沈阳市郊区30年耕层土壤碱解氮的时空变异特征——以沈阳市苏家屯区为例

Temporal and Spatial Variation of Soil Available Nitrogen in the Topsoil of Shengyang Suburb over 30 years:Taking Sujiatun District, Shenyang as An Example

研究大城市郊区耕层土壤碱解氮的时空变异特征,为土壤肥力的评价和管理提供科学指导。采用GIS技术与地统计学相结合方法,以辽宁省沈阳市苏家屯区为例,利用野外土壤调查数据,对1980、2000和2010年3期土壤碱解氮进行时空变异特征分析,结果表明:1980年土壤碱解氮含量等级主要集中在V级,占总面积47.3%,分布于临湖街道和永乐乡,整体呈现中部高,南北低的分布格局;到2000年,土壤碱解氮含量也主要集中在IV级和V级,分别占总面积57.0%和37.3%,IV级的面积有所扩大,主要分布于王纲堡乡、永乐乡的中部、北部和临湖街道的南部,与2000年相比,研究区域普遍上升范围为0~15mg·kg^(-1),包括临湖街道、王纲堡乡的东部和永乐乡的中部、北部,出现下降的区域主要是在王纲堡乡的中部和西部地区,其中西部地区下降范围达到大于15mg·kg^(-1)以上;到2010年,土壤碱解氮含量等级主要集中在III级和IV级,分别占总面积60.1%和23.6%,其中III级主要分布于王纲堡乡的中南部和永乐乡的大部分区域,IV级主要分布于临湖街道和王纲堡乡的北部,与2000年相比,碱解氮含量普遍上升,上升范围在0~15mg·kg^(-1)和15~30mg·kg^(-1)之间,上升范围较大是王纲堡乡和永乐乡;从总体上来看,研究区域在时间上,近30年研究区域碱解氮含量整体趋于上升。在空间上,土壤碱解氮含量分异明显,耕地资源的空间结构趋于复杂,且离城市越远,碱解氮增加的幅度相应也会大些,而这种时空变异特征与大城市边缘区农业生产者的经营行为差异密切相关,也为该区域耕地资源合理配置、科学管理等带来新的挑战。

The temporal and spatial variation characteristics of the available nitrogen(AN)in the topsoil of suburbs in large cities were studied to provide scientific guidance for the evaluation and management of soil fertility.By combining GIS technology with geostatistics and by using the soil survey data in Sujiatun district of Shenyang,Liaoning Province,the spatial temporal variation characteristics of soil available nitrogen were analyzed in the third period of1980,2000and2010.In1980,the content of soil available nitrogen grade was mainly in grade V,accounting for47.3%of the total area where was in Linhu Street and Yongle Village,with the distribution pattern in space high in center,low in north and south.In2000,the content of AN was mainly in grade IV and grade V,accounting for57%and37.3%respectively,and the area of grade IV expanded,mainly in Wanggangpu Village,central Yongle Village,north and south Linhu Street.Compared with1980,the AN in the study area generally increased by0-15mg·kg-1,and the area included Linhu Street,east Wanggangpu Village,central and north Yongle Village.The AN decreased area was mainly in central and western Wang Gangpu Village,with a reduction more than15mg·kg-1.In2010,the content of AN was mainly in grade III and grade IV,accounting for60.1%and23.6%respectively.The grade III was mainly in Yongle Village and south Wanggangpu Village,the grade IV was mainly in north Linhu Street and Wanggangpu Village.Compared with2000,the content of AN generally increased in the range of0-15mg·kg-1and15-30mg·kg-1,in Wanggangpu Village and Yongle Village.In general,the AN in the area has a trend of increase in recent30years.In space,the AN difference is obvious,leading to the spatial structure of cultivated land resources more complex,with more AN far from the city.The characteristics of spatial and temporal variation are closely related to the management behavior of farmers in the edge areas of large cities,which may also bring new challenges to the rational allocation of cultivated land resources and scientific management in the region.