COMPARISON OF VARYING AGRICULTURAL INTENSIFICATION ON WATER RESOURCES: COMPARISON OF THE NORTH CHINA PLAIN AND US HIGH PLAINS

There is increasing emphasis on agricultural intensification to meet rising food demand globally. In this study we compared intensive fertilization and irrigation in the North China Plain (NCP) with less intensive practices in the U.S. High Plains (USHP) related to adverse impacts on water resources. Using spatial datasets, impacts of varying agricultural intensities (multi-cropping, fertilization, and irrigation) on crop yield were compared between the NCP and USHP relative to impacts on groundwater quantity and quality. Crop yield during the past decade from intensive double cropping of wheat and corn in the NCP was only 15% greater than that of less intensive single–cropping corn in the USHP (2002–2011), although N fertilizer application was ~4 times greater and irrigation rate was ~2 times greater in the NCP than in the USHP. Irrigation and fertilization in both regions has markedly depleted groundwater resources and degraded groundwater quality. The impacts of intensive irrigation tend to counter intensive fertilization by flushing nutrients through the soil profile, and increasing groundwater contamination. This NCP–USHP comparison indicates that intensive management in the NCP does not significantly increase crop yield but has large scale negative impacts on water resources. Future efforts towards agricultural intensification should accurately assess the impacts of intensification relative to crop yields and water resources and should move towards more sustainable management.