Effect of nitrogen fertilizer source on yield and essential oil content of sweet basil (Ocimum basilicum L.) and forage maize (Zea mays L.) yield in intercropping

To evaluate the effect of nitrogen sources on yield and quality of sweet basil and forage maize under intercropping (additive series), a field experiment was carried out at the experimental field of faculty of agriculture, Lorestan University, Khorramabad, Iran, in 2013-2014 and 2014-2015 growing seasons. Experimental treatments were arranged as factorial in randomized complete block design with three replications. Experimental treatments included: without fertilizer (Control), 100% chemical fertilizer (N), bio-fertilizer (Nitroxin), integration of bio-fertilizer + 50% chemical fertilizer, and cropping patterns consisted of; sole cropping sweet basil and forage maize and the additive intercropping of maize + 25% sweet basil, maize + 50% sweet basil, maize + 75% sweet basil and maize + 100% sweet basil. Mean comparisons showed that in the second year sole cropping of sweet basil with 100% chemical fertilizer in second harvest had the highest total dry weight (3921.9 kg.ha-1). Among cropping systems the highest total dry weight (19220 kg.ha-1) was obtained from sole cropping of forage maize. Application of the integration of Nitroxin + 50% nitrogen chemical fertilizer in intercropping produced reasonable biological yield and essential oil yield, and did not show a remarkable difference with nitrogen chemical fertilizer. The highest LER (1.566) belonged to maize + 100% sweet basil with bio-fertilizer. The results showed that using the integration of bio-fertilizer + 50% chemical fertilizer can be considered as an enviromnet-friendly approach to reduce the consumption of chemical fertilizers in support of sustainable agriculture.