The Effects of Tuff Combination with Conventional Organic Media on Some Vegetative and Flowering Characteristics of potted Alstroemeria

Production of ornamental plants is a global trade. The economic value of ornamental plants has been significantly increased in the past two decades. These plants have high potential for continuous development of domestic and international markets in the future. Alstroemeria is a perennial, monocotyledon, ornamental plant which is used as a cut flower or potted flowering plant for the home and as herbaceous urban landscape plant. Popularity of this flower is increasing because of its beautiful flowers, wide range of colors (orange, pink, purple, red, yellow, white, and the other colors), year-round flowering, as well as high yield.Nowadays, soilless culture has been developed a lot. Permanent use of soil nutrients in developing countries without adequate replacement has reduced production capacity and nutrients of soils. Therefore, selecting a suitable substrate is one of the main factors in producing high quality potted plants. Many factors affect the quality and growth of flowers including medium. Thus, we try to use substrates which have positive effects on flowers’ quality and its growth. Such substrates must be economical without any pollution of water or soil. In this study, the effects of peat moss, cocopeat, leaf manure and spent mushroom compost in three levels of 40, 60 and 80% in combination with Tuff mineral soil plus control treatment (100% of Tuff mineral soil) were investigated on growth characteristics and flowering of potted alstroemeria. The experiment was conducted in a completely randomized design with 13 treatments and four replications in the research greenhouses of Islamic Azad University, Isfahan (Khorasgan) branch. Alstroemeria rhizomes (2 to 2.5 cm) were grown in four liter pots. About three centimeters of leca was poured in the bottom of each container and then pots were filled with specific volume ratios of substrates which had been mixed completely. After that, rhizomes were planted and pots were irrigated. Irrigation was carried out every three days in spring and every two days in summer. At the end of the experiment, the number of leaves, flowers and flowering branches, fresh and dry weight of the shoot, rhizome size and flower life were evaluated. Results showed that the highest number of flowering branches, leaf number, rhizome size and shoot dry weight were observed in peat moss 80% treatment. The highest vase life of the flowers was obtained from peat moss 80% and cocopeat 40%. The highest shoot fresh weight was observed in peat moss80% and fungal compost60%. On the other side, the lowest number of leaves and flowers, rhizome size, fresh and dry weights of aerial part were obtained from compost80%. The lowest number of flowering branches was produced by compost 80%, leaf manure 40%, leaf manure 60%, and control treatments. Also, the least vase life of flowers was observed in Tuff mineral soil and compost 80%. According to results, the presence of peat moss and cocopeat in the culture medium increased the growth and flowering characteristics significantly so that the highest means of traits were observed in media with higher peat moss amounts. In substrates containing peat moss, optimum absorption of nitrogen and potassium will improve the quantity and vase life of the flowers. Absorption of the adequate phosphorus causes better root growth and therefore better absorption of nutrients and increases the number, longevity and size of flowers. Better performance of organic substrates than mineral soils can be due to higher porosity and water holding capacity of these substrates. Considering the results obtained from chemical analysis of culture media, peat moss had a significant effect on plant growth and yield because of higher levels of manganese and zinc nutrients. On the other hand, the positive effect of cocopeat on increasing some of the studied traits may be due to the physical and chemical properties of this substance and its high ability to keep up water and nutrients which provide favorable growth conditions for plant. It seems that the use of this material in combination with the culture medium improves the nutrition, ventilation and growth of the plant; therefore, this medium is recommended for the growth of flowering plants, especially alstroemeria. The reason of decreased growth in media containing leaf manure can be high electrical conductivity of theses substrates.