Productivity of corn and soybean under solid and intercropping plantings with different levels of irrigation water in egypt

The present investigation was carried out at Giza Agricultural Experiments and Research Station, Faculty of Agriculture, Cairo University, (Egypt) during the two successive seasons 2015 and 2016 to determine productivity, WUE and LERs of intercropping soybean with corn in beds as compared with solid plantings of traditional ridges. The experiment included eighteen treatments which were the combinations between three applied irrigation water (75, 100 and 125% of the recommended water applied) and six cropping systems (50% soybean + 100% corn, 100% soybean + 100% corn, traditional solid corn, solid corn “mixed system”, traditional solid soybean and solid soybean “mixed system”). The experimental design was split plot design with four replications. The data indicated that all the studied soybean characters were affected negatively by intercropping with corn. Increasing soybean plant density under intercropping systems from 50 to 100% of solid culture achieved high seed yield without any significant reduction on corn grain yield. The interaction between levels of irrigation water and cropping systems did not affect soybean characters; meanwhile the reverse was true for corn crop. WUE was increased with decreasing irrigation water levels from 125 to 75% of the recommended irrigation water (8092 m³/ha). The results obtained have strongly coincided with the definition of land equivalent ratios (LERs). It was not affected significantly by applied levels of irrigation water but the converse was true for cropping systems and the interaction between previous factors. LERs of intercropping culture ranged between 1.39 and 1.52 as compared to solid plantings (1.0). Water use efficiency (WUE) was increased by decreasing applied irrigation water levels from 125 to 75% of recommended irrigation water level. High population densities of the intercrops with application 100% of applied irrigation water achieved the highest LER as well as WUE and could be recommended for Egyptian farmers.