Adjustment of planting geometry along with suitable maize cultivar can be a viable tool for maximizing land usage and net return. A two-year study was carried out at Serw Agricultural Experiments and Research Station, A.R.C., Domiate governorate, Egypt, during 2015 and 2016 seasons to evaluate intercropping cowpea with suitable maize cultivar and its planting geometry for maximizing land usage and net return. The treatments were the combinations between three maize cultivars (SC 30K08, TWC 310 and TWC 352) and three maize plant distributions (one plant/hill distanced at 25, 50 and 75 cm between hills, respectively). Ridge width with maize plant distribution formed maize planting geometry (25 cm × 140 cm, 50 cm × 140 cm and 75 cm × 140 cm). These treatments were compared in a split plot distribution in randomized complete block design with three replications. Maize cultivar SC 30K08 had the highest grain yield and its attributes compared with the other cultivars in both seasons. Also, maize planting geometry 25 cm × 140 cm resulted in the highest grain yield and its attributes compared with the other planting geometries in both seasons. Ear length, ear weight, 100-grain weight and grain yield/fad were affected significantly by maize cultivars × maize planting geometry. Intercropping cowpea with maize cultivar TWC 352 had the highest seed yield and its attributes compared with those intercropped with the other cultivars in both seasons. Also, maize planting geometry 75 cm × 140 cm resulted in the highest seed yield and its attributes through growing two cowpea rows between maize hills compared with the other maize planting geometries in both seasons. Number of pods/plant and seed yield/fad were affected significantly by maize cultivars × maize planting geometry. LER and LEC values of the intercrops were much greater than 1.00 and 0.25, respectively, for all the combinations indicating less land requirements of intercropping system than solid culture of both crops.

A TWO-year field experiment was carried out at El-Serw Agricultural Research Station, during the 2018 and 2019 seasons to study the effect of intercropping cowpea (Vigna unguiculata L.) with three maize (Zea mays L) hybrids (SC 168, SC176 and TWC 321) and four N fertilization treatments (120kg N/fed as urea (100% N mineral), 50% N mineral + 50% N nano, 75% N mineral + 25% N nano and 3.0cm 3 N nano/ L (100% N nano) on maize and cowpea productivity, land use efficiency and economic return. A split-plot design with three replicates was used. Results showed that maize hybrids had significant effect on yield and yield attributes of maize and cowpea in both seasons, with some exception. The S.C.168 hybrid gave the highest grain yield and its components, while intercropping cowpea with S.C.176 hybrid significantly increased yield and its attributes of cowpea in comparison with other hybrids. Applying 75% N mineral along with 25% N nano significantly increased growth, yield and yield components of maize and cowpea in both seasons. Significantly increase in yield and its attributes of maize and cowpea was realized by interaction between maize SC168 and 75% N mineral +25% N nano fertilization. Intercropping cowpea with maize SC168 that received 75% of the N mineral + 25% nano fertilizer recorded the highest LER 1.67 and 1.66, ATER 1.59 and 1.58, Aggressivity 0.28 and 0.23, gross return15865 and 15854 L.E./fed and net return 7983 and 7972L.E./fed in first and second seasons, respectively, as well as rationalizing the use of N mineral fertilizers.