Desiccation of potato haulm (aboveground part of potato plants): 21 trials carried out with pelargonic acid, acetic acid and chemical agents in various potato cultivars at NIBIO and growers’ fields (Hamar, Skarnes). 1-3 treatments, different doses and addition of paraffin oil and adjuvants included. Haulm desiccation, skin ripening, how easily the potatoes detach from the plant, tuber yield and crop quality recorded. Preliminary analysis shows promising effect in some treatments. Treatment twice is required. Cultivars reacted differently. Trials with crushing alone and subsequent flaming or hot water (HW) were carried out at growers’ fields (Hamar, Vormsund). Different HW doses, once or twice, also without crushing, included. In 2022-2024 also combined with chemical agents. In 2023, 1 extra trial for a master's thesis where different doses HW after crushing were tested. Preliminary impression is that crushing followed by large doses of HW, flaming, or spraying is most promising. Variable rate desiccation: In years 1-2, candidate fields (26) were found in growers’ fields (Viken, Innlandet) Software that automatically and daily registers new satellite images (Sentinel-2) of these fields developed When a new image is available, program loads parts of the image that overlap with the fields, and an index for plant cover and probability of clouds per pixel is automatically calculated At the same time as cloud free images were available, reference data (n=222+299 in year 1+2) with a handheld instrument for leaf area (LAI) were taken Ref. data provide an indirect measure on biomass/density. Based on ref.data, mathematical models are made that "translate" remote sensing data into LAI. A first model (Random Forest) showed good correspondence between spectral Sentinel-2 channels and LAI. In 2023 (Tr.lag), multispectral UAV data and ref. data (n=139) were collected for a master's thesis Correlation between UAV data and LAI was shown, but degree of explanation varied with model (Random Forest, Linear Regression), data quality and - quantity Of the UAV-based indices examined, WDVI and NDRE gave best prediction In 2024, a proof of concept trial was carried out in a grower’s field (Innlandet) Variable dosing based on UAV data (WDVI) was done with a field sprayer with single nozzle control (prototype). UAV-based spraying gave same level of desiccation as ordinary method (uniform dose) Compared to uniform dose, amount of agent (pyraflufen-ethyl) was reduced by ca 20%
Control of weeds and runners in strawberries: In 2021–2025, 5 trials were carried out (wherein 1 over 2 years) at producers’ fields, both in new and established crops Repeated treatments with hot water (alone or combined with mechanical row hoeing or mowing), bioherbicides (pelargonic acid, acetic acid) and chemical products were tested Various amounts hot water = HW (1.5 – 6 L m-2) and two distances to plants (2 and 4 cm, only in 2021) included Trial in 2025 is still ongoing; hence results are preliminary. Results (4 trials) show that pelargonic and acetic acid (10 %) had little effect on pre-harvest runners, but acetic acid had some effect after harvest in the 1-year field; adjuvant (Biowet) or oil (Fibro) did not improve effect Mizuki (2 x 100 ml) after harvest, and the strategy Spotlight Plus (40 ml)+Mizuki (200 ml), gave promising and long-lasting effect on runners. HW, alone or combined with mowing, has promising effect on runners and weeds both before and after harvest; mower enhanced the effect Repeated HW treatments appear as an alternative to chemical agents On large weeds, amount of HW must increase Kilter AS has carried out R&D to enable control of weeds and runners with a self-propelled robot with single-drop spraying
In 2021–2025, 5 trials were carried out at growers’ apple orchards (Toten: 1-y old, 2-y-old; Hardanger: three 1-y-old) Goal is glyphosate-free weeding Trials included HW (3 and 6 L m?²), mechanical row hoeing, bioherbicides (pelargonic acid, acetic acid) and common practice (glyphosate) Treatments were carried out 2-3 times in May–July In 2021 (Toten), HW (3 or 6 L/m²) gave ca 90% effect, which was better than glyphosate (ca 75% effect). Pelargonic acid and mechanical crushing gave 15–45% and 60% effect, resp. In 2022 (Hardanger), effects were weak, probably due to large weed plants. At Toten same year, HW (6 L/m²) and glyphosate gave ca 90% and 85% effect, resp., while HW (3 L/m²) and mechanical row hoeing gave ca 75%. Both doses of pelargonic acid (+oil) and acetic acid (+adjuvant) had weak effect, ca 40%. In 2023 (11 and 2-year-old), HW (6 L/m²) gave best control (6% and 9% weed cover) Half dose HW (3 L/m²) gave 16% and 20% cover, resp., which was better than glyphosate (23% and 55% cover, resp.), and significantly better than pelargonic acid, acetic acid and row hoeing HW had particularly good effect on annual weeds; and no gain by doubling the amount (6 L/m²) Weed dry-weight showed same pattern as visual assessment of weed cover
To reduce environmental and health risks by pesticides, authorities and growers seek alternative methods as part of integrated pest management (IPM). IPM has been mandatory since 2015 in Norway, and is based on 8 principles whereof non-chemical methods is one. The recent withdrawal of the desiccant Reglone (diquat) and the currently uncertain future of the widely used herbicide glyphosate (marketed as e.g. Roundup) cause serious challenges for Norwegian production of potatoes, strawberries and apples. The project SOLUTIONS will work on new solutions for: 1) Potato canopy desiccation, 2) Control of weeds and runners in field strawberries, and 3) Weed management in apple orchards. Measures to be tested are Bioherbicides, for example pelargonic acid and other organic acids; Thermal methods, for example hot water and electricity, alone or in combinations with current and new mechanical implements and newly approved products. SOLUTIONS will also work on two precision agriculture technologies: 1) Sensor-based dosing of new potato desiccant(s), and 2) Robot to control weeds and runners in field strawberries. The most critical R&D challenges faced in the project are reaching sufficient and reliable efficacies of the new agents and methods. For sensor-based dosing of desiccants, relying on satellite data in the visible spectrum might be a challenge due to clouds. For the robot, discriminating runners from objects like leaf stems of the strawberry mother plant may not be straightforward. SOLUTIONS is coordinated by NIBIO - Norwegian Institute of Bioeconomy Research. It is funded by Forskningsmidlene for jordbruk og matindustri and Grofondet AS. Collaborative and financial partners are Norsk Landbruksrådgiving, A-K maskiner AS, Heatweed Technologies AS, H.F. Maskin Teknikk AS, Kilter AS, Gartnerhallen and Norwegian producers of potatoes, field strawberries and apples.
