327 Farm Machinery Answer key Part A 1. Define tilt angle? It is the angle measured with respect to vertical line and to the surface line of disc. It affects the degree of penetration. With proper combination of tilt and disc angle, the depth of furrow, pulverization of the soil and draft required may be easier and commensurate in any particular condition of the soil. The tilt angle varies from 15º to 25º. 2. State the function of a harrow? Functions of Harrow: 1. To improve the seed bed by pulverization of soil. 2. To conserve the moisture, kill weeds and reduce evaporation 3. To cut the crop residues and cover the crops and mix vegetative matter with the soil 4. To break up clods, firm the top soil and put in better tilth for seeding and germination of seeds 5. To destroy the weeds 3. What do you mean by seed drill? Seed drills: Seed drill is used for sowing seeds of small sizes like wheat, gram etc., and must be capable of placing seed at a depth where optimum soil temperature and moisture are available for germination. A good seed drill must be able to ensure metering of correct and uniform amount of seed rate at a precise depth without causing any damage to it. Presently seed drills have additional feature of fertilizer attachment, pre emergence herbicide applicators, seed treatment attachments etc., 4. What do you mean by ULV sprayer? Ultra low volume (U.L.V.) sprayer is a equipment used to spray chemicals in a highly concentrated form, ie 1 to 10 liters of chemical solution per hectare of land is sprayed. This technique is employed in equipments with high speed rotating disc, motorized knapsack sprayers and aerial application aircraft for insecticide spraying. 5. Write down the working principle of a thresher? Working Principle: The following figure clearly explains the working principle of a thresher. It consists of a. Feeding unit, b. Threshing unit, c. Winnowing unit and d. Cleaning unit (set of sieves). The crop material is slightly pushed into the threshing unit. The threshing unit consists of a revolving threshing cylinder and a stationary concave arrangement. The crop mass stuck in- between this arrangement is subject to shear and compressive forces due variation in speed. As a result the cylinder having spikes strikes the crop material several times causing threshing of the major portion of the grain and breaking stalks into pieces. As the material passes further the converging gap of lower concave, increases the force and more rubbing between them causes further threshing. Mixture of grain and chaff pass down the concave opening where the chaff and light materials are taken away by the winnower. Grain with broken reaches set of sieves, where it is graded and good grains are sent to packing. 6. What is the use of cutter bar? The use of cutter bar is to cut the crops. 7. Write down the parts of mould board? Main parts of Mould board plough are as follows: a. Plough bottom - Share o Slip share o Slip nose share o Shin share o Bar point share - Mould board o General purpose o Black land o Sod or Breaker o High speed mould board - Land Slide - Frog b. Plough accessories - Plough frame and beam - Adjusting coulters, jointers - Gauge wheel - Lifting mechanism - Plough hitch - Leveling and depth adjusting mechanism - Furrow opener 8. Name different types of harrow? Types of Harrows: 1. Disc harrow 2. Spring tooth type harrow 3. Spike tooth type harrow 4. Roller harrow and packer Part B 9. Differentiate mould board plough and disc plough? Sl.No. Mould board plough Disc plough 01. It is sliding bottom It is rolling bottom 02. Sliding resistance is more No sliding resistance, only rolling resistance More energy required to pull because Relatively less energy required to pull, but due 03. of sliding resistance to its weight requires more energy Depth of cut and width of cut are Depth of cut and width of cut are controlled by 04. controlled by vertical and horizontal Tilt and Disc angle suction 05. Both are primary tillage implements 06. Used in relatively light soils Used in heavy, gumbo soils Less soil inversion compared to Disc 07. Good soil inversion if provided with scrapers plough Suitable for non sticky, scouring 08. Suitable for sticky, non scouring clay soils soils 10. Write a short note on roller harrows? Roller harrows: Roller harrows are used to break surface crusts, pulverize clods, firm loose soils and leave the soil suitable for sowing. This is a special type of field finishing implement, which is a combination of roller packer and a spring tine harrow. The implement has a front gang of independent, heavy cast iron rollers mounted on a tubular axle. The rollers are free to turn individually. The front gang on these harrows crushes the clods and leaves the surface smooth. The spring tooth digs up the clods which are deeper and bring them to the surface, breaks clods and lumps to separate them and close air pockets in the soil. The second roller then pulverizes the freshly separated clumps leaving a fairly firm well pulverized seedbed. 11. Name the types of fertilizer metering mechanism? a. Fertilizer metering mechanism used in a seed drill i. Spur wheel ii. Serrated disc iii. Star wheel b. Fertilizer metering mechanism used in a Planter a. Star wheel b. Revolving bottom plate 12. Write down the functioning of a duster? Functioning of a duster: The air from the pump is directed through a tube into the container where it agitates the dust and ejects it from a discharge orifice or a tube. 13. State the different types of feeding system of a thresher? Different types of feeding system: Different types of threshers have different types of feeding system. They are as follows: 1. Chute feed 2. Hopper feed 3. Conveyor feed 4. Feed roller type 14. Differentiate primary tillage and secondary tillage? Sl.no. Primary tillage Secondary tillage 01. It is a major soil breaking operation It is conditioning the soil 02. Depth varies from 15 to 30 cm Depth of ploughing is between 5 and 10cm 03. Implements used for this operation is Implements used for this operation is called as Primary tillage implements called as secondary tillage implements. 04. Example: Mould board plough, disc Example: Disc harrow, Spike tooth harrow plough etc., 05. More draft or energy is required Relatively less draft or energy is required 06. It is the first operation in the field It is done followed after primary tillage 07. Aim is to meet primary tillage objectives Aim is to meet secondary tillage objectives 08. Cutting, pulverization and inversion of the Stirring, breaking of clods and creating a soil are done in this operation fine tilth conditions are done in this operation 15. Describe the classifications of harrows? Types of Harrows: 1. Disc harrow 2. Spring tooth type harrow 3. Spike tooth type harrow 4. Roller harrow and packer Classification of Disc Harrows: The disc harrow can be classified based on i. Method of attachment with tractor i. Mounted on hydraulic system ii. Semi mounted on hydraulic system iii. Trailed type ii. Arrangement of gangs i. Single action disc harrows: Two gangs placed end to end, which throw soil in opposite directions. ii. Double action disc harrows: Two gangs are placed one behind the other. The front gang throws soil to the right and the rear gang pulls the soil back to the centre. Double action harrows are also known as tandem harrows. iii. Offset disc harrows: An offset disc harrow has two gang of disc. The concave disc on front gang moves the soil to right hand side and the rear to the left hand. The land tilled twice and the fields are nearly levelled after harrowing. The angle of the gang is variable and can be adjusted to suit particularly tilling requirements and soil conditions. 16. Explain the functions and operations of combine? Functions of Combine Harvester: A combine harvester has the following operations to perform. For each operation a separate mechanism exists. The various systems and their functions are listed below: a. Cutting system b. Threshing system c. Cleaning system a. Cutting system: The standing crop is guided to the cutter by the take in sweep. Depending on the condition of the crop various divider devices may be attached at the right and left of the trough. The cut crop is pulled to the middle of the trough by the feed auger where controlled prongs arrange the grain for the inclined conveyor and transport it to the threshing drum. Independent of the thresher action, the cutter can be turned off by means of the quick action of a clutch which is operated from the driving platform by a clutch pedal. b. Threshing system: Grain is threshed by the threshing drum and the threshing basket, also known as concave. For quick adjustment of prevailing conditions, a speed change of the threshing drum and a fine adjustment of the threshing basket are provided on the driving platform. Damage of the threshing basket and drum is prevented by the stone trap mounted in the front of the thresher. The guide drum carries the empty straw to the four vibrator trays, which separate the remaining grain from the straw. c. Cleaning system: The grain chaff mixture from the threshing basket and the vibrator collects on the stepped floor. Its vibration separates the grain from the chaff and short straw. Over a drop step the grain then reaches the first screening stage. The air blast removes chaff and straw from the cleaning unit.