An ergonomic evaluation of pedal operated paddy thresher for farm women

Abstract

Traditional paddy threshing is a labour intensive operation and mostly carried out by farm women in awkward posture. In this study, the performance of pedal operated paddy thresher was evaluated with 12 farm women and compared with traditional method, i.e. manual beating of paddy on wooden log. The mean working HR in pedal operated paddy thresher was found to be 134 beats/min, whereas it was 141 beats/min by traditional method. The corresponding work pulse (ΔHR) was 51 beats/min. The energy expenditure rate (EER) was 17.71 kJ/min with the use of paddy thresher whereas traditional method it was recorded as 19.34 kJ/min. It was observed that there was 20% increase in output with paddy thresher. The total cardiac cost of work (TCCW) and physiological cost of work (PCW) in paddy thresher was recorded as 1662 and 55, respectively. The reduction in drudgery was observed about 43% as compared to traditional method. The pedal operated paddy thresher is an improved and convenient technology developed for minimizing drudgery and grain losses occurring during traditional threshing operation.

Full text

Indian Journal of Agricultural Sciences 88 (2): 280–3, February 2018/Article
An ergonomic evaluation of pedal operated paddy thresher for farm women
ABHIJIT KHADATKAR1, R R POTDAR2, B S NARWARIYA3, H WAKUDKAR4 and U C DUBEY5
ICAR-Central Institute of Agricultural Engineering, Bhopal, Madhya Pradesh 462 038
Received: 24 May 2017; Accepted: 23 October 2017
ABSTRACT
Traditional paddy threshing is a labour intensive operation and mostly carried out by farm women in awkward
posture. In this study, the performance of pedal operated paddy thresher was evaluated with 12 farm women and
compared with traditional method, i.e. manual beating of paddy on wooden log. The mean working HR in pedal
operated paddy thresher was found to be 134 beats/min, whereas it was 141 beats/min by traditional method. The
corresponding work pulse (ΔHR) was 51 beats/min. The energy expenditure rate (EER) was 17.71 kJ/min with the
use of paddy thresher whereas traditional method it was recorded as 19.34 kJ/min. It was observed that there was
20% increase in output with paddy thresher. The total cardiac cost of work (TCCW) and physiological cost of work
(PCW) in paddy thresher was recorded as 1662 and 55, respectively. The reduction in drudgery was observed about
43% as compared to traditional method. The pedal operated paddy thresher is an improved and convenient technology
developed for minimizing drudgery and grain losses occurring during traditional threshing operation.
Key words: Cardiac cost, Drudgery, Heart rate, Paddy thresher, Physiological cost, Traditional
1Scientist (e-mail: abhijitnu2@gmail.com), 2Scientist
(e-mail: rrpotdar@gmail.com), 3Research Associate (e-mail:
bsnarwariya87@gmail.com), 4Scientist (e-mail: harsha.wakudkar@
gmail.com), 5Principal Scientist (e-mail: ucdubey1967@gmail.
com)
Agriculture has an important place in Indian economy
and the main work force in it is human power. The women
work force in agriculture and allied sectors is estimated
to be around 97 million which amounts to about 37% of
the total agricultural workers in the country (Anonymous
2014). Table 1 gives the population dynamics of Indian
agricultural worker and it was estimated that by 2020, the
population of agricultural worker will be about 230 million
of which 45% will be the female workers. India is one of
the world's largest producers of white rice and brown rice,
accounting for 20% of all world rice production. In India,
paddy is the principal food crop and its production reached
to a record high of 106.67 million tonnes in 2013-2014 crop
years (Anonymous 2017). In paddy cultivation, women
are the main power source as most of the operation like
sowing, weeding, transplanting, harvesting and threshing
is mainly done by them while men are engaged in other
post-harvest activities. In Madhya Pradesh, participation of
women in rice based cropping system was 40.51% and that
of men was 59.49%. Also, the maximum participation of
women was observed in rice crop (78.18%), followed by
wheat (12.76%), eld pea (3.22%) and blackgram (2.41%)
(Anonymous 2012).
According to Kathrivel and Shivkumar (2003),
threshing operation consumes 25% of the total energy
utilized in paddy cultivation. Traditional threshing is the
most drudgery prone operation performed by farm women
by beating the paddy bundle on stones or wooden platform
in bending posture. Working in a bending posture causes
more drudgery which needs to be eliminated with suitable
technology. In paddy threshing, farm women have to bend
over the work surface which is main cause of drudgery. This
drudgery can be minimized by using improved technology,
i.e. pedal operated paddy thresher.
Tiwari et al. (2011) in his study found that pedalling
is the most efcient way of utilizing power from human
116
Table 1 Population dynamics of Indian agricultural workers
(Banthia, 2004, Census of India 2002, Census of India
2006, Census of India, 2011) (No. in million)
Particular 1991 2001 2011 2020*
Country’s population 846.3 1029 1211 1323
No. of workers as % of
population 37.1 39.0 39.8 42.8
Total no. of workers 313.7 402 482 566
% of agricultural workers
to total workers 67.1 58.2 54.6 40.6
No. of agricultural workers 210.5 234 263 230
No. of male agricultural
workers 136.6 143 165.7 126.5
No. of female agricultural
workers 73.9 91 97.3 103.5
% of females in
agricultural workforce 35.1 39 37.2 45
* Estimated

281February 2018]
muscles. Pedal power enables a person to drive devices at
the same or higher rate as that achieved by hand cranking,
but with far less effort and fatigue. Kwatra et al. (2010)
compared the ergonomic data of farm women by threshing
the paddy bundles with traditional and improved method.
In the study, they found that there was 20.71% reduction in
heart rate with pedal operated paddy thresher as compared
to local one of beating on wooden platform.
Mohanty et al. (2008) worked on paddy thresher with
single and double operators and they found that there was
noticeable reduction in heart rate with double operator,
i.e. 10.82%. The total cardiac cost of work (TCCW) and
physiological cost of work (PCW) reduced by 19.84 and
20% with double operators. They also suggest increasing
the length of threshing drum to 75 cm, so that it can be
operated by two operators comfortably.
The pedal thresher was found 50-70 % more efcient
than manual threshing (Nag et al. 1980, Jena and Mohanty
2014). It was also observed from the study that the working
heart rate and oxygen consumption rate of male worker
required in pedal thresher was 126.5 beats/min and 0.79
l/min whereas for female worker it was 124.3 beats/min
and 0.68 l/min. Also, the relative cost of workload of pedal
thresher was 23.9 and 18.5% lower than that of manual
threshing by male and female workers (Nag et al. 1980).
There are some constraints at small holding farming
to do threshing by power thresher which includes
economic condition, small and scattered land holding and
unavailability/uncertainty in electricity etc. For them the best
way is to do threshing by using human power. Pedal operated
paddy thresher is a gender friendly technology developed to
reduce drudgery involved in threshing. Therefore, there is
necessity to study an ergonomic of farm women involved
in threshing operation of paddy.
MATERIALS AND METHODS
The ergonomic evaluation of paddy threshing operation
was carried out with twelve female agricultural workers
(subjects) of Bhopal district of Central India (Singh 2016).
In this study, two methods of paddy threshing were used
viz., traditional method (manual beating on wooden log)
and improved method (pedal operated paddy thresher).
Both manual beating and pedal thresher was operated for
60 min duration. During threshing with pedal operated
thresher, one person was engaged in supplying the paddy
bundle to the operator and other person was engaged for
manually moving the bundle over thresher and pedalling
the thresher (Fig 1). At the beginning and at the end of each
experiment, the subjects were given sufcient rest so that
all the physiological parameters regained to their normal
level. After achieving the resting heart rate, the subjects were
asked to perform the threshing operation by beating paddy
crop on wooden log for 60 min duration and then rest of
15 min was given to regain the physiological parameter to
its resting level. Same procedure was followed with pedal
operated paddy thresher with sufcient rest period between
the two methods of operation. The data were recorded for
both the threshing methods. The detail specication of the
thresher used in the study is given in Table 2.
The subjects selected were from the age group of
20-45 years as the highest strength level was obtained
between this age group. All the subjects were right handed,
physically t and well-practiced with both the means of
paddy threshing. The physiological responses of female
subjects were measured while threshing with traditional
method as well as improved method. The subjects were
familiarized with experiment procedure and were screened
for postural abnormalities or any occupational problems.
Before conducting the experiments for measurement
of physiological responses, each subject was checked
for cardiovascular, neuromuscular and musculoskeletal
disorders. The physical and physiological characteristics
namely age, weight, stature and maximum heart rate of
the selected subjects were also measured. A weighing
balance (100 kg capacity, least count 0.1 kg) was used for
the measurement of weight, stature was measured using
anthropometer and maximum heart rate was determined
by using the equation “220 - age (in years)”.
Before starting the activity subjects were given sufcient
rest to determine the resting heart rate (HR rest). The resting
data was noted for 15 min prior to any experiment.
The HR was measured by heart rate monitor of Polar
117
Fig 1 Paddy threshing with pedal operated paddy thresher
Table 2 Salient specications of the pedal operated paddy thresher
Specication Dimension
Overall dimension (l × w × h), mm 670 × 750 × 990
Weight, kg 39
Number of slats 10
No. of wire loops/slat 8-9
Capacity, kg/h 35
Power source one woman
ERGONOMIC EVALUATION OF PADDY THRESHER

282 [Indian Journal of Agricultural Sciences 88 (2)
make. The polar transmitter detects the HR and transmits it
to the wrist receiver.It is generally considered that the heart
rate gets stable after 3-5th minute of the work thereby HR
work and the OCR was measured between 6th to 60th minute
of work of each subject. The average HR and OCR were
taken for computational work. The oxygen consumption rate
(OCR) of subject on their measured heart rate was estimated
based on general equation as given by Singh et al. (2008).
OCR = 0.0114 × - 0.68 (1)
where, X = heart rate
The energy expenditure rate was measured by
multiplying the OCR (l/min) with 20.93 kJ (1 litre = 20.93 kJ)
EER= OCR × 20.93 (2)
The increase in heart rate per kg of grain threshed
(Δ HRKG) was determined by the following formula given
by Solanki et al. (2006):
Δ HRKG = [ΔHR/C].60 (3)
where, ΔHR = (Mean working HR – Resting HR), beats/min
C = Capacity of the thresher, kg/h
The total cardiac cost of the work can be obtained by
adding cardiac cost of work and cardiac cost of recovery.
When this total cardiac cost of work is divided by duration
for which this activity carried out, it gives physiological
cost of work. Following formulae were used to calculate
the total cardiac cost of work (TCCW) and physiological
costof work (PCW) (Singh et al. 2007).
CCW = ΔHR .tA ................ (4)
CCR = (AHR recovery - AHR rest).tR ................ (5)
where, CCW = Cardiac cost of work
ΔHR = Mean working heart rate – Mean resting heart
rate, tA = duration of activity, CCR = cardiac cost of
recovery, AHR recovery = Average recovery HR, AHR rest
= Average resting HR, tR = duration of recovery.
At the end of each experiment, the subjects were asked
to indicate their Overall Discomfort Rating (ODR) on visual
analogue discomfort scale from 0 to 10 (0-no discomfort,
10-extreme discomfort). To measure Body part discomfort
score (BPDS), a score based technique was followed
(Corlett and Bishop 1976). In this technique, the subject’s
body is divided into 12 regions and the subjects were asked
to indicate and score the painful regions from 0-10 point
scale. The subject was asked to mention all body parts with
their discomfort score, starting with the most painful and
the next painful and so on until all painful body parts have
been mentioned.
The data on performance of paddy threshing with
traditional as well as pedal operated paddy thresher, i.e.
output capacity and physiological responses like work
pulse (ΔHR), and subjective responses namely ODR and
BPDS during threshing operation were statistically analysed
using t-test. Analysis of variance (ANNOVA) was used for
comparing the results.
RESULTS AND DISCUSSION
Ergonomic evaluation of paddy threshing
It was observed that with pedal operated paddy
thresher the mean HR during work was 134 beats/min
and corresponding work pulse (Δ HR) was 51 beats/min.
The oxygen consumption rate (OCR) was 0.846 l/min and
the energy expenditure rate (EER) was found to be 17.71
kJ/min. In traditional system, i.e. by manual beating on
wooden log, the mean HR was found to be 141 beats/
min and corresponding work pulse (Δ HR) was 51 beats/
min. During manual beating the energy expenditure and
oxygen consumption was high and it was recorded as
19.34 kJ/min and 0.924 l/min, respectively. According
to categorization of the agricultural work given by
Nag et al. 1980, pedal operated paddy thresher work can be
put in the category of ‘moderate’ work but with the manual
beating of paddy on wooden log it is a ‘heavy’ category
work (Table 3).
Table 4 gives the comparison of physiological
parameters with manual beating and pedal operated paddy
thresher. The data on increase in heart rate per kg of grain
threshed indicated that manual beating is more drudgery
causing way of threshing as compared to improved method.
In pedal operated paddy thresher this value was 78 beats/
kg whereas it was 82 beats/kg in manual beating.
Physiological cost of work
The total cardiac cost of work (TCCW) and physiological
cost of work (PCW) was 1662 and 55 with pedal operated
paddy thresher and 1676 and 56 with traditional system as
shown in Table 4. In manual beating, worker has to raise
hand above the shoulder which is avoided in pedal thresher.
In pedal thresher combination of hand movement over drum
and leg are required. It is well known that human leg has
more strength than the other body part and thus ensuring
the pedalling the most efcient way of utilizing power from
human muscles and accordingly improved technology have
to developed.
Output capacity
The output capacity of the thresher was 39 kg/h as
against 31 kg/h in manual beating of paddy. It was observed
that there was 20% increase in output with paddy thresher. It
is predicted that increase in output may be due to increased
in number of strokes which resulted in more peripheral
speed of the threshing drum and thus the output.
Overall discomfort rate and body part discomfort score
118
Table 3 Categorization of the agricultural work (Nag et al. 1980)
Variable Light Moderate Heavy Extremely heavy
O2 consumption
(l/min)
0-0.435 0.436-
0.870
0.871-
1.305
>1.306
Energy cost
(kJ/min)
<9.10 9.11-
18.15
18.16-
27.22
>27.23
KHADAKAR ET AL.

283February 2018] ERGONOMIC EVALUATION OF PADDY THRESHER
The average ODR and BPDS of paddy threshing
operation was higher with traditional method than pedal
operated paddy thresher. The ODR and BPDS with
traditional method was 7.3 and 77, respectively. Whereas,
it was 4.1 and 54 with pedal operated paddy thresher. It was
observed that there was 43% drudgery reduction in ODR
and 30% reduction in drudgery with BPDS as compared to
traditional system. All the subjects experienced discomfort
mostly in lower leg and lower back. In pedal operated paddy
thresher, continuous pedalling is required for undisturbed
work which results in pain at lower leg whereas in manual
beating of paddy crop, the body part discomfort was mainly
in shoulder, in lower back due to bending working posture.
The ANOVA for threshing operation with pedal operated
paddy thresher and traditional method were signicantly
different (P<0.05) for ΔHR, output capacity, ODR and
BPDS. The ΔHR, ODR and BPDS were signicantly higher
in traditional method of paddy threshing as compared to
pedal operated paddy thresher. This indicated that the
drudgery in paddy threshing operation with pedal operated
paddy thresher was reduced. Similarly, the output capacity
with pedal operated paddy thresher was signicantly higher
than the traditional method.
The mean HR in pedal operated paddy thresher was 134
beats/min whereas it was 141 beats/min in manual beating of
paddy. The corresponding work pulse (ΔHR) was 51 beats/
min. The data on energy expenditure showed that manual
beating is heavy work and pedal threshing is moderate work
carried out by farm women. Also, on small scale threshing is
done by manual beating which leads to grain loss, which is
addressed through the use of pedal operated paddy thresher.
In our study on farm women we had higher output, i.e. 39
kg/h as against the 31 kg/h in manual beating. It was observed
that there was 20% increase in output with pedal operated
paddy thresher along with 30 and 43% drudgery reduction
based on ODR and BPDS, respectively as compared to
traditional method. Also, the postural analysis indicated
that threshing with pedal operated paddy thresher had less
bending and repetitive action of body parts.
119
REFERENCES
Anonymous. 2012. Empowering Women in Agriculture. ICAR-
DARE/Annual report 2011-12/Women in agriculture-11-12,
pp 93-5. Accessed at http://www.icar.org.in/les/reports/icar-
dare-annual-reports/2011-12/gender-issues-AR-2011-12.pdf
Anonymous. 2014. Research highlights of All India Coordinated
Research Project on Ergonomics and Safety in Agriculture,
CIAE, Bhopal. Technical Bulletin No. CIAE/2014/176.
Anonymous. 2017. AGRICULTURE - Statistical Year Book India
2016. Ministry of Statistics and Programme Implementation.
Accessed at http://www.mospi.gov.in/statistical-year-book-
india/2016/177.
Banthia J K. 2004. Census of India 2001 - Primary Census
Abstracts. Registrar General and Census Commissioner,
Government of India.
Census of India. 2002. India Vision 2020. Planning commission,
Government of India, New Delhi.
Census of India. 2006. Population projections for India and
States 2001-06, Report of the technical group on population
projections, National Commission on Population, Government
of India, New Delhi.
Census of India. 2011. Ofce of the Registrar General and Census
Commissioner, Ministry of Home Affairs, Government of India.
Corlett E N and R P Bishop. 1976. A technique for measuring
postural discomfort. Ergonomics 9: 175–82.
Jena D and Mohanty S K. 2014. Circulo-respiratory efciency of
agricultural workers in Odisha, India. International Journal of
Scientic and Technology Research 3(7): 265–9.
Kathrivel K and Sivakumar S S. 2003. Empowerment of women
in agriculture. Coordination Committee Report of AICRP
on Ergonomics and Safety bin Agriculture, 30, Tamil Nadu
Agricultural University, India.
Kwatra S, Deepa V and Sharma S. 2010. A comparative study on the
manual beating of paddy and manually operated paddy thresher
on farm women. Journal of Human Ecology 32(3): 183–7.
Mohanty S K, Behera B K and Satapathy G C. 2008. Ergonomics
of farm women in manual paddy threshing. Agricultural
Engineering International: the CIGR E Journal 10: Manuscript
MES 08 002.
Nag P K, Sebastian N C and Mavlankar M G. 1980. Occupational
workload of Indian agricultural workers. Ergonomics
23(2): 91–102.
Singh S P, Gite L P, Majumder J and Agarwal N. 2008. Aerobic
capacity of farm women using sub-maximal exercise technique
on tread mill. Agricultural Engineering International: the CIGR
E Journal. 10: Manuscript MES 08 001.
Singh S P, Mathur P and Rathore M. 2007. Weeders for drudgery
reduction of women farm workers in India. Journal of
Agricultural Engineering 44(3): 33–8.
Singh S P. 2016. Number of workers for assessing physiological
workload while operating farm equipment. Agriculture
Engineering Today 40(4): 36–41.
Solanki S N, Ramteke R T, Kawade S C and Gite L P. 2006.
Ergonomics evaluation of hand operated maize shellers. Journal
of Agricultural Engineering 43(4): 119–25.
Tiwari P S, Gite L P, Pandey M M and Shrivastava A K. 2011.
Pedal power for occupational activities: Effect of power output
and pedalling rate on physiological responses. International
Journal of Industrial Ergonomics 41: 261–7.
Table 4 Comparison of physiological parameter of threshing
operation
Parameter Threshing operation
Manual beating on
wooden log
Pedal operated
paddy thresher
HR avg, (beats/min) 141 134
EE avg, (kJ/min) 19.34 17.71
OCR, ( l/min) 0.924 0.846
Δ HRKG, (beats/kg) 82 78
TCCW 1676 1662
PCW 56 55
ODR 7.3 4.1
BPDS 77 54
Output, (kg/h) 31 39