A study to determine an equation of enveloping curve for regional flood peaks by maximum rainfall data

In this paper, Creagers equation and Groups equation are algebraically examined to determine an equation of an enveloping curve for regional flood peaks from the viewpoint of the curve profile. The applicability of a small drainage area with little observed data on flood peak discharge was examined in comparison to specific flood peak discharge calculated by a rational formula using data of maximum rainfall. In the algebraical consideration, the Creagers equation had an extreme value at a drainage area A=1.0 km², and the specific flood peak discharge became a maximum. Flood peak discharge calculated by Groups equation had an extreme value at a drainage area A=6,568 km², and it became a maximum. Except for Hokkaido, in catchment areas not exceeding 1,178 km², Groups curve q _K was closer to the curve q _DAD of specific flood discharge than Creagers curve qc. From the above research results, the Groups equation is applicability better than the Creagers equation, as the drainage area A is 1,178 km² or less.     

Changes in intake of milk and dairy products among elementary schoolchildren following experiential studies of dairy farming

This study intends to clarify the effects of hands‐on dairy farming experience on the consumption of milk and dairy products. A survey was conducted on 474 elementary schoolchildren and their parents at eight elementary schools that offered hands‐on dairy farming experience at four dairy farms in Hokkaido, Japan. In the survey, questionnaires were used to inquire about the children's milk and dairy product intake before and after the hands‐on experience. In addition, milk intake at school was investigated weekly for 3 months after the hands‐on experience. The parents were asked about the children's intake of milk and dairy products at home before and after the hands‐on experience. Analysis of the survey results indicated a significant increase in the amount and frequency of milk consumed and the frequency of yogurt consumed at home by the children immediately after the hands‐on experience. Accordingly, the study suggested that the hands‐on dairy farming experience had the effect of increasing children's milk and dairy product consumption at home.     

Determination of true absorption and fecal endogenous loss of zinc in goats

We determined the true absorption and endogenous fecal loss of zinc (Zn) in goats using its stable isotope. Three goats were fed with the diet containing 50 mg/kg Zn twice a day for 17 days. In the morning of day 11, the goats were given a meal labeled by ⁶⁷Zn as the tracer with dysprosium as the unabsorbed marker. Then the goats were given unlabeled diet as the rest of the morning feed. We measured dietary and fecal Zn concentration, ⁶⁷Zn abundance and dysprosium concentration in feces. The excretion pattern of the tracer Zn into feces differed from that of dysprosium. Therefore, we directly calculated the true absorption of Zn from Zn concentration and ⁶⁷Zn abundance in fecal samples collected after the labeled diet was given. The apparent absorption of Zn was –0.009 ± 0.016 mg/kg bodyweight (fractional absorption, ?1.07 ± 1.85%). The true absorption of Zn was 0.162 ± 0.018 mg/kg bodyweight (fractional absorption, 18.25 ± 2.01%). The endogenous fecal loss of Zn was 0.172 ± 0.004 mg/kg bodyweight and the intestinal secretion of Zn was 0.210 ± 0.009 mg/kg bodyweight. The present experiment indicates that stable isotopic Zn is a powerful tool for examining Zn metabolism in ruminants.     

Oxidation of bleached wood pulp by TEMPO/NaClO/NaClO2 system: effect of the oxidation conditions on carboxylate content and degree of polymerization

Oxidation of bleached wood pulp by the TEMPO/NaClO/NaClO₂ system was carried out at pH 3.5–6.8 and 25°–60°C with different amounts of NaClO, and investigated in terms of effects of the reaction conditions on carboxylate content and degree of polymerization (DP) of the oxidized pulp. Oxidation was accelerated by the addition of NaClO, when carried out at pH 6.8 and 40°–60°C. Addition of NaClO of more than 0.5 mmol per gram of the pulp was effective to accelerate the oxidation. Carboxylate content of pulp oxidized under such conditions increased to approximately 0.6 mmol/g within 6 h. Although DP of the oxidized pulp gradually decreased with oxidation time, no significant differences in DP of oxidized pulps were found at oxidation temperatures between 25° and 60°C, and DP values of more than 900 were maintained after oxidation for 54 h at 60°C.     

Groundwater flow and transport and potential sources of groundwater nitrates in the Ryukyu Limestone as a mixed flow aquifer in Okinawa Island, Japan

We investigated the groundwater flow and the transport and potential source of groundwater nitrates in the typical karst setting of the Ryukyu Limestone aquifer in the southern part of Okinawa Island, Japan. Analysis of groundwater hydrographs indicated that this is a ??mixed flow?? aquifer with the coexistence of slow diffuse flow in the matrices and rapid conduit flow in the caves and caverns. This relationship is indicated by the travel time of groundwater flow: 70?days in the matrices of the aquifer and 6?days through the caves and caverns. The conduit flow system was also confirmed by the distribution of relatively low concentrations of ²²²Rn near caverns. The sampling sites were categorized into upland field (UF) type and residential area (RA) type according to the land-use ratio on the upstream side with a 600-m influential radius, and cave and cavern (CC) type according to the hydrogeologic setting near two large caverns, even though the CC type should be categorized as the UF type from the viewpoint of land use. Cross plots of NO₃-N versus SO₄ ^2? showed that the predominant source of UF groundwater nitrates was chemical fertilizer. A difference was observed in average ??¹⁵N values between UF (8.9??) and RA (10.0??). On the other hand, the average ??¹⁵N value for CC (10.5??) was similar to that for RA, indicating that CC nitrates were not related to the surrounding land use. This phenomenon is considered as evidence that CC groundwater nitrates were carried by rapid groundwater flow through caves and caverns from residential areas located higher upstream compared to the influential areas. According to previous studies, animal and human waste was considered the predominant sources of RA and CC groundwater nitrogen. The contribution ratio of chemical fertilizer (R _CF) was calculated using mass balance equations under assumed predictability. There was a relatively high correlation between the rate of upland areas and of residential areas and R _CF. Average R _CF for UF, RA and CC was 41, 27, and 25%, respectively.     

Technological spillover in Japanese rice productivity under long-term climate change: evidence from the spatial econometric model

Rice productivity will be affected by climate conditions not only in own region but also in neighboring regions through technological spillover. Measuring such direct and indirect influence of future climate change is important for policy making. This study analyzes socio-economic and climate factors in rice total factor productivity (TFP) and evaluates technological spillover effects by using the spatial econometric model. To consider geographical situation, we use hydrological model in addition to crop-yield and crop-quality models. Results show that spatial autoregressive tendencies were observed in rice TFP, even though the influences of climate factors were removed. Such spatial dependence brings about synergistic effects among neighboring prefectures in northern Japan and depression effects, like a spatial trap, from neighbors in southern Japan. Substantial impacts of climate change were as high as socio-economic factors but different in degrees by regions. Also, future climate change estimated by the global climate model enlarged fluctuation degree in rice TFP because accumulative or cancel out effects of temperature and precipitation occurred year by year. Therefore, technological development in rice production and provision of precise climate prediction to farmers are important in order to ease and mitigate these influences.     

Current methods of price formation for new-demand rice distribution and relevant issues

This study uses transaction cost theory to analyze the market of rice whole crop silage (RWCS) and obtained the following two results. First, the institutional environment of RWCS market has an effect on transaction costs. The negative influence of RWCS is higher than that of rice for forage. This tendency corresponds to the manner in which livestock farmers get feed. Second, the RWCS market in the city of Katori shows the validity of an intermediate organization for efficient production utilization system. The intermediate organization in the city of Katori mainly serves to reduce transaction costs, which cannot be easily achieved individually. An intermediate organization can process complicated product information similarly and simplify the deal process. The city of Katori and Chiba-ken takes on the roles of providing policy explanations, offering technical information, matching suppliers with buyers, etc. Support from the reliable intermediate organization of the city of Katori and Chiba-ken enabled farmers in the city of Katori to invest in a Total Mixed Rations center and use paddy fields effectively. The price of RWCS in this area is insensitive to the price of both rice and imported feed. One factor behind this unresponsive pricing is the intermediate organization, which works as a system through which rice and livestock farmers obtain long-term benefits. The harmonious RWCS market system in the city of Katori rests on solidarity among rice farmers, livestock farmers, and the local government which strategically deals with the institutional environment.     

Methane flux characteristics in forest soils under an East Asian monsoon climate

Methane (CH₄) uptake by soil can possibly be suppressed more in regions with heavy summer precipitation, such as those under the East Asian monsoon climate, as compared to that in regions with a dry summer. In order to determine how precipitation patterns affect seasonal and spatial variations in CH₄ fluxes in temperate forest soils, such fluxes and selected environmental variables were measured on different parts of a hill slope in a cypress forest in central Japan. On the upper and middle parts of the slope, CH₄ uptake was observed throughout the year, and the uptake rates increased slightly with soil temperature and decreased with soil water content. The CH₄ flux predicted using data for the middle and upper parts of the slope ranged from −1.12 to −0.83 kg-CH₄ ha⁻¹ y⁻¹ (i.e. CH₄ uptake by soil) and from −2.30 to −2.04 kg-CH₄ ha⁻¹ y⁻¹, respectively. In contrast, in the relatively wet lower part of the slope near an in-stream wetland, large CH₄ emissions (>2 mg-CH₄ m⁻¹ d⁻¹) were observed during the rainy summer. In this wetter plot, the soil functioned as a net annual CH₄ source in a rainy year. Hence the variation in CH₄ flux with a change in soil water conditions and soil temperature on the lower part of the slope contrasted to that on the upper and middle parts of the slope. The predicted CH₄ flux for this lower plot ranged from −0.45 kg-CH₄ ha⁻¹ y⁻¹ in a dry year to 1.80 kg-CH₄ ha⁻¹ y⁻¹ in a rainy year. Our results suggest that consideration of the soil water conditions across a watershed is important for estimating the CH₄ budgets for entire forest watershed, particularly in regions subject to a wet summer.     

Diversity of <Emphasis Type="Italic">Citrus</Emphasis><Emphasis Type="Italic">depressa</Emphasis> Hayata (Shiikuwasha) revealed by DNA analysis

Citrus depressa Hayata is an indigenous mandarin species on the Ryukyu Islands located in the subtropical region of Japan. We deduced its phylogenetic relationships by evaluating accessions grown on various Ryukyu Islands via cleaved amplified polymorphic sequence analysis of cpDNA and sequence-related amplified polymorphism (SRAP). The cpDNA results indicated that C. depressa could be classified into two types. SRAP revealed patterns of diversity within C. depressa consistent with our cpDNA results. These results indicate that maternal origin may influence or is correlated with the constitution of the nuclear genome of C. depressa. Another Japanese mandarin species, Citrus tachibana (Makino) Tanaka was distinguished from C. depressa by SRAP markers. Moreover, both C. depressa and C. tachibana could be distinguished from other Citrus species. Our results suggest that Japanese mandarin possesses a characteristic genome with the genus Citrus.