Weed infestations pose significant challenges to global crop production, demanding effective and sustainable weed control methods. Traditional approaches, such as chemical herbicides, mechanical tillage, and plastic mulches, are not only associated with environmental concerns but also face challenges like herbicide resistance, soil health, erosion, moisture content, and organic matter depletion. Thermal methods like flaming, streaming, and hot foam distribution are emerging weed control technologies along with directed energy systems of electrical and laser weeding. This paper conducts a comprehensive review of laser weeding technology, comparing it with conventional methods and highlighting its potential environmental benefits. Laser weeding, known for its precision and targeted energy delivery, emerges as a promising alternative to conventional control methods. This review explores various laser weeding platforms, discussing their features, applications, and limitations, with a focus on critical areas for improvement, including dwell time reduction, automated navigation, energy efficiency, affordability, and safety standards. Comparative analyses underscore the advantages of laser weeding, such as reduced environmental impact, minimized soil disturbance, and the potential for sustainable agriculture. This paper concludes by outlining key areas for future research and development to enhance the effectiveness, accessibility, and affordability of laser weeding technology. In summary, laser weeding presents a transformative solution for weed control, aligning with the principles of sustainable and environmentally conscious agriculture, and addressing the limitations of traditional methods.

With recent developments allowing increased planter speeds, improving spatial uniformity of crop emergence will continue to be an important focus of research. Vertical vibration during planting usually interferes with the seed metering and delivery process, and thereby affects seeding quality. Two different row crop planters were instrumented with accelerometers to monitor vertical vibration of planter row units in five fields with a total area of 220 ha in both no-till and strip-tilled conditions. The test results showed that the row unit vibration linearly increased with planting speeds. The R² of each fitting equation was more than 0.90. The main frequencies of the vibration were concentrated in a low-frequency band of 3 Hz to 10 Hz. These frequencies did not show an increasing trend with the planter speed. However, the amplitude clearly increased when the planter speed increased. For the John Deere MaxEmerge™ 5 planter, the manually measured average plant spacing was close to the target plant spacing with a maximum error of 21 mm, and a max coefficient of variation (CV) of 24.3%; the standard deviation (SD) increased with travel speed and row unit vibration. For the John Deere ExactEmerge™ planter, the plant spacing was closer to the target plant spacing with a maximum error of only 5 mm and a max CV of 14.3%; the SD remained almost constant, at lower values than that of the MaxEmerge™ 5, at different speeds. For both planters, overall, the row unit vibration increased planting spatial variability. The quality of feed index decreased with increased vertical acceleration on the row unit while the miss index increased. However, the multiples index was generally unaffected by row unit vibration.

The handling of the remnants of rice crops in the field is not an easy operation, and farmers prefer burning, which causes air pollution, smog, and disease. This research reports the development of a novel precision crop seeder by handling the remnants of previous crops through mechanization. The precision seeder performed multiple operations in a single path, viz, chop residues, incorporate into soil, make mini trenches, and sow wheat with fertilizer application. The precision seeder has a 2040 mm working width, and specially designed C-type blades are used to shred the crop residue. A multiple-speed gearbox with a gear ratio of 1:0.52 is installed, with a further set of spur gears with 16, 18, and 20 teeth that provide 225, 250, 310, and 350 RPMs to the main rotor. In the middle of the seeder, after the main rotor shaft, 11 V-shaped trencher plates are fixed on the trencher roller for the making of trenches. The trencher roller is powered by star wheels, which showed good results. A zero-tillage-type sharp tip edge novel seeder unit was developed for the precise placement of seed and fertilizer. Seed and fertilizer were placed into the mini trenches through 11 seeder units through a ground wheel calibration system. The field capacity of the precision seeder was 0.408 ha/h and the operational cost was calculated 40.68 USD/ha. The seeder showed good results, with the production of 5028 kg/ha compared to conventional methods. The precision seeder provides a mechanized solution for wheat sowing with minimal operational costs by enhancing organic matter in soil with 13% more yield.

Yellow poplar (Liriodendron tulipifera) was chosen as the woody biomass for the production of charcoal for use in a liquid fuel slurry. Charcoal produced from this biomass resulted in a highly porous structure similar to the parent material. Micronized particles were produced from this charcoal using a multi-step milling process and verified using a scanning electron microscope and laser diffraction system. Charcoal particles greater than 50 µm exhibited long needle shapes much like the parent biomass while particles less than 50 µm were produced with aspect ratios closer to unity. Laser diffraction measurements indicated D10, D50, and D90 values of 4.446 µm, 15.83 µm, and 39.69 µm, respectively. Moisture content, ash content, absolute density, and energy content values were also measured for the charcoal particles produced. Calculated volumetric energy density values for the charcoal particles exceeded the No. 2 diesel fuel that would be displaced in a liquid fuel slurry.