排序方式： 共有13条查询结果，搜索用时 93 毫秒
1.
S. D. KIMURA YAN Xiao-Yuan R. HATANO A. HAYAKAWA K. KOHYAMA TI Chao-Pu DENG Mei-Hu M. HOJITO S. ITAHASHI K. KURAMOCHI CAI Zu-Cong M. SAITO 《土壤圈》2012,22(2):137-151
To analyze the effect of agricultural activity on nitrogen(N) budget at the watershed scale,a comparative study was conducted at two Japanese watersheds,the Shibetsu River watershed(SRW) and Upper-Naka River watershed(UNRW),and one Chinese watershed,the Jurong Reservoir watershed(JRW).The total area and the proportion of agricultural area(in parentheses) of the watersheds were 685(51%),1 299(21%),and 46 km 2(55%) for SRW,UNRW,and JRW,respectively.The main agricultural land use in SRW was forage grassland,while paddy fields occupied the highest proportion of cropland in UNRW(11% of total area) and JRW(31% of total area).The farmland surplus N was 61,48,and 205 kg N ha 1 year 1 for SRW,UNRW,and JRW,respectively.The total input and output for the whole watershed were 89 and 76,83 and 61,and 353 and 176 kg N ha 1 year 1 for SRW,UNRW,and JRW,respectively.The proportion of discharged N to net anthropogenic N input was 31%,37%,and 1.7% for SRW,UNRW,and JRW,respectively.The two watersheds in Japan showed similar proportions of discharged N to those of previous reports,while the watershed in China(JRW) showed a totally different characteristic compared to previous studies.The high N input in JRW did not increase the amount of discharged N at the outlet of the watershed due to high proportions of paddy fields and water bodies,which was an underestimated N sink at the landscape scale. 相似文献
2.
3.
MOHAMMAD AMZAD HOSSAIN YUKIO ISHIMINE HITOSHI KURAMOCHI HIKARU AKAMINE 《Weed Biology and Management》2002,2(3):153-158
The present study was undertaken from May 1996 to October 1997 in the glasshouse of the University of the Ryukyus, Okinawa, Japan to investigate standing water (12 cm deep) and shoot removal plus standing water regimes on morphological changes, growth, regrowth and biomass production of torpedograss ( Panicum repens L.). The stem internode was longer in standing-water-treated plants than that in untreated plants. The root-crown was developed from the submerged stem-node. Spike-like tillers and sheath-like leaf blades were observed in water-treated plants. Higher shoot biomass and lower rhizome biomass were obtained in standing-water-treated plants than that in untreated plants. Standing-water-treated plants attained higher total biomass than untreated plants. Standing-water stress was the factor that inhibited regrowth of torpedograss when the above-ground shoot was removed. Rhizomes without shoots of 6-month-old torpedograss did not survive in standing water for more than 6 months. The results indicate that torpedograss can survive in standing water if the shoots remain above the water surface. Shoot removal is one effective way to control torpedograss regrowth in standing water. The results of this study may be dependent on season, day length, water temperature, water pH, water depth and salt concentration in water. 相似文献
4.
5.
Effects of agricultural land-use change and forest fire on N2 O emission from tropical peatlands, Central Kalimantan, Indonesia 总被引：1，自引：0，他引：1
6.
MINORU ICHIHARA HIDEHIRO INAGAKI KAZUO MATSUNO CHIEKO SAIKI MASAYUKI YAMASHITA HITOSHI SAWADA 《Weed Biology and Management》2012,12(3):131-135
The potential impact of postdispersal seed predation by the field cricket, Teleogryllus emma (Ohmachi et Matsuura), on the seedling emergence of Italian ryegrass (Lolium multiflorum Lam.), a non‐native grass weed in Japan, was determined. The relationship between cricket density and the proportion of seedling emergence was investigated by conducting manipulative experiments in duplicate, using enclosures. One‐thousand seeds of Italian ryegrass were exposed to adult crickets at different densities (zero, one, two, four and eight individuals per 2.25 m2 enclosure) for 2 weeks. The proportion of seedling emergence decreased with increasing cricket density. The proportion of seedling emergence in the enclosures without the crickets was 90.9–97.2%, whereas the seedling emergence in the enclosures with eight crickets greatly decreased, to 0.5–2.5%. These results suggest that postdispersal seed predation by T. emma can substantially decrease the abundance of Italian ryegrass at an early life stage and reduce its population in environments with a high density of crickets. 相似文献
7.
Mizuki KURAMOCHI Takeshi IZAWA Mitsuru KUWAMURA Jyoji YAMATE 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(3):390
The administration with high dose (close to LD50) of thioacetamide (TAA), a hepatotoxicant used widely to induce experimental liver lesions, develops hepatocellular necrosis and subsequent inflammation (mainly M1-/M2-macrophages without neutrophil infiltration) in rats. We analyzed rat livers treated with a low dose TAA (50 mg/kg/body weight) at 6, 12, 18, 24 and 48 hr. The lesions in the affected centrilobular areas consisted of slight hepatocyte degeneration at 12 hr, and inflammatory cell infiltration at 18 and 24 hr; the lesions recovered until 48 hr. Translocation of intranuclei to cytoplasm of HMGB1, a representative molecule of damage-associated molecular patterns, was seen in some hepatocytes mainly at 6, 12, and 18 hr. As an interesting finding, at 12 hr, myeloperoxidase-positive neutrophil infiltration was observed in the affected centrilobular area. Additionally, CD68 M1-/CD163 M2-macrophages increased consistently at 12 to 48 hr. CXCL1, a chemokine for induction of neutrophils, began to increase at 6 hr and gradually increased at 12, 18 and 24 hr, apparently corresponding to the appearance of neutrophils. Collectively, the present findings at the low dose TAA indicated that along with M1-/M2-macrophages, neutrophils were characteristically seen, which might be elicited by cytoplasmic translocation of HMGB1 from nuclei. These finding would be useful for evaluation of hepatotoxicity at the early stages. 相似文献
8.
Three field trials were conducted from 2003–2004 at Utsunomiya University, Japan, to evaluate the safety and herbicidal activity of pyribenzoxim (benzophenone O -[2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxybenzoyl]oxime) in turfgrass. Pyribenzoxim showed a high level of safety in bentgrass ( Agrostis palustris Huds.) and zoysiagrass ( Zoysia matrella ) ≤ 300 g ai ha−1 and it controlled various major grass weeds, including annual bluegrass ( Poa annua L.), large crabgrass ( Digitaria sanguinalis L.), and green foxtail ( Setaria viridis L.), and broadleaf weeds, including common dandelion ( Taraxacum officinale Weber), horseweed ( Erigeron canadensis L.), shepherd's-purse ( Capsella bursa-pastoris (L.) Medic.), common chickweed ( Stellaria media L.), common lambsquarters ( Chenopodium album L.), creeping woodsorrel ( Oxalis corniculata L.), and common dayflower ( Commelina communis L.) by fall or spring application. In comparison with bispyribac-sodium (sodium 2,6-[bis(4,6-dimethoxy-2-pyrimidin-2-yl)oxy]benzoate), pyribenzoxim showed a higher safety level in bentgrass and a stronger herbicidal activity on grass weeds; in particular, annual bluegrass and large crabgrass. 相似文献
9.
Theoretical and numerical models were developed to investigate the effects of water temperature on the population dynamics of the kelp, Laminaria religiosa . The models describe seasonal changes in the biomass of kelp by calculation of growth and grazing rates of sea urchins, Strongylocentrotus nudus . Using the theoretical model, conditions were obtained to satisfy the statistical analysis of a relationship between water temperature and kelp harvests from a fishery census. The conditions require the negative second derivative of the growth rate with respect to temperatures, or the positive second derivative of the grazing rate. By using the numerical model, harvests of kelp were calculated for a change in water temperature over a given period. The period of a temperature change giving the maximum effects on the harvest was determined primarily by temperature dependence on the growth rate. Grazing by sea urchins had large effects on the harvest of kelp. A value of 104 was obtained for a ratio between harvests at the higher and the lower temperatures differing by ± 1∘ C. 相似文献
10.
Mizuki KURAMOCHI Takeshi IZAWA Mayuka HORI Kayo KUSUDA Junichiro SHIMIZU Toshie ISERI Hideo AKIYOSHI Fumihito OHASHI Mitsuru KUWAMURA Jyoji YAMATE 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(7):893-895
A 19-year-old female Bengal tiger (Panthera tigris tigris) was presented
with hind limb weakness, ataxia and respiratory distress. Computed tomography revealed a
mass between the left side of the T7 vertebra and the base of the left 7th rib. The tiger
then died, and necropsy was performed. Grossly, the vertebral mass was 6 × 5.7 × 3 cm, and
invaded the adjacent vertebral bone and compressed the T7 spinal cord. Histologically, the
mass was composed of large, clear, vacuolated and polygonal cells with osteochondral
matrix. Cellular and nuclear atypia were moderate. The vacuolated cells stained positively
for cytokeratin and vimentin and negatively for S-100. Based on these findings, the
present case was diagnosed as a vertebral chordoma; the first report in a tiger. 相似文献