The growing demand for agricultural output and limited resources encourage precision applications to generate higher-order output by utilizing minimal inputs of seed, fertilizer, land, and water. An electronically operated planter was developed, considering problems like ground-wheel skidding, field vibration, and the lack of ease in field adjustments of ground-wheel-driven seed-metering plates. The seed-metering plate of each unit of the developed planter is individually driven by a brushless direct current (BLDC) motor, and a BLDC motor-based aspirator is attached for pneumatic suction of seeds. The revolutions per minute (RPM) of the seed-metering plate are controlled by a microcontroller as per the received data relating to RPM from the ground wheel and the current RPM of the seed-metering plate. A feedback loop with proportional integral derivative (PID) control is responsible for reducing the error. Additionally, each row unit is attached to a parallelogram-based depth control system that can provide depth between 0 and 100 mm. The suction pressure in each unit is regulated as per seed type using the RPM control knob of an individual BLDC motor-based aspirator. The row-to-row spacing can be changed from 350 mm to any desired spacing. The cotton variety selected for the study was RCH 659, and the crucial parameters like orifice size, vacuum pressure, and forward speed were optimized in the laboratory with the adoption of a central composite rotatable design. An orifice diameter of 2.947 mm with vacuum pressure of 3.961 kPa and forward speed of 4.261 km/h was found optimal. A quality feed index of 93% with a precision index of 8.01% was observed from laboratory tests under optimized conditions. Quality feed index and precision index values of 88.8 and 12.75%, respectively, were obtained from field tests under optimized conditions.

Pneumatic planters are widely adopted in precision agriculture due to their superior field performance and minimal seed damage. However, variations in seed size, shape, and orientation can affect the ability of each orifice to pick and release a single seed accurately. Seed metering units typically incorporate seed cut-off and knock-out devices to improve singulation and ensure timely seed dropping, enhancing the quality feed index and reducing the precision index. These auxiliary devices—whether mechanical, electronic, pneumatic, or magnetic—increase system complexity, require skilled operation, necessitate additional maintenance, consume more energy, and heighten the risk of seed damage. The suctioned seed experiences impact from the seed metering plate during picking, and orifices are not fully sealed after seed pick-up, leading to a need for higher vacuum pressure. Additionally, field vibrations can adversely affect planter performance. To overcome these issues, this study developed a novel flexible orifice seed metering plate and optimised its operating parameters for cotton seed, adopting a central composite rotatable design (CCRD). The plates were developed by adding a layer of elastomeric material on rigid seed metering plate. The experiments were conducted using a developed electronic sticky belt setup in laboratory. An orifice diameter of 3 mm, vacuum pressure of 3.40 kPa, forward speed of 4.67 km/h, extended radius of 1 mm and coating thickness of 0.25 mm were found optimum with a quality feed index of 97.289% and precision index of 4.653%. Minimal difference between laboratory and field performance was noted when operated by an electronic planter. The miss index, multiple index, and precision index obtained under field conditions with rigid seed metering plate were found to be 4.4, 2.8, and 9.08% higher than coated seed metering plate, respectively. A comparatively lower optimal vacuum pressure and higher operation speed was achieved when coated seed metering plate was used in place of rigid seed metering plate. Hence coated seed metering plate can be a low-cost solution to achieve higher speed of precision planting with improved seeding performance. Graphical Abstract

Cotton, an economically significant crop, incurs high input costs for Bt cotton seeds. Commonly used varieties like RCH 2, Ajeet 155, Ankur 3028, and Suraj exhibit variations in seed size and mass, influencing the design of seed metering plates in pneumatic planters. Typically, each variety requires a specific metering plate optimized for orifice size, vacuum pressure, and operation speed, increasing costs, time loss, and labor dependency. This study aims to design a single seed metering plate accommodating all varieties, optimizing easily adjustable parameters such as vacuum pressure and operational speed. Employing a central composite rotatable design (CCRD), experiments varied orifice diameter (2.5–3.5 mm), vacuum pressure (2.5–5.5 kPa), and speed (2.5–5.5 km/h). Variety-specific optimal values were determined by initial optimisation using the response surface method (RSM). An average orifice diameter of 3 mm was then targeted by a second optimisation stage, which found the corresponding forward speed (4.16–4.22 km/h) and vacuum pressure (3.74–4.11 kPa) for each variant. Cost involved in purchase of different metering plates and timeliness cost associated with changing metering plates is saved and simultaneously precision seed sowing is achieved.

A tunnel sprayer has distinct recycling systems, which save a significant portion of the applied pesticide. Its performance is directly or indirectly influenced by various constructional parameters of the recycling system (nozzle spacing, nozzle angle, tunnel opening, and fin pitch) because they influence the movement of spray droplets, characteristics of the droplets, and recycling rate of the system. Therefore, the effect of these parameters was investigated for improvement in the tunnel sprayer’s performance. In this study, four adjustment mechanisms were developed for selected parameter’s regulation and tested using a hybrid tree (artificial and natural leaf). The non-significant results of spatial spray distribution revealed its accuracy and potential ability for maintaining spray uniformity across the tree canopy, except in the central zone of both trees. By considering the poor spray deposits at the central zone of both trees, the statistical analysis was carried out for spray deposits maximization and recycling rate minimization. The spray deposits varied from 1.016 × 10^− 4 to 2.944 × 10^− 4 µg/mm² and offered better plant protection. The sprayer saved up to 42.36% of the applied pesticide, which ensures economical farm operations and saves the environment. The optimized values for input parameters (i.e., X1: 350 mm, X2: 42.5 degrees, X3: 1100 mm, and X4: 41 mm) would improve the efficiency of the tunnel sprayer and conserve costly input resources.

Cotton is cultivated worldwide covering 32.5 million hectares of cultivable land. Cotton seed are valuable raw input to seed and oil industry. Seed properties are essential requirement for design of equipment used in farm, post-harvest processing, storage, cotton ginning as well as seed industries. Computer simulation study needs basic properties as input. The engineering properties were evaluated for five majorly cultivated cotton cultivars of India. Significant difference in properties was observed between varieties. The results defined cotton seed as a non-spherical particle with length, width and thickness varying between 6.05 to 10.99 mm, 3.73 to 6.91 mm and 2.94 to 5.73 mm respectively. Higher frictional force is generated when it interacts with painted mild steel, wood and rubber than PVC, stainless steel and aluminum. Reynolds number indicates transitional flow of cotton seed and coefficient of restitution identifies it between elastic and plastic body.