Strategies to Reduce Crop Water Footprint in Intensive Wheat-Maize Rotations in North China Plain

Abstract

The intensive use of groundwater and nitrogen fertilizer has led to serious negative impacts on the environment of the North China Plain (NCP). Water footprint is an emerging approach to assess the consumptive water use and the environmental impacts on winter wheat-summer maize systems. A seven-year rotation experiment was conducted to collect data on wheat and maize growth response to nitrogen rates and irrigation schedules and to explore how the water footprint was affected, using DSSAT 4.6 Wheat and Maize crop models. Results showed that the increase in farm inputs contributed greatly to the increase in water footprint, primarily through the grey water footprint. The water footprints of maize and wheat were more sensitive to the nitrogen rate and irrigation, respectively. An irrigation of 160 mm produced a minimum total water footprint and higher yield for wheat. The grey water footprint of maize increased linearly when the nitrogen rate applied to maize exceeded 60 kg ha−1. Water-saving irrigation with 300 kg ha−1 of nitrogen can maintain a higher grain yield and have little impact on the environment. The approach used and the results can help to develop management strategies to maintain high yields while minimizing the water footprint in NCP.