Analysis on landscape pattern in Yanhe River valley

【Objective】 The landscape pattern in Yanhe River valley was identified to provide some scientific information for reasonable land use and for improving soil and water conservation.【Method】 Using ENVI 4.0 to process the digital RS image in 2006 of Yanhe River valley,land use map was obtained with ArcGis 9.0 integrating with field investigation.According to the system of land use classification in 2007,7 classes including adobe land(urban abode land,rural abode land),farm land(irrigated land,dry land),garden(orchard),woodland(forest land,shrub land),grass land(natural pasture,other woodland),water water project land(inland interval,lake,reservoir,river) and other land(nudation,desert,marsh and agricultual facilities land) were determined.The structural characteristics of land use quantity and landscape structure were analyzed in this study.【Result】 The area of dry land is the largest of all land use types in Yanhe River valley,about 37%,followed by natural pasture,nudation and forest land respectively 22.17%,23.6% and 14.4%,and other land use is small.The frequency ratio of dry land,natural pasture and nudation are bigger than others.The even area of marsh is the largest;nudation and natural pasture are next.The diversity indices of all land use are small.The block shapes of dry land,forest land,natural pasture and nudation are simple and the number of block is of normal distribution.Farmland is prevalent,and the dominance indices of farmland,woodland,grassland and water water project land are larger than others.【Conclusion】 Land consolidation and scale operation are important in developing land resources in Yanhe River valley,and the decreasing quantities of land use block,depressing shape index,and increasing the area of water water project land,artificial grassland and artificial woodland can enhance diversity,homogenizing land use,and improve the stability of eco-system.