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| 1 | Effects of vegetation height and density on soil temperature variations显示文摘Reduction in vegetation cover caused by human activities has a great impact on soil temperature. It is important to assess how soil temperature responds to reduction of vegetation height and density. In this paper we first report the trends of mean annual soil surface and air temperatures recorded at the meteorological stations near the Ecological Research Station for Grassland Farming (ERSGF) from 1961 to 2007, then we setup an experiment using reed (Phragmites australis) stalks with different heights and densities to simulate effects of different vegetation height and density on soil and air temperatures. The warming rates of the mean annual soil and air temperatures were 0.043 and 0.041C a 1 , respectively. Changes of soil temperature were characterized by both increased mean annual maximum and minimum soil temperatures. At the experimental site, mean daily temperature, mean daily maximum soil and air temperatures increased significantly. In contrast, mean daily minimum soil temperature increased significantly while mean daily minimum air temperature decreased significantly as the height and density of reed stalks reduced during the experimental period. Mean diurnal soil temperature ranges were smaller than mean diurnal air temperature ranges. These results highlight that the importance of vegetation cover on soil and air temperatures. | SONG YanTao ZHOU DaoWei ZHANG HongXiang LI GuangDi JIN YingHua LI Qiang | 2013 | Chinese Science Bulletin2013，58，8： | 12 |
| 2 | Effects of fencing on vegetation and soil restoration in a degraded alkaline grassland in northeast China显示文摘In order to restore a degraded alkaline grassland, the local government implemented a large restoration project using fences in Changling county, Jilin province, China, in 2000. Grazing was excluded from the protected area, whereas the grazed area was continuously grazed at 8.5 dry sheep equivalent(DSE)/hm2. In the current research, soil and plant samples were taken from grazed and fenced areas to examine changes in vegetation and soil properties in 2005, 2006 and 2008. Results showed that vegetation characteristics and soil properties improved significantly in the fenced area compared with the grazed area. In the protected area the vegetation cover, height and above- and belowground biomass increased significantly. Soil pH, electrical conductivity and bulk density decreased significantly, but soil organic carbon and total nitrogen concentration increased greatly in the protected area. By comparing the vegetation and soil characteristics with pre-degraded grassland, we found that vegetation can recover 6 years after fencing, and soil pH can be restored 8 years after fencing. However, the restoration of soil organic carbon, total nitrogen and total phosphorus concentrations needed 16, 30 and 19 years, respectively. It is recommended that the stocking rate should be reduced to 1/3 of the current carrying capacity, or that a grazing regime of 1-year of grazing followed by a 2-year rest is adopted to sustain the current status of vegetation and soil resources. However, if N fertilizer is applied, the rest period could be shortened, depending on the rate of application. | Qiang LI DaoWei ZHOU YingHua JIN MinLing WANG YanTao SONG GuangDi LI | 2014 | Journal of Arid Land2014，6，4： | 9 |
| 3 | Risk assessment and regionalization of agro-meteorological hazards in Jilin Province, China显示文摘 | Zhang J Q Seiji Hayakawa Zhou Daowei | 2005 | Journal of Agri- cultural Meteorology2005，60，5： | 1 |
| 4 | Environment changes following burning in a Songnen grassland显示文摘 | Zhou Daowei Ripley E A | 1997 | Journal of Arid Environment1997，36，1： | 1 |
| 5 | Influence of chestnut tannins on welfare,carcass characteristics,meat quality,and lipid oxidation in rabbits under high ambient temperatu re显示文摘 | Huawei Liu Daowei Zhou Jianming Tong Venkata Vaddella | | 0，，： | 1 |
| 6 | Investigation on catalytic distillation for ethyl acetate production with different catalytic packing structures显示文摘The catalytic packing is the core component of the catalytic distillation,and how the catalyst exists in the packing has significant influence on the process.To investigate the effect of catalyst packings on the catalytic distillation process,the classical ethyl acetate reactive distillation system was utilized,and a supported catalytic packing(SCP)was prepared in comparison with the conventional tea-bag catalytic packing(TBP).Laboratory scale experiments showed that the ethyl acetate conversion of the SCP was superior to the TBP at a low catalyst loading.The effects of reaction kinetics,mass transfer performance and actual catalytic efficiency of the packings on this process were regarded as reasons and studied by combining the experiments and numerical simulation.Results suggested that the relatively immediate“in-situ separation”caused by the rapid reaction kinetics and better mass transfer performance of SCP may be a main reason for the difference of the conversion. | Zhiwei Wang Yu Zhang Zhi Zhang Daowei Zhou Zhikai Cao Yong Sha | 2023 | Chinese Journal of Chemical Engineering2023，53，1： | 0 |
| 7 | Vascular bundle connection between seed stalk and seed coat of Caragana arborescens显示文摘The purpose of this study was to investigate the morphology, transmission route of photosynthetic products in the seed stalk of Caragana arborescens Lam. at various stages after flowering and evaluate the role of the seed stalk in seed maturation using scanning electron microscopy. We found that the mature seed stalk mainly consisted of vessels,sclerenchymatous cells and parenchymatous cells. Elongated cells formed a ring at the junction between the seed stalk and seed, and a large hollow was produced by two layers of sclerenchymatous cells in the interior seed, which functions to sustain seed growth. The opening in the center of the ring was closed during an early stage of seed development, and the opening enlarged as the seed matured.There were two routes for material transport, which started from the seed stalk: one from the seed coat to the embryo,and another directly entering the embryo. Vessels, which are abundant in the seed stalk, are the pathway for absorption of nutrients by the seeds. The vessels were densely packed in the seed stalk, and secondary thickening of the cell wall of the vessels was characterized by net thread thickening, while the secondary thickening of the cell wall of the vessels within the seed was characterized by screw thread thickening. The morphological characteristics of the vessels were adaptive to its functions. | Zhihui Luan Daowei Zhou Diankun Shao | 2018 | Journal of Forestry Research2018，29，1： | 0 |
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