Ramie [Boehmeria nivea (L.) Gaud.] as a potential new fibre crop for the Mediterranean region: Growth, crop yield and fibre quality in a long-term field experiment in Central Italy

Ramie [Boehmeria nivea (L.) Gaud.] is a perennial herbaceous plant, of the Urticaceae family, native to China, Japan and Malay Peninsula, where it has been used as a textile fibre for many centuries. This species was introduced successfully in the Mediterranean region at the beginning of 1900, even though few researches have been carried out to assess the long-term productivity and stand duration in this area. For this reason, a 13-year field experiment was conducted, under the temperate climatic conditions of Central Italy, to evaluate the effects on ramie growth and yield of two different plant densities (50,000 and 33,300 plants ha−1), two harvest times (June and October) and crop stand duration. The chemical composition (cellulose, hemicellulose and lignin content) of bast and core was evaluated too. Ramie showed a good adaptability to the pedo-climatic conditions of the study site, with a growing period that goes from the beginning of March to the beginning of October. The obtained results showed that the harvest time significantly affected all the analysed parameters, while the plant density had no significant effect on stem development and stem basal diameter, and on crop and bast fibre yield. Furthermore, no significant interaction was observed between the plant density and the harvest time on total plant or stem and bast fibre dry yield, and on the main biometric characteristics. In spite of its tropical origin, ramie appears to be suited to temperate conditions giving 8.70 Mg/ha/year of stem dry yield and 2.46 Mg/ha/year of dry bast fibre from the 2nd to the 13th year of growth. The dry ramie plant was composed by weight of 62% stems and 38% leaves and cymes. The results pointed out that the crop can persists for many years (up to 13) giving a stable off-take of stems and bast fibre.