关键词: 棉花, 棉花, 种子, 低温, 温度指标, 适宜播种期

Abstract: With the accelerated pace of urbanization, the significant changes of urban underlying surface have made urban rainwater problems become increasingly prominent, such as the decrease of city surface infiltration rate, the shortage of groundwater resources, the increase of surface ponding time, the increase of runoff coefficient, and so on. And the phenomenon of water-logging in cities frequently occurs. These problems not only increased the pressure of municipal drainage network, but also made the contradiction between supply and demand of urban water more and more acute. It seriously restricted the development of the city. The rational application of water resources has become an important part of the study of various industries. [Objective]Rainwater is one of the important water resource. Collecting and utilizing rainwater can not only alleviate the shortage of urban water resources, but also be an effective way to solve the urban rainwater problems. Urban park is one of the main contents of urban construction, and it is also an important component of urban landscape and urban ecological system. A large number of domestic and foreign documents show that urban parks have multiple functions,such as managing rainwater, purifying rainwater and recycling rainwater. Urban park plays an important role in the sustainable utilization of water resources. The rational and effective use of rainwater in urban parks is an important way to reduce urban flood and alleviate the shortage of water resources in urban areas. [Method]Therefore, this paper take the basic elements of urban park as a starting point. The rainwater utilization technologies combined with pavement, green space, waters cape and building in urban parks are analyzed one by on. The technology that combines the rainwater utilization and pavement is analyzed from two aspects:permeable pavement and impervious pavement. Rainwater utilization technology combined with green land mainly analyzes sunken green space and rainwater garden. The rainwater utilization of waters-cape is mainly analyzed from artificial lake and wetland. Other aspects briefly introduced. Rainwater use in buildings is studied from the collection of rainwater from the roof and the greening of the roof. [Result]Through analysis, the feasibility and advantages and disadvantages of each technology were summarized. [Conclusion]On the basis of the previous research results, it summarizes the problems and looks forward to the future research direction of rainwater utilization technology in urban parks. It will provide some reference for rainwater utilization theory and practice in urban parks in the future.With the vigorous implementation of sponge cities in the country, rainwater harvesting and utilization in urban parks has been carried out step by step, but there are still some problems.For example, waterproof pavement is not paid attention to cleaning and maintenance, leading to lower water permeability.Or unreasonable installation of plants or pipes, can not guarantee the effect of rainwater collection. In addition to solving these practical problems, there are still some theoretical questions.The qualitative research of urban park rainwater utilization has been done in depth, and these research results need to be quantified at home and abroad. But these research results need to be quantified. In order to ensure the harmonious development of the city, the collection and reuse of rainwater should not only reflect the ecological and comfortable living environment, but also organic combine various rainwater utilization technologies and integrate them.Finally, the purpose of effectively solving the urban rainwater problem is achieved.