Effects of substrate warming in soilless culture on gerbera crop performance under seasonal variations

摘要

Gerbera cv. Fame was grown in perlite (3-5 mm) or attapulgite [palygorskite] substrates which were or were not heated to a minimum temperature of 19℃. After 2 years of use, both materials monitored good stability and bulk density did not change substantially with change in water status of the substrate. Air capacity was high for both materials but decreased in attapulgite after 2 years with heating. Easily available water and water buffer capacity were very limited, especially for attapulgite. Substrate heating increased total water consumption by 130-140% in attapulgite and 35% in perlite. When no heating was used perlite consumed 22% more water than attapulgite. Increased water consumption by plants growing in heated substrates continued afterthe winter and spring heating season had ended. Seasonal adaptation of plants was analysed in terms of transpiration, stomatal conductance and leaf water potential. Significant differences were found in flower production between substrates at the end ofthe production cycle (7 May) - 35.3 and 26.1 flowers/plant in perlite and attapulgite and 36.6 and 26.1 flowers in heated and unheated substrates, respectively. Between Oct. and Mar. yields were: perlite 25.3 flowers, attapulgite 19.0 flowers, heated substrate 25.9 flowers, unheated substrate 17.8 flowers/plant.