Effect of Plant Spacing and N Fertilization Levels of Watermelon Relay Intercropping with Faba Bean in Relation to Yield Productivity

This study suggested growing faba beans in the watermelon cultivated area by relay intercropped melon with faba bean to reduce the faba bean production-consumption gap, maximize the productivity per unit area, reduce the use of nitrogen fertilizer and increase the income of farms.  So, A field experiment was implemented during 2020/2021 and 2021/2022 seasons at Ismailia Experiment Station, ARC, Ismailia Governorate, Egypt, to study the effect of plant spacing (50, 75 and 100 cm) and N fertilization levels (40, 60 and 80 kg/fad) of watermelon relay intercropping with faba bean on yield for both crops, land equivalent ratio (LER), and profitability per unit area. A split-plot design was used with three replications. Plant spacing of watermelon were assigned in main plots and N fertilization levels were arranged in sub-plots. Results indicated that growth, yield and its attributes of faba bean were insignificant effect by watermelon plant spacing and N fertilization levels of watermelon as well as their interaction. Contrary, plant spacing and N fertilization of watermelon relayed with faba bean significantly affected watermelon traits. Where, increasing plant spacing from 50 to 100 cm between hills with applied 80 kg N/fad significantly increased branch length, number of branches/plant, number of fruit and mean fruit weight. However, the highest fruit yield (25.2 ton/fad as average of both seasons) produced by planting watermelon spacing at 75cm with applied 80 kg N/fad, but without significant differences with 60 kg/fad. Therefore, intercropping watermelon at plant spacing 75cm with applied 60 or 80 kg N/fad had the highest LER 1.75, ATER 1.05 and the highest in both seasons. While, the highest net return 25511 L.E/fad was achieved with 60 kg N/fad and at par with the net return 25502 L.E/fad by 80 kg N/fad. In conclusion, relay intercropping watermelon with faba bean at 75 cm plant spacing with applied 60kg N/fad produced 24.9 ton/fad fruits of watermelon plus 8.3 ardab/fad of seed faba bean and increased net return by 80.2%, as well as saved land by 75% and N fertilizer by 25% compared to sole watermelon culture, as average of both seasons