Effect of intercropping madumbe (Colocasia esculenta) and rice (Oryza sativa L.) on yield and land productivity under different irrigation water management techniques with effluent water

The need for the optimal use of land, without a yield penalty, in urban and ped-urban (UP) settlements is vital. This study investigated the effect of intercropping madumbe and rice with respect to yield and land productivity when irrigated with anaerobic baffled reactor (ABR) effluent under different irrigation water management techniques. It was hypothesized that intercropping under different irrigation water management techniques has no effect on the yield and land productivity. Field trials were conducted in the 2017 and 2018 cropping seasons with ABR effluent (without fertilizer) at the Newlands Mashu Experimental Site, Newlands East, Durban, South Africa. A randomized complete block design with 3 replications; cropping treatments of sole madumbe, sole rice and madumbe + rice (intercrop) and irrigation treatments of alternate wetting and drying (AWD), continuous flood irrigation (CFI) and wetting without flooding (WWF) was used. Growth and yield parameters at harvest were determined. Thereafter, land equivalent ratio (LER) was calculated to evaluate the productivity of the intercrop. The effect of intercropping was significant (P < 0.05) on the total number of irrigation events and total water use. There was a significant reduction (P < 0.05) in plant heights of both madumbe and rice at intercrop. However, the effect on plant height for treatment CFI was positive but not significant (P> 0.05) for both seasons. A significant (P < 0.05) reduction also occurred in the number of madumbe leaves/plant, and panicles/plant and tillers/plant for rice. Intercropping significantly reduced (P < 0.05) madumbe corm and rice grain yield over the two seasons relative to sole cropping. LER showed that intercropping madumbe with rice was not more productive (LER < 1) than sole cropping of madumbe. It was concluded that over the two-season period, intercropping madumbe and rice do not yield appreciably tinder any of the three irrigation management techniques applied and the study hypothesis is thus rejected.