The future of intercropping under growing resource scarcity and declining grain prices - A model analysis based on a case study in Northwest China

Intercropping, i.e. mixed crop species cultivation on a field, can potentially reduce pressure on land and water resources by generating higher resource use efficiencies and crop yields through exploitation of complementarities between species. Intercropping systems in China and elsewhere have come under pressure through labor migration, growing water scarcity, changing crop prices and other factors. However, little hard evidence is available on how these socio-economic factors interplay and affect the prevalence of intercropping systems now and in the near future. The objective of this study is to explore the effect of growing scarcity of (water and labor) resources and declining (maize) grain prices on the share of intercropping in the optimal cropping plan and on associated agricultural income levels in an intercropping-dominated agricultural system in China. To undertake this analysis, we developed a mathematical programming model to simulate crop production for a model village in Gaotai county in the Hexi Corridor in northwest China, for given resources and economic conditions in 2013 and possible changes (scenarios) in the future. In the Hexi Corridor, conventional wheat/maize intercropping contributed greatly to rising food production while cash crops integrated with maize provided important cash income. With the introduction of seed crops and stricter water regulations, intercropping has become less prevalent in this area in recent years. In the absence of water constraints and at price levels and labor availability in 2013, our model results indicate that an optimal land use would entail that all land would be devoted to intercropping. Sole cumin and sole cotton enter the optimal cropping plan when water becomes scarce and the maize price declines substantially, while increases in hired labor wages have a strong negative impact on intercropping only when on-farm labor becomes scarce.