RECIRCULATION OF ROSE DRAINAGE WATER UNDER SEMI-ARID CONDITIONS

ISHS Acta Horticulturae 401: International Symposium on Growing Media & Plant Nutrition in Horticulture

RECIRCULATION OF ROSE DRAINAGE WATER UNDER SEMI-ARID CONDITIONS

Authors:	M. Raviv, R. Reuveni, A. Krasnovsky, Sh. Medina
Keywords:	Rosa x hybrida, soil-borne fungi, soilless culture, tuff
Abstract: The Israeli agriculture is facing an ever-increasing problem of water shortage. Simultaneously, salinity and nitrate levels in the ground water are increasing too. These facts justify an effort aimed at both reducing nutrient leakage to the environment and water saving. This can be done by recycling drainage water (DW) of intensive, soilless operations which will save fertilizers. The main problems associated with recirculation of DW by growers of semi-arid areas are: The high salinity of the irrigation water; The high evapotranspiration rates that lead to a rapid increase in the salinity of the DW; The change in ionic ratios between the irrigation water and the DW; The risk of rapid spread of soil-borne diseases. Rose plants (CV. "Mercedes") were planted in tuff-filled polystyrene boxes in April 1993. Recirculation of DW started on December 1993. DW are collected and recirculated either with or without dilution with collected rain water. As control, a normal irrigation practice with free discharge of the DW is used. No effect of the recirculation treatments on yield quantity or quality was observed. Water and fertilizer use was reduced by ca. 25%. The increase in salinity of the DW was lower than calculated. Possible explanation for this phenomenon will be suggested. No phytopathogenic fungi were observed in the DW.
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