Abstract:
Addressing the global population surge expected to reach 10.4 billion by the
mid-2080s, especially in densely populated regions like India, poses significant
agricultural challenges. Integrating pulses into sustainable agriculture is crucial for food
security due to their benefits in enhancing soil fertility and resilient ecosystems. This
study focuses on developing a tractor operated pneumatic no-till pulse planter with
electronic control system for black gram and horse gram, essential pulses in Kerala.
Traditional planting methods are labor-intensive, inefficient and costly. The proposed
planter ensures accurate seed placement, uniform emergence, and minimal soil
disturbance. An electronic control system enhances precision in seed spacing placement
and improves overall efficiency.
The objectives of the study include determining seed properties, developing
planter with electronic control system, and evaluating the planter performance. A
vacuum disc-type metering mechanism was chosen for its precision in seed singulation,
minimal damage, and adaptability to various seed sizes and shapes. The investigation
included laboratory experiments for seed metering mechanisms, calibration, testing, and
field performance evaluation of the pneumatic planter for the black gram (VBN-6) and
horse gram (KS-2) seeds. Optimal settings for vacuum pressure, plate hole size, forward
speed, and the location of sensors were identified through extensive trials and statistical
analysis. The study observed that black gram seeds have a length of 2.32-3.88 mm,
width of 1.99-3.65 mm, and thickness of 1.56-2.07 mm, whereas horse gram seeds are
larger, with a length of 6.02-6.27 mm, width of 4.10-4.35 mm, and thickness of 2.16-
2.45 mm. The mean diameter of black gram seeds is 2.62 mm, and for horse gram, it is
4.22 mm. The optimum terminal velocity is 8.21 m s-1 for black gram and 8.68 m s-1 for
horse gram. The pneumatic planter uses a vacuum disc-type precision seed metering
mechanism with a vertically oriented rotating disc and an aspirator blower to ensure
precise seed placement. The planter was modified using electronically controlled
system using a stepper motor, which was regulated by a microcontroller for precise seed
plate rotation. The electronic system includes a stepper motor, rotary encoder, proximity
sensor, Arduino Nano microcontroller, vacuum pressure sensor, micro-step drive,
battery, and protective enclosure. The proximity sensor detects wheel spokes, the rotary
encoder provides speed and position feedback, and the vacuum sensor activates the
system under optimal conditions.
Laboratory experimental results on the pneumatic seed metering mechanism for
black gram and horse gram showed optimal seed spacing and reduced miss and multiple
indices with specific settings. The use of encoder sensor ensured the required spacing
of 15.0 cm with a lower miss index of 1-3 percent compared to the proximity sensor.
Smaller hole sizes and higher vacuum pressures improved seed placement accuracy.
The optimal spacing for horse gram was achieved with a 2.1 mm hole size, 4.0 kPa
vacuum pressure, and 1.0 km h-1 speed, resulted the required spacing of 9.2-12.9 cm
and with the lower miss index of 0.5 percent with encoder sensor. Encoder sensor,
forward speed of 2 km h-1 and vacuum pressure of 4 kPa were selected for field
evaluation. Field evaluation of a pneumatic planter with electronic controls for black
gram and horse gram assessed impact with different type of furrow opener and locations
of the encoder. When the location of encoder on steel wheel with shoe type furrow
opener was used a spacing of 14.8 cm was obtained a consistent miss index of 1.2
percent for black gram. The encoder on the steel wheel lowered the multiple index to
2.5-2.7 percent and improved quality of feed index from 96-96.2 percent for black gram.
Similar type of result showed with horse gram. The location of the encoder on the steel
wheel showed better results compared to its location on the pneumatic wheel due to
reduced slippage. Inverted t-type furrow opener work well in no-till field. Germination
rates were optimal at 95-96 percent in both black and horse gram. The study
recommended the location of encoder on steel wheel with shoe-type furrow opener
showed best performance. The field capacity and field efficiency of planter was 0.25 ha
h-1 and 90 percent respectively.
The total cost of the developed planter with electronic control system was
₹1,80,000. The pneumatic planter with electronic controls incurred an operating cost as
₹860.55 per hour and ₹3072 per hectare. As per the prevailing wage rates, the cost for
manual sowing is ₹4054 per hectare, the planter saved ₹982 per hectare. Hence, the 24
percent saving in cost of operation is found out ensured by using this developed planter.
Break-even point of 79.22 hours per year and a payback period of 1.13 years are
expected. It is concluded that the pneumatic planter with electronic control significantly
improves planting performance for black gram and horse gram by ensuring precise seed
placement, reducing misses and multiples, and enhancing quality and precision indices.
Economic analysis confirms its cost-effectiveness and potential to increase crop
productivity and profitability for farmers.