REMOTE SENSING MONITORING OF SOIL SALINIZATION—A REVIEW

Soil salinization is one of the most common land degradation processes, particularly occurring in arid and semi-arid regions, where precipitation is too low to maintain a regular percolation of rainwater through the soil. Under such a climatic condition, soluble salts are accumulated in the soil, influencing soil properties and environment, which cause the decrease of the soil productivity. That is to say, it is mainly caused by inter-effecting between the unreasonable human activity and frail eco-environments in the arid and semiaridregions. It becomes one of the disasters which worsen unceasingly for human economical development and ecological improvement. At the same time, in the arid and semi-arid areas, salinization of soil and the shortage of water resource is also one of the major threats to irrigated agriculture. Quantifying both the extent and distribution of salinization is important for management purposes. Hence, in 21 century, main subjects of soil science are improvement in soil quality, promotion in sustainable agricultural development and protection of environment. This requires careful monitoring of the soil salinity status and variation to curb the degradation trend, and secure sustainable land use and management. Multi-temporal optical and microwave remote sensing can significantly contribute to detecting temporal changes of salt-related surface features. Airborne geophysics and ground-based electromagnetic induction meters, combined with ground data, have shown potential for mapping depth of salinity occurrence. The author also conducts a lot of research works on spectroscopy, radarsat and remote sensing information processing, and gained great achievement. This paper mainly presents and summarizes domestic and foreign research progress, remote sensing monitoring methods, research objects, and research focus of soil salinization, and most important of all, reviews various sensors (e.g. aerial photographs, satellite and airborne multispectral sensors, microwave sensors, hyperspectral sensors, and so on.) and approaches used for remote identification and mapping of salt-affected areas. Constrains on the use of remote sensing data for mapping salt-salinity, interference of vegetation, and spectral confusions with other terrain surfaces. At the same time, effective study methods for solving soil salinization problems is given, thereby it can be given in a firm bases for developing and deepening the content and levels of soil salinization study. So we should take variable technique and greater efforts to control salinization.

کلیدواژه ها:

Soil Salinization ، Remote Sensing Monitoring ، Research progress