Domestic fresh asparagus is demanded in Japan from late autumn to winter. Asparagus production in greenhouse in winter needs a large amount of oil or electricity for heating, leading to CO₂ emissions and high costs, and an alternative heating system with low carbon emission is therefore required for winter cultivation of asparagus. Three heating systems were prepared for the asparagus fusekomi forcing culture (FFC) in a plastic greenhouse in mid-winter in Hokkaido, i) conventional system i.e. electrically heated wire system for soil heating, ii) a hot water system for soil heating only, iii) a hot water system for both soil and air heating. Hot water was produced by using wood pellet boiler. Average soil temperature at 14 cm depth in the culture bed remained within 15–20°C in each system. Freeze injury of emerged spears was avoided by the hot water heating, especially in the heating of both soil and air even when the outside temperature fell to –18°C. Hot water heating systems generated larger heat and the marketable spear yield showed 1.1–1.3 times of that in the electrically heated wire system. The CO₂ emission and annual cost for 1 kg marketable spear production in the hot water heating system was obviously higher than those in the electrically heated wire system, however the small improvement of spear productivity was recognized in the hot water heating system. Scale of the wood pellet boiler in the present examination, prototype boiler, was excessive for the asparagus production in 9 m-length bed, and suitable scale of wood pellet boiler asparagus production should be installed in future.

In plant nurseries, reducing the frequency of chemical application is becoming a challenge owing to the appearance of hardly controllable pathogens, spread of diseases, and demand by farmers. This study was therefore conducted to develop a practical, alternative fungal control strategy against powdery mildew by using hot water spray in a tomato nursery. The expected effects of hot water spray treatment are induced resistance and disinfection. Gray mold was used as an experimental model to determine the conditions for practical application of hot water spray for inducing resistance to plant fungi by heat shock treatment. Hot water dipping of tomato seedlings at 50°C for 20 s induced resistance against gray mold and increased the expression of some pathogenesis-related genes, viz., pathogenesis-related protein 1a (PR1a), basic intracellular β-1,3-glucanase (GluB), and basic intracellular chitinase (Chi9). A prototype of a towable hot water sprayer was developed, and its performance was tested in the field. When hot water was sprayed at 57°C ± 2°C while moving at a speed of 0.5 m/min, the leaf temperature of certain parts of the seedlings reached approximately 50°C for 20 s, thereby inhibiting powdery mildew. Moreover, it was not necessary to heat the whole plant at the target condition because heat shock is known to induce systemic resistance. These results suggest that hot water spraying might be an effective technique to prevent powdery mildew in tomato nursery.

Existing research on agricultural production management has not addressed the problem of selecting representative values of agricultural production indices. For agricultural production indices such as working hours per unit area and yield per unit area of crop production, there are cases wherein it is desirable to obtain typical values as representative values. This is because production indices tend to have long-tail distribution on one side in agriculture that is susceptible to the natural environment. In this research, we focused on the mode, which is a representative value with typicality of the agricultural production indices. However, a mode calculation method that can sufficiently withstand practical use has not yet been established. Usually, the mode is obtained as a class value of the maximum class after creating a histogram. However, even if the class width is kept constant, the mode obtained by the usual method is indefinite depending on how to determine the "anchor position" and uniqueness is not guaranteed. It is not desirable to use the most frequent value obtained by the usual method as the representative value of the production indices. Therefore, we selected Lp-norm estimation when the degree p is a positive decimal real number close to 0 as the mode calculation method without using histogram. However, computation of the Lp-norm estimator whose degree p is less than 1 is a nonlinear, non-convex problem, and so it is not easy to solve the global optimal solution strictly. In this study, we presented a simple calculation method for a non-convex problem using worksheets of spreadsheet software for calculating the unique mode through Lp-norm estimation including degree p less than 1, and we tried to apply the method to the mode of actual agricultural production indices.

Parts of the chaffer sieve and grain conveyor section of a combine were changed to high-throughput parts so that super-high-yielding rice （crude brown rice yield of 900 to 1000 kg/10 a） could be harvested stably. Harvesting tests were performed on the high-yield rice cultivar Hokuriku 193 using this combine to measure harvesting operation accuracy and work efficiency. Harvesting with this combine gave threshing and screening losses of no more than 3.0% and an impurity content of no more than 1.0%. Stable harvesting was possible, with a working time per 10 a was 19 min 43 s.

Agriculture is a production activity that revitalizes part of the ecosystem and generates products wanted or needed by people. However, what is discharged in all its processes will not last unless it is returned to natural circulation. “Nousagyou-gaku”, compiled by the Japanese Society of Farm Work Research, states that “Production of agricultural products in agriculture utilizes the law of nature's material cycling process and is carried out by controlling the environment for material circulation—to the extent that it can be artificially controlled—to achieve more efficient production from crops and livestock.”