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LECTURE 7. ERT 453 – DESIGN OF MACHINE SYSTEM IN BIOSYSTEM. MISS MUNIRA BT MOHAMED NAZARI School of Bioprocess Engineering. Ability to COMPARE machine components in a variety of situations and SELECT machines for specific operations. COURSE OUTCOME CO 3. Compare (C4); Select (C6);.
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LECTURE 7 ERT 453 – DESIGN OF MACHINE SYSTEM IN BIOSYSTEM MISS MUNIRA BT MOHAMED NAZARI School of Bioprocess Engineering
Ability to COMPARE machine components in a variety of situations and SELECT machines for specific operations. COURSE OUTCOMECO 3 Compare (C4); Select (C6);
IMPLEMENTS FOR THE PREPARATION OF SEED BEDS INTRODUCTION SEM 1 2012/2013
Machinery Design • Factors determining the maximum yield • Planting time • Depth of planting • Planting rate • Seedbed preparation • Soil fertility • Ploughing • Weed and insect control SEM 1 2012/2013
Seedbed • Is that layer of soil which have been tilled to a condition to promote germination, emergence and growth of seedlings. SEM 1 2012/2013
Seedbed Preparation Implements • Functions • Modifying the soil conditions for crop. • Provide a flat surface that was easy to implement irrigation. • However, it will give a negative impact if the implement too heavy, especially on wet and soft ground/surface. SEM 1 2012/2013
Types of Implements – Harrowing/Cultivation • Harrows • Disc • Blade • Drag • Spike tooth • Spring tyne • Cultivator • Spring loaded • Rigid tines • Puddlers SEM 1 2012/2013
IMPLEMENTS FOR THE PREPARATION OF SEED BEDS SEEDBED PREPARATION METHODS SEM 1 2012/2013
Seedbed Preparation Methods • May be accomplished by using three different methods. • Chemical site preparation. • Mechanical site preparation. • Combination of treatments. SEM 1 2012/2013
Chemical Site Preparation • Uses herbicides to terminate the existing vegetative cover that is present on the field. • This method should only be used when undesirable vegetation exists. • Chemically treated fields will have a cover of dead residue and should show minimal signs of living vegetation. • Will usually require multiple applications over a period of time to address all your weed problems depending on the vegetative composition of the field. SEM 1 2012/2013
Chemical Site Preparation • This type of site preparation tends to be more risky than conventional land preparation method due to possible weed flushes following wet periods. • Also should not be used when inter-seeding into already established desirable species. SEM 1 2012/2013
Chemical Site Preparation • Chemical site preparation consideration: • Involve using a no-till grassland drill to install seeds. • Planning to broadcast the seeds. • To maintain some type of cover on the field for erosion control. • Producer has no or inadequate tillage equipment available. SEM 1 2012/2013
Mechanical Site Preparation • Involves using some type of tillage implement to destroy the existing vegetative cover that is present on the field. • Operations may include disking, sweeps, or moldboard plowing that completely destroys standing vegetation. • Each producer has a unique set of different tillage tools and methods that can be used to prepare a seedbed. Following the final plowing the site should be firmed using equipment such as a roller, harrow, cultipacker, or other implement to firm but not pack the final seedbed. SEM 1 2012/2013
Mechanical Site Preparation • Should not be used when desirable vegetation and plans include interseeding other species. • Will destroys undesirable vegetation and may bury weed seeds at a depth where they cannot germinate, leaving the site clean and free of living vegetation. • Require multiple applications over a period of time to address all weed problems. SEM 1 2012/2013
Mechanical Site Preparation • Mechanical site preparation consideration: • Involve using a conventional grassland drill, or using a broadcast seeder. • Potential erosion problems. • Producer needs to prepare a site heavily infested with undesirable vegetation. • Mechanically prepared sites should be a clean, weed free, firm, moist, and smooth prior to planting. SEM 1 2012/2013
Combination of treatment • Commonly used when preparing a seedbed for native plants. • Under certain condition, existing vegetative cover may be destroyed by spraying (burn down herbicide) following by disking. • Should be used when hard to control vegetation exist or severe weed pressure is present. • Usually involves repeated chemical and/or mechanical treatments to accomplish the goal. SEM 1 2012/2013
Combination of treatment • Sites prepared using a combination of treatments may be planted with a; • No-till grassland drill, • Conventional grassland drill, or • Using a broadcast seeder, depending on the final operation. • Consideration should always be given to any erosion problems that potentially may exist. SEM 1 2012/2013
IMPLEMENTS FOR THE PREPARATION OF SEED BEDS SEEDBED PREPARATION OPERATIONS SEM 1 2012/2013
Seedbed Preparation Operations • It is frequently necessary to manipulate the soil in a number of ways to produce an environment which is satisfactory for crop development, drainage and mechanization operations. • Specific operations which may be required are; • Loosening of soil – general reduction in soil density or simply the creation of a number of fissures. • Clod size reduction – breaking clods into smaller aggregates. • Clod sorting – bringing larger clods and aggregates on surface. Large size clods on the surface are recommended because of their stability under rainfall, which helps in reducing soil erosion. • Seedbed compaction – achieved by filling the larger pore spaces with smaller soil aggregates, thus allowing good seed/soil contact without excluding air. • Smoothing – required for proper operation of sowing machines, better distribution of irrigation water and quick disposal of excess rainwater. SEM 1 2012/2013
Seedbed Preparation Operations • Implements for seedbed operations; • Loosening of soil – forward inclined tines, plough, discs, rotary cultivators. • Clod size reduction – tine cultivator and disc harrow. • Clod sorting – discs, scrubbers, rotary cultivators, plough. • Seedbed compaction – furrow press, press wheels, ring roll and vertical tines. • Smoothing – dutch/patela harrow. SEM 1 2012/2013
Tillage Equipments • PLOWS • Moldboard • Best operates at depths of 4 to 10 inches, which is not always desirable since it may result in a deep, loose seedbed. • Other disadvantages; • High labour requirement, • High cost operation, and • no plant residue remains on the surface for erosion control. • Advantages; • Preventing plant competition, • Effective in displacing existing perennial cover in a short time. • Preventing the formation of large “slabs”. SEM 1 2012/2013
Tillage Equipments • PLOWS • Disk Plow • Does not reduce weed competition as effectively as the moldboard, nor does it maintain residue on the surface for erosion control as well as subsurface tillage equipment. • Disking will work satisfactorily under drier soil conditions and handle more residue and shrubby growth than will the moldboard plow. SEM 1 2012/2013
Tillage Equipments • DISKS • One-way disk • Effective in reducing heavy residue and bringing heavy weed growth under control. • Disadvantage – leaves the soil loose, rather finely divided or pulverized, and more subject to blowing. • Offset disk and disk harrow • Effective in breaking down large clods, smoothening, compacting and killing small weeds. • Neither highly effective in maintaining residue on the surface nor in maintaining clods for resistance to blowing. • Disking leaves the soil too loose for immediate seeding. SEM 1 2012/2013
Tillage Equipments • HARROWS • Effective where smoothing is needed, as in hay fields. • Accomplish some compaction operation. • Spike harrows tend to leave the surface smooth and thus more subject to blowing. • Spring-tooth harrows – preventing soil blowing since they leave more clods on the surface. SEM 1 2012/2013
IMPLEMENTS FOR THE PREPARATION OF SEED BEDS HARROWING/CULTIVATION It is secondary tillage operation which pulverizes, smoothens and packs the soil in seedbed preparation and/or to control weeds. SEM 1 2012/2013
HARROWS • 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 materials with soil. • Used to break the clods after ploughing, to collect trash from the ploughed land and to level the seedbed. • There are several types of harrow used; SEM 1 2012/2013
Disc Harrows • It is harrow performs the harrowing operations by means of a set (or a number of sets) rotating steel disc, each set being mounted on a common shaft. • Two types depending upon the sources of power. • Tractor drawn • Animal drawn SEM 1 2012/2013
Disc Harrows Plain Disc Scalloped Disc SEM 1 2012/2013
Disc Harrows • Have a number of saucer-shaped disc mounted on one, two or more axles, which may be set at a variable angle to the line of draught. • Disc diameter = from 18 to 24 in (457 – 610 mm). • Action on the soil : • More precise action than small digging type ploughs. • Depends on the size of the disc, the depth of work and angle at which the disc gangs are set relative to the line of travel. SEM 1 2012/2013
Disc Harrows • Example: • If disc gangs are set perpendicular, penetration is shallow, but the surface of the soil is pulverized and the lower layers are compressed. • Weight of implement will influence the penetration of the disc. • Eg: heaviest agricultural type - 760 mm diameter disc, 8 mm thick = 160 kg per disc. • Penetration also assisted by a low hitch point, a low forward speed and sharpening of the discs. SEM 1 2012/2013
Disc Harrows • Scalloped disc penetrate better than plain. • For this reason, there is increasing tendency to use them for the front gangs of tandem implements. SEM 1 2012/2013
Disc Harrows • TRACTOR DRAWN DISC HARROW • Very suitable for hard ground, full of stalks and grasses. • It cuts the lumps of soil, clods and roots. • Discs are mounted on one, two or more axles which may be set a variable angle to the line of motion. • As the harrow is pulled ahead, the disc rotate on the grown. • Depending upon the disc arrangements, disc harrows are divided into classes. • Single action, and • Double action SEM 1 2012/2013
Disc Harrows • 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. SEM 1 2012/2013
Disc Harrows • 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. • Thus, the entire field is worked twice in each trip. • It may be of two types; • Tandem, and • Off-set SEM 1 2012/2013
Disc Harrows • Tandem disc harrow • It is a disc harrow comprising of 4 gangs in which each gang can be angled in opposite direction. SEM 1 2012/2013
Disc Harrows • Off-set disc harrow • It is a disc harrow with 2 gangs in tandem, capable of being off-set to either side of the center line of pull. • 2 gangs are fitted one behind the other. • The soil is thrown in both directions because discs of both gangs face in opposite direction. • 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. SEM 1 2012/2013
Disc Harrows • Penetration of Disc Harrow • Several factors affect the penetration of disc harrow in the field. • Penetration is not adequate if the disc gangs are set perpendicular to the line of draft. • If the hitch point is lowered, better penetration is achieved. • A sharp edges disc has more effective penetration compared to blunt edges disc. • Penetration is better in low speed than in high speed. SEM 1 2012/2013
Disc Harrows • Penetration of Disc Harrow • A few adjustments for obtaining higher penetration. • By increasing the disc angle. • By adding additional weight on the harrow. • By lowering the hitch point. • By using sharp edged discs edged discs of small diameter and lesser concavity. • By regulating the optimum speed. SEM 1 2012/2013
Disc Harrows • ANIMAL DRAWN DISC HARROW • It is attached to a universal frame which is mounted on 2 wheels. • The frame is pulled by an animal and it is provided with a seat for operator. SEM 1 2012/2013
Blade Harrows • Popular known as bakhar (India). • Generally used in clay soils for preparing seedbeds of both rainy and winter season crops. • Also used for covering the seed in rainy season sowing. Handle Frame SEM 1 2012/2013 Blade (made of steel)
Blade Harrows • The action of blade harrow is like that of sweep, moving into the top surface of the soil without inverting it. • Sometimes, it is used to chisel out the uncut portion left after ploughing by an indigenous plough. • Thus the primary function of the implement is to pulverize the soil and create soil mulch. • The width cut by the harrow varies from 38 to 105 cm. SEM 1 2012/2013
Blade Harrows • Frequent clogging with the roots and weeds which wrap along the edge of blade possess a serious problem and stoppage of work. • However, the improved V-shaped blade if fitted on the implement can provide relief from clogging. • Besides, it offers the advantage of reduction in draft, easy penetration and smooth working in the field. SEM 1 2012/2013
Drag Harrows • These harrows are used to; • break the clods, • Stir the soil, • Uproot the early weeds, • level the ground, • Break the soil crust, and • Cover the seeds SEM 1 2012/2013
Drag Harrows • Two kinds of drag harrows; • Spike tooth, and • Spring tine harrows. SEM 1 2012/2013
Drag Harrows • SPIKE TOOTH HARROW • Two types – either rigid or flexible. • The flexible type tractor drawn can be rolled up for transporting but the animal drawn harrows are always of rigid frame type. • There may or may not be provision for changing the angle of the spikes while operating the harrow. • The basic frame of the harrow may be triangle. • It has pointed steel pegs (teeth) about 23 cm long with their pointed ends towards ground. SEM 1 2012/2013
Drag Harrows • SPIKE TOOTH HARROW • Before operating the harrow in the field, adjustment should be made for efficient and effective operation. • The peg point is tilted backward vertically so that soil is not accumulated in the front. • The pegs of rigid harrows are fixed slightly tilted so that no arrangement is needed to change the angle. • The harrow is dragged over the surface by means of a chain or rope tied to the yoke. SEM 1 2012/2013
Drag Harrows • The animal drawn harrows cover almost 1 to 1.2 m width and are used to stir the soil to a depth of about 5 cm. • The depth of penetration can be increased by adding weights to the frame. SEM 1 2012/2013