Analysis Of Impacts Of Non-cultivated Landscapes On Crop Drought In Tai'an Counties Of Lower Liaohe Plain

Drought is one of the major disasters in agricultural production in the north.The results of previous studies have confirmed that the non-cultivated landscapes such as ponds and ditches around the farmland interact with the cultivated landscapes(crops)within the farmland,and there are interactions between different landscapes.At present,it is still unclear whether the different components,composition ratios and spatial distribution of non-cultivated landscapes such as ponds,ditches and woodlands around farmland are different for alleviating the degree of farmland crops when the crops in the farmland suffer from drought.Based on this,the following Tai'an County in the Liaohe Plain is a research area,guided by landscape ecology,based on MODIS synthetic data and land use status data,using RS,GIS,landscape index,correlation analysis,etc.The characteristics of farmland landscape and non-cultivation landscape pattern in the study area were analyzed.Based on the factors such as vegetation index(NDVI),vegetation evapotranspiration and potential evapotranspiration(ET/PET),the drought sensitivity index was used.DSI)classified the degree of drought degree of farmland,and finally focused on the mitigation effect of different non-cultivated landscape pattern characteristics on crop drought.The main findings are as follows:(1)The spatial heterogeneity of farmland non-cultivation landscape in Tai'an County is more significant,and the fragmentation and diversity of different areas are different.From the perspective of landscape scale,the farmland non-cultivation landscape in Tai'an County has a high degree of fragmentation,with a separation index(DIVISON)of 0.96 and a landscape shape index(LSI)of 93.80.The degree of diversity is also high,with a Shannon Diversity Index(SHDI)of 1.02 and a Shannon Uniformity Index(SHEI)of 0.42.From the perspective of non-cultivated landscape types,the fragmentation degree of forest land and pit-water surface plaques in the non-cultivated landscape of farmland is relatively high,and the density of plaque on the water surface of the pond is relatively large,and the distribution in the farmland is relatively discrete.The area of forest land is 72.77%,which is the dominant type of non-cultivated landscape in the study area,followed by the water surface of the pit pond,accounting for 2.66%of the area.The area of strong heterogeneity of non-cultivated landscape in Tai'an County is large.The proportion of high-value area of landscape separation index is 73.21%,and the proportion of high value area of landscape shape index is 68.7%.It is mainly distributed in Sanglin Town and Qidong Town in the north.Xifo Town,etc.;weak heterogeneous areas are small in size,scattered in most towns and towns,such as Fujia Town,Daniu Town and Xinkaihe Town.(2)The area of cultivated land affected by mild drought(-0.59<DSI<-0.29)in Tai'an County is 469.82km~2,accounting for 34.01%of the total area of Tai'an County,and is not affected by drought(-0.29<DSI<0.29).The area is 911.41km~2,accounting for 65.99%of the total area.The droughts are mainly distributed in the northwestern part of the towns of Qidong and Fujia,and are distributed in a contiguous manner;the droughts in the southeast of Huangshayu Town and Xinkaihe Town are relatively light and scattered.(3)The landscape pattern characteristics of farmland non-cultivation in Tai'an County have a significant impact on farmland drought.The landscape fragmentation index(landscape separation index,landscape shape index)was significantly correlated with the drought index DSI(P<0.01),and the landscape separation index was significantly negatively correlated with the crop drought index DSI(R=-0.640).The landscape shape index was significantly negatively correlated with the crop drought index DSI(R=-0.631).The landscape aggregation index(landscape spread index,maximum patch index)was significantly correlated with the drought index DSI(P<0.01),and the landscape spread index was significantly positively correlated with the crop drought index DSI(R=0.603).The maximum plaque index was significantly positively correlated with the crop drought index DSI(R=0.640).The diversity index(Shannon diversity index,Shannon uniformity index)was significantly correlated with drought index DSI(P<0.01),and the Shannon diversity index was significantly negatively correlated with the crop drought index DSI(R=-0.592).The Shannon uniformity index was significantly negatively correlated with the crop drought index DSI(R=-0.618).