Browsing by Subject "Herbicide reduction"

Now showing 1 - 4 of 4

Bi‐directional hoeing in maize
(2023) Naruhn, Georg; Schneevoigt, Valentin; Hartung, Jens; Peteinatos, Gerassimos; Möller, Kurt; Gerhards, Roland
The weed control efficacy (WCE) of mechanical weeding in the inter‐row area in conventional cropping systems can achieve more than 90%. Despite the use of special intra‐row tools (e.g., finger weeders), only a WCE of 65%–75% can currently be realized in the intra‐row area. To close the gap between inter‐row and intra‐row WCE, in this study, a new approach for high‐efficacy precise mechanical weeding is presented. By using a GPS‐based pneumatic precision seeder (Kverneland GEOseed), a square crop seeding pattern of 37.5 cm × 37.5 cm was established in maize to enable post‐emergence hoeing lengthwise and transverse to the sowing direction. Thus, the treated area by the hoeing blades is postulated to increase, resulting in higher WCE. For this, six field experiments were conducted in South‐Western Germany in 2021 and 2022. Goosefoot blades and no‐till sweeps were guided automatically using a camera for row detection and a hydraulic side‐shift control for the hoe. This bi‐directional treatment was compared to an herbicide application and to hoeing treatments only along and transverse to the sowing direction. The bi‐directional hoeing treatment increased the WCE compared to hoeing along the crop rows on average from 80% to 95% and was not significantly different from the herbicide applications in 2022. Precise sowing in combination with hoeing along and transverse the crop rows resulted in 5.3% crop losses compared to 2.2% for hoeing only along the sowing direction by using only 15 cm wide goosefoot blades, while in the herbicide treatment and the untreated control no crop losses were detected. While maize biomass was not significantly different from the herbicide treatment in most cases over both years, in 2022, even the grain yield of the bi‐directional hoeing treatment with goosefoot blades (7.8 Mg ha−1) was statistically equal to the herbicide treatment (6.9 Mg ha−1). This study demonstrates the great potential of bi‐directional hoeing as an effective alternative to chemical weed control in row crops such as maize, sunflower and sugar beet.
Mechanical weed control: Sensor-based inter-row hoeing in sugar beet (Beta vulgaris L.) in the Transylvanian depression
(2024) Parasca, Sergiu Cioca; Spaeth, Michael; Rusu, Teodor; Bogdan, Ileana
Precision agriculture is about applying solutions that serve to obtain a high yield from the optimization of resources and the development of technologies based on the collection and use of precise data. Precision agriculture, including camera-guided row detection and hydraulic steering, is often used as an alternative because crop damage can be decreased and driving speed can be increased, comparable to herbicide applications. The effects of different approaches, such as uncontrolled (UC), mechanical weed control (MWC), herbicide weed control (HWC), and mechanical + herbicide control (MWC + HWC), on weed density and yield of sugar beet were tested and evaluated in two trials (2021 and 2022) in South Transylvania Depression at the tested intervals BBCH 19 and 31. Weed control efficacy (WCE) depends on the emergence of the weeds and a good timing of weed controls in all the trials and methods, though the highest yield of sugar beet roots was recorded in the treatment MWC + HWC, with an increase up to 12–15% (56.48 t ha−1) yield from HWC (50.22 t ha−1) and a yield increase of more than 35–40% than MWC (42.34 t ha−1). Our trials show that it is possible to increase yield and have fewer chemical applications with the introduction of new precision technologies in agriculture, including sensor-guided mechanical controls.
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.