SOURCES OF FARM POWER

A farm power for various agricultural operations can be broadly classified as:
(1) Tractive work such as seed bed preparation, cultivation, harvesting and
transportation, and
(2) Stationary work like silage cutting, feed grinding, threshing, winnowing and lifting
of irrigation water.
These operations are done by different sources of power, namely human, animal, oil
engine, tractor, power tiller, electricity and renewable energy (biogas, solar and wind).
HUMAN POWER
Human beings are the main source of power for operating small tools and implements.
They are also employed for doing stationary work like threshing, winnowing, chaff cutting
and lifting irrigation Water. It is generally believed that there is surplus human power
available for agricultural operations in India. According to 2001 census figures, the total
Indian rural population is about 74 crores. Of the total rural population only 30 per cent is
available for doing farm work. Hence the total number of persons available would be about
74 x 0.30 = 22.2 crores. This figure includes both the landless labourers as well as the owners
of farms in the country. On the average a man develops nearly 0.I horsepower (hp.).
Therefore, the total power available through human source may be about 2.2 crore hp. But
there is a steady decline in the number of landless labourers available for doing farm work in
rural areas.
Population and Agricultural Workers (In Millions)
Year
Total
Population
Average
Annual
Exponential
Growth
Rate(%)
Rural
Population
Cultivators
Agricultural
Labourers
Other
Workers
Total
1991 846.3 2.14 628.7 110.7 74.6 128.8 314.1
(74.3) (35.2) (23.8) (41.0) (100.0)
2001 1027.0 1.93 741.7 127.6 107.5 167.4 402.5
(72.22) (31.7) (26.7) (41.6) (100.0)
Managing Labour Peaks: In crop production system, labour peaks develop due to high labour
demands in operations, which cannot be or have not been mechanized so far. For example,
AG ENGG 243 Lecture 2 2
the operations like transplanting of paddy, weeding and inter-culture operations or harvesting
of crops demand large number of human labour on each of the farms in the region. Such
peaks have got to be managed if one desires to have high return from his enterprise. In
general, the peaks are managed as follows:
i) Increasing the working hours.
ii) Extending the time period of operations.
iii) Adjusting the cropping pattern.
iv) Mechanizing the operations, wherever possible.
v) Decreasing the intensity of some operations.
Advantages: Easily available and used for all types of work.
Disadvantages: Costliest power compared to all other farms of power, very low efficiency,
requires full maintenance when not in use and affected by weather condition and seasons
ANIMAL POWER
The most important source of power on the farm all over the world and particularly in
India is animal. It is estimated that nearly 80 per cent of the total draft power used in
agriculture throughout the world is still provided by animals, although the number of
agricultural tractors has become double after every ten years since 1930. India with its 22.68
crore cattle possesses the largest number of cattle in the world. Among them the bullocks and
buffaloes happen to he the principal sources of animal power on Indian farms. However,
camels, horses, donkeys, mules and elephants are also used for the farm work. The average
force a bullock can exert is nearly equal to one tenth of its body weight. But for a very short
period, it can exert many more times the average force. Generally a medium size bullock can
develop between 0.50 to 0.75 hp. Thus the variation in power developed by animals is
considerable. Actually small size bullocks are not able to develop even 0.50 hp and most of
them are not fit for heavy work. Animals Can he a very cheap source of farm power if raised
by the farmer himself. It becomes the most costly source if the animal has to be bought from
outside. Considering the overall situation of the draft animals available in the country, it is
estimated that the total work animals may be about 7.56 crores in number, that is 33 per cent
of the total horse power output from the animals would be about 7.56 x 0.50 = 3.78 crore hp.
Advantages: Easily available, Used for all types of work, Low initial investment, Supplies
manure to the field and fuels to farmers and Live on farm produce.
Disadvantages: Not very efficient, Seasons and weather affect the efficiency, Cannot work at
a stretch, Require full maintenance when there is no farm work, Creates unhealthy and dirty
atmosphere near the residence and Very slow in doing work.
AG ENGG 243 Lecture 2 3
MECHANICAL POWER
The third important source of farm power is mechanical power that is available
through tractors and oil engines. The oil engine is a highly efficient device for converting fuel
into useful work. The efficiency of diesel engine varies between 32 and 38 per cent, whereas
that of the carburettor engine is in the range of 25 and 32 per cent. In recent years, diesel
engines and tractors have gained considerable popularity in agricultural operations. Small
pumping sets within 3 to 10 hp range are very much in demand. Likewise, oil engines of low
to medium speed developing about 14 to 20 hp are successfully used for flourmills, oil
ghanis, cotton gins, etc. Diesel engines of the larger size are used on tractors. It is estimated
that about one million tractors of about 25 bhp range are in use for agricultural operations in
India. Similarly, the total number of oil engines for stationary work may be taken as about 60
lakhs of 5 hp each. Thus the total power available from mechanical source would work out to
be 55 million hp (Oil engines = 0.60 x 5 = 3.0 crore hp, tractors = 0.1 × 25 = 2.50 crore hp.
Advantages: Efficiency is high; not affected by weather; can run at a stretch; requires less
space and cheaper form of power
Disadvantages: Initial capital investment is high; fuel is costly and repairs and maintenance
needs technical knowledge.
ELECTRICAL POWER
Now-a-days electricity has become a very important source of power on farms in various
states of the country. It is steadily becoming more and more available with the increase of
various river valley projects and thermal stations. On an average about 1/10th of the total
electrical power generated in India, is consumed for the farm work. The largest use of electric
power in the rural areas is for irrigation and domestic water supply. Besides this, the use of
electric power in dairy industry, cold storage, fruit processing and cattle feed grinding has
tremendously increased.
Advantages: Very cheap form of power; high efficiency; can work at a stretch; maintenance
and operating cost is very low and not affected by weather conditions.
Disadvantages: Initial capital investment is high; require good amount of technical
knowledge and it causes great danger, if handled without care.
WIND POWER
The availability of wind power for farm work is quite limited. Where the wind velocity is
more than 32 kmph, wind mills can be used for lifting water. Even today in India the wind
power has not been fully harnessed. The most important reason is its uncertainty.
AG ENGG 243 Lecture 2 4
Experimental results show that a wind mill having 3.6 diameter wheel mounted on 12.0 m
tower is able to produce from 0.1 to 0.9 hp with the wind velocity varying from 6.4 to 37
km/h. Thus the average capacity of a wind mill would be about 0.50 hp. There are about 2540
mills installed in India. Hence the total output may be about 1250 hp only, but it is one of the
cheapest sources of farm power available in the country.
Ministry of Non-Conventional Energy, Govt. of India have been making efforts to
popularise the wind mill for power generation and water lifting in rural areas. But this source
could not become attractive due to the following limitations of the system :
• Initial investment is high,
• Repair facilities are not available in rural areas,
• Even the matching pump sets and electric generators are not readily available in the
country,
• It not suitable for all situations in the country. For the present, the wind mills have
limited scope of the use in the country.
AG ENGG 243 Lecture 2 5
Comparison of Tractor and Animal Power:
S. No. Basis Tractor /Power Tiller Animal Power
1. Availability Only large size tractors above 25
hp size are available. Tillers up to
12 hp size are available
They are available in plenty.
2. Overload
capacity
Limited overload capacity Very high overload capacity for short
time.
3. Acceptability Not very common because of high
initial investment
The most important source of power
at present.
4. Tractive work This the best source of power for
any traction job. With cage wheels
it can be use for puddling also.
They are quite suitable for all kind of
farm work.
5. Stationary
work
All kinds of stationary works can
be performed.
Bullocks have limited use
for such works.
6. Transport
work
It is a quick means of medium
distance transport.
Bullocks are also used for
short and medium distance transport
work.
7. Initial
investment
Though cost per horsepower is
low but overall investment per
unit area is very high.
Cost per horsepower is high but
overall investment is less.
8. Cost of
maintenance
Reasonable Very high.
9. Rate of
depreciation
It is about I0 per cent year. In fact the value increases
in the beginning and then
decreases.
10. Cost of
operation
Cheaper per horsepower hour. It is costlier than tractor.
11. Limitations The technical know how of the
people in general is low and as
such farmers get discouraged to
buy a tractor. This may no longer
be valid
in next 20 years. Tractor gives low
field efficiency in small fields.
Constant care is required to keep the
animal in good
health. To some extent
medical facilities are now
available and as such it is
not very difficult to cure
a sick animal in rural
areas.
12. Idleness It does not consume any fuel or
lubricant while not in use.
Even during Idle period, it needs care,
feed and fodder. But, on the other
hand, it provides manure for the
crops.
13. Output Very high and suitable for timely
operations.
Low output.