Effects of seed mixture and N fertilization on nitrate content of grass- legume swards

摘要

A trial was set up at the Institute for Animal Husbandry, Belgrade-Zemun, as a two-factor, randomized block design and conducted on four occasions during 2003 and 2004. The first factor in the investigations was sward type: pure lucerne (Medicago saliva L.) and three mixtures of lucerne (mixture I, with cocksfoot (Dactylis glomerata L.), mixture II, with cocksfoot and tall fescue (Festuca arundinacea Schreb.) and mixture III with cocksfoot, tall fescue and sainfoin (Onobrychis viciifolia Scop.).The second factor was fertilization, with four different amounts of N (0, 70, 140 and 210 kg N ha~(-1)). Fertilization was carried out in two terms during a single year. The content of NO_3~- in herbage of grass-legume swards in both years was largely dependent on fertilization and the interaction of the two factors, whereas the sward type had no statistical significance. Herbage nitrate content increased with an increase in the amount of added nitrogen. Treatments with 210 kg N ha~(-1) resulted in a considerably higher concentration of NCV compared with the other treatments.