Effect of deficit irrigation and nitrogen on fruit, grain, and oil yield of hull-less seed pumpkin (Cucurbita pepo L.) under plastic mulch

Hull-less seed pumpkin (Cucurbita pepo L.) is an important medicinal plant and its seed and byproducts are used in the treatment of many diseases. Production of this plant uses a lot of water and nitrogen. Plastic mulch application may reduce the water and nitrogen requirements. Therefore, an experiment was conducted with the aim of evaluation of deficit irrigation and nitrogen effects on fruit, seed, and oil yield of hull-less seed pumpkin (Cucurbita pepo L.) under plastic mulch in 2016. A split plot layout in a randomized complete block design with three replications was used. Main plots included complete irrigation under plastic mulch, moderate stress (75% of complete irrigation under plastic mulch), severe stress (50% of complete irrigation under plastic mulch), normal irrigation without plastic mulch and sub-plots consisted of complete nitrogen requirement, 80% of the full nitrogen requirement and 60% of the full nitrogen requirement. The results showed that there were no significant differences between moderate stress (75% complete irrigation under plastic mulch) and normal irrigation without mulch for fruit, grain and oil yield. However, under moderate stress, the plastic mulch reduced water and nitrogen requirements by 25 and 20%, respectively and produced a grain yield and oil yield similar to complete irrigation. Therefore, this technique can be used for water conservation and sustainability of agricultural production systems in arid and semi-arid areas.