Performance of certain medicinal and aromatic plants as intercrops in som (persea bombycina kost.) plantations

A field experiment was conducted during 2007–10 at Lahdoigarh, Jorhat, Assam to study the performance of Stevia [Stevia rebaudiana (Bertoni) Hemsl.], Brahmi [Bacopa monnieri (L.) Wetts.] and Patchouli (Pogostemon cablin Benth.) as intercrops with Som (Persea bombycina Kost.), a host plant of muga silkworm (Antheraea assamensis Heifer). The growth and yield of these plants as intercrops under shade of Persea bombycina Kost. were compared to those grown as sole crops under open condition. All three crops showed relatively higher values in case of survival percentage under shade of Persea bombycina Kost. than open condition. Plant height, plant spread, leaf area index (LAI), fresh and dry herb yield, net return and benefit: cost ratio (BCR) of P. cablin Benth. and B. monnieri (L.) Wetts. were also higher in shade condition than open condition which indicated that P. cablin Benth. and B. monnieri (L.) Wetts. preferred partial shade for better growth and yield which indicated possibility of growing these plants as intercrops in existing matured P. bombycina Kost. plantations. In case of S. rebaudiana (Bertoni) Hemsl., there was significant reduction in growth, yield, net return and BCR in shade compared to open condition. The highest BCR of 1.91 was recorded with P. cablin Benth. under shade against 1.61 in open condition. However, BCR of B. monnieri (L.) Wetts. (1.51 as intercrop) and S. rebaudiana (Bertoni) Hemsl. (1.62 as intercrop) envisaged the possibility of growing these two plants also in the interspaces of P. bombycina Kost. plantations as an additional source of income to the muga farmers.