Changes of crude protein content in Italian ryegrass influenced by spring nitrogen application

Abstract

During a three-year field experiment with Italian ryegrass forage in the first production year, a dynamics of crude protein content under the influence of different levels of spring nitrogen application was examined. Crude protein content decreased from stem elongation to flowering, but the changes had different intensity among years and treatments. The highest crude protein content during stem elongation was obtained using the highest nitrogen rate - 150 kg ha-1, even 100% higher than control treatment in 2006 and 2007. Differences among treatments decreased prior flowering, and all treatments hay yield was equable per year. The highest hay yield was reached in 2007. and it was influenced by spring nitrogen rates.

U trogodišnjim ispitivanjima krme italijanskog ljulja prve proizvodne godine praćena je dinamika sadržaja sirovih proteina pod uticajem različitih nivoa primenjenog azota u proleće. Prema očekivanju, sadržaj proteina je opadao od fenofaze vlatanja do cvetanja, ali su promene bile različitog intenziteta po godinama, kao i među tretmanima. Najveći sadržaj proteina pri vlatanju je bio pri najvećoj primenjenoj dozi azota od 150 kg ha-1, čak dvostruko veći u odnosu na kontrolu tokom 2006. i 2007. godine. Razlike među tretmanima prihrane su se smanjivale do cvetanja, a i prinos sena svih tretmana je bio ujednačen po pojedinim godinama. Najviši prinos sena je ostvaren u 2007. godini i povećavao se s rastućim dozama azota.