Modified linkage analysis for water-land nexus driven by interregional trade

The scope of water and land resource management has been expanded by the interregional trade beyond a single region's boundary along the trans-regional production chain, and the nexus thinking facilitate the understanding of the multi-resource interrelationships and interactions. For the investigation of the water-land nexus, besides the consideration of land use, this study first considered the soil erosion caused by agricultural activities to reveal the water-land nexus from both land cover and soil layer perspectives. The integrated nexus strength (INS) indicator combining with linkage analysis was introduced to detect the distant connections of water and land in ten counties and one city of the Heihe River Basin in Northwestern China. The results show that, from the regional perspective, Minle and Ganzhou in the middle reaches of the Heihe River Basin were essential regions for the water-land nexus, as they imported and exported products embodied with intensive water resource, land use, and soil erosion. Suzhou was the major net importer with imports from counties in middle reaches, including Gaotai, Linze, Ganzhou, and Minle. Jinta, located in the downstream of the Heihe River Basin, faced with serious water scarcity, land desertification, and soil erosion problems, still exported large amounts of agricultural products embodied with numerous resources. From sectoral perspective, the Grain Crops and Cash Crops sectors in the middle reaches had higher values of INS-net forward linkage (export direction), due to that the agricultural sector was primary resource consumers in supply chains to support the following production processes. For INS-net backward linkage (import direction), the Foods and Services sectors in the middle reaches were the dominant sectors, in the reason that food processing and service production processes required more primary products with intensive embodied resources to fulfill their production activities.