日本虎杖覆盖对连作的影响——日本西阿瓦陡坡土地农业系统传统耕作评价

禾本科物种(例如银草、芦苇)在日本传统的地膜覆盖农业中普遍使用,西阿瓦地区是全球重要的农业遗产系统(GIAHS)所在地。传统上,这里的农民使用银草覆盖农业土壤。但当地农民从长期的经验中了解到,日本虎杖覆盖更适合该地区茄科作物的种植。目前尚不清楚日本虎杖覆盖物为何对茄科作物的种植有益。在本项研究中,我们假设日本虎杖覆盖物可能会有效避免连续种植马铃薯的危害。因为过去每年都会种植两次本地马铃薯,因此,我们调查了日本虎杖覆盖对连续种植马铃薯以及番茄种植后对马铃薯产量的影响。在2018年进行的田间试验中,我们首先在连续马铃薯栽培的土壤和未耕种的土壤中比较了日本虎杖覆盖、银草覆盖和无草覆盖(对照)对马铃薯产量的影响,结果表明日本虎杖覆盖减少了马铃薯产量的降低程度。其次,我们比较了番茄种植后的土壤和未耕种的土壤中的虎杖覆盖和无草覆盖对马铃薯产量的影响,结果再次表明了日本虎杖覆盖减少了马铃薯生长和产量下降的程度。这些发现表明用日本虎杖覆盖有助于避免连续种植马铃薯的风险。     

LATE CENOZOIC GOLD VEINS AND VOLCANIC COLLAPSE TECTONICS IN THE ISLAND ARC JUNCTIONS OF THE JAPANESE ISLANDS

0 Introduction The Japanese Islands consist of five volcanic arcs (Fig.1).The North-East and SouthWest Japan arcs together form the Honshu arc,to which the Kurile arc joins at Hokkaido,whereas the Izu-Mariana arc joins at Izu-Fossa Magna,and the Ryukyu arc joins at Kyushu.These regions where volcanic arcs converge,are termed "island arc junctions".     

Evolution of Dentary Diastema in Iguanodontian Dinosaurs

The dentary diastema of iguanodontians has been considered to be related to its unique jaw mechanism for herbivorous adaptation.The dentary and diastema lengths of iguanodontians were measured and compared to elucidate the evolution of iguanodontian diastema.A gap in ratios between most non-hadrosaurid iguanodontians and hadrosaurids was observed,suggesting that all non- hadrosaurid iguanodontians,expect for Ouranosaurus nigeriensis and Protohadros byrdi,lack a diastema or have a short diastema,although ...     

Suppressive Effects of Traditional Mulching Using Japanese Knotweed (Fallopia japonica) on Solanaceae Crop Diseases

Poaceae plant species, such as silver grass, are commonly used in mulching activities Japan. In contrast, local farmers have traditionally used Japanese knotweed (Fallopia japonica) mulch in the cultivation of solanaceous crops in the Nishi-Awa area of Japan, which is a Globally Important Agricultural Heritage Systems site. We have previously evaluated the positive effects of Japanese knotweed mulching on solanaceous crops, such as eggplants, tomato, and potato. In the present study, we observed that the naturally occurring diseases in the solanaceous crops tended to decrease when the knotweed mulching system was adopted, in comparison to when Poaceae mulch was adopted. In eggplants, leaf mold and powdery mildew decreased under Japanese knotweed mulching. We further evaluated the effects of Japanese knotweed mulching by inoculating test plants with Pseudomonas cichorii. We observed suppression of bacterial disease and tomato mosaic virus under Japanese knotweed mulching and following spraying with Japanese knotweed extracts. In addition, disease-resistance genes were expressed at high levels in Arabidopsis thaliana, a model plant, following treatment with Japanese knotweed extracts. The results suggest that Japanese knotweed has potential applications in future sustainable agriculture activities.     

Collating Historic Weather Observations for the East Asian Region:Challenges,Solutions,and Reanalyses

正1.Introduction Historic instrumental weather observations,made on land or at sea from as early as the 17th century(e.g.,Camuffo et al.,2010),are integral to extending our understanding of the decadal and centennial variations of Earth’s climate and for comparison with paleo-proxy data.The potential of such data is shown to best effect when used in dynamical 4D global     

High-density CO2 inclusions in the Colorado Front Range

A fluid density in an inclusion is commonly observed to be too low for the P-T estimates for the postulated time of trapping, and is generally attributed to a fluid loss during the uplift process. It is more difficult to explain a fluid density which is too high. In the 1700 m.y. Front Range migmatites, such high densities occur in some of CO₂ inclusions which were deduced to have formed during the migmatization episode. The peak P-T estimates for migmatization in the Front Range are 4–6 kb and 650°–700° C (in sillimanite field) but pressures required to form the most dense inclusions are >7.6 kb (in kyanite field). The high density is not likely to be a relic of a higher pressure condition earlier than the main migmatization episode for the following reasons: (a) no kyanite (or any other relic high pressure phase) has been found in the Precambrian Front Range; (b) the high density inclusions are rare in zones with least signs of deformation and melting (paleosomes and quartz inclusions within feldspar grains) which instead contain relatively undisturbed early inclusions; (c) high density inclusions with Th <–30° C are associated with heavily altered plagioclase caused by hydrothermal activity which was a late event in leucosome formation. Further, there is evidence for post-entrapment change(s) in density: an intragranular trail in quartz contains CO₂ inclusions that exhibit almost the whole range in Th (–40 to +24° C) as displayed by the entire population of the early CO₂ inclusions (–66 to +30° C). The density of an inclusion in the trail is not related to inclusion size but to the position of the inclusion relative to apparent micro-shear zones crossing the CO₂ trail. A change to a higher density (=a smaller volume) could have resulted from an initially isobaric cooling path which intersects CO₂ isochores with increasingly higher densities. Additional excess pressure may have resulted from overthrusting. However, because high density inclusions occur selectively in the zones in which plagioclase shows alteration indicating a high and because there is a correlation between shear zones and high density inclusions, it is postulated that local hydrolytic weakening of quartz was necessary for the decrease of inclusion volume which occurred during deformation. The localized deformation may also result in an excess pressure. However, the introduction of a small amount of H₂O into these inclusions as a possible cause of high density inclusions cannot be ruled out.     

黑河流域土地利用变化对地下水资源的影响

土地利用与覆被变化对区域水文过程具有深刻影响。利用1960s以来的三期遥感数据和1980年以来的地下水长期观测数据, 从地下水补给和排泄系统两方面, 分析了近30年来甘肃省黑河流域中游地区土地利用与覆被变化对地下水系统的影响, 结果表明：以1985年为界, 随土地利用与覆被变化强度不同, 前后15年土地利用变化对地下水系统补给的影响分别达到2.602亿m³/a和0.218亿m³/a, 对排泄系统的影响分别为2.035亿m³/a和4.91亿m³/a, 在保持区域人工开采量不超过3.0亿m³/a的合理幅度下, 土地利用变化对区域地下水资源变化起着决定作用;在区域土地利用与覆被变化和近10年来人类较大规模开采影响下, 甘肃省张掖盆地地下水资源变化出现了显著的区域差异性。认识土地利用变化对流域地下水系统的作用与区域地下水资源的时空变化特征, 对流域水土资源合理利用规划与管理有重要意义。     

Analyses of age and population genetic structure of the broadbanded thornyhead Sebastolobus macrochir in North Japan suggest its broad dispersion and migration before settlement

Body size, age, and population genetic structure of the broadbanded thornyhead Sebastolobus macrochir inhabiting areas off the Pacific coast of Tohoku and off Abashiri, the Sea of Okhotsk, Japan, were analyzed. On the basis of significant differences in body size (growth) between certain year classes at Tohoku and Abashiri, it appears that S. macrochir does not migrate extensively after settlement and subsists on food within the settled environment. Meanwhile, no genetic isolation was observed between the populations at these two sites. Thus, it is highly likely that its pelagic egg balloons, larvae, and juveniles widely disperse and migrate before settlement.     

The composition and role of the fluid in migmatites: a fluid inclusion study of the Front Range rocks

Monophase negative-crystal shaped CO₂ inclusions occurring isolated, in small clusters, or in well-healed intragranular fractures are common in the leucosome quartz of the 1700m.y.-old migmatites from the east-central Colorado Front Range. They are, however, quite rare in the mafic selvage and paleosome (host rock) quartz. The mode of occurrence suggests that these are the earliest inclusions to form. In addition to the difference in abundance of the inclusions, there is a difference in CO₂-density distribution between migmatitic zones. The temperatures of homogenization for the leucosome inclusions range and +l°C from –67° C to +20° C with two maxima (at –21° C) while those for the paleosome and selvage inclusions are –37° C to +20° C with a single maximum at + 5° C. These differences between the migmatitic zones which occur on the scale of a few centimeters suggest that the formation of these inclusions was related to the migmatization process. The densities corresponding to the Th maxima are appropriate for the P-T conditions for migmatization estimated from the mineral geobarometer/geothermometer. These inclusions must contain nearly pure CO₂, as their final melting temperatures (–56.5° to –57.2° C) are very close to that of the triple point of CO₂. Their composition also was confirmed by Raman spectroscopic analyses.It has been proposed by other workers that CO₂ fluid in the inclusions could form from an H₂O-CO₂ fluid when H₂O is partitioned into the silicate melt. Such partitioning should result in some early H₂O-rich inclusions: H₂O must be released as the melt crystallizes. As found in migmatites from other areas, most aqueous inclusions in the Front Range rocks are obviously much younger than the early CO₂ ones. However, early H₂O-rich fluid may still be preserved, at least in three ways: (A) in rare, isolated or clustered inclusions within quartz inclusions in feldspar; (B) as inclusions in microcline porphyroblasts; (C) in hydrous alteration products of feldspar. (A) contain dilute fluids, 1 to 6 wt% NaCl equivalent. The densities of (A) as well as those of the early CO₂ inclusions found in the quartz inclusions in feldspar are appropriate for the range of P — T conditions estimated for migmatization. These early inclusions must have been preserved because of protected environment. Inclusions (B), found to contain H₂O (and possibly CO₂) by infrared analyses, must be early because they are absent from recrystallized grains. (B) and (C) are much more common in the leucosome than in the other zones suggesting that they are related to migmatization process. The concentration of early CO₂ inclusions in the leucosome is consistent with the model of migmatization in which fluid concentration in the leucosome was a cause of melting.     

FORMATIVE MECHANISM OF AKAISHI MOUNTAINS AND ENREI BASIN IN CENTRAL JAPAN

1 Introduction It is common in mobile belts that uplifting mountains are neighbored by synchronously subsiding basins.The coupling mechanism of such subsidence and uplift is an important target to clarify the dynamics of mobile belts.We investigate the coupled mountain uplift and basin subsidence in the Central Japan highland,the junction of three island arcs (the Northeast Japan,the Southwest Japan and the Izu-Ogasawara arcs).The highland over 3 000 m in height is composed of mountain ranges,plateaus and intramountain basins (Fig.1).