Effects of different irrigation programs and nitrogen levels on nitrogen concentration, uptake and utilisation in processing tomatoes (Lycopersicum esculentum)

A study was conducted to investigate the effect of different irrigation programs and nitrogen (N) levels on N concentration, uptake and utilisation by the processing tomato (Lycopersicum esculentum). The amount of water used was determined based on a screened class-A pan. Irrigation treatments consisted of 2 different irrigation intervals (I-5, 5 days; I-10, 10 days) and 3 plant-pan coefficients (K(cp)0.50, 0.50; K(cp)0.75, 0.75; K(cp)1.00, 1.00). Nitrogen treatments consisted of 3 N levels (N-0, 0 kg/ha; N-80, 80 kg/ha; N-160, 160 kg/ha). The irrigation interval, plant- pan coefficient and N fertiliser rate affected all parameters examined; however, theNfertiliser rate had the greatest impact. Nitrogen applications increased N concentrations in the leaf, tomato and vegetative biomass. Plant total N uptake and benefit rate from fertiliser was highest with the N-160, I-10 and K(cp)0.75 and K(cp)1.00 treatments. Results show that the N-160, I-10 and K(cp)0.75 treatments can be used for increasing plant N uptake and the benefit rate from fertiliser.