Water–land nexus in food trade based on ecological network analysis

Abstract

Massive amounts of water and land embodied in crops are transferred via food trade. This study established a network-based framework for the water–land nexus in food trade to investigate the spatial linkages of water, land, and food. Based on the gravity model and linear programming optimization, the food trade model was first built to simulate crop trade. Then water consumption and land use for various crops in different regions were inventoried to establish the food-related virtual water network and food-related virtual land network. Grey water related to water quality, blue and green water related to water quantity, were incorporated into the food-related virtual water accounting framework to identify the role of food trade in the spatial reallocation of water. Similarly, the food-related virtual land network was built based on the land use for different crops and the food trade model. Finally, a case study was conducted using ecological network analysis to analyze the properties and connections within the food-related virtual water/land networks of China. The results showed that the green and grey water consumption associated with food production, the effects of which have previously been neglected, account for a huge proportion of the total water consumption, especially in water-scarce provinces. The controllers/dependents in the networks that have strong control relationships with other provinces were identified. The proposed network-based framework for the water–land nexus may help boost synergies associated with spatial reallocation of water and land via food trade and explore pathways for sustainable management of water, land, and food resources.