一、灌溉土地的类型新建的灌溉系统,并不总是提供农作物丰收而不对土壤和地下水造成不良影响的。在干旱地区,修建水库、渠道和灌溉系统以后,人们常常可以看到人类、动物和植物疫病的传播和其他麻烦事情,例如杂草蔓延等。事实上,这是由于许多灌溉系统的设计、施工和运用事先没有经过充分的研究和对自然环境的整个特点了解不够所致。 I. Types of irrigated land Newly irrigated systems do not always provide the harvest of crops without adversely affecting soil and groundwater. In arid areas, after the construction of reservoirs, channels and irrigation systems, people can often see the spread of human, animal and plant diseases and other troubles such as the spread of weeds. In fact, this is due to the fact that many irrigation systems have not been adequately studied in advance, and their understanding of the entire nature of the natural environment has not been adequately studied in advance.