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AGEN 211: AGRICULTURAL ENGINEERING II (3 credits)
Course Outline
- Stages of agricultural mechanization development; Aims and objectives
of agricultural mechanization. Sources of farm power โ Human, animal
and mechanical power sources; types of tractors, features and
specifications, comparison of various tractor types; Engines โ Internal
combustion engines, functions of various parts of the engine;
Mechanical power transmission: Principal reasons for the application of
drives, different types of couplings and their applications, chain drives,
belt and pulley drives, Tractor Power Transmission System.
Course Outline - continued
- Tillage: Objectives of tillage, primary and secondary tillage equipment
(ploughs, harrows, etc). Planters and seed drills; methods of seed
establishment, functions of a seeder, seed metering devices. Fertilizer
distribution/broadcasters. Husbandry equipment: Field
sprayers/dusters: Types of sprayers (hydro-pneumatic, mist blowers
etc). Factors affecting sprayer performance. Harvesting equipment:
Harvesting methods, combine harvesters (basic operations, working
principles, combine losses). Selection and maintenance of farm
machinery, Farm machinery costing and records.
Instructor: Dr. E. B. Sabi
- This includes development, application and management of all
mechanical aids for field production, water control, material
handling, storing and processing. Mechanical aids include hand
tools, animal drawn equipment, power tiller, tractor, oil
engines, electric motors, processing and hauling equipment.
- It should be noted that farm mechanization is not the same as
tractorization, which simply means the use of tractors for farm
work. In Ghana, three levels of farm mechanization can be
identified. These include hand tool technology, draught animal
technology and engine power technology.
Hand tool technology is the lowest level of farm
mechanization. It refers to tools and implements that
rely on human muscle as the prime mover. Such tools
include machete, cutlass, hoe, digger, axe, spade, shovel,
trowel, sickle, rake, fork and shear. More than 90% of
farm operations in Ghana are carried out using hand
tools.
Draught animal technology refers to a range of
implements, machines and equipment, which are
powered by animals. The animals include donkeys,
horses, camels, oxen and buffalos.
Mechanization in farming operations are classified under
the following heads:
- Land clearing and levelling
- Seed bed preparation
- Sowing
- Weeding and Inter-culture
- Fertilizer application and
- Harvesting and threshing
Land Clearing and Levelling
Mechanization is evident in clearing, levelling, bund
forming, and bed forming for gravity flow irrigation and
several such activities. For land development, bullock
drawn implements, have been developed and are
commercially available such as:
i. Scoop ii. Buck scraper iii. U-Leveller iv. Float leveler
Cultivator and disc harrow cover more area and quality
of ploughing is also found better. Peg tooth harrow,
spring tine harrow and patella harrow operated by
animal and tractor are better machinery. Disc harrow
and cultivator either animal drawn or tractor drawn,
have high coverage. Tractor rotovators save time and
energy to the extent of 30-35% in heavy soils.
3. Sowing
Seed drills or seed cum fertilizer drills (Bullock drawn or
tractor drawn) facilitate line sowing and proper application
of seed and fertilizer in the field. Thus, there is saving of
10-15% inputs. About 30% loss of fertilizer is estimated if
not properly applied.
- For precise application of seed and fertilizer, mechanically
metered seed drill and seed-cum-fertilizer, operated by
animal and tractor have been developed and are being
manufactured to suit specific crops and regions for
sowing/planting of wheat paddy, coarse cereals, pulse, oil
seeds, maize and potato.
4. Weeding and Interculture
The common hand hoe used by farmers for removal of
weeds takes 300-700 man-hours to cover one hectare
depending upon crop, soil and weed infestation. The
yield is affected to the extent of 20-60% if weeds are not
controlled. Use of long handle weeders, (wheel hoe and
peg type weeders) reduce this weeding time to 25-
hours per hectare.
5. Fertilizer Application
Fertilizer is generally applied in the field by broadcasting.
If it is not placed in the soil properly, it evaporates and
only partial quantity is available to the plants. Seed-cum-
fertilizer drills and planters allow placement of seeds and
fertilizer simultaneously either in the same row in
separate bunds or in different furrows.
6. Harvesting and Threshing
Harvesting and threshing consumes about 10-35% of
the total energy for farming. These are arduous
operations for the farmers. Multi-crop threshers are
suitable for threshing major cereals, oil seeds and
pulses. These threshers have provision to control (i)
concave clearance (ii) Threshing drum speed (iii) blowers
speed independently so as to reduce grain breakage and
improve cleaning of grain. These are preferred for
threshing of oil seeds and pulses like soybean, peas,
pigeon pea and sunflower.05/06/2022 AGEN 201 AGRICULTURAL ENGINEERING II 16
Paddy crop is easy to thresh by beating but losses are
quite high. Pedal operated paddy thresher reduces
drudgery to an extent. Rasp bar type paddy thresher
causes less breakage to paddy stem and thus straw can
be put to better use. Low cost hand maize sheller is a
simple device for removing kernels from maize cobs. Its
output is considerably high compared to manual
shelling. Women can also operate hand maize sheller
easily.
Objectives of Farm
Mechanization
The potential benefits or objectives of agricultural
mechanization include:
i. an extension of the cultivated areas possible by the
capacity to do more work in the time available;
ii. increased economic returns to the farmer;
iii. improved timeliness and precision of operations;
iv. improvement of the working environment;
v. reduction of drudgery of farm work;
vi. improved dignity of farm work;
vii. and increased agro-business activity.
05/06/2022 AGEN 201 AGRICULTURAL ENGINEERING II 19
Extension of Cultivated Areas
With the use of machines, more land can be brought under cultivation.
A farmer who uses manual labour has a great limitation to the size of
farm he can cultivate within a specified time.
Most agricultural operations are time dependent. For example, the
period for tillage is between April and May in most parts of northern
Nigeria. Within this available time, those who have access to machines
can quickly complete their farm work within the first three weeks of
rain. This implies that they can use the remaining time to do other
things including bringing more land under cultivation
