Evaluation of Yield, Quantity and Quality Traits in intercropping of Peppermint (Mentha Piperita L.) and Fenugreek (Trigonella foenum - graceum L.) under Different Planting Dates

In order to investigate the effect of different planting dates on yield, quantity and quality traits in replacement intercropping system of peppermint and fenugreek, a field experiment was conducted as split-plot arrangement based on randomized complete block design with three replications, in University of Guilan, during growing season of 2015 - 2016. The experimental treatments were planting dates in three levels (October 2, February 29 and April 29) assigned to main plots and planting systems in five levels (sole cropping of peppermint, sole cropping of fenugreek and replacement intercropping peppermint- fenugreek with ratios 1:1, 2:2 and 2:1 (two rows of fenugreek: one row of peppermint) as sub plot. The results showed that yield of both crops were higher in sole cropping in comparison intercropping systems. The highest land equivalent ratio (LER) was obtained in 1:1 intercropping ratio. Grain yield of fenugreek in 29 February and 29 April in comparison to autumn planting date 23% and 47% were decreased respectively, and its biological yield 15% and 32% were declined. Also in these planting dates, peppermint leaf dry weight 48% and 57 % was decreased. The highest essential oil percent of both crops was achieved from planting date of February 29 and 1:1 intercropping ratio interaction. The highest essential oil yield of both crops was obtained from autumn planting date and their sole cropping. The planting dates had no significant effect on total chlorophyll of peppermint. In general, in this study, autumn planting date improved quantity and quality traits and intercropping advantages.