Effect of simultaneous and overlapped intercropping ratios on essential oil yield of peppermint (Mentha piperita L.) and forage quality of guar (Cyamopsis tetragonoloba L.)

To evaluate the effect of simultaneous and overlapped intercropping ratios on yieldand quality essential oilof peppermint (Mentha piperita L.) and forage of guar (Cyamopsis tetragonoloba L.),an experiment was conducted as factorial arrangements in randomized complete block design with four replications in Agricultural Sciences and Natural Resources University of Khuzestan, Iran during 2017-2018. Experimental factors included: planting time at two levels (simultaneous and overlapped planting of peppermint and guar) and intercropping ratios at five levels (sole planting of peppermint, sole planting of guar, 50% peppermint + 50% guar, 25% guar + 75% peppermint and 25% peppermint 75% guar. The results showed that at simultaneous intercropping the highest forage yield obtained from sole guar (6348 kg.ha-1), which was not significantly different from the planting ratio of 75% guar + 25% peppermint. In overlapped intercropping, the highest forage yield obtained from sole guar and 75% guar + 25% peppermint planting ratio, respectively. The highest guar ADF (36.4%) obtained from the planting ratio of 50% peppermint + 50% guar under overlapped intercropping. The highest peppermint essential oil content (2.1%) obtained from 50% peppermint + 50% guar planting ratio in the simultaneous intercropping. The highest essential oil yield (9.49 kg.ha-1) belonged to the treatment of sole peppermint. The highest LER (1.42) belonged to 75% guar + 25% peppermint plating ratio in overlapped intercropping. The results showed that for increasing the quality of guar forage, simultaneous intercropping and 75% guar + 25% peppermint planting ratio and -for improving  peppermint essential oil yield, overlapped intercropping and 50% peppermint + 50% guar planting ratio was suitable.