Studies on production techniques of some herb plants: I Effect of Agryl P17 mulching on herb yield and volatile oils of basil (Ocimum basilicum L.) and marjoram (Origanum majorana L.)

Agryl P17 fiber-mulching of cold-sensitive herbal plants, basil (Ocimum basilicum L.) and marjoram (Origanum majorana L.), were studied at three locations in Finland (1984—1985). The growing sites were Helsinki (60° 14' N), Sahalahti (61° 28' N), and Inari (69° 04' N) for both species in 1984, and Helsinki for marjoram in 1985. Agryl P17 mulching increased basil yield at all locations. The uncovered basil yielded approximately 54 kg/100 m2 and when grown under the mulch, more than three fold, 191 kg/ 100m2. In the north (Inari), however, basil and marjoram did not give practically any yield. Marjoram did not benefit from mulching either in the south: the yield was 96 kg without and 80 kg/100m2 with mulching. The vegetation under the mulch was severely affected by fungus diseases. The volatile oil content in the dried basil herb ranged from 0.46 to 0.93 %. There were no significant differences in the total oil content whether basil was grown with or without Agryl P17. The oil content in marjoram ranged from 1.94 to 2.55 % the total content being significantly higher when grown under the cover