Water utilization in intercropping: A review

Strip intercropping has been widely applied in arid and semi-arid regions due to high and stable productivity and efficient utilization of resources. Intercropping can increase water use efficiency (WUE) of crops and optimize the soil moisture environment for crop development. Competition and complementarity are two aspects of the same interspecific relationship between crops, and a quantitative understanding of the competition and complementary effects of intercrops on soil resources is important for advancement of intercropping systems. The characteristics and mechanisms of water utilization and interspecies relationships in intercropping are reviewed in this paper. The main regulation approaches for efficient water utilization in intercropping are based on interspecific competition and complementarity include crop species, irrigation and fertilization regimes, plant density, spatial arrangement, tillage and mulching practices, and environmental factors. Interspecific competition and complementarity are leading factors influencing water utilization of intercrops and studies on synergistic effects of competition and complementarity in intercropping systems are of importance for water utilization. Future research should investigate the relationship between water competition and complementation between different intercrops and inter-zone water migration. Integrating results from different studies could provide a basis for enhancing WUE of intercropping through advanced understanding of approaches for regulating interspecific interactions. This would provide support for the development and adoption of intercropping systems in water-deficient areas.