Human and Draft animal Power

Human & Draft Animal Power
BULACAN AGRICULTURAL STATE COLLEGE
Course code & title: AGEN 100 – Basic Farm Machineries and Farm Mechanization
Prepared by: Engr. Vincent S. Dangan, Professional Agricultural Engineer

Introduction
Land cannot be tilled, seed cannot be planted, and crops cannot be harvested
without energy. The various forms of human and animal power and the means of
harnessing them for agriculture, as well as their characteristics, advantages, and limitations,
are discussed in this presentation.
2

Relationships among force, work and power
FORCE
• A force can be visualized as a pull or push that tends to move an object.
• In tillage tools, this force is usually referred to as draft.
• Units: Newton (N), kilogram of force (kgf), pound of force (lbf)
WORK
• The term work includes the dimensions of force and distance.
• Work = force x distance
• The time required to do a job is not part of the definition of work. To plow one hectare of
land requires the same amount of work whether the job is completed in a day or an hour.
• Units: Newton-meter (N-m), kilogram of force-meter (kgf-m), Joule (J)
3

Relationships among force, work and power
POWER
• Powers is the rate at which work is performed.
• The faster the work is done, the greater the power requirement.
• Units: horsepower (hp), kilowatt (kW), Newton-meter per second (N-m/s), pferde starke
(ps)
4

Units of Measurements
5

Units of Measurements
6

Conversion of Units
7
Length
1 km = 1000 m
1 m = 100 cm
1 m = 3.28 ft
1 cm = 10 mm
Mass
1 kg = 2.2 lbs
1 kg = 1000 g
Time
1 hr = 60 min
1 min = 60 s
1 hr = 3,600 s
Force
1 N = 0.225 lbf
Work
1 N-m = 1 J
Power
1 J/s = 1 W
1 hp = 33,000 ft-lbf/min
1 hp = 0.746 kW

Sample Calculations
8
Convert the following:
2 m = __ ft
2 m = __ cm
2 kg = __ lbs
2 m x
3.28 ft
1 m
= 6.56 ft
2 m x
100 cm
1 m
= 200 cm
2 kg x
2.2 lbs
1 kg
= 4.4 lbs

Sample Calculations
9
1.5 hr = __ s
1 lbf = __ N
2 hp = __ kW
3 kW = __ hp
1.5 hr x
3,600 𝑠
1 hr
= 5,400 s
1 lbf x
1 N
0.225 lbf
= 4.44 N
2 hp x
0.746 kW
1 hp
= 1.49 kw
3 kW x
1 hp
0.746 kW
= 4.02 hp

Human Power
• Human power is the lowest among the power
sources. But it can perform some agricultural
operations that requires low power requirement.
• Man develops a total power of 0.5 hp from the
food he eats. However, only 0.1 hp is available for
useful work. The remainder is expended on bodily
functions.
• Humans cannot compete successfully with animals
or engines as a source of power for repetitive jobs
such as pumping water for irrigation.
• A Human is unique, however, because of
intelligence.
10
Figure 1. Human-powered treadle pump (Campbell, 1990)

Man-Hour Requirement
• Man-hour per hectare describes the rate at which an operation can be performed. This is
can be used in estimating how much person can do the job in a given area; or how long
will it take for the given number of persons to complete the operation.
11
Table 1. Man hour requirement for various agricultural operations

Man-Hour Requirement
12

Sample problems
13

Sample problems
14

Draft Animal Power
Draft animal power refers to the muscle power of draught
animals used for the following tasks:
a) pulling agricultural implements
b) hauling carts
c) giving motive power to devices such as water
pumps, cane and seed crushers, and electricity
generation equipment
d) carrying loads on the back, as pack animals
e) handling, dragging and stacking timber logs in
forests
f) hauling sledges in snow-covered regions.
15

Draft Animal Power
• Domestic work animals exist in all regions
of the world. Animals assist in eliminating
poverty, reducing drudgery and creation of
wealth. Animal traction is particularly
important for food security in smallholder
farming systems. Animals can assist
directly with crop production (ploughing,
planting, and weeding).
• Food production, distribution and rural
trade are also assisted through animal-
powered transport (on-farm, marketing,
riding, pack transport). Animals save
household (women and children) time and
effort by carrying water and fuel wood.
16

Draft Animal Power
• Animal power can also be used for water-
lifting, milling, logging and land
excavation and road construction. Many
different types of animal are employed,
particularly cattle (oxen, bulls and cows),
buffaloes, horses, mules, donkeys and
camels.
17

Draft Animal Power
18
• A draft animal’s force is approximately 10% of its weight.
Horses have a higher output than other animals. Unlike a
tractor, an animal cannot be worked continuously.
• The period during which an animal can be worked daily
usually varies from 8 to 10 hours for horses and mules, and
from 6 to 8 hours for adult oxen. (Campbell, 1990)

Draft Animal Power
19
• The force system acting on a draft animal. Increasing the angle
of pull (α) will reduce the implement draft.
• The angle of pull (α) should be 30 degree.

Draft Animal Power
20
Table 2. Draft and horsepower of man and various animals.
Source: (Campbell, 1990)
• Below is the table for various draft animals and its draft power. However, it is impossible
to provide data for draft animals, since performance depends on individual
characteristics such as breed, weight, sex, age, training, quality of feed, and so on.
(Campbell, 1990)

Draft Animal Power
21
Animal Power = draft x speed
where:
draft = N, lbf, Kgf
speed = m/s, ft/s
animal power = W, N-m/s

Sample problems
22

Sample problems
23

Factors affecting Animal Performance
24
1. Environmental Conditions
2. Choice of Animals
3. Use of animals
4. Livestock Management

Disadvantages
25
• Require feed and care when not working.
• Work at heavy load limited to short period
• Require frequent resting period
• Cannot work efficiently in hot weather.
• Working speed is limited and relatively low.
• Not efficient for stationary work.
• Require a relatively large amount of time for feeding,
harnessing, and care.

References
26
• Campbell, J. K. (1990). Dibble Sticks, Donkeys, and Diesels. International Rice Research Institute.
• Belonio, D. A. (2019). Human and Draft Animal Power
• http://www.fao.org/fileadmin/user_upload/ags/publications/draugth_ap_overview.pdf

Human and Draft animal Power

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Human and Draft animal Power