The association of age, stature, and trellis height (TH) with the upper body musculoskeletal symptoms (MSS) in Japanese vineyard farmers was investigated to provide basic information for MSS health improvement and the creation of new version of mechanical wearable supports, such as the agri-robot suits. A total of 151 vineyard farmers responded to the questionnaire-based survey about workload and MSS with age, stature, and TH. Logistic regression, linear regression, and correlation analysis was used to test the association of MSS with age, stature, and TH in shoulder, upper back, and low back regions. Different significant risk factors for the upper back, shoulder, and lower back were noted. Older age, high TH, and small height difference (HD) between the stature and TH significantly increased the risk of shoulder, upper back, and lower back MSS, respectively. MSS were higher in the upper body than the lower body. These risk factors vary depending on the specific body region. High incidence rate (100%) was reported in the study population. Among farmers who desired to buy the robot suit (58%), asked for support of the whole body (42%), upper body (46%), and lower body (12%). The risks of MSS in vineyard farmers are high. Intervention measures such as relaxing postural stress by taking a regular break every hour might be beneficial. Lightening the muscle strain of the high risk body parts by reducing considerable exertion with mechanical support is also a great option. The wearable agri-robot suit should be improved, mainly focusing on the specific risk factors of the shoulder, upper back, and lower back regions to reduce physical strain. It is also worth to develop the suit in detachable design which can support whole body, upper part only, and lower part only.

To assess the effects of timing of nitrogen supplemental application on and grain yield, and lodging resistance considering culm strength, we conducted a field study using the Japanese noodle wheat (Triticum aestivum L.) cultivars Ayahikari and Iwainodaichi. Supplemental nitrogen at the rate of 80 kg/ha was applied at three different Zadoks growth stages, GS30 (ear at 1 cm), GS32 (2nd node detectable), and GS39 (flag leaf ligule just visible). Grain yield increased significantly by the application of the supplemental nitrogen at GS30 and GS32. Maximum tiller number increased at GS30, whereas the percentage of productive culms significantly increased at GS32. Grain number per spikelet and grain number per spike significantly increased at GS30 and GS32. Chlorophyll content (SPAD value) of the flag leaf at late maturity increased at GS39. The 1000-grain weight, however, was not significantly affected by any treatment. Further, supplemental nitrogen application increased the moment of the aerial part at GS30, GS32, and GS39, but decreased the bending moment at breaking of the basal internode at GS30 and GS32. As a result, the lodging index significantly increased by supplemental nitrogen at GS30 and GS32. These findings suggest that supplemental nitrogen between GS30 and GS32 has sizeable positive effects on wheat yield but decreased resistance to lodging.

Extensive use of sterol demethylation inhibitor (DMI) fungicides against strawberry powdery mildew has resulted in DMI-resistant genotype emergence. In this study, we examined the preventive effect of hot water spraying (HWS) on the occurrence of powdery mildew in everbearing strawberry, predominantly infected by DMI-resistant powdery mildew fungi from 2016 to 2018. Hot water of 54 ± 1°C was sprayed on Natsuakari for 20 s to achieve the target leaf temperature of 50°C. Disease occurrence under the chemical fungicide (F) + HWS treatment was less severe than that under the F treatment until the end of the cultivation period in February 2018. However, the preventive effect of HWS was not observed in already infected leaves. The incidence of DMI-resistant genotype was 0% at the start, and it increased to 62% and 100% in the infected fruits and leaves (including F+HWS) in September and November 2016 until the end of cultivation, respectively. On the contrary, disease severity increased between August 2017 and February 2018 under the F treatment, whereas only a slight infection was detected under the F+HWS treatment. Thus, HWS could induce resistance in strawberry against powdery mildew fungi, including DMI-resistant fungi, and effectively control the occurrence of powdery mildew in long-term everbearing strawberry cultivation.

Our previous study showed greater yields of potato tubers weighing 60 g or more with staggered planting than with conventional planting. In staggered planting, seed potatoes were planted in a staggered pattern at a distance of 150-mm. The soil was then immediately ridged using a commercial rotary hiller at 1500-mm intervals, which included four seed rows in two ridges. On the other hand, in conventional planting, the soil was ridged at 750-mm intervals, which included one seed row per ridge. However, with the previous staggered planting method, in which planting and ridging were performed separately, the tines of the hiller tended to nudge the seed potatoes and bring them up to the ridge surface, causing them to green. We therefore modified the potato planter that had been developed for staggered planting in a previous study to perform simultaneous ridging and planting, which included two seed rows per ridge at 750-mm intervals. We then compared the impact of staggered planting using the new planting method on potato quality with that of conventional planting and the previous staggered planting method in 2016 and 2017. With the previous staggered planting method, the greening rate of potatoes was significantly higher with staggered planting than with conventional planting in 2016. On the other hand, with the new staggered planting method, due to ridges follows the planting, no significant difference was found in the greening rate between the new staggered planting and conventional planting in either 2016 or 2017. In 2016, the weight of individual potato tubers and the potato yield as tubers weighing over 60 g were both significantly greater with staggered planting than with conventional planting, regardless of the planting method. In 2017, however, there were no differences in the weight of individual potato tubers or the potato yield as tubers weighing over 60 g between staggered and conventional planting.