Yield advantage and water productivity of maize-mungbean inter-cropping systems in the Dry Zone of Sri Lanka; a modelling approach

Water is not efficiently used in most of the cropping systems in South Asia. Therefore, water-efficient agricultural practices are of immense importance when increasing the area to be cultivated, and/or conserving rain water to be used in drier regions through irrigation. Inter-cropping of maize ( Zea maize L.) with mungbean ( Vigna radiate L.) R. Wilczek may offer benefits in utilising water efficiently and maintaining or improving land productivity. Simulation models are useful tools to assess the performance of agricultural systems. The present study was conducted to evaluate the irrigation water requirement and yield of the maize-mungbean inter-cropping system in comparison with mono-cropping, using APSIM. Simulation results revealed that the maize-mungbean intercrop required only 4 % more water than the maize mono-crop (P>0.05). Moreover, intercrop maize yield was only 3 % less than that of the maize mono-crop (P>0.05) However, yield of mungbean was 21 % less in the intercropping system than the mono-crop system (P<0.05). The land-equivalent ratio of the maize-mungbean intercropping system was 1.8. Efficient use of water under the inter-cropping system, with a similar yield of maize to that obtained under mono-crop of maize, combined with an additional mungbean harvest highlights the greater efficiency of the maize-mungbean inter-cropping system in the Dry Zone of Sri Lanka.