一、引言土壤的冻结情况能影响越冬作物和果树的生长和发育,能影响农事活动,也能影响大气近地层的热状况。土壤冻结情况的资料可供各方面土木施工的参考。因此,土壤冻结情况的研究,对于国民经济的发展有着重要的意义。目前,我国对土壤冻结情况的调查研究还很少。在广大地区內,用仪器系统的观测土壤冻结情况是从54年才开始的。以前,我国北部个别地方虽然进行过一些调查工作,但是这些调查都不是系统的长期的,因而对全面的了解土壤的冻结情况是不够用 I. INTRODUCTION Soil freezing can affect the growth and development of overwintering crops and fruit trees and can affect agricultural activities as well as the thermal conditions in the near-surface atmosphere. Information on soil freezing conditions is available for all aspects of civil construction. Therefore, the study of soil freezing has great significance for the development of national economy. At present, there is still little research on soil freezing in our country. In vast areas, the use of instrumented systems to observe soil freezing has only begun 54 years ago. In the past, although some surveys were conducted in some places in northern part of our country, these surveys are not systematically long-term, so it is not enough to fully understand the frozen soil