Composted Azolla as a peat alternative in bedding of Begonia rex

Abstract

Azolla has caused environmental problems due to its rapid growth and high biomass production in wetlands of Guilan province. This study was conducted to investigate the possibility of using composted Azolla instead of peat in Begonia rex production. The plant was grown for 5 months under greenhouse in a peat + perlite (2: 1 v/v) (P: PE) and composts (25, 50, 75 and 100%) instead of peat in P: PE. Begonia is generally purchased and enjoyed by people for its spectacular foliage. The results showed that compost increased all nutrients in the growth medium, but in the leaves of the plant only potassium increased. By increasing the amounts of compost between 25 and 100%, the bulk density of the growing medium decreased (0.12-0.07 g/cm3) compared to the control (0.21 g/cm3). The amount of potassium in the growth media containing 25% and 75% Azolla compost increased significantly compared to the control. Substitution of 25% compost instead of peat compared to the control, caused a significant increase (p = 0.05) in leaf number (13.91), leaf fresh weight (50.08 g), leaf dry weight (2.01 g), root wet weight (2.23 g) and root length (33.66 cm). Substitution of 25-100% compost increased pH and Electrical conductivity of growth media. With regard to the high relative price of peat with respect to compost, 25% compost is economically preferred. According to the results, compost is a good alternative to peat, but this does not mean the application of high levels of compost in the growth media.