helps the plough to penetrate into the soil to a proper depth. This clearance varies according to the size of the plough. Fig.7. Vertical and horizontal clearances Horizontal suction (Horizontal clearance) It is the maximum clearance between the land side and a horizontal plant touching point of share at its gunnel side and heal of land side (Fig. 7b). This suction helps the plough to cut the proper width of furrow slice. This clearance varies according to the size of the plough. It is also known as side clearance. Throat clearance It is the perpendicular distance between point of share and lower position of the beam of the plough (Fig.8).  Fig.8. Throat clearance of plough Vertical clevis It is a vertical plate with a number of holes at the end of the beam to control the depth of operation and to adjust the line of pull (Fig. ). Fig.9. Clevis and line of pull Horizontal clevis It is a device to make lateral adjustment of the plough relative to the line of pull. Plough size The perpendicular distance from wing of the share to the line jointing the point of the share and heel of land side is called size of plough. The size of the mouldboard plough is expressed by width of cut of the soil. Tractor Drawn Implements Tractor drawn implements possess higher working capacity and are operated at higher speeds. These implements need more technical knowledge for operations and maintenance work. Tractor drawn implements may be a) Trailed type b) Semi-mounted type and c) Mounted type. Trailed type implement It is one that is pulled and guided from single hitch point but its weight is not supported by the tractor. b) Semi-mounted type implement  This type of implement is one which is attached to the tractor along a hinge axis and not at a single hitch point. It is controlled directly by tractor steering unit but its weight is partly supported by the tractor. c) Mounted type implement A mounted implement is one which is attached to the tractor, such that it can be controlled directly by the tractor steering unit. The implement is carried fully by the tractor when out of work. Centre of power It is the true point of hitch of a tractor (Fig.10 ). Centre of resistance It is the point at which the resultant of all the horizontal and vertical forces act (fig.10 ). The centre lies at a distance equal to 3/4th size of the plough from the share wing. Line of pull It is an imaginary straight line passing from the centre of resistance through the clevis to the centre of pull (power) (Fig.10 ). Pull It is the total force required to pull an implement. Fig.10. Centre of resistance Draft It is the horizontal component of the pull, parallel to the line of motion. D = P cos  where D is draft (kgf) and P = pull in (kgf)  = angle between line of pull and horizontal. Draft (kgf) x speed (metres per second) Metric hp = 75 Draft depends upon 1) sharpness of cutting edge 2) working speed 3) working width 4) working depth 5) type of implement 6) soil condition and 7) attachments. Side draft It is the horizontal component of the pull perpendicular to the direction of motion. This is developed if the centre of resistance is not directly behind the centre of pull. Unit draft It is the draft per unit cross sectional area of the furrow. 1) Fixed type (one way) mouldboard plough One way plough throws the furrow slice to one side of the direction of motion and is commonly used everywhere. It may be long beam type or short beam type 2) Two-way or Reversible plough It is mouldboard plough which turns furrow slice to the right or left side of direction of travel as require. Such ploughs have two sets of opposed bottoms. In such plough, all the furrow can be turned towards the same side of the field by using one bottom for one direction of travel and the other bottom on the return trip. Two sets of bottom are so mounted that they can be raised or lowered independently or rotated along an axis. Two way ploughs have the advantages that they neither upset the slope of the land nor leave dead furrows or back furrows in the middle of the field. Turn wrest plough There are some reversible ploughs which have single bottom with such an arrangement that the plough bottom is changed from right hand to left hand by rotating it through approximately 180° about a longitudinal axis. This type of plough is called turn wrest plough (Fig. 11). while moving in one direction, the plough throws the soil in one direction and at the return trip the direction of the plough bottom is changed , thus the plough starts throwing the soil in the same direction as before.  Fig.11. Turn wrest plough Model questions: List the types of mould board and mention its advantages. Mention the advantages of mould board plough over country plough. Define horizontal suction. Define draft. Define side draft List types of share and their applicability Differentiate turn wrest plough and reversible plough. Mention the components of mould board plough with a neat sketch and explain their importance What do you mean by unit draft. Lecture 3. DISC PLOUGH - COMPONENTS AND FUNCTIONS - ADVANTAGES AND DISADVANTAGES. Disc Plough It is a plough which cuts, turns and in some cases breaks furrow slices by means of separately mounted large steel discs. A disc plough is designed with a view of reduce friction by making a rolling plough bottom instead of sliding plough bottom. A disc plough works well in the conditions where mouldboard plough does not work satisfactorily. Advantages of disc plough  A disc plough can be forced to penetrate into the soil which is too hard and dry for working with a mouldboard plough.  It works well in sticky soil in which a mouldboard plough does not scour.  It is more useful for deep ploughing.  It can be used safely in stony and stumpy soil without much danger of breakage.  A disc plough works well even after a considerable part of the disc is worn off in abrasive soil.  It works in loose soil also (such as peat) without much clogging. Disadvantages of disc plough It is not suitable for covering surface trash and weeds as effectively as mouldboard plough does. Comparatively, the disc plough leaves the soil in rough and more cloddy condition than that of mouldboard plough. Disc plough is much heavier than mouldboard plough for equal capacities because penetration of this plough is affected largely by its weight rather than suction. There is one significant difference between mouldboard plough and disc plough i.e. mouldboard plough is forced into the ground by the suction of the plough, while the disc plough is forced into the ground by its own weight. Types of Disc Plough Disc ploughs are of two types (i) Standard disc plough and (ii) Vertical disc plough. (i) Standard disc plough It consists of steel disc of 60 to 90 cm diameter, set at a certain angle to the direction of travel. Each disc revolves on a stub axle in a thrust bearing, carried at the lower end of a strong stand which is bolted to the plough beam (Fig.1 ).  Fig.1. Standard disc plough The angle of the disc to the vertical and to the furrow wall is adjustable. In action, the disc cuts the soil, breaks it and pushes it sideways. There is little inversion of furrow slice as well as little burying of weeds and trashes. The disc plough may be mounted type or trailed type. In mounted disc plough, the side thrust is taken by the wheels of the tractor. Sometimes a rear wheel is fitted to take side thrust of the plough to some extent. In trailed type, side thrust is taken by the furrow wheel of the plough. Disc is made of heat treated steel of 5 mm to 10 mm thickness. The edge of the disc is well sharpened to cut the soil. The amount of concavity varies with the diameter of the disc. The approximate values being 8 cm for 60 cm diameter disc and 16 cm for 95 cm diameter. A few important terms connected with disc plough is explained below Disc - It is a circular, concave revolving steel plate used for cutting and inverting the soil. Disc angle - It is the angle at which the plane of the cutting edge of the disc is inclined to the direction of travel (fig.2 a). Usually the disc angle of good plough varies between 42° to 45°. Tilt angle - It is the angle at which the plane of the cutting edge of the disc is inclined to a vertical line (Fig. 2b). the tilt angle varies from 15° to 25° for a good plough. Scraper - It is a device to remove soil that tend to stick to the working surface of a disc. Concavity - It is the depth measured at the centre of the disc by placing its concave side on a flat surface.  Fig.2. Angles of disc plough Draft of disc plough The disc plough is lighter in draft than the mouldboard plough, turning same volume of soil in similar conditions. In very hard soil, some extra weight is added to the wheel which increases the draft. The bearings and scrapers of the disc plough also affect the draft. Model questions: 1. List the advantages of disc plough over mould board plough 2. Mention the conditions where in you will use disc plough 3. Define disc angle. 4. Define tilt angle. 5. Define concavity 6. List the types of disc plough 7. Differentiate disc and tilt angles. 8. Mention the components of disc plough with a neat sketch and explain their importance Lecture – 4. ROTARY TILLER, CHISEL PLOUGH AND SUB - SOILERS - OPERATION - USES AND ADVANTAGES OTHER PLOUGHS Rotary tiller The rotary cultivator is widely considered to be the most important tool as it provides fine degree of pulverization enabling the necessary rapid and intimate mixing of soil besides reduction in traction demanded by the tractor driving wheels due to the ability of the soil working blades to provide some forward thrust to the cultivating outfit.  The functional components include tynes, rotor, transmission system, universal joint, levelling board, shield, depth control arrangement, clutch and three point linkage connection (Fig.1). Rotary tiller is directly mounted to the tractor with the help of three point linkage. The power is transmitted from the tractor PTO (Power Take Off) shaft to a bevel gear box mounted on the top of the unit, through telescopic shaft and universal joint. From the bevel gear box the drive is further transmitted to a power shaft, chain and sprocket transmission system to the rotor. The tynes are fixed to the rotor and the rotor with tynes revolves in the same direction as the tractor wheels. The number of tynes varies from 28 - 54. A levelling board is attached to the rear side of the unit for levelling the tilled soil. A depth control lever with depth wheel provided on either side of the unit ensures proper depth control. The cost of the unit varies from Rs.62, 000/- to 1,10,000/-. The following types of blades are used with the rotor. i. 'L' type blade - Works well in trashy conditions, they are more effective in cutting weeds and they do not pulverize the soil much. ii. Twisted blade - Suitable for deep tillage in relatively clean ground, but clogging and wrapping of trashes on the tynes and shafts. iii. Straight blade - Employed on mulchers designed mainly for secondary tillage. The benefits of the rotary tiller are effective pulverization of soil ensures good plant growth, stubble and roots are completely cut and mixed with the soil and proper ground levelling after the operation.  2. Chisel plough Chisel ploughs are used to break through and shatter compacted or otherwise impermeable soil layers. Deep tillage shatters compacted sub soil layers and aids in better infiltration and storage of rainwater in the crop root zone. The improved soil structure also results in better development of root system and the yield of crops and their drought tolerance is also improved. The functional component of the unit include reversible share, tyne (chisel), beam, cross shaft and top link connection (Fig.2). Fig.2. Chisel plough Chisel plough consists of heavy chisel type tyne which is pulled through the soil normally at a depth greater than that at which conventional ploughing would be done and bursting up the underlying layers of soil without bringing the sub-soil to the surface. The tynes of the implement are sturdy and strong enough to withstand the stresses applied when they are working at depth where the soil conditions are hardened. The implement frame is also strongly constructed usually of box section steel to withstand the stresses applied. The chisel plough has a sturdy but light structure made of 3 mm thick hollow rectangular tubular mild steel sections. The share has a lift angle of 20 degree, width of 25 mm and a length of 150 mm. The implement is protected by a shear pin, which prevents damage from over loading. The implement could be used for deep tillage upto a depth of 40 cm. The cost of the implement is Rs.7,000/-. The coverage is 0.42 ha/hr when operated at a spacing of 1.5 m between rows. The salient features of the unit are: The implement could be used for deep tillage upto a depth of 40 cm for bursting of the sub-soil hard pan, improving the drainage and aerating the soil.  Reduces the bulk density of soil  Two fold increase in hydraulic conductivity of sub-soil  Conserves around 30 to 40% more soil moisture  Roots proliferation is improved from 40 to 45%  Nutrient mobility especially N and K increased by 20 to 30% and 30 to 40% respectively.  Enhances the crop yield by 15 to 20%  Residual effect can be realized for three seasons  Easily operated by any 35 to 45 hp tractor. Fig.3. Sub soiler 3. Sub-Soil plough The function of the sub-soiler is to penetrate deeper than the conventional cultivation machinery and break up the layers of the soil, which have become compacted due to the movement of heavy machinery or as a result of continuous ploughing at a constant depth These compacted areas prevent the natural drainage of the soil and also inhibit the passage of air and nutrients through the soil structure. The sub-soiler consists of heavier tyne than the chisel plough to break through impervious layer shattering the sub-soil to a depth of 45 to 75 cm (Fig.3) and requires 60 to 100 hp to operate it. The advantages are same as that of chisel plough. The cost of the unit is Rs.13, 000/-. Model questions: List the advantages of chisel,plough Mention the conditions where in you will use sob soil plough List the types of rotary blades Mention the components of tractor drawn rotary tiller with a neat sketch and explain their importance Differentiate rotary tiller and chisel plough. Lecture - 5 SECONDARY TILLAGE - OBJECTIVES, CULTIVATOR - COMPONENTS AND FUNCTIONS. HARROWS - TYPES - COMPONENTS AND FUNCTIONS. Secondary tillage Tillage operations following primary tillage which are performed to create proper soil tilth for seeding and planting are secondary tillage. These are lighter and finer operations, performed on the soil after primary tillage operations. Secondary tillage consists of conditioning the soil to meet the different tillage objectives of the farm. The implements used for secondary tillage operations are called secondary tillage implements. They include different types of harrow, cultivators, levellers, clod crushers and similar implements. These operations are generally done on the surface soil of the farm. Secondary tillage operations do not cause much soil inversion and shifting of soil from one place to other. These operations consume less power per unit area compared to primary tillage operations. The main objectives of secondary tillage operations are i) To pulverize the soil of the seedbeds in the field. ii) To destroy grasses and seeds in the field. iii) To cut crop residues and mix them with top soil of the field and iv) To break the big clods and to make the field surface uniform and levelled. Secondary tillage implements may be tractor drawn or bullock drawn implements. Bullock drawn implements include harrows, cultivators, hoes etc. 1. Harrow Harrow is a secondary tillage implement that cuts the soil to a shallow depth for smoothening and pulverizing the soil as well as to cut the weeds and to mix the materials with the soil. There are several types of harrow used in India such as disc harrow, spike tooth harrow, spring tooth harrow, acme harrow, patela, triangular harrow, bade harrow, guntaka and reciprocating power harrow. 1.1. Disc harrow It is a harrow, which performs the harrowing operation by means of a set, or a number of sets of rotating slat discs, each set being mounted on a common shaft. Disc harrow is found very suitable for hard ground, full of stalks and grasses. It cuts the lumps of soil, clods and roots. Disc are mounted on one, two or more axles which may be set at a variable angle to the line of motion. As the harrow is pulled ahead, the discs rotate on the ground. Depending upon the disc arrangements, disc harrows are divided into two classes a) Single action and b) Double action. Single action disc harrow It is a harrow with two gangs placed end to end, which throw the soil in opposite directions. The discs are arranged in such a way that right side gang throws the soil towards right, and left side gang throws the soil towards left (Fig. 1a).  Fig.1. Types of disc harrow Double action disc harrow A disc harrow consisting of two or more gangs, in which a set of one or two gangs follow behind the set of the other one or two, arranged in such a way that the front and back gangs throw the soil in opposite directions. (Fig.1b ). Thus the entire field is worked twice in each trip. It may be of two types a) Tandem and b) Off-set. a) Tandem disc harrow It is a disc harrow comprising of four gangs in which each gang can be angled in opposite direction (Fig.2 ). b) Off-set disc harrow It is a disc harrow with two gangs in tandem, capable of being off-set to either side of the centre line of pull. Two gangs are fitted one behind the other. the soil is thrown in both directions because discs of both gangs face in opposite directions. It is very useful for orchards and gardens. It travels left or right of the tractor. The line of pull is not in the middle, that's why it is called off-set disc harrow (Fig.3 ). Off-set disc harrow is based on the basic principle that side thrust against the front gang is opposed by the side thrust of the rear gang. Hence the gangs are arranged at suitable angles so that both thrusts are counter balanced with each other.  Fig.2. Tandem disc harrow Fig.3. Offset disc harrow Disc harrows are of two types depending upon the source of power tractor drawn and animal drawn. A disc harrow mainly consists of disc, gang, gang bolt, gang central lever, spool or arbor bolt or spacer, bearings, transport wheels, scraper and weight box (Fig.4). Fig.4. Disc harrow i. Disc: It is a circular concave revolving steel plate used for cutting a inverting the soil. Disc is made of high glass heat-treated hardened steel. Tractor drawn disc harrows have concave discs of size varying from 35-70 cm diameter. Concavity of the disc affects penetration and pulverization of soil. Usually two types of disc are used in disc harrows, plain disc and cut away disc. Plain discs have plain edges and they are used for all normal works. Most of the harrows are fitted with plain discs only. Cut away discs have serrated edges and they cut stalks, grass and other vegetation. They are not effective for pulverization of soil but it is very useful for puddling the field especially for paddy cultivation. ii. Gang: Each set of discs that are mounted on a common shaft is called the gang. iii. Gang bolt or arbor bolt: It is a long heavy of square headed bolt from the other end, a set of discs are mounted on the gang bolt. The spacing between the discs on the gang bolt ranges from 15 to 25 cm for light duty and 25 to 30 cm for heavy duty harrows. The angle between the axis of the gang bolt and the direction of travel is called the gang angle. iv. Gang control lever: A lever, which operates the gang mechanisms of the disc harrow, is called the gang control lever. v. Spool or spacer: The flanked tube, mounted on the gang bolt between every two discs to prevent the lateral movement of the disc on the shaft is called the `spool’ or `spacer’. It is just a device for keeping the discs at equal spacing on the gang bolt. It is usually cast in special shapes and sizes and is generally made of cast iron. vi. Bearing: Bearing is essential to counter act the end thrust of the gang due to soil thrust. The harrow bearings are subjected to heavy radial and thrust roods chilled cast iron bearings are used to heavy radial and thrust loads and they are also used due to their durability. vii. Transport wheel: In trailing type disc harrow, the transport wheels are provided for transport work on roads and for preventing the edges of the discs from damage. Mounted type disc harrows do not require wheels for transport work. viii. Scraper: It prevents disc from clogging. It removes the soil that may stick to the concave side of the disc. ix. Weight box: A box like frame is provided on the main frame of the harrow for putting additional weight on the implement. Additional weight helps in increasing the penetration of the disc in the soil. There are several factors which affect the penetration of disc harrow in the field. If the disc gangs are set perpendicular to the line of draft, the penetration is not adequate. Penetration can be increased by adding some additional weight on the frame of the harrow. For obtaining maximum penetration, the gangs should be set with the forward edges of the discs parallel to the direction of motion. If the hitch point is lowered, better penetration is achieved.  A sharp edged disc has more effective penetration compared to blunt edged disc. It is observed that penetration is better in low speed than in high speed. The following are a few adjustments for obtaining higher penetration By increasing the disc angle By adding additional weight in harrow By lowering the hitch point By using the sharp edged discs of small diameter and losses concavity By regulating the optimum speed. 1.2. Spike tooth harrow It is a harrow with peg shaped teeth of diamond cross section to a rectangular frame. It is used to break the clod, stir the soil, uproot the weeds, level the ground, break the soil and cover the seeds. Its principle is to smoothen and level the soil directly after ploughing. Spike tooth harrows may be of rigid type and flexible type. The animal drawn spike tooth harrow is usually of rigid type. These may or may not have provisions for changing the angle of spikes in operating conditions. Tractor drawn harrows are usually flexible type. It has got the advantage of being turned up for transporting purpose (Fig.4.) This harrow mainly consists of teeth, tooth bar frame, clamps, guard, braces, levers and hooks. The teeth are made up of hardened steel with square/triangular/circular in section. The teeth are so placed on tooth bar that no tooth is directly behind the other. Teeth are fastened rigidly to the tooth bar. Clamps are rigidly fixed so as not to be loose while in operation. Fig.4. Spike tooth harrow Fig.5. Spring tooth harrow 1.3. Spring tooth harrow It is a harrow with tough flexible teeth, suitable to work in hard and stony soils. Spring tooth harrow is fitted with springs having loops of elliptical shape. It gives a spring action in working condition. It is used in the soil when obstruction like stone, roots and weeds are hidden below the ground surface. This type pulverizes the soil and helps in killing weeds. This type of harrow mainly consists of teeth, tooth bar, clamps, frame, lever and links. Usually the teeth are made of spring steel. Sometimes reversible points are provided so that one end may be used after the other end is worn out. The teeth are fastened to the tooth bar by means of tooth clamps. They are provided to give rigidity and support to the harrow. The levers are provided for setting the teeth for varying the depth of harrowing (Fig.5). For light harrowing, the adjustment is done in slanting position. Draft hooks on each corner of every section for hitching purpose. 1.4. Acme harrow It is a special type of harrow having curved knives. It is also called as knife harrow. The front part of the knife breaks the soil and crushes the clods (Fig.6). This harrow obtains a good pulverization. It is good for mulching also. Fig.6. Acme harrow Fig. 7. Patela 1.5. Patela It is a wooden plank used for smoothening the soil and crushing the weeds. It is also used for breaking clods, packing and levelling the ploughed soil and to remove the weeds. It is made of a wooden plank with a number of curved steel hooks bolted to a steel angle section, which is fixed or hinged to the rear side of the plank (Fig.7). The cutting edge levels and packs the soil and the curved hooks uproot and collect the weeds. 1.6. Triangular harrow It is a spike tooth harrow with triangular frame (Fig.8). The frame is made of wood and pointed spikes are fitted in the frame. The teeth of the spikes are fixed and not adjustable. 1.7. Blade harrow (Bakhar) It is an implement which consists of one or more blades attached to the beam or frame, used for shallow working of the soil (Fig.9) with minimum soil inversion. It is used to prepare seedbeds mostly in clayey soils. It works like a sweep, which moves into top surface of the soil without inverting the soil. Fig. 8. Tri angular harrow Fig.9. Blade harrow 1.8. Guntaka It is an important type of blade harrow. It is an implement, which consists of one or more blades attached to a frame or beam. It is used for shallow working of the soil with minimum soil inversion (Fig.10). It is mainly used to prepare the seed bed mostly in clay soils. The function of Bakhar the same as that of the guntaka. 1.9. Reciprocating power harrow It is a harrow fitted with rigid tynes driven by the power take off in a reciprocating, transverse or rotary motion as the machine moves forward. The power tiller harrow is a rear mounted reciprocatory comb type. It has two horizontal oscillating arms having staggered pegs in two rows at 200 mm spacing. Two sets of slider crank mechanisms provide power from power tiller PTO through universal joint and bevel gear reduction box to the arms. An eccentric embedded flywheel actuates the pitman (Fig.11). The two arms move in opposite directions and hence the implement is dynamically balanced. The amplitude of vibration is 200 mm and the frequency of operation is 400 cycles per minute. A transport wheel provided in the rear of the unit ensures depth control. The unit is attached to the power tiller through the hitch point provided in front portion of the unit. The oscillating pegs breaks the clod, pulverizes the soil to a fine tilth. The width of the harrow is 1500 mm. The power reduction of the bevel gear transmission and the belt pulley drive is 1:2.5 and 1:2 respectively. The cost of the unit is Rs.3, 400/-. The field capacity of the unit is 0.5 ha/day. Fig.11. Reciprocating harrow Fig. 12. Bund former 2. Bund former It is used for making bunds or ridges by collecting the soil. Bunds are required to hold water in the soil, thereby one can conserve moisture and prevent run-off. The size of the bund former is determined by measuring the maximum horizontal distance between the two rear ends of the farming boards. Bund former consists of forming board, beam and handle (Fig.12). i. Forming board: It is that part which gathers the soil to form the bund. It is made of mild steel. The thickness of the material is about 1.6 mm for light; 2.0 mm for medium and heavy soil. The forming boards are bolted to the farm board supports. ii. Beam: Beam transmits the pull of the animals to the forming board and form board supports. It is made of hard wood. iii. Handle: Wooden handle is usually used for controlling the movement of the bund former. 3. Soil scoop Soil scoop is used in excavating ditches, clearing drain and moving soil over short distances. It consists of a blade, soil trough, hitching loop and handle ( Fig.13). i. Blade: Blade is made of light carbon steel with carbon content varying from 0.5 – 0.6%. The angle of the cutting blade varies from 12 to 15 angle only. ii. Soil trough: The blade is riveted or bolted to the soil trough. It is made of mild steel sheet. It has two handle holders for inserting the wooden handles. iii. Hitching loop: The ends of the loop are fitted to the side of the soil trough. The loop is made of mild steel round. iv. Handle: There are two handles made of timber or mild steel plate used to control the movement of back reaper. Fig.13. Soil scoop 4. Ridger It is an implement importantly used to form ridges required for sowing row crop seeds and plants in well-tilled soil. The ridger is also used for forming field or channels, earthing up and similar other operations. Ridger is also known as ridging plough and double mould board plough. The ridger generally has ’V’ shaped or wedge shaped share fitted to the frog. The nose or tip of share penetrates into the soil and breaks the earth. The mould boards lift, invert and also cast aside the soil, forming deep channels and ridges of the required size. A ridger consists of beam, clevis, frog, handle, mould boards, share and sliding share. 5. Puddler Puddler is an implement for churning the soil with water. It is used to prepare paddy fields with standing water after initial ploughing with melur or country plough. It breaks up the clods and churns the soil. The main purpose of puddling is to reduce leaching of water or decrease percolation of water, to kill the weeds by decomposition and to facilitate transplantation of paddy seedlings by making the soil softer. Puddling is done in standing water of 5-10 cm depth. A common puddler has puddling units each having four straight blades or paddles or fan type blades or squirrel type blade mounted on an axle. The axle with the puddling units is fully mounted on two bearings fitted on a frame made of metal or wood. The weight of the puddler is 30-40 kg. A puddler consists of a frame, puddling unit, axle, metal cross beam and handle. i. Frame: The frame consists of front, rear and side pieces made of steel or wood. ii. Puddling unit: Puddling unit consists of blades made of mild steel. The blades are rigidly fixed to metal cross beam. iii. Metal cross beam: This holds the blades in position. This is made up of mild steel plate. iv. Axle: The axle is made up of mild steel bar of 25 mm in diameter. v. Beam: The beam is made up of wood and is suitably placed in the frame with the help of bracer and the other end to the yoke to hitch the animal. 5.1. Helical bladed puddler This is a bullock drawn puddler. In a central shaft or axle at radial arms are fixed at both the ends and one at the centre to provide required support to the helical blades. Six to eight blades of 5 cm width are helically bent and fixed in the radial arms by welding. In operation, it continuously slices the soil and the weeds and the cut weeds are buried in the soil for decomposition. This implement is used after having one or two initial ploughing with the indigenous plough. The main frame and beam are normally made of wood. There will be continuous contact between blade and the soil which gives a uniform load to the neck of the animal, thereby intermittent jerks on the neck of the animal as observed in other types of puddlers is avoided. It gives better slicing of soil as required for puddling purposes. The coverage is 0.6 ha/day. The cost of the unit is is Rs.1200/- 6. Leveller Land levelling is expected to bring permanent improvement in the value of land. Levelling work is carried out to modify the existing contours of land so as to achieve certain objectives desired for efficient agricultural production system. These objectives include (i) efficient application of irrigation water, (ii) improved surface drainage, (iii) minimum soil erosion (iv) increased conservation of rain water specially on dry lands and (v) provision of an adequate field size and even topography for efficient mechanisation. The animal drawn leveller consists of a wooden levelling board with a handle. Depending upon the soil condition the shape of the board varies. In the front portion of the board two hooks are provided for connecting it to the yoke. 7. Green manure trampler In application of green manure, it is necessary to cut the plants and burry it in the soil. No soil inversion is required in this case. In that case green manure trampler is engaged. It is a bullock drawn implement used to trample and press the green manure crop in the field. There are two type slat and disc type. In slat type, the long radial slats are fixed to the central axis through the supporting disc. In disc type, a number of flat discs are fitted to the central axis. The size of the trampler is its maximum working width. The main parts of a green manure trampler are frame, axle bearing, disc, slat and the handle. i. Disc: It is a circular revolving steel plate used for cutting and trampling the green manure crops in the soil. Disc is made of high glass heat-treated hardened steel. Numbers of discs are mounted on a rotating shaft. The discs are spaced apart with flanges and the flange in turn is fixed with the axle. The axle rests on bearing at both ends and rotates freely. The bearings are housed in a wooden or iron framework. The number of discs depends on the size of the trampler. In operation the sharp cutting edge of the disc cuts the plants and simultaneously buries in the soil. ii. Slat: Four or five straight mild steel blades with sharp edges are mounted on the periphery of supporting discs. Each supporting disc is fixed in its position with the help of a flange. The flanges are fixed to an axle. The axle rests on bearing at both ends and rotates freely. The bearings are housed in a wooden or iron framework. In operation the sharp cutting edge of the blade cuts the plants and simultaneously buries in the soil. Handle: Wooden handle is attached to the handle support. The end of which is inturn attached to the frame. CULTIVATORS It is an implement for inter cultivation with laterally adjustable tines or discs to work between crop rows. This can be used for seed bed preparation and for sowing with seeding attachment. The times may have provision for vertical adjustments also. The cultivator can be 1) Disc cultivator, 2) Rotary cultivator, 3) Tine cultivator. Disc cultivator It is a cultivator fitted with discs. Rotary cultivator It is a cultivator with tines or blades mounted on a power driven horizontal shaft. Tine cultivator It is a cultivator fitted with tines having shovels. The cultivator stirs the soil, and breaks the clods. The tines fitted on the frame of the cultivator comb the soil deeply in the field. A cultivator performs functions intermediate between those of plough and the harrow. Destruction of weeds is the primary function of a cultivator. The following are a few important functions performed by a cultivator. 1. Interculture the fields. 2. Destroy the weeds in the field. 3. Aerate the soil for proper growth of crops. 4. Conserve moisture by preparing mulch on the surface. 5. To sow seeds when it is provided with sowing attachments. 6. To prevent surface evaporation and encourage rapid infiltration of rain water into the soil. Depending upon the type of power available for the implement, the cultivator can be classified as 1) Tractor drawn, 2)Animal drawn. Tractor Drawn Cutlivator It may be 1)Trailed 2) Mounted. Trailed type cultivator It consists of a main frame which carries a number of cross members to which tines are fitted. At the forward end of the cultivator, there is a hitch arrangement for hitching purpose. A pair of wheels are provided in the cultivator. The life is operated by both wheels simultaneously so that draft remains even and uniform. The height of the hitch is adjusted so that main frame remains horizontal over a range of depth setting. The tines in each row are spaced widely to allow free passage of the soil and trash around them. The tines in subsequent rows are staggered so that the implement can cover the entire width nicely. The depth of working is set roughly by adjusting the tine in their clamps and the final depth control is done by a screw lever. Usually the tynes are damaged due to turning the implement at the headland without lifting it up. Care should be taken to lift the tines off the ground before turning. Mounted Cutlivator Tractors fitted with hydraulic lift operate the mounted type cultivators. A rectangular frame of angle iron is mounted on three point hydraulic linkage of the tractor. The cross members carry the tines in two staggered lines. For actual cutting the soil, different types of shovels and sweeps are used. a few important shovels and sweeps are a) Single point shovel b) Double point shovel c) Spear head shovel d) Sweep e) Half sweep f)Furrower.  Depending upon the type of soil and crop, shovels are chosen for use on the cultivators. Usually tractor drawn cultivators are of two types, depending upon the flexibility and rigidity of tines (i) Cultivator with spring loaded tines (ii) Cultivator with rigid tynes. Cultivator with spring loaded tines A tine hinged to the frame and loaded with a spring so that it swings back when an obstacle is encountered, is called spring loaded line. Each of the tine of this type of cultivator is provided with two heavy coil springs (Fig. 14), pretensioned to ensure minimum movement except when an obstacle is encountered. The springs operate, when the points strike roots or large stones by allowing the tines to ride over the obstruction, thus preventing damage. On passing over the obstruction, the tines are automatically reset and work continues without interruption. The tines are made of high carbon steel and are held in proper alignment on the main frame members. This type of cultivator is particularly recommended for soils which are embedded with stones or stumps. A pair of gauge wheel is provided on the cultivator for controlling the depth of operation. The cultivator may be fitted with 7, 9, 11, 13 tines or more depending upon the requirements. Fig. 14. Tractor drawn cultivator Cultivator with rigid tines Rigid tines of the cultivators are those tines which do not deflect during the work in the field. The tynes are bolted between angle braces, fastened to the main bars by sturdy clamps and bolts. Spacing of the tines are changed simply by slackening the bolts and sliding the braces to the desired position. Since rigid tines are mounted on the front and rear tool bars, the spacing between the tynes can be easily adjusted without getting the tines choked with stubbles of the previous crop or weed growth. A pair of gauge wheel is used for controlling the depth of operation. Duck foot cultivator It is a type rigid cultivator which is used mostly for shallow ploughing, destruction of weeds and retention of moisture. It consists of steel frame and rigid tines to which sweeps are attached. The implement is attached to the tractor with three point hitch system and is controlled by hydraulic system. The sweeps are fabricated from high carbon steel. Number of sweeps can be reduced according to requirement. Usually this cultivator is about 225 cm long; 60 cm wide with 7 sweeps. Model questions: List the advantages of disc harrow Mention the conditions where in you will use secondary tillage implements List the types of harrows Mention the components of tractor drawn cultivator with a neat sketch and explain their importance Differentiate tandem disc harrow and single action disc harrow Define gang angle. What is the use of puddler and bund former Mention types of cultivators and explain any two with a neat sketch. What is the use of duck foot cultivator. Differentiate green manure trampler with puddler Differentiate disc plough and disc harrow Lecture 6. Problems on field capacity and field efficiency of tillage implements. Theoretical field capacity It is the rate of field coverage of the implement, based on 100 per cent of time at the rated speed and covering 100 per cent of its rated width. w idth (cm) x speed (metre / sec) x 36 Theoretical field capacity in hectares / hr = 10000 Effective field capacity It is the actual area covered by the implement based on its total time consumed and its width. Field efficiency It is the ratio of effective field capacity and theoretical field capacity expressed in percent. Effectifive field capacity x 100 Field efficiency = Theoretica l field capacity Effective field capacity is calculated as follows Sx W E x C= 10 100 Where C = effective field capacity, hectare per hr. S = speed of travel in km per hour. W = theoretical width of cut of the machine in metre, and E = field efficiency in per cent. Problem.1. A 5 x 20 cm double action disc harrow is operated by a tractor having a speed of 5 km/h. Calculate the actual field capacity , assuming the field efficiency of 80 percent. Solution: Size of the harrow (width) = 5 x 20 = 100 cm Sx W E x Area of coverage = 10 100 = (1 x 5 x 80) / 1000 = 0.4 ha/h Problem 2. A 3 x 30 cm plough is moving at a speed of 4 km/h. calculate how much time it take to plough 500 x 500 m field when the field efficiency is 70 %. Solution : Width of the plough = 3 x 30 = 90 cm = 0.9 m Effective field capacity = (0.9 x 4 x 70)/ 1000 = 0.25 ha/h = 2500 m2/h Time required = 500 x 500/ 2500 = 100 h Problem.3. A 4 bottom 40 cm mould board plough is operating at 5.5 km/h speed with 75 % field efficiency. Calculate what is the rate of doing work in hectares per hour. Solution : Width of the plough = 4 x 40 = 160 cm = 1.6 m Area covered = 1.6 x 5.5 x 75/1000  = 0.66 ha/h Problem. 4. An indigenous plough has a 20 cm wide furrow at the top and 10 cm depth. Calculate the volume of soil handled per day 8 hours if the speed of working is 2.5 km/h. Solution: Furrow cross section = 10 x20/2 = 100 cm2 Distance traveled in 8 hours = 8 x 2.5 x 1000 = 20,000 m Volume of soil handled = 20000 x 100/ 10000 = 200 m3 Model questions 1. A three bottom 40 cm M.B plough is working at speed of 4 km/h. Calculate the effective field capacity if the field efficiency is 80 percent. 2. A four bottom 30 cm M.B plough is working at a speed of 4.5 km/h. Calculate the actual field capacity if the field efficiency is 70 percent. Lecture - 7 SOWING METHODS, SEED AND FERTILIZER DRILLS - COMPONENTS AND FUNCTIONS Seeding or sowing is an art of placing seeds in the soil to have good germination in the field. A perfect seeding gives Correct amount of seed per unit area. Correct depth at which seed is placed in the soil. Correct spacing between row-to-row and plant to plant. Seeding methods (i) Broadcasting (ii) Dibbling (iii) Drilling (iv) Seed dropping behind the plough (v) Transplanting (vi) Hill dropping (vii) Check row planting. (i) Broadcasting Broadcasting is the process of random scattering of seed on the surface of seedbeds. It can be done manually or mechanically both. When broadcasting is done manually, uniformity of seed depends upon skill of the man. Soon after broadcasting the seeds are covered by planking or some other devices. Usually higher seed rate is obtained in this system. Mechanical broadcasters are used for large-scale work. This machine scatters the seeds on the surface of the seedbed at controlled rates. (ii) Dibbling Dibbling is the process of placing and seeds in holes made in seedbed and covering them. In this method, seeds are placed in holes make at definite depth at fixed spackling. The equipment used for dibbling is called dibbler. It is a conical instrument used to make proper holes in the field. Small hand dibblers are made with several conical projections made in a frame (Fig. ). This is very time consuming process, so it is not suitable for small seeds. Mostly vegetables are sown in this way. (iii) Drilling Drilling consists of dropping the seeds in furrow lines in a continuous flow and covering them with soil. Seed metering may be done either manually or mechanically. The number of rows planted may be one or more. This method is very helpful in achieving proper depth, proper spacing and proper amount of seed to be sown in the field. Drilling can be done by (1) Sowing behind the plough (2) Bullock drawn seed drills (3) Tractor drawn seed drills. (iv) Seed dropping behind the plough It is very common method used in villages. It is used for seed like maize, gram, peas, wheat and barley. A man drops seeds in the furrow behind the plough. Sowing behind the plough can be done by a device known as malobansa. It consists of a bamboo tube provided with a funnel shaped mouth. One man drops the seeds through the funnel and other man handles the plough and the bullocks. This is a slow and laborious method. (v) Transplanting Transplanting consists of preparing seedlings in nursery and then planting these seedlings in the prepared field. It is commonly done for paddy, vegetable and flowers. It is very time consuming operation. Equipment for placing plants in the soil is called transplanted. (vi) Hill dropping In this method, seeds are dropped at fixed spacing and not in a continuous stream. Thus the spacing between plant to plant in a row is constant. In case of drills, the seeds are dropped in continuous stream and the spacing between plant to plant in a row is not constant. (vii) Check row planting  It is a method of planting, in which row-to-row and plant-to-plant distance is uniform. In this method, seeds are planted precisely along straight parallel furrows. The rows are always in two perpendicular directions. A machine used for check row planting is called check row planter. SEED DRILL Seed drill is a machine for placing the seeds in a continuous flow in furrows at uniform rate and at controlled depth with or without the arrangement of covering them with soil. Function of seed drill: Seed drill performs the following functions To carry the seeds. To open furrow to an uniform depth To meter the seeds To place the seed in furrows in an acceptable pattern To cover the seeds and compact the soil around the seed. Seed cum fertilizer drill Seed drills, fitted with fertilizer dropping attachment, distribute the fertilizer uniformly on the ground. It is called seed cum fertilizer drill. Such a drill has a large seed box which is dividend lengthwise into two compartments, one for seed and another for fertilizers. Seed drill may be classified as (i) Bullock drawn (ii) Tractor drawn. Depending upon the method of metering the seeds, bullock drawn seed drill can be further divided into two groups Those in which seeds are dropped a) by hand, b) mechanically. There are a number of bullock drawn implements which are used for sowing seeds in which seeds are dropped by hand. The most popular implement is three lined cultivators with seeding attachment. In different parts of the country it is made in different sizes and shapes. COMPONENTS OF SEED DRILL A seed drill with mechanical seed metering device mainly consists of : (i) Frame (ii) Seed box (iii) Seed metering mechanism (iv) Furrow openers (iv) Covering device (vi) Transport wheels. Frame The frame is usually made of angle iron with suitable braces and brackets. The frame is strong enough to withstand all types of loads in working condition. Seed box  It may be made of mild steel sheet or galvanized iron with a suitable cover. A small agitator is sometimes provided to prevent clogging of seeds. Covering device It is a device to refill a furrow after the seed has been placed in it. Covering the seeds are usually done by patta, chains, drags, packers, rollers or press wheels, designed in various sizes and shapes. Transport wheel There are two wheels fitted on the main axle. Some seed drills have got pneumatic wheels also. The wheels have suitable attachments to transmit power to operate seed dropping mechanism. SEED METERING MECHANISM The mechanism of a seed drill or fertilizer distributor which deliver seeds or fertilizers from the hopper at selected rates is called seed metering mechanism. Seed metering mechanism may be of several types: (a) Fluted feed type (b) Internal double run type (c) Cup feed type (d) Cell feed mechanism (e) Brush feed mechanism (f) Auger feed mechanism (g) Picker wheel mechanism (h) Star wheel mechanism. (a) Fluted feed type It is a seed metering device with adjustable fluted roller to collect and deliver the seeds into the seed tube. Fluted feed type mechanism consists of a fluted wheel, feed roller, feed cut- off and adjustable gate for different sizes of grains. (Fig.1 ). Fig.1. Fluted roller type Fig.2. Internal double run The feed roller and the feed cut-off device are mounted a shaft, running through the feed cups. The roller carries grooves throughout its periphery. It rotates with the axle over which it is mounted throws the grains out on the adjustable gate from where it falls into the seed tube The fluted rollers which are mounted at the bottom of the seed box, receive seeds into longitudinal grooves and pass on to the seed tube through the holes provided for this purpose. By shifting the fluted wheel side ways, the length of the grooves exposed to the seed can be increased or decreased and hence the amount of seed is controlled. Thus a number of selection is available between closed position and full exposure of fluted wheel. The fluted feed mechanism is more positive in its metering action than the internal double run method. (b) Internal double run type It is a seed metering device in which the feed wheel is provided with fine and coarse ribbed flanges. It consists of discs, mounted on a spindle and housed in a casing fitted below the seed box (Fig. 2). It has double faced wheel,. Internal double-run type roller one face has a larger opening for larger seeds and the other face has smaller opening for smaller seeds. A gate is provided in the bottom-of the box to cover the opening not in use. The rate of seeding is varied by adjusting the speed of the spindle which carries the discs. (c) Cup feed mechanism It is a mechanism consisting of cups or spoons on the periphery of a vertical rotating disc which picks up the seeds from the hopper and delivers them into the seed tubes. It consists of a seed hopper which has two parts. The upper one is called grain box and the lower one is called feed box. The seed delivery mechanism consists of a spindle, carrying a number of discs with a ring of cups attached to the periphery of each disc (Fig. 3). The spindle with its frame and attachment is called seed barrel. When the spindle rotates, one disc with its set of cups rotates and picks up few seeds and drops them into small hoppers. The cups have two faces, one for larger seeds and the rate at which the seed barrel revolves. This type of mechanism is common on British seed drills. Fig.3. Cup feed mechanism (d) Cell feed mechanism - It is a mechanism in which seeds are collected and delivered by a series of equally spaced cells on the periphery of a circular plate or wheel. (e) Brush feed mechanism - It is a mechanism in which a rotating brush regulates the flow of seed from the hopper. A number of bullock drawn planters in the country have Brush feed mechanism. (f) Auger feed mechanism - It is a distributing mechanism, consisting of an auger which causes a substance to flow evenly in the field, through an aperture at the base or on the side of the hopper. Many of the fertilizer drills on the country have got Auger feed mechanism. (g) Picker wheel mechanism - It is a mechanism in which a vertical plate is provided with radially projected arms, which drop the large seeds like potato in furrows with the help of suitable jaws. (h) Star wheel mechanism - It is a feed mechanism which consists of a toothed wheel, rotating in a horizontal plane and conveying the fertilizer through a feed gate below the Star wheel. FURROW OPENERS The furrow openers are provided in a seed drill for opening a furrow. The seed tube conducts the seed from the feed mechanism into the boot from where they fall into the furrows. TYPE OF FURROW OPENERS Different type of furrow openers are: (1) Shovel type (2) Shoe type (3) Disc Type (single disc, double disc). (1) Shovel Type Shovel type furrow opener are widely used in seed drills. There are three of shovels in use. They are: (a) reversible shovel (b) single point shovel and (c) spear point shovel. Shovel type openers are best suited for stony or root infested fields. These shovels are bolted to the flat iron shanks at the point where boots are fitted which carry the end of the seed tubes. In order to prevent shock loads due to obstructions, springs are provided. It is easy in construction, cheaper and easily repairable. It is very common with usual seed drill. (2) Shoe Type It works well in trashy soils where the seed beds are not smoothly prepared. They are made from two flat pieces of steel welded together to from a cutting edge. It is specially suited for black cotton soil. Shoe is made of carbon steel having minimum carbon content of 0.5 per cent with a minimum thickness of 4 mm. (3) Disc Type They are two types : (a) Single disc type and (b) Double disc type. Single disc type It is furrow opener consisting of one concave disc. Disc type furrow openers are found suitable where plant debris or trash mulches are used. It consists of a curved disc made of hardened steel. It is set at an angle which while operating, shift the soil to one side making a small ridge. The disc is kept clean by two scrapers, one toe shaped at the convex side and one ‘T’ shaped at the concave in the field. It works in sticky soils also, but the discs are costly and maintenance work is a bit difficult. Double disc type In double disc type furrow opener there are two flat discs, set at an angle to each other. The disc open a clean furrow and leave a small ridge in the center. The seeds are dropped between the two discs, providing more accurate placement. It is suitable for trashy lands. Seed drills attached with tractors having high speeds, usually use this type of furrow opener. The furrow opener consists of : (1) tine (2) shovel (3) seed tube (4) boot for seed and fertilizer. Shovel - It is made of carbon steel having carbon content of 0.5 per cent and a minimum thickness of 4.0 mm. Seed tube - It is a tube which carries the seeds from the metering device to the boot. Seed tubes are provided at the lowest lines through suitable boots and furrow openers. The most common to the furrow lines through suitable boots and furrow openers. The most common type of seed tube is the steel ribbon one. The ribbon is rolled in the form in such a way that lower edge of the tube is thinner than the edge. Polythene or rubber tubes are also used of this purpose. The minimum diameter of seed and fertilizer tube is 25 mm. Boot - It is a part of the sowing machine which conveys the seeds or fertilizers from the delivery tube to the furrow. It is bolted or welded to the tine. It is a harrow casting, into which the lower end of the seed tube is inserted and to which the furrow openers are attached. Model questions: 1. List the advantages of seed drills. 2. Mention the methods of sowing 3. List the types of seed metering mechanisms 4. Mention the components of seed drill with a neat sketch and explain their importance 5. Differentiate seed drill and seed planter. 6. Mention types of furrow openers and their uses. 7. What are the functions of seed drill. Lecture -8 PLANTER - PROBLEMS RELATED TO SEED DRILLS AND PLANTERS. PLANTER Planter is normally used for those seeds which are larger in size and can not be used by usual seed drills. Function of planter: (i) to open the furrow (ii) to meter the seed (iii) to deposit the seed in the furrow (iv) to cover the seeds and compact the soil over it. A planter consists of: (i) hopper (ii) feed metering device (iii) knock out arrangement (iv) cut-off mechanism (v) furrow opener and (vi) other accessories. A planter has seed hopper for each row. Hopper is usually made of mild steel or any other suitable material. Seed metering device in a planter: There are a number of seed metering devices in a planter but the most common device consist of a rotating plate at the bottom of seed hoppers. In some planters, vertical rotors as well as inclined rotors are also used. The most common is the horizontal seed plate used in planters. The horizontal seed plates have got suitable notches or holes called cell. Depending upon the type of notches on the plates, it is of three types. (i) Edge drop (ii) Flat drop (iii) Hill drop. The edge drop carries the seed on edge in the cell of the plate. The flat drop carries the seed on a flat in the cell of the plate. Only one seed is allowed in the cell m cell at each time. In hill drop, the cells round the edge of the plate are large enough to admit several seeds at a time.  The rotating plate receives the seeds from the hopper. The plate moves under an arrangement called cut-off which allows only those seeds which are accommodated in the cells. Cut-off mechanism cuts-off or brushes out excess seeds from the cells of the feed mechanism. Knock out mechanism is a device which knocks out the seeds from the cells or picker heads of the mechanism. It consists of rollers, star wheels or rounded points which are forced into the cells by the pressure of a spring and eject seeds out of the cells. The spacing of seeds or hills in the row is determined by the ratio of linear or peripheral speed of the cells to the forward speed of the planter and by the distance between the cells in the metering unit. The accuracy of the planter depends upon several factors such as: (i) speed of seed plate (ii) shape and size of cells (iii) shape of hopper bottom and (iv) uniformity of seed size. Planter is usually used for those seeds which are required to be sown at equal intervals between plant to plant. Manual Rice Planter It is used for transplanting of paddy seedlings. The unit consists of skid frame, movable tray and seed picking fingers. Mat type seedlings are placed on the inclined trays. When the fingers are pushed downward they pick up the seedlings and place them in the ground. Seedlings are left on the ground during return stroke. The plant to plant spacing can be controlled by the opener. It may be 5-6 rows with comb type finger. Its working capacity may be 0.2 – 0.25 ha/8 hrs. Japanese Rice Transplanter Rice transplanter has become very successful in Japan after 1970. Rice transplanting by hand is very arduous, expensive and labour consuming operation. Development of any machine for successful transplanting would save enormous labour time and money. Several unsuccessful attempts were made in Japan earlier but recent designs of rice transplanter has become very successful among the farmers. More than 60% of the land of Japan at present is covered by paddy transplanter. If this machine is modified and improved according to Indian condition, it will be very useful machine for rice growing areas in India. The present paddy transplanter consists of (i) Air cooled gasoline engine (ii) Main clutch (iii) Running clutch (iv) Planting clutch (v) Seeding table (vi) Float (vii) Starwheel (viii) Accelerator lever (ix) Ground wheel (x) Handle (xi) Four bar linkage mechanism Seedlings: Growing of seedlings for this transplanter is most difficult work. Seedlings are grown in special seedling trays. It is called mat seedling. Mat seedlings are grown by some standard procedure in controlled environment in a nursery. Operation: The seedlings are raised in special trays as mat seedlings. The mat seedlings are placed on the seeding table of the transplanter in slanting position. When the engine is started, the running clutch and planting clutch are operated. Four bar linkage mechanism is there to catch 3 or 4 seedlings at a time and to separate them from the mat and fix in the puddled soil. A float is there to support the machine on the water while working in the field. There are two ground wheels made of iron for facilitating the movement of the transplanter. There is a marker also which demarcates the transplanting width while in operation. Power from the engine goes to the main clutch from where it is divided into two routes, one goes to planting clutch and the other goes to running clutch. Unless planting clutch is operated , the four bar linkage mechanism does not work. The engine is of about 1.2 to 1.8 HP only. The machine maintains row to row spacing of 28 cm to 30 cm and plant spacing of 14 cm to 16 cm only. The planting capacity of the machine is about 0.05 to 0.1 hectare per hour. Calibration of seed drill: The procedure of testing the seed drill for correct seed rate is called calibration of seed drill. It is necessary to calibrate the seed drill before putting it in actual use to find the desired seed rate. It is done to get the pre determined seed rate of the machine. The following steps are followed for calibration of seed drill. Procedure: i. Determine the nominal width (W) of seed drill W = M x S, Where, M = Number of furrow openers, and S = Spacing between the openers, m Find the length of the strip (L) having nominal width (W) necessary to cover 1/25 ha (1 /25 x 10000 m2) L = 400/W, meter iii. Determine the number of revolutions (N) of the ground wheel of the seed drill required to cover the length of the strip (L) L = xDxN = 400/W N = 400/ x D x W revolutions per minute iv. Jack the seed drill so that the ground wheels turn freely. Make a mark on the drive wheel and a corresponding mark at a convenient place on the body of the drill to help in counting the revolutions of the ground wheel v. Fill the selected seed in the seed hopper. Place a container under each boot for collecting the seeds dropped from the hopper vi. Set the seed rate control adjustment for maximum position and mark this position on the control for reference vii. Engage the clutch and rotate the ground wheel for N = 400/ x D x N, revolutions per minute viii. Weigh the quantity of seed collected in the container and record the observation. ix. Calculate the seed rate in kg/ha x. If the calculated seed rate is higher or lower than the desired rate of selected crop, repeat the process by adjusting the seed rate control adjustment till the desired seed rate is obtained. Solved examples 1.Calculate the cost of seeding one hectare of land with bullock drawn seed drill of 5 x 22 cm size. The speed of bullocks is 3 km/hr. Hire charge of bullocks Rs.30/- per pair, hire charges of seed drill Rs.15/- per day and wage of operator Rs.30/- per day of 8 hours. Sol: Width of seed drill = 5x22 = 110 cm = 1.1 m Area covered/hr = width x speed = 1.1 x 3x1000 m = 0.33 ha Time taken/ha = 1/0.33 = 3.03 hrs. Cost of seeding/ha = 30+15+30 = Rs.9.37 4. Cost of seeding per hectare = 3.03 x 9.37 = Rs.28.39 2 The following results were obtained while calibrating a seed drill. Calculate the seed rate per hectare. (i) No. of furrows = 10 (ii) Spacing between furrows = 20 cm (iii) Diameter of drive wheel = 1.5 metre (iv) RPM = 500 (v) seed collected = 20 kg. Sol. Effective width of seed drill = 10 x 20 cm = 2 m Circumference of drive wheel =  x 1.5 m Area covered in one revolution =  x 1.5 x 2 m Area covered in 500 revolution =  x 1.5 x 2 x 500 = 4712.3m Seed dropped for 4712.3 m = 20 kg 20 x 10000 Seed dropped/ha = ------------------- = 42.22 kg. 4712.3 3 Calculate the time required for sowing 1.6 hectares of land by five furrows seed drill going 12.5 cm deep. The speed of seed drill is 3.2 km/hr and pressure exerted by the soil on the seed drill is 0.42 kg/cm. The space between furrow openers is 10 cm and loss in turning is 10%. Sol. Total width of seed drill = 5 x 10 cm = 50 cm 50 3.2 x 1000 Theoretical area/hr = ---------- x -------------------- = 0.16 ha 100 10000 0.16 x 90 Actual area/hr = --------------- = 0.144 ha 100 1.60 Time for sowing 1.6 ha = --------- = 11.11 hrs. 0.144 4. Calculate the seed rate/hectare of a 7 x 17 cm seed drill whose main drive wheel is 124 cm diameter and total weight of grain collected in 20revolutions is 0.423 kg. Sol. Total width of seed drill = 7 x 17 = 119 cm = 1.19 m Circumference of main drive wheel =  x 124 cm = 3.90 m Area covered per revolution = 1.19 x 3.9 = 4.64 m 10000 No. of revolutions/ha = ---------- = 2155.17 4.64 20 revolutions required 0.423 kg of seed. 2155.17 x 0.423 Seed required for 2155.17 revolution = ------------------------ 20 = 45.58 kg. Seed rate = 45.58 kg. Model questions: 1. List the advantages of seed planter 2. Mention the conditions where in you will use transplanters 3. List the types of seed planter mechanisms 4. What do you mean by seed calibration and explain its importance 5. Differentiate trans planter and planter. 6. The following observations are recorded while calibrating the seed drill. Number of furrows = 10 Spacing between the furrows = 20 cm Diameter of the ground wheel = 1.5 m Speed of rotation of ground wheel = 500 Weight of seed collected = 20 kg. Calculate the seed rate. Lecture - 10 INTERCULTURAL TOOLS AND IMPLEMENTS - SWEEP, JUNIOR HOE, MANUAL AND POWER OPERATED WEEDER - COMPONENTS AND FUNCTIONS. Dry land weeder Dryland weeders with long handles are suitable for weeding in row crops in rainfed and garden lands. The long handle eliminates the back strain and provides comfort to the operator for continuos operation in standing posture. This is a long handled tool and consists of 25 mm dia. 1200 mm long conduit pipe over which 520 mm long handle is fitted (Fig.1). To the bottom of the vertical pipe frame, two arms m