The demand for labor-saving crops and domestically produced feed has increased, as has the cultivation of grain maize in upland fields that were previously used for rice cultivation. Compared to wheat and soybeans, grain maize can be managed more efficiently in large-scale operations and on large plots, making the application of highly efficient cultivation and harvesting systems advantageous during optimal periods. Plowing tillage maintains grain maize growth and yield, increases root lodging resistance, and reduces work time by 19%-36% compared to conventional rotary tilling. Also, using a maize header for harvesting reduces work time by 21% while maintaining accuracy comparable to a reel header. Standard operating procedures for highly efficient work systems, from cultivation to harvest, have been developed and implemented for social adoption and extension. This review assesses various aspects of these integrated, highly efficient work systems for grain maize production in upland fields converted from Japanese paddy fields.

The practice of pressing down on young wheat plants by ground rolling or trampling has been used in Japan for a long time to increase yield. Among the reported effects of rolling are delays in spikelet formation, apical development, and internode elongation; however, the underlying mechanism is unknown. Wheat can be injured by frost if exposed to temperatures of −2°C or lower after the jointing stage, and the risk is increased by a warm winter and early sowing. This review presents the results of research on the prevention of frost injury by rolling, the conditions for effective rolling, and how rolling delays spike development.

Annual crops, cultivated on 60%-80% of global cropland, form a critical cropping system that supports the majority of food production but requires significant inputs, whose deficiency can lead to soil and nutrient loss. In contrast, perennial cultivation systems, which are planted once and harvested repeatedly, have shown the potential to reduce inputs and help retain soil carbon. Therefore, the primary breeding method for developing perennial major crops has been interspecific hybridization between conventional annual varieties and their relative species. Research has focused on minor crops, such as buckwheat, because their perennial species exhibit waterlogging tolerance. However, developed perennial varieties and breeding lines face more challenges than annual crops, including hybrid sterility, low productivity, susceptibility to plant pests and diseases, and weed potential. Additionally, frost or soil freezing tolerance traits are essential for wintering, especially at high altitudes and in high-latitude regions. In this review, we highlight the differences between annual and perennial species, summarize studies that advance perennial traits and hybrid development, and introduce the latest domesticated perennial hybrids. To maintain stable food production, the development of new breeding technologies for perennial crops are a promising option.

We developed a prototype remote-controlled hammer-knife mower capable of mowing weeds over 1 m high on steep slopes. The work efficiency of the prototype is twice that of a commercially available remote-controlled mower and 2.6 times that of a walking-type mower. In flat fields with clusters of tall goldenrods, the prototype was twice as efficient as a brush cutter.

The growing number of large agricultural corporations in Japan requires an efficient means to evaluate crop growth and yield formation for multiple fields. Using a combine harvester with a yield monitor sensor, we collected wheat yield data for 76 fields cultivated by an agricultural corporation. This study used functional regression and functional data analysis (FDA) to analyze the relation between inter-field wheat yields and growth using the time-series Normalized Difference Vegetation Index (NDVI) calculated from Sentinel-2 satellite imagery. The observed inter-field yield variation was 17–361 g m⁻². FDA applied functional regression with two explanatory variables: the estimated functional NDVI and the sowing date. The inter-field yield variation was explained by the coefficient of determination (R²) = 0.39. The coefficient function indicated that functional NDVI affected yield. This study assessed the possibility of using satellite information for agricultural management and provided an alternative to analyzing time series data to infer crop growth and yield variation.

Applying spent mushroom substrate (SMS) in sugarcane farming can be an effective use of organic resources, promoting growth while improving soil fertility. However, most SMS is disposed of as waste, and application methods have not been adequately studied. Therefore, we verified the effects of SMS made from bagasse (SMS-B) on sugarcane and its potential to reduce environmental impacts, such as chemical fertilizer use and climate change, comparing its application with that of chemical fertilizers (CF), bagasse, and SMS from sawdust (SMS-S). The SMS-B application increased dry matter weight by producing more tillers than CF. Additionally, SMS-B improved many soil chemical properties compared with CF. SMS-B promotes the early growth of sugarcane because it contains more nutrients and has a lower C:N ratio than bagasse or SMS-S, likely due to differences in the materials used for mushroom cultivation, as SMS-B was made from composted bagasse. With a 30% CF reduction, SMS-B achieved a higher dry matter weight than the recommended CF application. Compared to the other treatments, SMS-B resulted in higher total soil carbon content relative to the amount of applied carbon. These results indicate that the application of SMS-B can promote the early growth of sugarcane and effectively reduce environmental impacts via reducing chemical fertilizer use and increasing total soil carbon content.

Lactic acid bacteria (LAB) are used in the food industry for fermentation and preservation. Additionally, certain LAB provide beneficial activity to animal or human health. This study assessed five LAB strains, including Latilactobacillus sakei A60 and 4-44, Lactiplantibacillus paraplantarum D02, and Latilactobacillus curvatus 4-36 and 4-43, as new fermentation starters with both antimicrobial and probiotic activities. The strains showed growth at 5℃ and over 6% (w/v) NaCl, which are the conditions expected in food processing and storage. Their antimicrobial activity against eight microorganisms commonly associated with food spoilage was examined at various growth temperatures. They exhibited antimicrobial activity at 25℃, 30℃, and 37℃ and showed higher activity at 25℃ than at 30℃ and 37℃. All strains except D02 showed antimicrobial activity at 5℃. In terms of probiotic activities, all strains showed high or comparable mucin-binding activity, and strains A60 and 4-43 exhibited relatively higher tolerance to bile than that of Lacticaseibacillus rhamnosus GG, a potential probiotic bacterium. Strains A60, D02, and A-36 showed increased mucin adhesion via culturing with 6% (w/v) NaCl. These strains would be useful not only in food processing and storage but also in health-related applications, as they colonize the intestine and suppress the growth of pathogenic bacteria.

This study focuses on Vietnam, a nation prone to various natural disasters, including storms, typhoons, floods, flash floods, and landslides. Utilizing annual panel data from 2010 to 2020 at the provincial level, we conducted a panel data analysis of provincial natural disaster damage in monetary terms considering meteorological, hydrological, geographic, and socioeconomic factors, including elevation, terrain ruggedness index (TRI), precipitation, gross regional domestic product (GRDP) per capita, and agricultural GRDP. Our hybrid model results indicate that precipitation was a significant contributor to economic damage. Two geographical factors, elevation and TRI, also influenced it. Elevation was associated with a decrease in economic damage, while TRI was associated with an increase. Economic development, as indicated by GRDP per capita, was found to be associated with an increase in natural disaster damage at lower levels of GRDP per capita; however, this relationship shifted to one of decreasing damage after reaching a certain threshold in GRDP per capita. Provinces with higher agricultural GRDP tended to suffer greater damage, but within-province agricultural development was not statistically significant at the 5% level. This finding aligns with the understanding that crop farming and the aquaculture industry are more susceptible to natural disasters because they are more directly exposed to natural elements. This also implies that regions where agriculture comprises a significant share of the economy are less resilient to natural disasters. These findings offer valuable insights for policymakers for sustainable economic development.

High pathogenicity avian influenza (HPAI) viruses of clade 2.3.4.4b have caused outbreaks worldwide, affecting both wild and domestic birds, as well as occasionally mammals. Mallards (Anas platyrhynchos), the natural hosts of influenza A viruses, are major migratory birds in Japan and strong contributors to the transmission and maintenance of the viruses. To further understand the pathological consequences and potential for viral persistence, histopathological examinations were conducted on mallards that survived 14 days post-inoculation with H5N1 and H5N8 clade 2.3.4.4b HPAI isolates. Five of the ten mallards that underwent autopsy exhibited multifocal encephalitis of variable severity. Two showed severe encephalomalacia and calcifications, one of which also had persistent viral antigens within the necrotic foci. Furthermore, marked atrophy of the lymphoid tissues, particularly the thymus, was observed and appeared to correlate with the severity of encephalitis. These findings indicate that residual encephalitis and lymphoid depletion can persist despite resolution of the infection, suggesting potentially lasting health effects in mallards following HPAI viral infection. Notably, some mallards showed no histological lesions, indicating their potential as viral carriers.

Sudangrass possesses advantageous traits, including slender stalks and vigorous summer growth. However, its high nutrient absorption efficiency predisposes it to nitrate accumulation in the stems and poses a risk of nitrate poisoning in cattle. This study evaluated 42 lines of 33 sudangrass varieties, comprising germplasm from the National Institute of Agricultural Sciences (NIAS) gene bank and commercial varieties. Sudangrass lines exhibited diverse phenotypic characteristics in the field trials. Genotyping-by-sequencing (GBS) was used to analyze genomic DNA, categorizing sudangrass into three groups based on 3975 single-nucleotide polymorphisms (SNPs). Cluster I, with 22 lines, such as Haysudan, displayed shorter and thicker culms resembling sorghum with fewer tillers. Cluster II, comprising eight lines, including Balesudan, exhibited enhanced tillering and biomass production. Cluster III, represented by 12 lines, such as Piper, showed moderate traits but greater susceptibility to northern leaf blight. Cultivation of sudangrass under varying cattle compost application rates revealed differences in nitrate-nitrogen concentrations, confirming a trend of increased accumulation with higher fertilization levels. Nitrate-nitrogen levels were higher in the first harvest but declined in the second. To meet the regulatory limit of 0.2% total nitrate-nitrogen (dry weight), compost applications below 5 t・10 a⁻¹ are recommended. Among the tested lines, some exhibited nitrate-nitrogen concentrations near the regulatory threshold even under a high compost application rate of 15 t・10 a⁻¹, while maintaining high dry matter yields. Lines such as GB13, which combine high biomass production with low nitrate accumulation, showed great potential as valuable breeding materials.