Monitoring of Urea Concentration in Drip Fertirrigation

Abstract

Topographic slope negatively affects irrigation uniformity when associated with fertilizer application via irrigation water. The concentration of the injection solution at the emitter outlet can adversely affect the uniformity of the drip system. Therefore, the objective was to evaluate the ideal concentration that maintains high levels of uniformity for the nitrogen solution, applied via fertigation, in different concentrations of the injection solution, with different levels of slope. The experiment was conducted out in a protected environment at the Laboratory of Irrigation and Fertigation (LIF), Cascavel-, PR. The experimental design was conducted out in randomized blocks in a 4x3 factorial scheme, in which the concentration of fertilizer was evaluated at three levels of slope: with plots divided into two factors, the main factor being the type of water, represented by four plots: clean water (from artesian well) and water with nitrogen fertilizer, urea (44% N) in three concentrations (2 g L-1; 4 g L-1; 6 g L-1); and as a second factor, the slope levels, represented by the subplot: level (0%), uphill of 2% and downhill of 2%. The addition of 4 g L-1 urea concentration affected the uniformity at all slope levels, presenting values for UD< 90%, observed in the Shewhart control chart. The increase in urea concentration by 6 g L-¹ affected the distribution uniformity of the system in level, with values for UD< 70%. The system was able to apply concentrations up to 2 g L-1 in level, presenting Cpl = 2.86.