The damage caused by Thrips tabaci to a susceptible hybrid of early white cabbage was studied in field experiments undertaken during 2004 and 2005. The three treatments tested were beds of cabbage mulched with: (1) barley straw, (2) hay, and (3) black polyethylene (PE) sheeting. Bare-soil (un-mulched) beds were used as the control treatment. One early and one late experiment were performed in both years. In the early experiments, the mulches were applied at the start of the experiment, whereas in the late experiments the soil was first covered with black polyethylene for approximately 1 month. In both years, the springs were cold and wet, and so the thrips appeared late and their numbers were low. The highest mean actual weight and trimmed weight were recorded for cabbage grown in 2005 under PE mulch (actual early: 995 g, actual late: 1184 g, trimmed early: 870 g, trimmed late: 1056 g). Year 2004 gave lower values (110g for both variables) under barley straw and hay mulch (165 g and 160 g, respectively). There was no evidence of an allelopathic effect of water extracts of either barley straw or hay.
Planting speed has an important impact on plant spacing variability and also grain yield. In a two-year study, the effects of planting speeds of 6, 9, and 12 km/h on maize plant spacing and, consequently, ear parameters were investigated. We wanted to determine whether increasing the planting speed increases the plant spacing parameters and what effects this has on ear parameters and grain yield. In both experimental years, no differences between the three planting speeds were found in terms of mean plant spacing, plant density, the multiple index, and the miss index. However, the standard deviation of reference spacings and precision increased with the increase in planting speed from 6 to 12 km/h. In 2022, the differences between plant spacings measured using UAV photogrammetry and manual measurements were smaller (<1 cm) than in 2023. The plant spacing data obtained from 3D point clouds show a strong correlation (r = 0.97) with the manual measurements for all three planting speeds. The proposed method is suitable for measuring plant spacing in maize. In 2022, no differences appeared in grain yield and ear parameters between the planting speeds; however, in 2023, the grain yield and kernel mass per ear were greater at planting speeds of 6 and 9 km/h than at a planting speed of 12 km/h in 2023. Individual ear analysis in 2023 showed an increase of 0.73 g in kernel mass per plant with a 1 cm increase in plant spacing, resulting in a 58 kg/ha yield increase.
26 February 2024 in Acta Agriculturae Scandinavica, Section B — Soil & Plant Science
Four types of nozzles were tested on large-scale trials with a 40 m2 plot unit size. The Avi Twin 110-01 (80 L ha−1), 110-02 (160 L ha−1), 110-03 (240 L ha−1), and 110-04 (320 L ha−1) symmetric double fan injector nozzles were tested during the 2020/2021 and 2021/2022 growing seasons. This study aimed to evaluate the performance of spray nozzles with regard to deoxynivalenol (DON) accumulation in durum wheat grains. Artificial inoculation with Fusarium spp. was performed after durum heads were protected with fungicide. The percentage of heads covered with fungicide droplets, grain yield, yield-related traits, technological quality parameters, and concentrations of DON were determined. Compared to the control (without fungicide treatment), the Avi Twin 04 nozzle caused a reduction of 45.0% in the DON concentration on average across both growing seasons. This positively corresponded to the percentage of heads covered with fungicide droplets, which was highest when this nozzle was utilized. In both trial years, the DON reduction caused by the 110-04 twin nozzle was higher than that caused by the 110-01 nozzle. Treatment with the 110-04 nozzle more effectively improved the grain yield, 1000-kernel weight, and test weight compared to treatment with the 110-01 nozzle and the untreated control. The differences in technological quality were less pronounced when different spray nozzles were used.