Energy use Efficiency and Economic Feasibility of Self-propelled Single Row Cotton Picker over Traditional Cotton Picking Practices

Cotton cultivation and production has been increasing quantitatively in the country over the years which is estimated to be around 13 million hectares with a productivity of 486 kg ha-1 and a production of 343.47 lakh bales in the year 2022-23 (Committee on Cotton Production and Consumption (COCPC), 2023), respectively. Cotton farming in India provides livelihood to 6 million farmers and around 40 -50 million people are employed in its trade and processing. Although 41 per cent of the total area under cotton in the world is accounted by India, the average productivity of cotton is still low as compared to the world average of 762 kg ha^-1 (COCPC, 2023) because of the cultural practices and staggered blooming characteristics. More than 4 million cotton farms in India are less than 5 acres making them incapable of practicing large scale mechanization.
       
India, being one of the five largest cotton producing countries in the world, the entire cotton is picked manually. Seed cotton (kapas) picking consumes 231 to 975 (average 517) labour-h ha^-1 with conventional practice of hand picking. An exceptionally good picker in a heavy crop will pick up to 68 kg day^-1 of clean cotton but average lies much below than 50 kg day^-1 (Prasad  et al., 2007). Since labour is fast becoming a bottleneck and important cost factor and therefore manual picking will soon become unviable in Indian cotton production. Increase in the wage rate of human labour is the major factor responsible for the drastic rise in cost of cotton cultivation which accounts for 30% of the total cost of cultivation (Reddy et al., 2018). Hence, the key in reducing the cost of cultivation of cotton is by reducing the dependency on human labour which can be achieved by the advent of mechanization.
       
Mechanization in cotton picking is considered to be of vital importance at present situation. Efforts were made in the past by various research organizations in developing knapsack pneumatic cotton pickers, power tiller mounted and tractor drawn pickers but none of them could find its place and satisfy the requirement of small land holding farmers. Barring these few instances, this area of research and development was not given much attention and a holistic approach has been lacking. Considering the issues and challenges with respect to high operation costs, labour scarcity and adaption to various field condition, a research work has been undertaken to design, develop and evaluate a self-propelled single row cotton picker.
       
A self-propelled single row cotton picker was developed and evaluated for its performance. The current paper highlights the economic feasibility of the developed self-propelled single row cotton picker and its impact on the traditional cotton picking practices. Energy use efficiency and net energy spent in machine harvesting and manual picking were calculated.

Traditional cotton picking practices
 
Cotton picking in India has predominantly been a manual process. Cotton picking is an important source of employment for women in rural areas providing supplementary income. Workers, often women and children, would go into the fields and carefully handpick cotton bolls from the plants. This method allows for selective harvesting, ensuring that only mature cotton bolls are collected while leaving immature ones to ripen further. Manual pickers typically carry baskets or cloth bags to collect the harvested cotton. These containers are lightweight and easy to carry, allowing pickers to move efficiently through the fields (Fig 1).


       
In many rural areas of India, cotton picking has traditionally been a communal activity. Families or groups of villagers would come together to help each other with the harvest, fostering a sense of community and cooperation. In Manual picking, workers spend 75 to 85% of their time in the intermediate storage and collection whereas only 15 to 25% of the time is spent on actual picking of cotton buds (Brittany et al., 2017).
       
Labour availability has dropped from 70.3% of the population in 1961 to 48.9% in 2010 and cost of picking cotton from the farm has increased to Rs. 10-12 a kg now from Rs. 4 in 2007 (Business Line, 2012). Hence, the key in reducing the cost of cotton production is by reducing the dependency on human labour which can be achieved by the advent of mechanization.
       
The time taken for manual picking of cotton was collected by noting the time taken to pick open cotton bolls on each plant and replicated it for a hectare. On an average 44,444 plants are sown in a hectare with a spacing of 120 x 40 cm (row to row x plant to plant) (Gunasekaran et al., 2020). The average time noted for manual picking of cotton was calculated as 517 labour hr ha^-1.
 
Self-propelled single row cotton picker
 
Machine with an overall working volume of 1 m³ with 8 picking rollers and provision to adjust the converging angle between 4-8o. It consisted of gearbox, picking rollers, main frame, hydraulic drive system, crop guiding unit and inspection system (Fig 2). Main frame constitutes two parts viz., gearbox frame and picker roller frame held together by bolt and nut connection. Gearbox with hydraulic motors is welded to the front end of the main frame. Output shafts of the gearbox are connected with universal couplings. One end of the picking roller is connected to universal coupling and other end to the 3-way adjustable supporting frame. Rubber embedded stripper plates are arranged parallel to rotating rollers to clean the picking elements. Crop guiding unit is provided at the bottom along with collection trough to collect and avoid ground loss. Crop inspection system consists of a camera arranged at the plant entrance and a display at drivers’ dashboard to guide the operator in the field. Machine travels over cotton crop canopy for picking of cotton bolls from all the sides without crushing the plant.


 
Field capacity
 
It is the actual area covered by the machine based on its total time consumed and actual working width under field condition. It is expressed in terms of area covered per unit time of operation. It is calculated by Kepner et al., 2005 as
 

  

 
Field efficiency
 
Field efficiency is the actual average rate of coverage by the machine, based upon the total operation set time. It is a function of the rated width of the machine, speed of operation and the amount of time lost during the operations. Effective field capacity is usually expressed as hectare per hour (Kepner et al., 2005).
 

  

 
Energy consumption
 
Efficient use of the energy resources is vital in terms of increasing production, productivity, competitiveness of agriculture, as well as ensuring sustainability. Energy spent in harvesting the crop by manual and machine picking was assessed to predict the energy use efficiency, productivity and net energy through inputs spent.
       
Energy input in traditional picking include man hour’s alone expressed in megajoules per hectare (MJ ha^-1). Energy value of human was taken as 1.96 MJ h^-1 and cotton as 11.80 MJ ha^-1 (Gokdogan  et al., 2016). Energy input in the mechanical picking include the amount of diesel fuel consumed and the man hour’s spent during harvesting.
Diesel fuel energy input was determined by:
 

                                Ef = 47.78 D        …(Pandey et al., 2022)                       

Where,
E_f = Fuel (diesel) energy spent, MJ h^-1.
47.78 = Unit energy value of diesel, MJ l^-1.
D = Amount of fuel consumed, l h^-1.
       
Energy use efficiency, energy productivity, specific energy and net energy were calculated by given formula (Yilmaz et al., 2004) (Zahedi et al., 2014) (Gokdogan et al., 2016), respectively. Energy output is the cotton yield obtained through traditional and mechanized sowing expressed in terms of megajoules per hectare (MJ ha^-1).  The crop output was measured by weighing the cotton (collected cotton and ground loss) during the harvest and averaged.
 

 

 

 

 

 

    

Net energy = Energy output (MJ ha^-1) - Energy input (MJ ha^-1)

 
Cost economics
 
Cost of operation (Rs. h^-1 and Rs. h^-1), Break-even point, Payback period and Benefit cost ratio of the self-propelled single row cotton picker was calculated as per the procedure described by IS: 9164-1979. The fixed and variable costs were taken into consideration to estimate the cost of operation per hectare and cost of operation per hour. Straight line method was adopted and detailed calculations are given in Table 1 (Hunt, 2001).


       
Also, conventional practices of manual picking were studied and capacity of the manual labours in terms of man-hours ha^-1 and kg day^-1 were determined. The costs incurred in both conventional and mechanical cotton picking were compared and savings in cost was pointed out.
 
Break-even point
 
The break-even point is defined as the point at which neither profit is made nor loss incurred. The break-even point is equal to the annual fixed cost divided by difference between the custom rate per hour and the operating cost per hour. The break-even point was calculated as (Mohan et al., 2023).  
 

 

                                                                                                             
Where,
AFC = Annual fixed cost for the machine, Rs. yr^-1.
CF = Custom fee, Rs. h^-1.
C = Operating fee, Rs. h^-1.
CF = Cost of operation h + 25% overhead charges) + (25% profit over new cost.

Payback period
 
It is the number of years it would take for an investment to return its original cost through the annual cash revenue it generates, if the net cash revenues are constant each year. the payback period is calculated as (Mohan et al., 2023).
 

             

                                                                                                                        
Where,
PEP = Payback period, yr.
IC = Initial cost of the machine, Rs.
ANP = Average net annual profit, Rs yr^-1.
ANP = (CF - C) AU.
AU = Annual use, h yr^-1.
 
Benefit cost ratio
 
Benefit cost ratio is used to determine the relationship between the cost and benefits from the machine. Benefit cost ratio should be more than one.
 

Benefit cost per hectare = Cost of manual picking - Cost of machine picking

 
Therefore,
 

 

                                                                                                                                                                                                                    (Mohan et al., 2023)

Impact of traditional cotton picking on the production cost and energy spent in the field was analyzed and compared with mechanized harvesting and is presented under the following subheads. Fixed and variable costs of the manual and machine picking were calculated and tabulated in Table 1. Energy consumption in both practices was calculated and presented below.
 
Field capacity
 
The actual field capacity and efficiency of single row cotton picker was found to be 0.14 ha h^-1 at a forward speed of 1.0 km h^-1, 0.22 ha h-1 at a forward speed of 1.7 km h^-1 and, 0.30 ha h^-1 at a forward speed of 2.5 km h^-1. Maximum field capacity was noted at a travelling speed of 2.5 km h^-1 and maximum efficiency was found to be 85.4% at a forward speed of 1.0 km h^-1.

Performance parameters
 
Single row cotton picker was evaluated for its performance with picking capacity, collection efficiency, ground loss and thrash content. Maximum picking capacity was found to be 379.10 kg h^-1 at a forward speed of 2.5 kmph with a roller speed of 177 rpm. Increasing the forward speed from 1.0 to 2.5 kmph resulted in an increased picking capacity by 50% but has a significant effect on the unpicked and trash content. Higher cotton output of 1459.09 kg ha^-1 was noted when forward speed 1.7 km h^-1 matched with a picking roller speed of 177 rpm. Optimum picking efficiency, collection efficiency and trash content of 76.24%, 63.05% and 43.87% was noted at 1.7 km h^-1 and 155 rpm, respectively.
 
Energy consumption
 
Energy spent in case of manual and machine picking was calculated to predict the energy use efficiency, productivity and net energy through inputs spent. Average yield collected during the harvest from traditional varieties was noted as 1500 kg and short duration high yielding varieties as 1800 kg. Energy use efficiency was found to be less in case of manual picking i.e., 17.4% compared to 31.7% in machine picking. Energy productivity in case of manual and machine picking was calculated to be 1.48 kg MJ^-1 and 2.65 kg MJ^-1, respectively. Specific energy per tonne in case of manual picking was high (675.5 MJ ton^-1) due to higher energy input in relation to less crop output. Similar net energy spent was noted by Yilmaz et al., (2004 and Gokdogan et al., (2016). And net energy available per hectare was high in case of machine picking (20,562.0 MJ ha^-1) due to high density sowing practices and high crop output. 
 
Economic feasibility of the developed single row cotton picker
 
Cost of self-propelled single row cotton picker was calculated to be is Rs. 8,50,000.
 
Initial assumptions for self-propelled single row cotton picker (Sahey, 2004)
 
Initial cost of high clearance tractor (C), Rs    :   5,25,000  
Salvage value (S), Rs                                     :   10% of C              
Useful life (IS 9164:1979), (L), years              :   10        
Annual usage (IS 9164:1979) of tractor,        :   480
(H), hours                                                                                            
Interest rate (i), %                                           :       10          
Initial cost of single row cotton                        :     3,00,000
picker (C), Rs                                                                            
Useful life (IS 9164:1979), (L), years              :     10        
Annual usage (IS 9164:1979),                        :      400
(H), hours                                                                                                             

Cost of operation using developed prototype was found to be 789 Rs h^-1 and 5,175 Rs ha^-1 (Table 2). Cost of manual picking was noted as 37.5 Rs h^-1 (Rs. 300 per day) and 18,000 Rs ha^-1 (Considering 3 pickings with 10 manual pickers for 2 days) (Fig 3). About 70% saving in cost and 90% saving in labour hours was noted with machine picking. Custom hiring cost (Rs h^-1) was calculated by adding 25 per cent overhead charges and 25 percent profit over new cost and found to be Rs. 1,232.8 h^-1.




       
Labours hours spent in manual picking was calculated to be 480 man h ha^-1 (Considering 3 pickings per season with 10 manual pickers for 2 days). On the other hand, machine picking consumed 13.62 man h ha^-1 with 90% saving in labour hours compared to manual picking. Similar labour saving was noted by Sharma et al., (2015).
 
Payback period
 
To return the investment through annual cash revenues, the machine should be operated for custom hiring. Custom hiring charges are defined as 25% over cost of machine operation.
Initial cost of machine, Rs                 =                 8,50,000
Custom hiring charge, Rs h-1             =         (Cost of operation,
                                                                       h-1 + 25 per cent                                                                           
                                                                     over head charges)                                                                               
                                                                     + 25 per cent profit
                                                                         over new cost                                                            
                                                             =              1,232.8
Average net annual             =                      (CHC - TOC) x            
benefit, Rs                                                      Annual utility
                                                =                  (1232.8-789) x 400
                                                =                           1,77,520
Payback period, yr               =
       
                                                =                                  
                                                       =                     4.8
Benefit-cost ratio
 
Benefit cost ratio is an indicator that summarize the overall value for money of the machine. Higher the benefit cost ratio greater the profit for the investment and it should always be more than 1. The benefit-cost ratio of the developed machine was 2.5:1.
 
Breakeven analysis
Breakeven analysis was done using two methodologies i.e., theoretical and graphical to ensure the degree of correlation.
 
Custom hiring charge, Rs h-1                       =             1232.8
Total operating cost, Rs h-1                          =                789
Total fixed cost per year, Rs                       =            1,21,680
Breakeven point, h yr-1                                 »                275
Breakeven point, Rs yr-1                               =          BEP´CHC
                                                                         =            3,38,006
       
In first methodology, i.e., from the formula, breakeven was calculated as 275 hours per year with a revenue of Rs. 3,38,006 yr^-1.
       
In second methodology, to construct a breakeven chart, number of hours per year (x) is plotted on X-axis and revenue or cost (Rs.) on Y-axis. Breakeven hours per year and revenue per year are mapped on the chart meeting at a point (275,338006) as depicted in Fig 4. Total fixed cost line i.e., Rs. 1,21,680 is constant for any number of working hours and represented by a straight line passing parallel to X-axis. Custom hiring cost (CHC) starts at point (0,0), increases with increasing working hours and passes through theoretical breakeven point. Total cost line (TCL) represents ‘variable cost(x)+fixed cost’ with increasing working hours and coincides with total CHC line and theoretical breakeven point. From the Fig 4, before BEP (275,338006) the TCL is greater than CHC that means the area between the total CHC line and total cost line represent losses during that period. Whereas, after BEP the TCL is lower than CHC which means the area between CHC and total cost line represent profit.


       
From the graph, breakeven hours per year was found to be 275 h yr^-1 and revenue per year was calculated to be 3,38,006 Rs yr^-1.

Cost of self-propelled single row cotton picker was calculated to be is Rs. 8,50,000. Cost of operation using developed prototype was found to be 789 Rs h^-1 and 5,175 Rs ha^-1 with a saving of 70% compared to manual picking. Labours hours spent in manual picking was calculated to be 480 man h ha^-1 (Considering 3 pickings per season with 10 manual pickers for 2 days). On the other hand, machine picking consumed 13.62 man h ha^-1 with 90% saving in labour hours compared to manual picking. The benefit-cost ratio of the developed machine was 2.5:1. Payback period of the machine was calculated as 4.8 years. Breakeven analysis was done using two methodologies i.e., theoretical and graphical to ensure the correctness and was found to be 275 h yr^-1. Energy use efficiency was found to be less in case of manual picking i.e., 17.4% compared to 31.7% in machine picking. Similarly, energy productivity in case of manual and machine picking was calculated to be 1.48 kg MJ^-1 and 2.65 kg MJ^-1, respectively. And net energy available per hectare was high in case of machine picking (20,562.0 MJ ha^-1) due to high density sowing practices and high crop output.

The authors acknowledge Dr. NTR College of Agricultural Engineering, Acharya N.G. Ranga Agricultural University, Bapatla and Regional Agricultural Research Station, Tirupati for funding and facilities provided to the research.
 
Disclaimers
 
The views and conclusions expressed in this article are solely those of the authors and do not necessarily represent the views of their affiliated institutions. The authors are responsible for the accuracy and completeness of the information provided, but do not accept any liability for any direct or indirect losses resulting from the use of this content.
 
Informed consent
 
No personal or identifiable information was collected, ensuring confidentiality and anonymity. The study adhered to ethical research standards and data was collected with the full awareness and consent of the involved stakeholders.