Evaluation of Yield, Yield Components and Land Equivalent Ratio in replacement intercropping of Fennel (Foeniculum vulgar Mill.) with Mung Bean (Vigna radiata L. Wilczek)

Intercropping as an approach for development of sustainable agriculture systems is pursuing the purposes such as creating ecological balance, further exploitation of resources, increase the quantity and quality of yield and reduce losses due to pests, diseases and weeds and reduce the dependence of farmers to pesticides, to maintain product quality and marketability. Jahani et al (2007) reported that intercropping of lentil and cumin has significantly increased dry weight of vegetative organs, biological yield, 1000-seed weight and number of seeds per cumin umbrella and seed yield. Legume/non-legume intercropping system due to the beneficial use of resources produces more yields. In review of about the fennel and fenugreek intercropping, intercropping of the two plants significantly increased the fennel seed yield compared with monoculture.

The experiment was conducted in 2014-2015 growing season based on randomized complete block design with three replications at Agricultural Research Station, Faculty of Agriculture, Ferdowsi University of Mashhad. Experimental treatments were 25% mung bean + 75% fennel, 50% mung bean + 50% fennel, 75% mung bean + 25% fennel, monoculture of mung bean and monoculture of fennel. Species were sown at the same time in 12/06/2015 in rows with a distance of 50 cm. At harvesting time, dry matter, seed yield and yield components of these crops were measured. Yield advantages of intercrops over monocultures were compared by land equivalent ratios. Seeds of fennel were analyzed for essential oil content.  

The highest seed yield, biomass and essential oil of fennel for monoculture with 1460.4, 12286.4 and 50.4 kg per hectare respectively and the lowest values for 25% fennel + 75% mung bean treatment with 263.2, 5843.3 and 8.1 kg per hectare respectively were observed. Also, the highest seed yield and biomass of mung bean for monoculture with 2167.1 and 8900.5 kg per hectare respectively and the lowest values for 25% fennel + 75% mung bean treatment with 740.5 and 2540.5 kg per hectare respectively were observed. The highest essential oil contents of fennel with 3.56% was observed in ratio of 50% fennel + 50% mung bean and the lowest value was observed in 25% fennel + 75% mung bean with 3.1%. It seems that interspecific competition between fennel and mung bean due to the abiotic stresses (competition) led to increasing essential oil percent in intercrops. The highest essential oil yield of fennel was observed in monoculture with 50.4 kg/ha and the lowest value was observed in 25% fennel + 75% mung bean with 8.1 kg/ha. The highest mung bean harvest index was 28% in 25% mung bean + 75% fennel and the lowest was observed in 50% mung bean + 50% fennel with 23.5%. Also, the highest fennel harvest index was observed with 12% in monoculture and the lowest in 25% fennel + 75% mung bean with 4.5%. The highest value of total land equivalent ratio (1.07) was obtained in ratio of 50% mung bean + 50% fennel indicating 7 percent yield advantage of intercropping compared to pure stands of species of these two products compare to each other that represents of showing the more efficient use of land. The lowest value by intercrops of land equivalent ratio was observed in ratio of 25% mung bean + 75% fennel which was 9% lower than the monoculture.

In general, intercropping of fennel with mung bean, had positive effect on biological and seed yield of two species as well as percent and yield of fennel essential oil. So, in order to reduce the consumption of chemical fertilizers in sustainable agriculture and as for nitrogen biological fixation ability of mung bean, intercropping this plant with fennel can be increased resources efficiency and improve of the quality and quantity yield of fennel.