TILLAGE EQUIPMENT Flashcards
Any physical soil manipulation which changes the structure of the soil, kills
weeds, and rearranges dead plant materials.
Tillage
Objectives of tillage:
To develop a desirable soil structure for a seedbed.
To control weeds, cut roots and bury green materials.
To incorporate manure and chemical fertilizer.
a. higher water infiltration rate.
b. decreased water surface runoff.
c. greater water holding capacity.
d. promote root penetration.
Tillage or objectives of tillage
For wetland conditions:
4. To turn the soil into a soft “puddle”.
5. To form a hard layer which reduces water leaching.
tillage
3 classifications of tillage
Primary tillage
Secondary tillage
General-purpose tillage
initial cutting, breaking and usually inversion of the soil
Primary tillage
Implements used are moldboard, disc and chisel plows and subsoilers cutting the
soil to a depth of 6” to 36”
Primary tillage
Often referred to as plowing.
Primary tillage
subsequent breaking, pulverization and leveling of the soil
making it ready for planting.
Secondary tillage
Implements used are disc, spike-tooth and spring-tooth harrows preparing the soil to a depth of 3” to 6”.
Secondary tillage
Often referred to as
harrowing.
Secondary tillage
Combined primary and secondary tillage in one
operation.
General-purpose tillage
Implements used are the rotavators and floating tillers cutting the soil
to a depth of up to 6”.
General-purpose tillage
Often referred to as rotavating.
General-purpose tillage
Terms used in plowing:
unplowed soil.
Land
Terms used in plowing:
soil cut, lifted, inverted and thrown to one side of the plow bottom.
Furrowslice
Terms used in plowing:
trench or canal left by the furrowslice.
Furrow
Terms used in plowing :
raised ridged when two furrowslices overlap each other
Backfurrow
Terms used in plowing:
trench left equal to two furrows when furrowslices are thrown on
opposite sides.
Deadfurrow
Terms used in plowing:
unbroken side of the furrow.
Furrow wall
Primary Tillage Equipment are classified into two:
Moldboard plow and Disc plow
one of the oldest and most important agricultural equipment
for land preparation.
Moldboard plow
It cuts the soil to a depth of 6” to 18 “.
Moldboard plow
Basic parts of moldboard plow bottom: provides the cutting edge of the plow bottom.
Share
Basic parts of moldboard plow bottom: receives the furrowslice from the share; lifts,
inverts and throws it to one side of the plow bottom.
Moldboard
Basic parts of moldboard plow bottom: counteracts the side pressure exerted by the
furrowslice on the plow bottom.
Landside
Clearances of the moldboard plow bottom: bend downward of the point of the share to
make the plow penetrate the soil to the proper depth.
Vertical clearance
Clearances of the moldboard plow bottom: bend outward or sideward of the point of
the share towards the unplowed land to make the plow cut the
proper width.
Horizontal clearance
perpendicular distance between
the wing and the point of the share. This also expresses the width of cut
of the plow bottom.
Size of the moldboard plow bottom
– it was developed in an effort to reduce friction in the sliding
moldboard plow bottom by using a rotating disc plow bottom.
Disc plow
Basic parts of disc plow bottom:
curved plate placed on the concave side of the disc to
scrape off the soil and throw it on one side of the plow bottom.
Scraper
Basic parts of disc plow bottom:
round and concave disc of heat-hardened steel with
sharpened edges to cut the soil. It is rotated by the soil during
soil cutting.
Disc
– rear wheel that presses against the furrow
wall to resist the side pressure exerted by the soil against the
plow.
Rear furrow wheel
Angles of the disc plow:
angle the disc makes with the vertical to make the
disc penetrate the soil to the proper depth (15 – 25 degrees).
Tilt angle
angle the disc makes with the direction of travel to
make the disc cut the proper width and allow the disc to rotate
(42 – 45 degrees).
Disc angle
expressed in terms of diameter of the
disc. The width of cut, however, is influenced by disc diameter, depth of
cut and disc angle.
Size of the disc plow bottom
determined by the resistance of the soil to tillage operation, the
speed of plowing, sharpness of the cutting edge and over-all adjustment of the
plow.
Draft of Plows
resistance of the soil is expressed as
specific draft.
Specific Draft: Sandy soil
3 Lbs/in2 or 0.21 Kg/cm2
Specific Draft: Sandy loam
3-6 Lbs/in2 or 0.21-0.42 kg/cm2
Specific Draft: Silty loam
5-7 lbs/in2 or 0.35-0.49 kg/cm2
Specific draft of: Clay loam
6-8 lbs/in2 or 0.42-0.56 kg/cm2
Specific draft of: Heavy clay
10-11 lbs/in2 or 0.70-0.77 kg/cm2
Specific Draft : Virgin soil, clay
12-15 lbs/in2 or 0.85-1.06 kg/cm2
Specific Draft : Gumbo, moist
16-18 lbs/in2 or 1.13-1.27 kg/cm2
Specific draft: Dry adobe
18-20 lbs/in2 or 1.27-1.41 kg/cm2
Increase in draft due to speed
1 MPH- 1.6 KPH
DRAFT: 100%
increase in draft due to speed
2 MPH- 3.2 KPH
114%
increase in draft due to speed
3 MPH- 4.8 KPH
128%
increase in draft due to speed
4 MPH- 6.4 KPH
142%
increase in draft due to speed
5 MPH- 8.0 KPH
156%
increase in draft due to speed
62 MPH- 9.6 KPH
170%
Formula for field capacity
C=SWEff/10
where:
C = Field Capacity, Ha/hr
S = Speed, Kph
W = Width of cut, m
Eff = Field Efficiency, decimal
Formula for draft requirement based on soil type
Ds=SpecificDraftWd
where:
Ds = Draft, kg
Specific Draft = Kg/cm2
from Table 1
W = width of cut, cm
D = depth of cut, cm
Formula for Adjusted draft requirement due to speed of plowing (from Table 2)
Da=Ds*value from table 2 (increase in draft due to speed{in decimal})
Formula for Draft horsepower requirement:
Hp(draft)= Da*S/274
where:
Da = Adjusted Draft, Kg
S = Speed, Kph
Formula for Tractor Horsepower:
Hp(tractor)= Hp(draft)/0.8
3 types of secondary tillage equipment
Disc harrow
Spike-tooth harrow
Spring-tooth harrow
consists of two or more sets of disc gangs cutting the soil to a
depth of 3” to 6”. A disc gang is made up of a number of discs mounted on a
common axle
Disc harrow
Basic parts of disc harrow:
round and concave discs
Discs
Basic parts of disc harrow:
an assembly of discs all rotating together on a
common shaft (3 -13 discs/gang at 6” to 12 “ spacing per disc).
Disc gang
Basic parts of disc harrow:
a washer on one of the common shaft to absorb the
end thrust of the gang.
Bumpers
Basic parts of disc harrow:
two to three bearings per gang.
Bearings
Types of disc harrows that consist of two gangs of discs placed
end-to-end which throws the soil in opposite directions.
Single-action disc harrow
Types of disc harrows that consist of four gangs of discs. Two gangs in front as in single –action and two gangs at the rear.
Double-action disc harrow
Types of disc harrows that consists of two gangs of disc. One gang located behind the other and operated in an offset position in
relation to the tractor.
Offset disc harrow
arrangement to attain maximum stirring and raking of the
soil. The cross bars can be rotated to change the angle of the teeth
Spike-tooth harrow
consists of long, flat and curved teeth made from spring
steel. The curved teeth are welded to cross bars on a staggered arrangement.
The spring characteristic allows the teeth to flex and slide over obstructions
Spring-tooth harrow
General-purpose tillage equipment has two types:
Rotavators and Floating power tillers
constructed with a set of cutting knives or tines mounted on a
horizontal power-driven shaft rotating at high speed. The knives slice thin
sections of the soil and pulverize them by centrifugal force
Rotavators
are mounted on 2-wheel or 4-wheel tractors and driven by
the tractor PTO.
Rotavators
are suited for both dry and wet land operations.
Rotavators
specially designed power tillers for wet land operation
fitted with front-mounted cutting blades on a cagewheel
Floating power tiller
