## 1 Introduction  
Energy is a valuable input in the realm of production agriculture. Availability of adequate and appropriate energy supply, along with its effective and efficient utilization, is essential for a cost-efficient agricultural production. Amongst the agricultural operations, tillage (seed-bed preparation) consumes about 25% of available energy from the prime mover equipment such as tractor. Importantly, fossil fuels account for 92% of this energy supply [1; 2; 3; 4]. Numerous studies have examined energy requirements of tractor-implement systems under different operational conditions such as working depth, speed [4; 5; 6; 7; 8], soil types, soil moisture, and compaction levels [9]. It has also been claimed that compared to tillage, the intercultural operations such as weeding require more energy [10]. Mechanical weeding is still by far the most deployed method of weeding, although traditionally, weeding tools were pulled by the draft animals and in modern times by self-propelled or tractor machinery. These tools deploy mechanical energy/power derived from chemical energy of the fuels from internal combustion engines to uproot, cut, and bury the weeds. Mechanical weeding tools are intended to control weeds in both inter and intra-row regions around the crops. The inter-row weeds are those present between the rows while intra-row weeds are the ones between the plants within the rows [11]. Commercially available mechanical weeders can control the inter-row weeds as a standalone operation; however, eradicating intra-row weeds is still a challenge and therefore they are mostly controlled manually. Manual weed control has its own challenges of being tedious, expensive, and inductive of health hazards. The biggest challenge against mechanical weeding of intra-row weeds is avoiding plant damage. Prior studies have reported around 33% of crop yield loss due to mechanical intra-row weeding operations [12; 13; 14; 15]. The period of crop-weed competition is 4-5 weeks after plantation and is therefore the instance when the first weeding is recommended, followed by second and third as the need arises. Most importantly, inter-, and intra-row weeding operations are conducted separately. All these frequencies of machinery operations for only weeding operations demand excessive energy and cost requirements, and fossil fuel consumptions thereby endangering production sustainability. In lieu of this situation, an intra-row weeding system that is efficient in operation and results in minimal crop damage is desired. A prototype of a vertical axis rotor weeder (RVA), to eradicate weeds by cutting, uprooting, or mixing in soil was designed and developed. A sensor-based vertical axis rotor (RVA) type weeder was developed that is simple in design, offers easy attachment and detachment with a tractor. RVA has been suggested to have low tractor draught requirements and losses from rolling resistance and wheel slips. RVA is also a widely used equipment for secondary tillage operation [16; 17; 18; 19; 20; 21]. Importantly, vertical axis rotors do not produce tillage hardpans compared to power take-off (PTO)-driven rotary tillers. Furthermore, the soil pulverization capacity of RVA can be adjusted by adjusting the travel and angular speeds of the rotor [22; 23; 24; 25; 26]. Energy consumption during a farm operation is one of the most important considerations for researchers, design engineers, and manufacturers when designing/developing agricultural machinery. An optimal management of this energy consumption can optimize fuel consumption and operation costs. This essentially requires design engineers/researchers to have in-depth knowledge of computing specific energy requirements of the soil engaging tool. The specific energy requirements of a soil-engaging tool can be influenced by multiple factors, including the design and operational parameters of the tool and the soil properties.