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991.
鱼塘种稻是指利用水产养殖的池塘种植水稻的一种农业生产活动。发展鱼塘种稻,可在稳定鱼塘养殖面积的同时扩大水稻种植面积,提升粮食安全,并减少养殖尾水污染。2022年早季在广州开展的鱼塘种稻试验取得初步成功。供试水稻品种为粤泰油占、黄广油占、美香占2号、泰丰优208、广红3号、粤香430、粤农丝苗、五山丝苗、南晶香占等9个,养殖品种为大口黑鲈、澳洲淡水龙虾、鲫鱼和黄颡鱼等4个。结果表明,在鱼塘种植条件下,不同水稻品种间的产量差异显著,且与稻田种植差异大,以粤香430产量最高,每667 m2达到390.8 kg,比产量最低的泰丰优208增产148.6%。4个养殖品种均表现良好,成活率高,生长速度快,其中以澳洲淡水龙虾表现最佳。目前鱼塘种稻还存在成本偏高、技术标准缺乏、基础研究滞后等问题,亟需从浮板研制、稻渔品种搭配、水稻品种筛选、肥料运筹、有害生物防控、配套农机装备等方面加强协作攻关,同时加强相关基础理论研究。通过技术集成,建立鱼塘种稻绿色高产高效综合技术模式,制定技术标准。随着研究深入和技术熟化,鱼塘种稻将为我国特别是南方地区的粮食安全、农民增收、环境保护和美丽乡村建设... 相似文献
992.
在对三亚市热带森林旅游资源及周边环境进行调研的基础上,用SWOT分析方法,对三亚市森林旅游发展的优势、劣势、机会和威胁进行分析,提出三亚市森林旅游发展的相应对策,以期促进三亚市绿色经济产业更快更好的发展。 相似文献
993.
本文在多年实地调查和资料收集的基础上,对歙县山核桃的资源分布、生产管理等现状进行了调查,分析了山核桃生产中存在的主要问题,提出了产业发展应采取的措施和对策,为歙县山核桃产业健康发展提供借鉴。 相似文献
994.
Life strategies of cephalopod paralarvae in a coastal upwelling system (NW Iberian Peninsula): insights from zooplankton community and spatio‐temporal analyses 下载免费PDF全文
Álvaro Roura X. Antón Álvarez‐Salgado Ángel F. González María Gregori Gabriel Rosón Jaime Otero Ángel Guerra 《Fisheries Oceanography》2016,25(3):241-258
The early life stages of cephalopods ‐ octopods, squids, sepiolids and ommastrephids ‐, are uncommon in zooplankton samples and little is known about their life strategies. Accordingly, cephalopod paralarvae were examined in the upwelling ecosystem of the Ría de Vigo (NW Spain) at night from 2008 to 2010. Multivariate analyses and generalized linear models (GLMs) were used to explore relationships between cephalopod paralarvae and the zooplankton communities that they inhabited in 2008. In addition, the foraging strategy and prey preferences of Octopus vulgaris paralarvae within these communities were determined. Multivariate and GLM results showed a strong association of cephalopod paralarvae with coastal and frontal zooplankton communities. Octopus paralarvae were shown to be specialist predators with a strong preference for decapod zoeae in each of the communities examined. Using the three years of sampling, GLM analyses of paralarval spatio‐temporal variations in relation with the upwelling strength showed a positive relationship with upwelling intensity for O. vulgaris and sepiolids, as well as contrasting temporal, horizontal and vertical distributions for the different paralarvae analysed. Under strong upwelling events, Octopus paralarvae were more abundant in surface waters, whereas the abundance of loliginids and sepiolids was higher in the water column. This vertical behaviour in conjunction with the physical conditions of the Western Iberian Upwelling ecosystem suggests the coexistence of two different life strategies: a coastal strategy displayed by loliginid and sepiolid paralarvae that are retained over the shelf, and an oceanic strategy displayed by O. vulgaris paralarvae that are dispersed far from the shelf. 相似文献
995.
Rice–fish-farming systems constitute a unique agro-landscape across the world, especially in tropical and sub-tropical Asia. Rice is a globally important staple food crop, with a wide distribution and constituting diversified varieties. The introduction of fish rearing to rice farming creates an integrated agro-ecological system. China boasts a history of 1700 years in rice–fish-farming practice. It is no longer a sole agro-production practice, but an agro-cultural pattern. Therefore, it has been listed by the Food and Agriculture Organization of the United Nations (FAO) and the United Nations Educational, Scientific and Cultural Organization (UNESCO) as one of the Globally Important Ingenious Agricultural Heritage Systems (GIAHS). Qingtian County of the Zhejiang province has been selected as a pilot conservation site. The rice–fish-farming systems in China diversify China's agro-landscape and favor the conservation of species variety of both rice and fish. The survival of deep-water rice, an indigenous rice variety, and Oujiang red carp, an indigenous fish variety, are cases in point. Being low external input systems, the rice–fish-farming systems necessitate only small amounts of pesticide and fertilizer. The application of pesticides can be lowered to 50% of that of modern, high-input rice production; sometimes, no pesticide application is required. The natural enemies of rice pests show a prominent rise, making the bio-control of rice diseases and pests highly feasible. The rice–fish-farming system is also of great significance in global food security and global change. It provides food and animal protein for subsistence farmers living in ecologically-fragile mountainous regions. It also reduces economic risks that these farmers potentially face. The nitrogen-fixation role of the system increased the content of organic matter, total nitrogen and total phosphorus in the soil by 15.6–38.5%. It also reduces the emission of CH4 by nearly 30% compared with traditional rice farming. However, the economical development and industrialization in China pose a threat to rice–fish farming and, consequently, the numbers of farmers involved in rice–fish farming are decreasing. This calls for the Chinese government to engage itself in the conservation and development of this system and to innovate the existing technologies. It would also be useful, in the meantime, to exploit and conserve rice–fish farming as eco-tourism resources, so that the income of the mountainous farmers can be increased and this important, indigenous agro-culture be conserved and developed. 相似文献
996.
GLMs, GAMs and GLMMs: an overview of theory for applications in fisheries research 总被引:19,自引:0,他引:19
This paper provides an overview of the modelling process using generalized linear models (GLMs), generalized additive models (GAMs) and generalized linear mixed models (GLMMs), especially as they are applied within fisheries research. We describe the essential aspect of model interpretation and construction so as to achieve its correct application. We start with the simplest models and show the progression from GLMs to either GAMs or GLMMs. Although this is not a comprehensive review, we emphasise topics relevant to fisheries science such as transformation options, link functions, adding model flexibility through splines, and using random and fixed effects. We finish by discussing the various aspects of these models and their variants, and provide a view on their relative benefits to fisheries research. 相似文献
997.
I. G. Cowx 《Fisheries Management and Ecology》1999,6(1):21-34
Stocking, transfer and introduction of fish are commonly used to mitigate loss of stocks, enhance recreational or commercial catches, restore fisheries, or to create new fisheries. However, many stocking programmes are carried out without definition of objectives or evaluation of the potential or actual success of the exercise. The present paper describes a strategic approach to stocking aimed at maximizing the potential benefits. A protocol is discussed which reviews factors such as the source of the fish, the stocking density, the age and the size of fish at stocking, the timing of stocking, and the mechanism of stocking. Finally, the effects of social, cultural and economic constraints on the potential outcome of stock enhancement programmes are discussed. 相似文献
998.
999.
阿坝州退耕还林(草)的对策与措施 总被引:2,自引:2,他引:0
本文在分析阿坝州退耕还林(草)的必要性和存在问题的基础上,对搞好退耕还林应采取什么样的对策措施作了评析,并提出了一些建议。 相似文献
1000.
红色旅游不仅是促进旅游业发展和拓展社会经济发展空间的新增长点,更是爱同主义思想教育和精神文明建设的重要组成部分。新疆红色旅游是将红色人文景观和绿色自然景观相结合,将革命传统教育与促进旅游产业发展相结合的一种新型主题旅游形式。本文通过对新疆红色旅游资源进行分析,提出新疆红色旅游资源开发的战略构想。 相似文献