Calcium, magnesium and potassium concentrations prediction in a recirculated nutrient solution of a greenhouse soilless rose crop

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.