Browsing by Person "Saile, Marcus"

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Agronomic and technical evaluation of herbicide spot spraying in maize based on high-resolution aerial weed maps - an on-farm trial
(2024) Allmendinger, Alicia; Spaeth, Michael; Saile, Marcus; Peteinatos, Gerassimos G.; Gerhards, Roland; Allmendinger, Alicia; Department of Weed Science, Institute for Phytomedicine, University of Hohenheim, 70599 Stuttgart, Germany; (A.A.);; Spaeth, Michael; Department of Weed Science, Institute for Phytomedicine, University of Hohenheim, 70599 Stuttgart, Germany; (A.A.);; Saile, Marcus; Department of Weed Science, Institute for Phytomedicine, University of Hohenheim, 70599 Stuttgart, Germany; (A.A.);; Peteinatos, Gerassimos G.; ELGO-DIMITRA, Leof Dimokratias 61, Agii Anargiri, 135 61 Athens, Greece;; Gerhards, Roland; Department of Weed Science, Institute for Phytomedicine, University of Hohenheim, 70599 Stuttgart, Germany; (A.A.);; Rossi, Vittorio
Spot spraying can significantly reduce herbicide use while maintaining equal weed control efficacy as a broadcast application of herbicides. Several online spot-spraying systems have been developed, with sensors mounted on the sprayer or by recording the RTK-GNSS position of each crop seed. In this study, spot spraying was realized offline based on georeferenced unmanned aerial vehicle (UAV) images with high spatial resolution. Studies were conducted in four maize fields in Southwestern Germany in 2023. A randomized complete block design was used with seven treatments containing broadcast and spot applications of pre-emergence and post-emergence herbicides. Post-emergence herbicides were applied at 2–4-leaf and at 6–8-leaf stages of maize. Weed and crop density, weed control efficacy (WCE), crop losses, accuracy of weed classification in UAV images, herbicide savings and maize yield were measured and analyzed. On average, 94% of all weed plants were correctly identified in the UAV images with the automatic classifier. Spot-spraying achieved up to 86% WCE, which was equal to the broadcast herbicide treatment. Early spot spraying saved 47% of herbicides compared to the broadcast herbicide application. Maize yields in the spot-spraying plots were equal to the broadcast herbicide application plots. This study demonstrates that spot-spraying based on UAV weed maps is feasible and provides a significant reduction in herbicide use.
A comparison of seven innovative robotic weeding systems and reference herbicide strategies in sugar beet (Beta vulgaris subsp. vulgaris L.) and rapeseed (Brassica napus L.)
(2023) Gerhards, Roland; Risser, Peter; Spaeth, Michael; Saile, Marcus; Peteinatos, Gerassimos
More than 40 weeding robots have become commercially available, with most restricted to use in crops or fallow applications. The machines differ in their sensor systems for navigation and weed/crop detection, weeding tools and degree of automation. We tested seven robotic weeding systems in sugar beet and winter oil‐seed rape in 2021 and 2022 at two locations in Southwestern Germany. Weed and crop density and working rate were measured. Robots were evaluated based on weed control efficacy (WCE), crop stand loss (CL), herbicide savings and treatment costs. All robots reduced weed density at least equal to the standard herbicide treatment. Band‐spraying and inter‐row hoeing with RTK‐GPS guidance achieved 75%–83% herbicide savings. When hoeing and band spraying were applied simultaneously in one pass, WCE was much lower (66%) compared to the same treatments in two separate passes with 95% WCE. Hoeing robots Farmdroid‐FD20®, Farming Revolution‐W4® and KULTi‐Select® (+finger weeder) controlled 92%–94% of the weeds. The integration of Amazone spot spraying® into the FD20 inter‐row and intra‐row hoeing system did not further increase WCE. All treatments caused less than 5% CL except for the W4‐robot with 40% CL and the combination of conventional inter‐row hoeing and harrowing (21% CL). KULT‐Vision Control® inter‐row hoeing with the automatic hydraulic side‐shift control resulted in 80% WCE with only 2% CL. Due to the low driving speed of maximum 1 km h−1 of hoeing robots with in‐row elements, treatment costs were high at 555–804 € ha−1 compared to camera‐guided inter‐row hoeing at 221 € ha−1 and broadcast herbicide application at 307–383 € ha−1. Even though the costs of robotic weed management are still high, this study shows that robotic weeding has become a robust, and effective weed control method with great potential to save herbicides in arable and vegetable crops.
Exploring the effects of different stubble tillage practices and glyphosate application combined with the new soil residual herbicide cinmethylin against Alopecurus myosuroides Huds. in winter wheat
(2022) Messelhäuser, Miriam Hannah; Saile, Marcus; Sievernich, Bernd; Gerhards, Roland
Effective control of Alopecurus myosuroides Huds. (blackgrass) solely with a chemical treatment is not guaranteed anymore because populations exhibit resistance to almost all herbicide modes of action. Integrated weed management (IWM) against blackgrass is necessary to maintain high weed control efficacies in winter cereals. Four field experiments were conducted in Southwest Germany from 2018 to 2020 to control A. myosuroides with a combination of cultural and chemical methods. Stubble treatments, including flat, deep and inversion soil tillage; false seedbed preparation and glyphosate use, were combined with the application of the new pre-emergence herbicide cinmethylin in two rates in winter wheat. Average densities of A. myosuroides in the untreated control plots were up to 505 plants m−2. The combination of different stubble management strategies and the pre-emergence herbicide cinmethylin controlled 86–97% of A. myosuroides plants at the low rate and 95–100% at the high rate until 120 days after sowing. The different stubble tillage practices varied in their efficacy between trials and years. Most effective and consistent were pre-sowing glyphosate application on the stubble and stale seedbed preparation with a disc harrow. Stubble treatments increased winter wheat density in the first year but had no effect on crop density in the second year. Pre-emergence application of cinmethylin did not reduce winter wheat densities. Multiple tactics of weed control, including stubble treatments and pre-emergence application of cinmethylin, provided higher and more consistent control of A. myosuroides. Integration of cultural weed management could prevent the herbicide resistance development.
Integrated weed management in a pesticide free area
(2023) Saile, Marcus; Gerhards, Roland
Weed control is a challenging task for farmers in highly specialized crop production systems. The competition of weeds for light, nutrients and water causes significant yield losses. Chemical weed control is still the standard method in European cropping systems. Due to their high selectivity and efficacy against a wide range of weed species, herbicides provide the most efficient weed control in most crops. However, negative impact of herbicides on the environment, loss of biodiversity, possible risks to consumers due to residues in food chain and the increase and spread of herbicide-resistant species force farmers to reduce herbicide use and call for alternative weed control methods. Mechanical weed control methods including hoeing and harrowing represent the most promising alternative direct weed control methods. Weed control costs for mechanical methods are still higher than for herbicides and weed control efficacy is often lower with less than 80 % compared to around 95 % for herbicides. The efficacy of mechanical weed control is dependent on external factors such as soil water content, soil texture, and weed species diversity in the particular field. Herbicides can therefore not be replaced by a single mechanical weed control method. It needs an Integrated Weed Management (IWM) strategy including preventive and direct methods of weed suppression. In this study, IWM were investigated for typical arable farming systems in Southwestern Germany. Studies for this thesis were conducted from 2017 to 2022. The objectives of the thesis were to combine preventive and curative methods of weed control in diverse cropping systems and to improve mechanical weed control methods by precision farming technologies. The results of the thesis have been published in five papers. The first article addressed the effects of preventive weed control by stubble tillage, cover cropping, and the use of glyphosate treatments against Alopecurus myosuroides and volunteer cereals. In two field trials at two sites, cover crop mixtures achieved equal weed control efficacy of up to 100 % as the dual glyphosate treatment. Stubble tillage practices resulted in lower control but caused the highest energy consumption. The second article focused on the effect of two seeding dates (early-, delayed-sowing) and different herbicide strategies on A. myosuroides control on winter cereals. This study was conducted over three years at three locations. Delayed sowing reduced weed emergence by 30-40 %. Delayed sowing in combination with the pre-emergence herbicide cinmethylin provided equal weed control efficacy as a combination of pre-emergence and post-emergence herbicides. The third article focused on the control of A. myosuroides including the combination of integrated stubble management and various application rates of the pre-emergence herbicide cinmethylin. In four field trials over a two-year period, the pre-emergence herbicide cinmethylin was applied at two application rates at two sites. Control success of up to 100 % was achieved through the combination of inversion tillage, false-seedbed preparation and the reduced rate of cinmethylin. The results also showed a high variation of the effect of preventive measures. The fourth article deals with IWM in spring oats and winter wheat. Field experiments were conducted at two locations over two years in five field trials. Chemical weed control was combined with sensor-based mechanical weed control. Data showed that sensor-based mechanical weed control (hoeing and harrowing) in the field trials achieved equal weed control efficacy of up to 100 %. However, highest grain yields were recorded for the combination of pre-emergence herbicide and post-emergence mechanical weed control. The last article dealt with a new cultivation system without chemical synthetic pesticides but with mineral fertilizers (MECS). The hypothesis was that MECS would increase the competitiveness of the crop on the weeds and generate higher yield benefit compared to the organic cultivation system. Field trials were conducted at four sites over two years. Three different cropping systems, an organic cropping system managed according to organic farming guidelines, a conventional cropping system and a MECS, were compared in a 5-year crop rotation. After two years of studies, no clear conclusion can be made how MECS affects the interaction of crops and weeds. Weed control efficacy in MECS was lower than organic farming. The increase in weed pressure in MECS will cause problems in the subsequent crops. Yields were significantly higher in MECS compared to the organic system and only slightly lower than in the conventional system. It can be concluded from these studies that IWM in combinations with precision farming technologies for mechanical weeding can replace herbicides. However, weed control costs were higher with non-chemical weed control methods.
Precision chemical weed management strategies: A review and a design of a new CNN-based modular spot sprayer
(2022) Allmendinger, Alicia; Spaeth, Michael; Saile, Marcus; Peteinatos, Gerassimos G.; Gerhards, Roland
Site-specific weed control offers a great potential for herbicide savings in agricultural crops without causing yield losses and additional weed management costs in the following years. Therefore, precision weed management is an efficient tool to meet the EU targets for pesticide reduction. This review summarizes different commercial technologies and prototypes for precision patch spraying and spot spraying. All the presented technologies have in common that they consist of three essential parts. (1) Sensors and classifiers for weed/crop detection, (2) Decision algorithms to decide whether weed control is needed and to determine a suitable type and rate of herbicide. Usually, decision algorithms are installed on a controller and (3) a precise sprayer with boom section control or single nozzle control. One point that differs between some of the techniques is the way the decision algorithms classify. They are based on different approaches. Green vegetation can be differentiated from soil and crop residues based on spectral information in the visible and near-infrared wavebands (“Green on Brown”). Those sensors can be applied for real-time on/off control of single nozzles to control weeds before sowing after conservation tillage and in the inter-row area of crops. More sophisticated imaging algorithms are used to classify weeds in crops (“Green on Green”). This paper will focus on Convolutional Neural Networks (CNN) for plant species identification. Alternatively, the position of each crop can be recorded during sowing/planting and afterward herbicides can be targeted to single weeds or larger patches of weeds if the economic weed threshold is exceeded. With a standardized protocol of data communication between sensor, controller and sprayer, the user can combine different sensors with different sprayers. In this review, an ISOBUS communication protocol is presented for a spot sprayer. Precision chemical weed control can be realized with tractor-mounted sprayers and autonomous robots. Commercial systems for both classes will be introduced and their economic and environmental benefits and limitations will be highlighted. Farmers ask for robust systems with less need for maintenance and flexible application in different crops.
Weed control in a pesticide‐free farming system with mineral fertilisers
(2023) Saile, Marcus; Spaeth, Michael; Schwarz, Jürgen; Bahrs, Enno; Claß‐Mahler, Ingrid; Gerhards, Roland
Negative impacts of pesticides on the environment and human health, the risk of pesticide residues in the food chain, and the problems with herbicide‐resistant weed biotypes support the need for alternative cropping systems. The objective of this study was to investigate weed populations, weed management and crop yield in a pesticide‐free cropping system with the use of mineral fertilisers. Conventional‐, organic‐ and mineral‐ecological cropping systems (MECS) with 6‐year crop rotations including winter wheat, maize, winter triticale or winter rye, soyabean or spring pea, and spring barley were established in a randomised complete strip plot design with four repetitions. Experiments were conducted at four locations in Germany. Preventive and sensor‐guided mechanical weed management strategies were applied in all crops in the organic system and in MECS. Herbicide were applied in the conventional farming system. Weed densities, weed species composition, weed control efficacy (WCE) and crop yield were analysed over 2 years in 2020 and 2021. Conventional farming had the highest WCE and 1–7 weeds m−2 (2.7% weed coverage) after herbicide application. In the organic cropping system and MECS, up to 27 weeds m−2 were counted after camera‐guided weed hoeing. Weed coverage in MECS (9.7%) was higher than in the organic cropping system with 7.7%. Crop yield in MECS was equal to the conventional farming system and 20% higher yield than in the organic farming system. MECS represents a promising new and productive cropping practice if an effective integrated weed management strategy is applied.