Effect of nitrogen fertilizer and compost on photosynthesis and growth of Virginia fanpetals <em>(Sida hermaphrodita</em> Rusby<em>)</em>

Abstract

As a perennial bioenergy crop Sida hermaphrodita can play an important role on marginal lands in the near future. In a controlled pot experiments the influence of various proportions of compost (10, 20, 30, 50%) and nitrogen fertilizer (100 kg N ha^–1) on biomass, plant height, and carbon allocation were investigated during the establishment phase. Furthermore, ecophysiological parameters (gas exchange, chlorophyll fluorescence, chlorophyll content,) were determined with non-destructive methods. The results of this experiment demonstrated that nitrogen fertilization and compost application has an overall positive effect on the overall growth performance. During the establishment phase, the fertilized plants reached a mean high of up to 127 cm (maximal plant height up to 168 cm). Photosynthesis was not influenced by the treatments and the mean net CO₂-exchange rates varied between 5,8 and 9,9 μmol m^–2 s^–1 and the electron transport rate between 34,5 and 53,9 μmol m^–2 s^–1. The application of compost and nitrogen for a better biomass production of Sida on marginal soils is possible, however the growth is limited in the first year with negative effects on the establishment of larger crops.