Although direct seeding in rice cultivation has potential for labor- and cost-saving benefits in comparison with transplanting, the latter remains the predominant method in Japan because the former shows some weaknesses in seedling emergence and establishment, and in lodging resistance. We therefore set out to compare seedling emergence and establishment in direct seeding culture under different daily temperature ranges. We compared a windbreak-shielded and control plot using pot-grown plants under outdoor conditions. In the windbreak plot, which was subject to a high maximum temperature and wide daily temperature range, seedling emergence and establishment rates were higher than in the control plot. Additionally, detailed laboratory tests revealed that the influence of post-seeding daily temperature ranges on seedling emergence was greater under low-temperature than high-temperature conditions. Moreover, changes with time in the measured values for seedling emergence rates and those estimated using the Arrhenius equation were approximately the same. We also used maximum and minimum temperatures to calculate early sowing limits for direct seeding of paddy rice at different locations in the Hokuriku region; previously, daily mean temperature has been used as the basis of early sowing limit calculations. The two calculation methods showed different early sowing limits. Moreover, early sowing limits based on daily temperature ranges were observed to occur earlier in the inland and later in the coastal area when compared with early sowing limits based on daily mean temperature.

With the objective of transmitting high level skills to clean the interior of a combine harvester, a method to create a new cleaning manual based on empirical knowledge was developed. Firstly, in this method, the knowledge of expert workers is extracted from interviews and from watching videos of them performing cleaning works. Secondly, the extracted knowledge is summarized in a table and finally, written in sentences with corresponding figures. To verify its effect, a cleaning manual was created based on the developed method and a cleaning test was conducted. As a result, the amount of residual grain remaining in the machine after cleaning significantly decreased.

A grain conveyor structure was developed to reduce the time required for internally cleaning a combine harvester. In the developed structure, the horizontal plane parts in the grain conveyor were slanted to promote slipping of grains. Further, the cleaning ports were enlarged and located in optimized positions to enable the easy discharge of grain residues. The results of the examinations conducted using a headfeeding combine harvester indicated that the time required for the removal of grain from the grain conveyor of the developed structure was approximately half of that required using the conventional structure.

Forage rice (Oryza sativa L.) must be cost competitive with other fodders, and thus an important goal is increasing its dry matter (DM) and total digestible nutrient (TDN) yields, while reducing labor and costs. Although the direct seeding of rice does not have higher yield stability than transplanting, it has the potential to reduce labor and costs. The objective of this study was to determine the effects of seeding rate (2, 4, or 6 g m^–2) and row spacing (10 or 30 cm) on DM and TDN yields in direct-seeded and double-harvested forage rice in a well-drained paddy field. The seeding rate did not affect the total DM and TDN yields of the first and second crops, although those total yields were higher at 10 cm row spacing than at 30 cm row spacing. The DM yield and tiller number of the first crop increased with increasing seeding rate. Both were higher at 10 cm row spacing than at 30 cm row spacing. The seeding rate did not affect the DM and TDN yields of the second crop harvested at heading, although those yields were higher at 10 cm row spacing than at 30 cm row spacing. Neither seeding rate nor row spacing affected the DM and TDN yields of the second crop harvested at dough ripe. Thus, increasing the seeding rate is effective for increasing the DM and TDN yields of the first crop and reducing row spacing is effective for increasing total DM and TDN yields of the first and second crops. This cultivation method is expected to facilitate forage rice production by reducing labor and costs in temperate regions.

Mt. Wakakusa in Central Japan is a semi-natural grassland which has been maintained by repeated application of prescribed burnings of vegetation for more than 500 years. We assessed the spatial variability of selected soil properties and constructed their distribution maps using a geostatistical method to provide spatial information on soil resource for sustainable land management in this grassland. All the examined soil properties showed intermediate (coefficient of variation [CV] = 10%-90%) or high (CV > 90%) variability, except for the soil pH (CV < 10%), suggesting that the precision soil management approach is recommendable in the study site. The variogram analysis revealed that all of the soil properties, except for the electrical conductivity with a very weak spatial dependency (nugget-to-sill [N/S] ratio > 0.75), showed a very strong or moderately strong spatial dependency (N/S ratio ≤ 0.50), which might occur under the strong influence of intrinsic factors such as the inherent soil quality. The soil maps constructed by the ordinary kriging method helped in understanding the distribution patterns of the examined soil properties and identifying specific locations with signs of degradation and pollution. These spatial distribution patterns should be considered when developing a sustainable soil management strategy in Mt. Wakakusa grassland.

In Indonesia, plantations of rubber tree (Hevea brasiliensis), which have been expanding rapidly in lowland areas of the Sumatra Island, are predominantly managed by smallholder farmers using a limited amount of fertilizers. The rapid growth of the rubber tree and the intensive collection of latex during an economic lifetime (ca. 25 years) of the rubber tree poses a risk of soil fertility decline in the rubber gardens, but changes in soil fertility under smallholder rubber farming have not been well assessed in this region. In the present study, we aimed to examine if the soil fertility declines under smallholder rubber farming through the assessment of the changes in the general soil fertility parameters along a chronosequence of rubber tree stands (n = 24; stand age, 3-27 years old) in a West Sumatran lowland. Our results revealed that all the parameters assessed in this study such as organic carbon, total nitrogen, available phosphorus, and exchangeable bases were found independent on the tree stand age and did not show any clear trends of decrease/increase during rubber cultivation period. These findings indicate that soil fertility decline under smallholder rubber farming system is unlikely in the study region.

Understanding the mechanism of disease resistance is critical for combating rice blast disease that causes the most deleterious effects on rice yield, and for evolving successful blast tolerance breeding programs using blast resistance (R) genes. The qPbm11 locus in the blast resistant cultivar Miyazaki-mochi exerts panicle resistance similar to the well-known quantitative panicle resistance gene Pb1. qPbm11 and Pb1 show similarity in panicle blast resistance, quantitative resistance, and proximity of loci on the rice genome. Pb1 resistance is dependent on the expression of transcription factor WRKY45. To identify the resistance mechanism of the qPbm11 locus, we downregulated WRKY45 in the cultivar Miyazaki-mochi through an Agrobacterium-mediated transformation and surveyed its panicle resistance. WRKY45 RNAi transgenic Miyazaki-mochi plants exhibited similar levels of panicle resistance compared to WT, indicating that the qPbm11 locus is independent of the Pb1 resistance pathway. Our results suggested that cloning the genes responsible for qPbm11-mediated resistance along with Pb1 using pyramiding technology could enhance panicle resistance in rice.

We investigated the effects of interplanting on fruit yield in greenhouse-grown tomato by integrating the first (short) and second (long) crop periods in the cooler northern area of Japan. The marketable fruit yield was similar regardless of interplanting in the first crop period, whereas it increased with earlier planting dates in the second and total crop periods. Therefore, planting immediately after the harvest of the first fruit trusses of the first crop period was effective in achieving a continuous harvest and substantial yield improvement upon conclusion of the harvest of six trusses; moreover, there were no incidences of stem lowering in the first crop period. The plant dry weight was also similar regardless of interplanting in the first crop period. However, the total dry weight and fruit dry weight increased with early interplanting in the second and total crop periods. The marketable fruit yield and total dry matter production of the whole crop period increased when cultivation started in March compared with that in April. The dry matter allocation to the fruit was similar among the treatments in all crop periods. The total fresh and dry fruit yields were significantly correlated with the cumulative light interception over the total crop period. Therefore, fruit yield was the highest when cultivation started in March with interplanting in the early-summer resulting in the highest light interception and dry matter production.

Porcine noroviruses have been previously reported by some Japanese research groups. However, there is limited information regarding their epidemiology and pathogenicity in pigs. Here, we attempted to determine the frequency of norovirus infection in pigs in Japan. Fecal samples were collected from 190 healthy pigs in the Tokai region of Japan and checked for noroviruses by reverse transcription-PCR. Noroviruses were present in 11 of the 190 fecal samples (5.8%) and were genetically related to the porcine noroviruses previously detected in other regions of Japan. Our data suggest that porcine noroviruses are circulating among populations of healthy pigs without clinical signs in Japan.

Understanding the spatio-temporal elimination pattern of grazing cattle is important for grazing management. We thus developed a new method of detecting defecation events using a three-axis accelerometer. The accelerometer was fixed on the tails of three Japanese Black steers in a pasture, with the x-, y-, and z-axes being set to the front-to-back, side-to-side, and vertical directions relative to the normal tail position, respectively. The defecation behavior was also visually observed. The 3-sec moving average was calculated from raw acceleration data and charted along the time course. The x-axis and z-axis accelerations showed convex upward and downward curves, respectively, at the defecation events. By using the synchronous signs of both curves, we could visually detect virtually all defecation events. And in order to detect defecation events automatically, we created six variables (i.e., maximum, minimum, and area in convex curve per 30 sec for x- and z- axes) and applied quadratic discriminant analysis (QDA) and a support vector machine (SVM). The critical success index values in QDA and the SVM were 0.8 and 0.98, respectively, using the leave-one-out cross-validation method. We concluded that the use of an accelerometer on a steer’s tail is effective in visually and statistically detecting defecation events.