A study on Prince Edward Island was initiated to assess the impact of organic fertility amendment rate and timing treatments and deflowering on the growth, yield, and berry size and soluble solids, and plant and soil available nutrients of blackcurrants (Ribes nigrum L cv. Titania.). Plants at the site with lower leaf P and K showed lower growth and yield (492-2540 kg ha-1) than the other site (3935-5016 kg ha-1No significant differences were found in final size or 2011 yield at the site with larger bushes, while at the other site the medium spring fertility treatment gave the greatest growth and yield, followed by the high spring fertility treatment. Deflowering increased yield but not growth at the site with recommended ranges of leaf P and K; at the site with P and K deficiencies, growth increased in 2010 and 2011. There was no interaction between deflowering and amendment timing.

In situ measurements of soil nitrogen dynamics is a potential method for evaluating the health of constructed wetlands following oil sands mining. The objective of this study is to measure and compare the soil nitrogen availability of a reclaimed fen (Sandhill fen) with a nutrient-rich reference fen (Poplar fen) and a nutrient-poor reference fen (Pauciflora fen) in the Athabasca oil sands region of northern Alberta. Total Nitrogen (TN), Nitrate (NO3-) and Ammonium (NH4+) supply rates were determined along wetland hillslope transects using Western Ag Innovations Plant Root Simulator (PRSTM) probes at all three sites in 2014. Net N mineralization, net nitrification and net ammonification were determined simultaneously using the buried polyethylene bag sampling method. Overall, TN supply rates were greatest at the poor fen and least at the constructed Sandhill fen. In contrast, mineralization was greatest at the rich fen but again least at the Sandhill fen. Mineralization at the Sandhill fen was controlled evenly by ammonification and nitrification, whereas the two natural sites were controlled by ammonification. Relatively low N supply rates and mineralization at the Sandhill fen were likely due to lower soil organic matter and limited soil moisture in these newly constructed substrates. Spatial differences along the hillslopes also varied among sites. The Sandhill fen had higher TN supply rates at the upslope positions but no significant differences in net N mineralization rates along the hillslopes. The rich fen also had higher TN supply rates at the upslope but greatest mineralization rates downslope. These results highlight the importance of N storage and transport processes and offer insight into the N status of a constructed fen. / Thesis / Master of Science (MSc)