Monitoring turfgrass species by ground-based and satellite remote sensing

Like all modern agriculture sectors, turfgrass production and management is headed towards cost reduction, resource optimization and reduction of the environmental impact. In recent years, within the European Union several legislative, monitoring and coordinating actions have been undertaken to encourage sustainable use of resources, reduction in the use of chemicals and improvement of the urban environment. In this respect, two concepts that are strictly related to most of the aspects above are: “precision agriculture” and “precision conservation” and more specifically “precision turfgrass management.” Optical sensing has become a crucial part of precision turfgrass management and spectral reflectance in particular has been an active area of research for many years. However, while turfgrass status evaluation by proximity-sensed spectral reflectance appears to be an established and reliable practice, much more could be achieved in terms of monitoring of large turfgrass areas through remote sensing, and in particular through satellite imagery. This thesis reports the results of four trials attempting: a) to evaluate the spectral signatures of several turfgrass species\cultivars, for future use in satellite monitoring. This experimental study focused on 20 turfgrass species\cultivars, including perennial ryegrasses, tall fescues, kentucky bluegrasses, bermudagrasses (ecotypes, seeded and vegetatively propagated cultivars) and zoysiagrasses. Various agronomical and biological parameters were studied (quality, color, dry matter, chlorophyll, carotenoids, nitrogen content) and turfgrass spectral reflectance for all entries was gathered. Results showed that, within the same species, selected vegetation indices are often able to discriminate between different cultivars that have been established and maintained with identical agronomical practices. Evaluation of the spectral reflectance of plants using field spectroradiometry provides the possibility to identify different species\ cultivars, especially through the use of hyperspectral proximity and remote sensing; b) to calculate on these 20 species and cultivars the most interesting vegetation indices by simulating the available wavelengths deriving from World View 2 satellite imagery. Results showed that within the same species selected vegetation indices are often able to discriminate between different varieties that have been established and maintained with identical agronomical practices; c) to evaluate the proximity sensed spectral reflectance on Festuca arundinacea turf with 9 water replenishment levels (Linear Gradient Irrigation System) and 2 nitrogen conditions. ET0 was estimated using the Hargreaves and Samani method. The following parameters were determined: turf quality, drought tolerance, pest problems, temperature of the surface, clippings weight and relative nitrogen content, turf growth and soil moisture. Spectral reflectance data were acquired using a LICOR 1800 spectroradiometer. Pearson correlation coefficients were studied among all parameters and vegetation indices. Nitrogen fertilization influenced significantly turf quality, clippings weight, nitrogen content and turf growth. Water replenishment influenced significantly all parameters except nitrogen content. Among all parameters the highest correlation coefficient was registered relating drought tolerance with turf quality (r = 0.88) and with surface temperature (r = - 0.88). Among vegetation indices results showed that Water Index (WI) and Normalized Difference Water Index (NDWI), are better able to discriminate between different levels of water replenishment. Comparing WI with NDWI, the correlation coefficients were higher for Water Index in all the parameters, in particular the highest WI value was registered for drought tolerance (r = 0.91). This preliminary research demonstrates that spectral remote sensing can be a useful diagnostic tool to detect water stress in turfgrasses; d) to compare N status in different turfgrasses, from remote multi-spectral data acquired by GeoEye-1 satellite and by two ground-based instruments. The study focused on creating a nitrogen concentration gradient on 3 warm-season turfgrasses (Cynodon dactylon x transvaalensis ‘Patriot’, Paspalum vaginatum ‘Salam’, Zoysia matrella ‘Zeon’) and 2 cool-season (Festuca arundinacea ‘Grande’, Lolium perenne ‘Regal 5’). The linear gradient ranged from 0 to 342 kg ha-1 of N for the warm-season and from 0 to 190 kg ha-1 of N for the cool-season turfgrasses. Proximity and remote reflectance measurements were acquired and used to determine Normalized Difference Vegetation Index (NDVI). Results showed that the N status is highly correlated with the spectral reflectance. Our results prove that NDVI measured with the ground-based instruments are highly correlated with data from satellite. The correlation coefficients between the satellite and the other sensors ranged from 0.90 to 0.99 for the warm-season and from 0.83 to 0.97 for the cool-season species. 'Patriot' had a clippings N concentration ranging from 1,20 % to 4.1 %, thus resulting the most reactive species to N fertilization. GeoEye-1 satellite can adequately assess the N status of different turfgrass species, and its spatial variability within a field depending on the N rates applied on the surfaces. In future information obtained from satellite could allow target management depending on the real need of the turf

Carbohydrate Metabolism During Wintering Period in Four Zoysiagrass Genotypes

A key barrier to widespread use of warm-season grasses in the transition zone between the temperate and subtropical climates is represented by the winter dormancy, a temporary suspension of visible growth of any plant structure including the meristem. In this environment, species with different photosynthetic carbon cycle coexist, leading to asynchrony in growth among warm- and cool-season grasses. The objectives of the present study were (i) to assess the carbohydrate content in four representative zoysiagrasses Zoysia japonica 'El Toro', 'Meyer', Z. pacifica, and Z. matrella 'Zeon' during three successive phases of vegetation phenology, senescence, dormancy, and green-up, and (ii) to characterize the metabolic responses to phenological variations under natural acclimation. Japanese lawn grass genotypes 'El Toro' and 'Meyer' showed longer dormancy periods than fine-leaved Z. pacifica and 'Zeon'. In Japanese lawn grass genotypes, the progressive decline of photosynthetic pigments was similar to that observed in the color retention. Over the experimental period, a significantly greater amount of starch reserves was observed in sprigs (horizontal stems) in the Japanese lawn grasses than in the fine-leaved zoysiagrasses. In general, total soluble sugars (TSS) in leaves and sprigs did not show evidence of sugar starvation during the senescence phase. TSS increased significantly during cold acclimation, resulting in a higher metabolic activity at the onset of green-up to support spring regreening in all zoysiagrasses except 'Meyer' leaves

Performance of Different Cool-Season Species and Cultivars Overseeded on Bermudagrass and Managed with Autonomous Mower

With global warming, the cultivation area of bermudagrass is moving northwards in the Mediterranean area despite its winter dormancy and loss of green color. The most common solution is overseeding with perennial ryegrass, which can be complicated to remove in spring. DLF breeders have released a new cultivar of annual ryegrass that is stress tolerant and easy to transition in spring. A trial was carried out on a sod farm in Pisa, Italy. Twenty-nine varieties of cool-season grasses, encompassing both forage and turf species, were overseeded on a hybrid bermudagrass variety ‘Tifway’ (Cynodon dactylon x transvaalensis). The aim of this trial was to compare the overseeding potential of various cool-season turfgrass species and cultivars and to identify which ones perform best in terms of cleanness of cut when overseeded on hybrid bermudagrass in autumn and maintained at a mowing height of 25 mm. Moreover, the following parameters were also assessed: actual turf height (cm); cumulated height (cm); turf visual color and quality (1–9 scale); and visual ground cover (%). Plots were managed with an autonomous mower, which adopted a daily mowing frequency and was set to work with systematic trajectories. The results showed differences between cultivars, and the annual ryegrass showed the best spring transition (scoring a mean value of 96% green cover in July 2023) compared to the other entries. The best result of CoC was measured for rough-stalked meadow grass ‘Sabrena 1’ and tall fescue ‘Turfway’ with 0.9 mm

Agronomic and Phytochemical Characterization of Chickpea Local Genetic Resources for the Agroecological Transition and Sustainable Food Systems

Legume crops play a key role in hastening both the agroecological and protein transition and improving the sustainability of cropping systems. Among legumes, chickpea (Cicer arietinum L.) is a valuable source of protein, fibers, and nutraceutical compounds, providing important agri-environmental effects. Nevertheless, few studies have explored the effect of genetic characteristics on production and quality traits in chickpea. Chickpea landraces seem particularly interesting for their positive agronomic and quality characteristics, opening the door for innovation in sustainable food systems. Thus, the present study aimed to characterize two chickpea Tuscan landraces (Rugoso della Maremma and Cappuccio della Valtiberina) in comparison with widely distributed commercial chickpea varieties (Ares, Maragià, Pascià, Principe, Reale, Sultano, and Vittoria). Our findings highlighted positive agronomic traits of landraces in terms of seed yield and yield components, demonstrating performance that is either superior or comparable to commercial varieties. Notably, Cappuccio della Valtiberina showed the highest 1000-seed weight (425.50 g), followed by Maragià (432.92 g), Principe (392.32 g), and Reale (382.79 g), and the highest harvest index (0.55), similar to Reale (0.55). Overall, landraces achieved 18.75% higher yields than commercial varieties. Regarding chickpea quality, landraces exhibited profiles comparable to those of commercial genotypes in terms of protein and oil content, as well as nutraceuticals. Interestingly, the two landraces had the most favorable ω-6/ω-3 ratios (Cappuccio della Valtiberina, 12.45; Rugoso della Maremma, 13.71) among the genotypes except for Maragià (11.78), indicating better nutritional quality compared to commercial varieties (>14.00). These results demonstrated that landraces could offer promising prospects for future chickpea breeding programs, aiding in the selection of genotypes capable of adapting to changing growing conditions and supporting the development of sustainable food systems

A New Method for Hybrid Bermuda Grass (Cynodon dactylon × C. transvaalensis Burtt.-Davy) Vegetative Propagation

Hybrid Bermuda grasses (Cynodon dactylon × C. transvaalensis Burtt.-Davy) represent one of the greatest contributions to the growing quality of turfgrass in the warm season and transition zone areas of the world. Hybrid Bermuda grass production relies on vegetative propagation from sod or sprigs. In the past, efforts have focused on improving the technique of stolonizing (or sprigging) for establishment in new areas. Such propagation requires bulk harvesting and planting of all rhizomes and stolons. We have developed a novel method of propagation and establishment from a single node harvested from greenhouse grown stolons. Despite a stolon fraction bearing a single node being suitable for effectively propagating a warm-season turfgrass, the technique has been held as economically impractical until now. Our method has been developed to obtain the multiplication of plant material in soilless conditions by harvesting single-node sprigs, propagation of plants from the single nodes, and transplant of single plants in the field. The investigation aimed to identify values for method set-up. Indeed, node and internode size variability with differential between maximum diameters is crucial for discrimination. For Patriot Bermuda grass stolons, nodes exhibited a maximum diameter of 2.43 ± 0.46 mm, while internodes had a maximum diameter of 1.54 ± 0.16 mm. Based on these findings, a 2 mm sieve was selected, achieving an optimal ratio between the node fraction and internode residues. The sieve yielded 87% of node fractions and only 1% of internodes from the initial mix, demonstrating its efficacy. Further results for the transplanting phase indicated that a double release resulted in an average success rate of 98.8%, with only 6.9% blank cells when using a single release. The average was 149 plants per tray over 160 cells, representing a 93.1% success rate. These results underscore the efficiency and acceptability of the overall propagation process in alignment with market references

Innovative Techniques for Managing Dollar Spot in Warm- and Cool-Season Turfgrasses: The Case of UV-B and UV-C Irradiations

The management of Dollar spot, the fungal disease of turfgrasses, is complicated and, today, tends to include new eco-friendly approaches. The aim of this study is to evaluate the effect of UV-B and UV-C lamps against the infection of Clarireedia species in warm- and cool-season turfgrasses. In vitro tests were performed to evaluate the growth of C. jacksonii mycelium on Potato Dextrose Agar, irradiated with UV-B and UV-C at heights of 5 and 15 cm, 5 s per day for three consecutive days. The same treatments, prolonged for seven days, were applied on naturally infected potted Agrostis stolonifera and Cynodon dactylon × C. transvaalensis, for in vivo tests. Disease severity, antioxidant capacity, and pigment content were assessed at the end of the experiment. Only UV-C reduced the growth of C. jacksonii after 48 h at 5 cm (−36%) and 72 h at both distances (−15 and −27%). Agrostis stolonifera showed symptoms, reduced by UV-C at 5 cm, and fungal structures, except in UV-C exposed samples. Total antioxidant capacity increased after UV-B exposure at 5 cm (+10%). No variations in terms of photosynthetic pigments were observed. These results confirm the potential of UV-C lamps for the containment of Dollar spot

Steaming and flaming for converting cool-season turfgrasses to hybrid bermudagrass in untilled soil

Turfgrass species can be classified into two main groups: cool-season and warm-season species. Warm-season species are more suited to a Mediterranean climate. Transplanting is a possible method to convert a cool-season to a warmseason turfgrass in untilled soil. It generally requires the chemical desiccation of the cool-season turfgrass. However, alternative physical methods, like flaming and steaming, are also available. This paper compares flaming, steaming, and herbicide application to desiccate cool-season turfgrass, for conversion to hybrid bermudagrass (Cynodon dactylon x C. transvaalensis) in untilled soil, using transplanting. Two prototype machines were used, a self-propelled steaming machine and a tractor-mounted liquefied petroleum gas flaming machine. Treatments compared in this work were two flaming treatments and two steaming treatments performed at four different doses together with two chemical treatments with glufosinateammonium herbicide applications. The cool-season turfgrass species were tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne). The desiccation effect of the various treatments on cool-season turf was assessed by photographic survey 15 days after treatment. The percentage cover of hybrid bermudagrass was visually assessed at 43 weeks after planting. Steaming and flaming effects on both parameters were described by logistic curves. The highest doses of steaming and flaming almost completely desiccated cool-season turf, and similar hybrid bermudagrass cover was established by both the methods as the chemical application (50% to 60%). Thus both flaming and steaming may be considered as valid alternatives to herbicides aimed at turf conversion

Use of Flaming to Control Weeds in ‘Patriot’ Hybrid Bermudagrass

Flaming could be an alternative to the use of chemical herbicides for controlling weeds in turfgrass. In fact, the European Union has stipulated that chemical herbicides should be minimized or prohibited in public parks and gardens, sports and recreational areas, school gardens, and children’s playgrounds. The aim of this research was to test different doses of liquefied petroleum gas (LPG) to find the optimal flaming dose that keeps a ‘Patriot’ hybrid bermudagrass (Cynodon dactylon · Cynodon transvaalensis) turf free of weeds during spring green-up, but also avoids damaging the grass. Five LPG doses (0, 29, 48, 71, and 100 kgha–1) were applied in a broadcast manner over the turf experimental units using a selfpropelled flaming machine. This equipment is commercially available and usable by turfgrass managers. Treatments were applied three times during the spring to allow the maximum removal of weeds from the turfgrass. Data on weed coverage, density, biomass, and turfgrass green-up were collected and analyzed. Results showed that 3 weeks after the last flaming, the greatest LPG doses used (i.e., 71 and 100 kgha–1) ensured the least amount of weeds (range, 5–16 weeds/m2) of low weight (range, 7– 60 gm–2) and a low weed cover percentage (range, 1% to 5%), whereas the green turfgrass coverage was high (range, 82% to 94%). At the end of the experiment, the main weed species were horseweed (Conyza canadensis), field bindweed (Convolvulus arvensis), narrow-leaved aster (Aster squamatus), and black medic (Medicago lupulina). Flame weed control is a promising technique to conduct weed control in turfgrass. Further studies could be conducted to investigate the use of flaming in other species of warm-season turfgrasses

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 kghaL1), 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 highquality sports turfs, thus saving time as well as reducing noise and pollution

Assessment of the Effects of Autonomous Mowers on Plant Biodiversity in Urban Lawns

Gaining information on the impact of lawn management with autonomous mowers on the floristic composition is crucial to improve their plant biodiversity. In this study, an autonomous mower with a reduced mowing frequency and a more sporadic mowing management system with a ride-on rotary mower were compared in terms of the effect on three dicotyledonous species (Phyla nodiflora, Lotus corniculatus and Sulla coronaria) transplanted onto stands of Bermuda and Manila grass. Regardless of the management system, P. nodiflora achieved the best results in terms of survival for both lawns (74.92 and 58.57% in Manila and Bermuda grass, respectively). In Bermuda grass, a higher percentage of surviving individuals was observed for the ordinary mower management system (42.59%), rather than with the autonomous mower (9.10%), while no differences emerged on Manila grass. On both Manila and Bermuda grass, a higher average percentage of coverage for single individual was observed for the ordinary mower management system (1.60 and 0.37%, respectively) compared to the autonomous mower system (0.55 and 0.08%, respectively). P. nodiflora had a higher percentage of individuals with flowers with the ordinary management system rather than with autonomous mower system both on Manila (60.73% and 33.90%, respectively) and Bermuda grass (48.66 and 3.32%, respectively). Despite a lower impact on the planted species being observed for the ordinary mower management system, encouraging results were obtained with the autonomous mower, for instance regarding the percentage of surviving individuals for P. nodiflora (33.95%) and L. corniculatus (22.08%) on Bermuda grass and the percentage of individuals with flowers for the same two species (33.90 and 13.59%, respectively) on Manila grass. Furthermore, the autonomous mower management system’s primary energy consumption over the year was lower compared to that of the ordinary system both on Manila (200.4 and 614.97 kWh ha−1 year−1, respectively) and Bermuda grass (177.82 and 510.99 kWh ha−1 year−1, respectively)