Although the demand for cherry tomatoes is increasing, the time required to perform each cherry tomato cultivation task should be reduced as it requires a longer than large-sized tomatoes. Recently, summer-autumn-harvest cherry tomatoes using non-training cultivation with a net in an open field （sauvage cultivation）, which is a labor-saving cultivation, have been developed and promoted. Sauvage cultivation should reduce working hours （excluding harvesting time） and costs compared with conventional cultivation, although removing plants （residues） from nets after cultivation is laborious. Biodegradable nets, when buried in soil, can be degraded with plants as organic matter and become part of the soil. Therefore, the need for troublesome removal from plants for disposal can be eliminated, improving work efficiency. This study evaluates the dismantling process in sauvage cultivation when using biodegradable nets in terms of work time and action categories. Furthermore, collecting basic data on degradability of the biodegradable net evaluated the usefulness of the nets. As a result, the use of biodegradable nets reduced the dismantling time. Therefore, biodegradable nets may apply to sauvage cultivation for labor-saving and light work on dismantling because biodegradable nets can be buried and disposed of with plants.

In this study, for large-scale （63.9ha/240 parcels）, a Four-crop rotation system with two production years （rice–wheat/barley–soybean） on paddy fields, we analyzed the relationship between rainfall measured using an IoT sensor and farm work history obtained from a GPS log etc. based on the standard values of workable rainfall published by the Ministry of Agriculture, Forestry and Fisheries （MAFF standard value）. In addition, we tried to propose desirable future values of workable rainfall. Fertilization, tillage, puddling, transplanting, and pest control for rice cultivation as well as herbicide spraying and levee weeding for rice, soybean, and wheat/barley cultivation were considered workable even under rainfall levels exceeding the standard value. Thus, the cultivation technology improved in each aspect: devising a work system in preparation for rainfall risk, using the agricultural machine popularized since the announcement of the MAFF standard value, popularization of liquid herbicides, performance improvement of the agricultural machine itself as seen in autopilot rice transplanters, and popularization of pesticides that are not easily affected by rainfall. In contrast, the workable rainfall for rice, soybean, and wheat/barley cultivation was considered to be below the standard value. Management decisions, such as those for maintaining crop quality and reducing the use cost of grain cooperative drying facility, also have a considerable impact on the response to rainfall risks. To improve the MAFF standard value, the values suitable for situations in recent years should be updated, and the temporal classification of rainfall levels on farm working days should be subdivided. Further, by considering the operation system, agricultural machine characteristics, soil types, etc. as factors, a more accurate standard value can be established.

Direct seeding has become increasingly popular in an onion cultivation in the last decade, especially in Hokkaido. Although direct seeding can save time and costs of raising seedlings, onion farmers usually face three challenges. First, the germination rate of seeded onions is not good. Second, direct seeding makes it more difficult to control weeds than transplanting. Third, herbicides for weeds also cause damage to seeded small onions. It is vital to enhance the initial growth of seeded onions to solve these problems. The purpose of this study was to confirm whether drip irrigation/fertigation with a satellite system could enhance the initial growth of seeded onions and increase the yield in the actual commercial field of Hokkaido as an on-farm experiment. The results in 2021 showed that germination rate of drip fertigated plot was at 95%, while conventional cultivation plot was at 75%. We also confirmed that drip fertigation enhanced the initial growth. The yield of fertigated onions was 1.8 times greater than the yield by conventional cultivation. At the same time, we could decrease nitrogen fertilizer by 16% compared with the conventional value. Drip fertigation also increased the percentage of larger onion bulbs. The results also confirmed that the satellite image analysis was valid and useful to estimate the quantity of evapotranspiration and decide the amount of irrigation water. For these reasons, drip fertigation systems with satellite image analysis should be considered one of the best methods for direct seeding of onions.