Study On Relation Between Oriental Migratory Locust And Soil Moisture Content Based On Remote Sensing Technology

This paper deals with order the relations between soil moisture content and occurrence/outbreack of oriental migratory locust, Locusta migratoria manilensis (Meyen) , in the study area Huanghua county of Hebei province, the region which has been severely suffering from the locust plague based on the information on the spatial distribution of the plague of locust using the data of locust density extracted based on the remote sensing technology in conjunction with the in situ data of soil samples taken in field as well as the ground measured remotely sensed data.In the study, the multitemporal TM and ETM+ image data were used in extracting the spectrum data of vegetation before and after harm by locust respectively in 2002 during which the locust plague (summer locust) seriously occurenced in that region, and the degree and distribution of locust plague are estimated through monitoring the degree at which vegetation was suffering the damage. In addition, based on the vegetation index before the harm by locust the information of distribution of locust density were extracted, and the map of locust density at different lavels were obtained in the three most important important locust areas in Huanghua.Through this study the following conclusions were made:(1) In the locust regions of Huanghua county, the more lower soil moisture content in the later perion of locust hatching the higher of locust plague. In other words, the regions with lower soil moisture content are more suitable for locust occurrence.(2) In the study area, the most important periods during which soil moisture condition has an effect on locust occurrence are from September to October when fall locust is at oviposition time, and from March to April when summer locust is at hatching. In these time periods, too much soil moisture will bring negative effects on locust occurrence or outbreak.(3) The combined consideration of soil moisture content and the earth's surface temperature has indicated that there is n obvious difference in soil moisture condition between the time period when fall locust is at oviposition time and the time period when summer locust is at hatching. During the years when locust outbreak seriously occurred, soil drought is obviously higher than that of the years when locust plague is absent.