Morphological characteristics of the interspecies hybrid between Sorghum and Sudan grass under intensive nitrogen nutrition

Abstract

The object of this study was a two-year trial (2009 and 2010) regarding variability of morphological characteristics of species belonging to Sorghum genus, more specifically interspecies hybrid between sorghum and Sudan grass Siloking as affected by different applications of nitrogen. The following morphological characteristics were analysed: plant height, number of leaves, leaf ratio, stem ratio, and number of shoots. Samples were taken from the first cut when the effect of the applied nitrogen doses was the strongest. The results showed that increasing nitrogen quantities significantly affected the tested morphological characteristics, especially the intensity of tillering (increased number of secondary stems), number of the formed leaves, and ratio of leaf weight in the total above-ground biomass. The effect of applied nitrogen depended on the weather conditions, i.e. distribution of precipitation, so that plants reached maximum height when 105 kg N ha-1 was applied in the dry year and 180 kg N ha-1 in the wet year.

Predmet ove studije su dvogodišnja istraživanja (2009. i 2010.) varijabilnosti morfoloških osobina vrste roda Sorghum interspecies hibrida sirka i sudanske trave Siloking zavisno od upotrebljenih količina azota. Analizirane su morfološke osobine: visina biljka, broj listova, udeo lista, udeo stabla, broj izdanaka, a uzorci su uzimani iz prvog otkosa kada je i efekat upotrebljenih azotnih hraniva bio najveći. Rezultati su pokazali da rastuće količine azota značajno utiču na ispitivane morfološke osobine posebno na intenzitet bokorenja (povećanje broja sekundarnih stabala), broj formiranih listova, kao i udeo lisne mase u ukupnoj nadzemnoj biomasi. Efekat upotrebljenog azota zavisio je od vremenskih uslova, odnosno od rasporeda padavina, te su biljke dostigle najveću visinu u varijanti sa primenjenih 105 kg ha-1 azota u sušnoj, a u varijanti sa 180 kg ha-1 u vlažnoj godini.