Evaluation the effects of relay intercropping of Styrian pumpkin (Cucurbita pepo L.) with irrigated and rainfed chickpea (Cicer arietimum L.) on yield and yield components as affected by chickpea residue mulch

In order to study the effects of cropping systems and mulch application in relay intercropped Styrian pumpkin (Cucurbita pepo L.) with chickpea (Cicer arietinum L.), a field experiment was conducted as factorial layout based on a randomized complete block design with three replications at the Agricultural Research Station, College of Agriculture, Ferdowsi University of Mashhad, during growing season of 2010 2011. Treatments were five levels of cropping systems (monoculture of irrigated chickpea, monoculture of rainfed chickpea, monoculture of Styrian pumpkin, relay intercropping of irrigated chickpea/Styrian pumpkin, relay intercropping of rainfed chickpea/Styrian pumpkin) and two levels of chickpea residue mulches (with and without mulch). The results showed that plant height, number of pods per plant, biological yield, seed yield and 1000-seed weight chickpea were affected by different cropping systems (p≤0.05). Relay intercropping of rainfed chickpea/Styrian pumpkin increased number of pod per plant and seed yield of chickpea up to 37 and 23 compared to monoculture of rainfed chickpea, respectively. In additrion, results showed that the interaction effects between cropping systems and mulch application were significant (p≤0.05) on number of fruit, fruit yield, number of seed per fruit, 1000-seed weight and seed yield of Styrian pumpkin. The highest Styrian pumpkin seed yield (398 kg.ha-1) was shown in relay intercropping of irrigated chickpea/Styrian pumpkin. Styrian pumpkin seed oil percent was not affected by treatments (p≥0.05). However, application of chickpea residue mulch reduced the oil percent. Assessment of land equivalent ratio showed that the total systems of relay intercropping was superior compared to monocultures and the highest land equivalent ratio (2.37) was observed in relay intercropping of rainfed chickpea/Styrian pumpkin without mulch system. In general, the positive effect of intercropping on yield and yield components of chickpea, especially in the dry conditions and improved quantitative characterization of Styrian pumpkin herb, it can be inferred that the relay intercropping could be a suggested strategy for using resources to achieve optimal performance in order to achieve sustainable agricultural principles.