ISHS Acta Horticulturae 792: V International Symposium on Irrigation of Horticultural Crops
EFFECT OF DIFFERENT COVERS ON GROWTH AND NITRATE ACCUMULATION IN ICEBERG LETTUCE (LACTUCA SATIVA L.) AND ESCAROLE (CICHORIUM ENDIVIA L.) |
| Authors: | E.M. Suarez-Rey, T. Soriano, F.M. Quesada, M.I. Morales, N. Castilla |
| Keywords: | plastic mulch, floating cover, nitrate, leaching, evapotranspiration |
| Abstract:
Extensive horticulture has a long history in the Granada Vega in southern Spain. Traditional crops include tobacco, potato, corn and asparagus, usually watered by surface irrigation methods and heavily fertilized. The necessity to reduce aquifer contamination by fertilizers, the social pressure against tobacco with the decrease in European subsidies to this crop and the search for crop systems to maximize farmers income make it necessary to propose alternatives to traditional crop rotations. A study was conducted to establish a recommendation system for water and nitrogen management in horticultural rotations. Two crops, iceberg lettuce (spring season) and escarole (fall season), under three different crop management systems (plastic mulch, plastic mulch combined with floating cover and control) were studied in Granada in 2005. Evapotranspiration (ET), biomass production, leaf area, nutrient concentration in plant organs and nitrate content in drainage water were monitored. For both crops, the control treatment had higher ET values than the protected treatments. Enhanced leaf development under the floating cover compensated for the lower evaporative demand giving similar values of crop ET for both protected treatments. Protected lettuces (mulched and mulched with floating cover) reached their commercial fresh weight one week before the control. The results of this study suggest that the amount of N fertilizer applied to the protected treatments in lettuce could be lower than the recommended values for the control treatment to reduce nitrate concentration in the groundwater without negatively affecting production. Only the protected treatments in escarole were commercially viable in our climatic conditions. | |
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