EFFECT OF SOME CULTURAL PRACTICES ON GROWTH AND PRODUCTION OF SOME MEDICINAL PLANTS

Abstract

Two field experiments were conducted during 1993 and 1994 seasons in the Experimental Station of the Medicinal Plants, Faculty of Pharmacy, Cairo University, Giza. The aim was to investigate the effect of plant spacing and some weed control treatments and their interaction on weed control, growth, yield and chemical constituents of peppermint (Mentha piperita L.) and sweet marjoram (Majorana hortensis L.) plants. Obtained results revealed that dense planting reduced the existence of weeds. This was more pronounced in sweet marjoram than peppermint. Wider plant spacing (60 em with peppermint and 50 em with sweet marjoram) increased significantly the mean number of branches, fresh and air dry weights of herb and oil yield in fresh and air dry herb produced per plant. Otherwise, decreasing the spacing between plants to 20 em apart resulted in a significant increases in fresh and dry weights and oil yield per plot for each of peppermint and sweet marjoram herb. No treatments performed better than black polyethylene soil mulch and hand hoeing treatments in controlling peppermint and sweet marjoram weeds. However, the efficiency of weed control treatments with peppermint can arranged in descending order as follows, soil mulching, hand hoeing, oxadiazon, pendimethalin and oxyfluorfen, whereas with sweet marjoram was: soil mulching, hand hoeing,