Mowing Systems Research Articles

Nexus Between Life Cycle Assessment, Circularity and Sustainability Indicators—Part II: Experimentations

Considering the growing number of metrics and indicators to assess the circular economy transition, it is paramount to shed light on how they complement and differ from traditional approaches, such as life cycle assessment or sustainability performance indicators. This study provides new empirical insights on the correlation between life cycle assessment, circularity, and sustainability indicator-based approaches to design circular and sustainable products. Specifically, the importance lies in analyzing how the results generated by these different approaches can be used to support the design of products that are not only circular but also sustainable. A practice-based project, involving over 175 engineering students over two consecutive academic years, is conducted with the purpose of comparing and improving the circularity and sustainability performance of three product alternatives of lawn mowing systems (gasoline, electric, autonomous). Notably, the following resources are deployed: 18 midpoints environmental indicators calculated by life cycle assessment, nine product circularity indicators, and numerous leading sustainability indicators. Critical analyses on the usability, time efficiency, scientific soundness, and robustness of each approach are drawn, combining quantitative results generated by each group with the feedback of future engineers. Last but not least, the developed workshop could be reused or adapted to train further the designers, engineers, and managers of tomorrow in deploying life cycle, circularity, and/or sustainability-indicator-based approaches to make more informed and sustainable decisions, e.g., between design trade-offs.

A novel solution with rapid Voronoi-based coverage path planning in irregular environment for robotic mowing systems

This paper presents a novel solution of coverage path planning for robotic mowing applications. The planning algorithm is based on the Boustrophedon motions and the rapid Voronoi diagram. The coordinate conversion and the sweeping vector is defined by minimum bounding box and the Voronoi travel paths are designed to reduce the computational cost and execution time compared to conventional heuristic methods. The tracked path is controlled via dynamic feedback in standard lawn mowing robots under robot operating system (ROS). Within ROS, the information exchanging among different tasks of both extensive simulation cases and experimental field tests can be conducted easily. When meeting unknown obstacles, the proposed algorithm can re-plan its paths dynamically. The performance of the proposed algorithm is compared to several conventional coverage algorithms in terms of time efficiency, coverage, repetition, and robustness with respect to both concave and convex shapes. The field tests are conducted to demonstrate that the applicability of the sensor fusion and robustness of the proposed algorithm for the complete coverage tasks by robotic mowers.

Development of User-Integrated Semi-Autonomous Lawn Mowing Systems: A Systems Engineering Perspective and Proposed Architecture

This concept paper outlines a conceptual framework for the design and development of user-integrated semi-autonomous lawn mowing systems. This is approached from a systems engineering perspective, considering both hardware and software elements and integration with the user. This is an important and emerging field of study within the several engineering communities, including robotics, agricultural engineering, smart city development, and general systems engineering. In several sections of this paper, a review of current progress on this problem is presented (both in general and related to specific aspects of the system), followed by a discussion of the problem from a systems engineering perspective, a general system architecture developed by the authors, a preliminary set of design requirements, and a discussion of some practical implementation strategies. This work is meant to provide a baseline and motivation for the further development and refinement of these systems within the agricultural engineering and robotics communities and is relevant to both academic and commercial research.

Energetic Aspects of Turfgrass Mowing: Comparison of Different Rotary Mowing Systems

Turfgrass mowing is one of the most important operations concerning turfgrass maintenance. Over time, different mowing machines have been developed, such as reel mowers, rotary mowers, and flail mowers. Rotary mowers have become the most widespread mowers for their great versatility and easy maintenance. Modern rotary mowers can be equipped with battery-powered electric motors and precise settings, such as blade rpm. The aim of this trial was to evaluate the differences in power consumption of a gasoline-powered rotary mower and a battery-powered rotary mower. Each mower worked on two different turfgrass species (bermudagrass and tall fescue) fertilized with two different nitrogen rates (100 and 200 kg ha−1). The battery-powered mower was set at its lowest and highest blade rpm value, while the gasoline-powered mower was set at full throttle. From the data acquired, it was possible to see that the gasoline-powered mower had a much higher primary energy requirement, independent of the turf species. Moreover, comparing the electricity consumption of the battery-powered mower over time, it was possible to see that the power consumption varied according to the growth rate of both turf species. These results show that there is a partial waste of energy when using a gasoline-powered mower compared to a battery-powered mower.

Comparison between Different Rotary Mowing Systems: Testing a New Method to Calculate Turfgrass Mowing Quality

Poor quality in turfgrass mowing is highlighted by the shredded leaf tips with necrotic tissues that give an unsightly brownish colour to the turf and may also lead to turf disease. Mowing quality is also typically assessed by visual rating, thus the score depends on the person doing the assessment. To make the evaluation of mowing quality not subjective, an innovative method was developed. The aim of the trial was to examine the effects of different mowing systems and two different nitrogen rates (100 and 200 kg ha−1) on two turfgrass species in order to test the new mowing quality calculation. Three different mowing systems were used: a battery-powered rotary mower set at 3000 rpm and 5000 rpm respectively and a gasoline-powered rotary mower set at full throttle. The battery-powered mower at low blade rpm produced a poorer mowing quality and turf quality than the gasoline-powered mower and battery-powered mower at high rpm, which produced a similar mowing quality and turf quality. Leaf tip damage level values showed a significant correlation with the results of the visual mowing quality assessment. Lower leaf tip damage level values (slightly above 1) corresponded to higher visual mowing quality scores (around 8).

Autonomous Rotary Mower versus Ordinary Reel Mower—Effects of Cutting Height and Nitrogen Rate on Manila Grass Turf Quality

High-quality sports turfs often require low mowing and frequent maintenance. Sports turfs often consist of hard-to-mow warm season turfgrasses, such as zoysiagrass (Zoysia sp.) or bermudagrass (Cynodon sp.). Although autonomous mowers have several advantages over manually operated mowers, they are not designed to mow lower than 2.0 cm and are consequently not used on high-quality sports turfs. All autonomous mowers are only equipped with rotary mowing devices and do not perform clipping removal. An ordinary autonomous mower was modified to obtain a prototype autonomous mower cutting at a low height. The prototype autonomous mower was tested on a manila grass (Zoysia matrella) turf and compared its performance in terms of turf quality and energy consumption with an ordinary autonomous mower and with a gasoline reel mower. A three-way factor experimental design with three replications was adopted. Factor A consisted of four nitrogen rates (0, 50, 100, and 150 kg·ha−1), factor B consisted of two mowing systems (autonomous mower vs. walk-behind gasoline reel mower with no clipping removal), and factor C consisted of two mowing heights (1.2 and 3.6 cm). Prototype autonomous mower performed mowing at 1.2-cm mowing height whereas ordinary autonomous mower mowed at 3.6-cm mowing height. The interaction between the mowing system and mowing height showed that the turf quality was higher when the turf was mowed by the autonomous mower and at 1.2 cm than at 3.6 cm. Autonomous mowing not only reduced the mowing quality, but also reduced the leaf width. Lower mowing height induced thinner leaves. Nitrogen fertilization not only increased the overall turf quality, reduced weed cover percentage, but also reduced mowing quality. Autonomous mowers also had a lower energy consumption if compared with the reel mower (1.86 vs. 5.37 kWh/week at 1.2-cm mowing height and 1.79 vs. 2.32 kWh/week at 3.6-cm mowing height, respectively). These results show that autonomous mowers can perform low mowing even on tough-to-mow turfgrass species. They could also be used on high-quality sports turfs, thus saving time as well as reducing noise and pollution.

Autonomous Mower vs. Rotary Mower: Effects on Turf Quality and Weed Control in Tall Fescue Lawn

Autonomous mowers are battery-powered machines designed for lawn mowing that require very low human labour. Autonomous mowers can increase turf quality and reduce local noise and pollution compared with gasoline-powered rotary mowers. However, very little is known about the effects of autonomous mowing on encroaching weeds. The aim of this research was to compare the effects of an autonomous mower and an ordinary gasoline-powered mower on weed development in an artificially infested tall fescue (Festuca arundinacea Schreb.) turf with different nitrogen (N) rates. A three-way factor experimental design with three replications was adopted. Factor A consisted of three N rates (0, 75, and 150 kg ha−1), factor B consisted of two mowing systems (autonomous mower vs. walk-behind gasoline rotary mower equipped for mulching), and factor C which consisted of four different transplanted weed species: (a) Bellis perennis L., (b) Trifolium repens L.; (c) Trifolium subterraneum L.; and (d) Lotus corniculatus L. Of these, B. perennis is a rosette-type plant, while the other three species are creeping-type plants. The interaction between mowing system and transplanted weed species showed that the four transplanted weed species were larger when mowed by the autonomous mower than by the rotary mower. The autonomous mower yielded larger weeds probably because the constant mowing height caused the creeping weed species to grow sideways, since the turfgrass offered no competition for light. N fertilization increased turf quality and mowing quality, and also reduced spontaneous weed infestation. Autonomous mowing increased turf quality, mowing quality, but also the percentage of spontaneous weed cover.

Autonomous Mower Saves Energy and Improves Quality of Tall Fescue Lawn

Battery-powered autonomous mowers are designed to reduce the need of labor for lawn mowing compared with traditional endothermic engine mowers and at the same time to abate local emissions and noise. The aim of this research was to compare autonomous mower with traditional rotary mower on a tall fescue (Festuca arundinacea) lawn under different nitrogen (N) rates. A two-way factor experimental design with three replications was adopted. In the study, four N rates (0, 50, 100, and 150 kg·ha−1) and two mowing systems (autonomous mower vs. gasoline-powered walk-behind rotary mower equipped for mulching) were used. As expected, N fertilization increased turf quality. At the end of the trial, the autonomous mower increased turf density (3.2 shoots/cm2) compared with the rotary mower (2.1 shoots/cm2) and decreased average leaf width (2.1 mm) compared with the rotary mower (2.7 mm). Increased density and decreased leaf width with autonomous mowing yielded higher quality turf (7.3) compared with the rotary mower (6.4) and a lower weed incidence (6% and 9% cover for autonomous mower and rotary mower, respectively). Disease incidence and mowing quality were unaffected by the mowing system. The autonomous mower working time was set to 10 hours per day (≈7.8 hours for mowing and 2.2 hours for recharging) for a surface of 1296 m2. The traditional rotary mower working time for the same surface was 1.02 hours per week. The estimated primary energy consumption for autonomous mower was about 4.80 kWh/week compared with 12.60 kWh/week for gasoline-powered rotary mowing. Based on turf quality aspects and energy consumption, the use of autonomous mowers could be a promising alternative to traditional mowers.

Influence of Different Mowing Systems on Community Characteristics and the Compensatory Growth of Important Species of the Stipa grandis Steppe in Inner Mongolia

The Stipa grandis steppe is a type of steppe in the Central Asian sub-region, and it is an important resource for livestock production in China. Mowing is one of the main management methods for this steppe. Verifying the response of the Stipa grandis steppe communities to different mowing frequencies is essential for the rational utilization of pastures and the protection and recovery of natural steppe. In this study, we investigated the community characteristics and compensatory growth of important species of the Stipa grandis steppe community under four mowing frequencies (TAY: twice a year; OAY: once a year; OTY: once every other year; NM: no mowing/enclosure), and found that different frequencies of mowing significantly influenced the community characteristics and the compensatory growth of dominant plant species. In the enclosure, species density was significantly lower, and height and biomass were significantly greater than in the mowing treatments. At the beginning of the growing season, mowing had a significant impact on the individual miniaturization of Stipa grandis, Leymus chinensis, and Anemarrhena asphodeloides. Mowing also had a significant impact on the diversity of the community. The Shannon diversity index, the Pielou evenness index, and the richness index were higher under OTY than other mowing frequencies. Under different mowing frequencies, growth rates were significantly different after the aboveground portions were cut, while the levels of biomass were not significantly different. Stipa grandis, Leymus chinensis, and Anemarrhena asphodeloides had less compensatory height growth under OAY compared to the other treatments; however, there were no significant differences in the relative growth rates of the three species under different treatments. Stipa grandis exhibited equivalent compensatory height growth; both Leymus chinensis and Anemarrhena asphodeloides exhibited over-compensatory growth. Based on the results of community characteristics and the compensatory growth of the dominant species, mowing every other year is currently the most practical mowing system.

Control of Both Winter Annual and Summer Annual Weeds in No-till Corn with Between-row Mowing Systems

In previous research, summer annual weeds were successfully controlled in no-till corn with between-row mowing systems that consisted of soil-residual preemergence herbicides banded over corn rows followed by mowing weeds close to the soil surface one or two times later during the growing season. The objective of this research was to determine whether between-row mowing systems could successfully control both winter annual and summer annual weeds as well as broadcast herbicides perform in no-till corn. In two of three years in Missouri, between-row mowing systems controlled and reduced both winter annual and summer annual weed cover and prevented weeds from reducing corn yields. Corn yields for the following no-till weed management systems equaled the weed-free check: winter annual weed control with between-row mowing plus preplant, banded, postemergence-applied glyphosate at 1.1 kg ae/ha and later summer annual weed control with postplant, banded, preemergence-applied atrazine plus S-metolachlor at 2.2 plus 1.8 kg ai/ha followed by between-row mowing. Winter annual weeds growing between rows were controlled with one mowing, and later summer annual weeds were controlled with either one late or “middle” mowing or two mowings (i.e., early and late). Total herbicide use was reduced 50% (i.e., 25 and 25%, respectively) in no-till corn. Commercially acceptable corn stands were needed for between-row mowing systems to adequately control weeds. In one of three years when corn stands were half of those of the other two years, broadcast herbicides performed better than between-row mowing systems in no-till corn.Nomenclature: Atrazine, S-metolachlor; corn, Zea mays L. ‘Pioneer 33G28’ ZEAMX

Between-row Mowing Systems Control Summer Annual Weeds in No-till Grain Sorghum

In previous research, use of PRE soil residual herbicides was reduced 50% in no-till corn and soybean by banding herbicides over crop rows followed by mowing weeds growing between rows two times. The research goals were (1) to determine whether such between-row mowing systems adequately controlled weeds and prevented grain yield loss in other competitive field crops, such as no-till grain sorghum, and (2) to compare broadcast herbicide treatments with between-row mowing systems. PRE atrazine plus dimethenamid at relative rates of 0.75× and 1× (where 1× = 1.7 plus 1.3 kg ai/ha, respectively) were band-applied over rows shortly after planting followed by two between-row mowings close to the soil surface. In 2 of 3 yr in Missouri, this system controlled giant foxtail and common waterhemp as well as broadcast herbicides in no-till sorghum. In 2 of 3 yr, between-row mowing systems also prevented yield loss in no-till sorghum as well as both broadcast herbicides at the same rates and the weed-free check.Nomenclature: Atrazine; dimethenamid; giant foxtail, Setaria faberii (L.) Beauv. SETVI; common waterhemp, Amaranthus rudis Sauer. AMATA; corn, Zea mays L. ZEAMX; sorghum, Sorghum bicolor (L.) Moench SORVU ‘Northup King GS10’and ‘Pioneer 84G62’; soybean, Glycine max (L.) Merr.

Preemergence Banded Herbicides Followed by Only One Between-Row Mowing Controls Weeds in Corn

Research was conducted to determine the minimum number of between-row mowings necessary to control annual weeds, chiefly giant foxtail and common waterhemp, without corn yield loss. Over 2 yr in Missouri, the between-row mowing systems that were evaluated consisted of a 38-cm band of PRE atrazine plus metolachlor at 2.2 plus 2.2 kg ai/ha applied over corn grown in 76-cm rows shortly after planting followed by one, two, or three between-row mowings close to the soil surface. Based on rated total weed control, between-row total weed cover, and corn yield, the weed-free check was statistically indistinguishable from a treatment in which banded PRE herbicide was followed by only one between-row mowing, late, when weeds were relatively large. When mowed once at 52 to 64 days after planting (DAP), giant foxtail and common waterhemp were greater than 85 cm tall. The yield was not increased by mowing earlier or more than once.

Regrowth characteristics of lucerne under different systems of grazing management

The regrowth characteristics of lucerne (Medicago sativa cv. Hunter River) were measured within an experiment conducted at Lawes, south-eastern Queensland, from 1971 to 1977 (Leach 1979). The experiment included six grazing and three mowing treatments: (1) R32/G4, (2) R32/G16, (3) R44/G4, (4) R44/G16, (5) R56/G4, (6) R40/G8, (7) R36/M, (8) R48/M and (9) R60/M, where R represents the days of rest between grazings (G) or mowings (M) and G the days of grazing after each rest period. These treatments formed cycle lengths of 36, 48 or 60 days, and regrowth experiments were usually undertaken when the ends of two or more defoliation cycles coincided. There were 15 regrowth experiments: experiments 1-9 were conducted over the first 720 days, experiments 10–14 over the next 720 days, and experiment 15 after another 720 days. In experiments 1-9 an initial harvest was made on day 0, and the regrowth was measured after 8 and 24 days. In experiments 10-14 there were harvests on days 0 and 24, and in experiment 15 on days 0 and 14. Amounts of regrowth were more strongly influenced by season and by soil moisture status than by imposed treatments, with final yields differing by up to 10-fold between winter and summer experiments. Seasonal differences in shoot size, and to a lesser extent in shoot numbers, were also much larger than treatment effects within experiments. These results appeared to be a consequence of the grazing and mowing systems being selected from within a recommended range for lucerne, and also of ensuring that moisture equivalent to the long-term average was received each month. Within experiments the yield of regrowth increased as the resting interval between defoliations increased, with a twofold difference between treatment extremes in some experiments. In general, grazing for 16 days led to better regrowth yields than grazing for 4 days which was in turn superior to mowing. Retaining residues after grazing generally increased regrowth, particularly following 16 days of grazing. However, residues greater than 80–100 g m-2 decreased regrowth. Most treatment differences were particularly evident on day 8, which indicated that treatments affected regrowth mainly through the speed of regrowth resumption after grazing or mowing. Although treatment effects on total regrowth yield were attributable to change in both shoot numbers and shoot size, the latter component was usually the more important determinant. Regrowth yield per unit area was maintained by compensating increases in yield per plant, whilst lucerne density fell from an initial 50 plants m-2 to about 30 plants m-2 over the first 3 years, but subsequent losses of lucerne plants led to decreased yields per unit area.