| dc.description.abstract | The effects of i) biophysical processes such as crop water uptake, and elements absorption and ii) chemical processes such as fertilizers dissolution and pH changes, on Ca2+, Mg2+ and K+ concentration in a recirculated nutrient solution of a greenhouse soilless rose crop (Rosa hybrida 'First Red'), were studied. Measurements of greenhouse microclimate variables, crop water uptake as well as pH, EC and Ca2+, Mg2+ and K+ concentration in nutrient solutions kept in storage tank or applied for crop fertigation, were carried out during autumn 2001. The results showed that variations of Ca2+ concentration in the nutrient solution were highly correlated to crop water uptake, crop Ca 2+ absorption, fertilizer dissolution and pH variation of the nutrient solution. The concentration of Mg2+ in the nutrient solution was correlated to EC of the solution. Equations for Ca2+, Mg 2+ and K+ concentrations prediction in the recycled nutrient solution were developed and calibrated. Validation gave satisfactory results. | en |
