辽河三角洲土壤盐分与上覆植被野外光谱关系初探*

土壤盐渍化是辽河三角洲主要的环境问题之一,尽管已受到广泛关注,但人类活动引发的次生盐渍化面积仍在不断增长。这就需要认真、及时地监测土壤盐渍化的现状及其变化趋势以阻止土壤次生盐渍化的不断发展,确保土地利用和管理的可持续发展。多源、多时相、多光谱和微波遥感技术已被广泛用于监测土壤盐渍化的时空变化研究中。航空遥感技术、地面土壤盐分探测技术、实验室和野外光谱分析技术与地面土壤盐分测试数据相结合进行土壤盐渍化监测极具发展潜力。当干旱、半干旱区植被覆盖度低于25%~35%时,土壤的光谱特征差别明显,利用遥感、土壤光谱数据与土壤盐分分析数据相结合进行土壤盐渍化监测是最为有效的方法之一。如果植被覆盖度大于此阈值,监测精度下降,只能通过上覆植被信息间接推断土壤盐渍化状况。研究的主要目的就是探讨土壤盐渍化与上覆植被光谱之间的关系,尝试利用上覆植被光谱信息推断辽河三角洲土壤盐渍化状况。

Preliminary study on relationships between soil salinity and above vegetation field-derived spectra in Liaohe River Delta, Liaoning Province, China

Soil salinity is a major environmental hazard in Liaohe River Delta, Liaoning Province, China. In spite of considerable efforts dedicated to soil salinization, the extent of secondary salinization tends to increase. This requires careful monitoring the soil salinity status and variation to curb soil salinization trends, and secure sustainable land use and management. Multi-sensor and multi-temporal and multi-spectral and microwave remote sensing data has been widely used to detecting temporal and spatial changes of soil salinization. Airborne remote sensing and ground-based electromagnetic induction meters and laboratory and field spectrometers, combined with ground soil salinity data, have shown potential for monitoring soil salinization. When the vegetation cover threshold is below 25%~35% in semi-arid and arid, soils differ widely in their spectral response, and it is a most effective method to monitoring soil salinity by integrating soil salinity data and soil spectral data. However, if the vegetation cover threshold is beyond 25%~35%, the above method doesn''t work well, soil salinity can be only inferred from the above vegetation spectra. The objective of this research is to discuss the relationships between soil salinity and above vegetation field-derived spectra, and use above vegetation field-derived spectra to predict soil salinity status in Liaohe River Delta tentatively. The result shows that it is feasible.