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1.
本文对福建省贮木场的发展历史进行扼要回顾,分析和评述了木材市场开放后福建省贮木场的现状,针对发展中存在的问题,并紧紧围绕经济发展的两个根本转变,对贮木场的发展出路提出看法。 相似文献
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S. Leibovitch B. L. Ma Wanga E. Maloba D. L. Smith 《Journal of Agronomy and Crop Science》1992,169(3):209-215
Aspects of intensive management practices such as high-yielding cultivars, narrow-row spacings and fungicide treatments could potentially increase cereal yields in regions with a short crop-growing season and occasionally dry and hot weather. A field experiment was carried out at McGill University, Canada for three years (1987 to 1989) to test the effects of triadimefon (1-[4-chlorophenoxy]-3,3-dimethyl-1-[1H-1,2,4-triazol-1-yl]-2-butanone, or Bayleton, a trade name) fungicide (0 vs. 140 g a.i. ha−1 ) and row spacing (10 vs. 20 cm) on the yield components, yield and other agronomic traits (spike emergence, days to maturity, leaf disease and plant height) of spring barley ( Hordeum vulgare L.) cv. Cadette, Laurier and Leger. A cultivar by row spacing interaction resulted in a 11 to 13.5 % increase in grain yield due to narrow rows for Laurier in two out of the three years and up to 16 % for Leger in one year. Over the three years grain yields were on average increased 6 to 12 % due to use of the narrower row spacing. Fungicide application to barley at the early heading stage effectively controlled leaf diseases without influence on yield components or grain yield. Our results indicate that some components of intensive management such as narrow row spacing can be applicable in regions with a short crop-growing season. 相似文献
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专门化肉用种羊选定、引进后,通过适应性研究,在较大规模养羊业生产实践中。对现代集约化肉羊业的主要关键技术进行研究、完善和创新,组装集成并应用于生产。技术研究应用结果既为市场提供了大批专门化肉用种羊和优质安全的杂种肉羊,取得了高水平的研究成果及显著的经济效益和社会效益.又为我国目前正在迅速发展的集约化肉羊业提供了可靠的技术支持和理想的生产模式:从适宜的专门化肉羊品种到运用高效母羊快速扩繁技术.建立和完善有效的肉羊杂交利用体系,普遍应用种羊鲜、冻精生产大批肉用杂种羔羊,种植高产优质饲草及其科学加工调制和利用.建立严格兽医防疫制度.实行放牧 补饲或全舍饲的精细管理和集约化育肥,至生产优质、安全、标准肉羊,获得显著的经济效益和社会效益。 相似文献
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Use of ongrownArtemia in nursery culturing of the tiger shrimp 总被引:1,自引:0,他引:1
Juvenile and adultArtemia produced in a semi flow-through culture system were used as food for postlarval shrimp. The growth performance of shrimp reared on such ongrownArtemia live prey is identical to the growth obtained when feeding newly hatchedArtemia. However, a significantly better stress resistance is obtained when the postlarvae are exposed to a low salinity in a stress test. Besides nutritional and energetic advantages, the use ofArtemia biomass for feeding postlarval shrimp also results in improved economics as expenses for cysts and weaning diets can be reduced. 相似文献
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Rivka Manor Ran Segev Marcia Pimenta Leibovitz Eliahu D. Aflalo Amir Sagi 《Aquacultural Engineering》2002,26(4):263-276
In the process of exploring ways to intensify crayfish culture, a growout system of individual cages (cells) was designed to determine the effects of gender and cell size on the growth of the red claw crayfish Cherax quadricarinatus. Cells of three different diameters—large (25 cm), medium (20 cm) and small (16 cm)—were used. When crayfish were stocked at a mean weight of approximately 10 g, growth rate of males was significantly higher than that of females. The growth rate of the males in the large cells was 0.31±0.14 g/day, while that of the females was 0.18±0.09 g/day. The size of the cell had significant influence on the weight of males. Male crayfish in the large and medium cells grew better than those in the small cells. When males were stocked at a higher mean weight (about 23 g), their mean weight after 206 days was higher in the large cells (69.28±15.72 g) than in the small cells (58.11±12.66 g), suggesting that the growth of large males was also affected by cell size. Regardless of cell size, male animals of this species grew faster than females under conditions of individual cells. This intensive culture method appears to present a powerful improvement in yields, by as much as two orders of magnitude, in comparison with communal cultures. 相似文献
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净化育苗循环水生物流化床特性的研究 总被引:6,自引:1,他引:6
比较了生物流化床与生物固定床的水净化特性,生物流化床氨氮负荷和硝化率提高3倍。用电子显微镜和营养琼脂培养法观察了流化床中生物粒子表面的细菌分布与生长情况,生物粒子表面生物膜丰富,均匀,生长繁殖快,活性好。在15万尾/m3的密度下,循环水培育鲤苗,15天体重达21.2mg,体长达12.58±0.94mm,成活率90%。 相似文献
9.
Effects of intensive fishing on the perch population in a large oligotrophic lake in eastern Finland
The perch population in Lake Höytiäinen was intensively fished to reduce the density of the population and hence also the predation pressure by perch on vendace larvae. A hypothesis suggests that this predation can prevent recovery of commercially important vendace stock from a state of low-density. In the 1990s the density of the perch population in Lake Höytiäinen has increased, while the vendace stock has been sparse. Intensive fishing was conducted by professional fishermen with a paired bottom trawl, seine net, hoop net and small fish traps and by recreational fishermen with small fish traps. The size of perch population during the intensive fishing period was studied by test fishing with multi-mesh gillnets and the Leslie method in which trawl YPUE was regressed on the cumulative yield. The results suggest that the population size clearly diminished in the area where the fishing pressure was strongest. YPUE of test fishing decreased ca. 30% whereas the Leslie method gave almost a decrease twice as large as that of the former. Mean weight of perch increased in the trawl and test fishing catches during the intensive fishing period. The most effective fishing gear was trawl (62% of the total yield), but importance of trap net fishing by recreational fishermen was also high as they caught 22% of the total yield. 相似文献
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