Correlation between plant available nitrogen content of the soil and nitrate content in hop (Humulus lupulus L.) leaves before the second top dressing and their impact on hop yield

Gnojenje z dušikom (N) vpliva na količino in kakovost pridelka hmelja sorte Aurora. Namen je preveriti različne odmerke N v obliki KAN-a (27 %) za prvo dognojevanje (A sklop 0 kg N/ha, B sklop 25 kg N/ha, C sklop 50 kg N/ha, D sklop 75 in E sklop 100 kg N/ha) in njihov vpliv na vsebnost Nmin v tleh in nitratnega N v listih hmelja v času tik pred drugim dognojevanjem hmelja sorte Aurora. Po izvedenih analizah so za drugo dognojevanje dodani različni odmerki N (0, 25, 50, 75, in 100 kg N/ha) v vseh sklopih, za tretje dognojevanje pa je odmerek N enak za vse parcele (50 kg N/ha). V obdobju tehnološke zrelosti je izvrednoten pridelek storžkov in analizirana vsebnost nitratov ter vsebnost alfa-kislin v storžkih. Rezultati kažejo pozitivne trende korelacijskih povezav med Nmin v tleh in vsebnostjo nitrata v listih hmelja pred drugim dognojevanjem. V poskusnih razmerah pa Nmin v tleh in vsebnost nitratov v listih hmelja pred drugim dognojevanjem ne kaže vpliva na pridelek storžkov. Obstaja pa tudi šibka povezava med skupno količino dodanega dušika v treh odmerkih in količino pridelka.Fertilization with nitrogen (N) has an impact on quantity and quality of hop yield of variety Aurora. Main aim of this thesis was testing different amounts of N in the form of KAN fertilizer (27 % N) on the yield of variety Aurora. Test was done on different parts of soil with different amounts of fertilizer for the first fertilization (on the part A 0 kg N/ha, on the part B 25 kg N/ha, on the part C 50 kg N/ha, on the part D 75 kg N/ha and on the part E 100 kg N/ha). Than was also tested fertilizer’s impact on the content of Nmin in the soil and nitrates in the leaves before the second fertilization using different rates of N (0, 25, 50, 75, 100 kg N/ha). For the third fertilization we used 50 kg N/ha. At the time when the sort Aurora was technically ripped, we weighed the hop cones, analysed the amount of nitrates and alpha-acids in them. Analyses has shown the positive trends of correlation between Nmin in the soil and amount of nitrates in the leaves before second fertilization. We assume that because of growth circumstances the amount of Nmin in the soil and nitrates in the leaves did not have any impact on the hop production. Even correlation between amount of Nmin in the soil before second fertilization and amount nitrates in the hop leaves in the time before second fertilization and the hop harvest is weak, such as correlation between yield and total nitrogen rates