Agronomic traits of tomato at different ammonium nitrate concentrations in the nutrient solution

Cilj istraživanja bio je utvrditi agronomska svojstva dva kultivara rajčice u hidroponskom uzgoju na kamenoj vuni, pri standardnoj i 50 % povećanoj koncentraciji amonijevog nitrata u hranjivoj otopini. Tijekom plodonošenja brani su plodovi s 8 grozdova prikraćenih na 5 plodova. Utvrđeni su masa i prinos tržnih plodova po grozdu i ukupno, broj tržnih i netržnih plodova po m2 te udio netržnih plodova sa simptomima vršne truleži. Po m2 ubrano je od 99,2 do 112,0 tržnih plodova, a udio netržnih plodova je iznosio od 5,42 do 8,38 %. U interakciji sa standardnom otopinom oba kultivara su na svim grozdovima razvila krupnije plodove. Tijekom plodonošenja razvili su plodove podjednake krupnoće (od 205 do 207 g). Najkrupnije plodove, mase 220 g razvio je kultivar Buran uz primjenu standardne hranjive otopine. Kultivar Buran je ostvario 7,24 % viši ukupni tržni prinos od kultivara Belle (21,40 kg/m2) dok je primjenom standardne hranjive otopine ostvaren 13,79 % viši prinos u odnosu na otopinu s povećanom koncentracijom NH4NO3 (20,74 kg/m2). Najviši ukupni tržni prinos ostvario je kultivar Buran uz primjenu standardne hranjive otopine (24,55 kg/m2), a najniži kultivar Belle uz primjenu hranjive otopine s povećanom koncentracijom amonijevog nitrata (20,13 kg/m2). Zbog razvijenih krupnijih plodova i višeg ostvarenog prinosa te manjeg udjela netržnih plodova prilikom primjene standardne otopine za krupnoplodne kultivare se ne preporučuje povećanje koncentracije amonijevog nitrata u hranjivoj otopini.The aim of this research was to determine the agronomic traits of two tomato cultivars grown in soilless culture on rockwool, fertigated with the standard and 50 % increased ammonium nitrate concentration in the nutrient solution. During the harvest period, fruits from 8 clusters shortened to 5 fruits were harvested. Fruit weight and marketable yield per cluster and in total, the number of marketable and unmarketable fruits per m2 and share of unmarketable fruits with blossom-end rot symptoms were determined. Between 99.2 and 112.0 marketable fruits was harvested per m2, while the share of unmarketable fruits varied from 5.42 to 8.38 %. Both cultivars developed larger fruits in all clusters when they were fertigated with the standard nutrient solution. During the harvest period they developed fruits which weighed between 205 to 207 g, respectively. Cv. ‘Buran’ fertigated with the standard nutrient solution has developed the highest fruit weight (220 g). The same cultivar has achieved a 7.24 % higher marketable yield than cultivar Belle (21.40 kg/m2). Fertigation with the standard nutrient solution resulted in 13.79% higher yield compared to the solution with higher NH4NO3 concentration (20.74 kg/m2). The highest total marketable yield (24.55 kg/m2) was achieved by cv ‘Buran’ fertigated with the standard nutrient solution, while the lowest (20.13 kg/m2) was achieved by cv. ‘Belle’ fertigated with nutrient solution that contained higher concentration of ammonium nitrate. Because of the higher fruit weight and marketable yield, and also the lower unmarketable fruits share was achieved with the standard nutrient solution, increasing the ammonium nitrate concentration for beefsteak cultivars is not recommended