节水灌溉技术形成性考核册作业答案（Water-saving irrigation technology formative assessment Book homework answer）Water-saving irrigation technology formative assessment Book homework answer1, according to the amount of rain, our country is divided into five precipitation zone:(1) rain belt: annual rainfall of more than 1600mm, rich rice, tropical and subtropical crops, is the main producing areas of China in double cropping rice. (2) humid zone: the annual rainfall is more than 8001600mm, is the main producing areas of rice in China, and winter wheat, rape and other crops. (3) semi humid zone: the annual rainfall 400800mm, is Chinas major wheat, cotton and other crops in dry areas. (4) semi arid zone: the annual rainfall 200400mm, mainly for the pastoral area. (5) arid zone: the annual rainfall is less than 200mm, almost no agriculture.2, agricultural water-saving technology including water-saving and drought resistant crop varieties, covering technology, water-saving cultivation technology, adjustment of crop planting structure, soil moisture, water retaining agent application.3, Chinas current situation and development trend of water-saving irrigation technology:(1): the development of canal seepage control technology has good performance, low price, easy construction materials, the development of a number of construction machinery; there is lining in high cost, some technical problems need to improve, construction machinery performance, type less; (2) low pressure pipeline technology, made certain achievements in technology and developed a number of suitable materials, equipment and construction technology; problems are mainly materials, equipment and technology needs further improvement and research; (3): sprinkler irrigation technology has a certain scale, developed a variety of sprinkler irrigation equipment and complete production; problems are sprinkler irrigation materials, equipment quality and performance type of distance, there is a large gap between the advanced level, durable, technology and management level is relatively low; (4) improving surface irrigation technology: Based on our reality Using many improved methods, achievements; problems is the lack of technology, equipment, field method can be popularized in large area of land; (5): rice water-saving irrigation has been successfully achieved large area thin shallow wet dry irrigation control, the problem is to study the comprehensive application of single technology the.4, Chinas main methods of canal seepage:(1) soil lining: the characteristics of local materials, low cost, simple construction, but the frost resistance and poor durability; (2) soil cement seepage prevention: can use local materials, low cost, easy construction, but the frost resistance of the poor; (3) stone waterproof: frost resistance and anti impact performance is good, construction simple, strong durability, but impervious ability is difficult to guarantee, labor; (4) membrane: good anti-seepage effect, light weight, convenient transportation, low cost, convenient construction; (5): concrete anti-seepage effect, impact resistance, good durability, but the construction is complicated, cost high; (6): the advantages and disadvantages of asphalt concrete and asphalt concrete are similar, but the former is lacking.5, anti frost design should be carried out according to local conditions, safe and reliable, economic and reasonable principle, and according to the following requirements: (1) collecting relevant information, and according to the soil, groundwater depth and channel to the basic principle of the same divided canal; (2) by calculation or experiment, determine the design section of representative points deep freeze and frost heave, frost heave classification of foundation soil; (3) selection section, anti-seepage materials and structures suitable;(4) the frost heave displacement of each parts of checking channels, to determine the anti freezing measures necessary.6, has the advantages of low pressure pipeline: effectively increase water use efficiency, energy saving, land saving, low cost, timely irrigation, increase production.The current situation of the development of China has a rapid development in the North China well irrigation district, has achieved remarkable economic and social benefits, has a certain development in the northwest and southern regions.7, low pressure pipeline system: water pump and pipeline system, water distribution device, protection equipment. The network system can be divided into mobile, fixed, semi fixed, combined with four types of pipe and canal.8, steps and methods of network at all levels to determine the diameter:(1) to determine a reasonable irrigation system; (2) the design flow calculation at all levels according to the pipeline control irrigation area, crop types and water requirement (in accordance with the water peak or key irrigation period of crop and one of the bigge