Korean Journal of Soil Science and Fertilizer ISSN:0367-6315(Print) 2288-2162(Online) 한국토양비료학회 학회지

Italian ryegrass (Lolium multiflorum Lam.) was cultivated in a field experiment, on sandy loam soil of the Saemangeum reclaimed land, under different sowing rates and N fertilizer levels to estimate the optimum N fertilizer requirement and the most suitable sowing rate for seed production. The experiment was conducted in a split-plot design with four replications. The main-plots were four sowing rates of 10, 20, 30, and 40 kg ha^-1 and sub-plots were five N fertilizer application rates of 0, 45, 90, 135, and 180 kg ha^-1. Harvest index decreased with increasing sowing and N fertilizer rate. The highest N use efficiency was obtained at 10 kg ha^-1 sowing rate and 45 - 90 kg ha^-1 N fertilizer application rates. Maximum seed yield of Italian ryegrass based on the regression curve of N fertilizer application level was 102 kg ha^-1 and was decreased with further N application. Economically, optimum rates of N application ranged from 70 to 101 kg ha^-1 depending on the sowing rate. Results from this experiment, could therefore inform producers of the best combination of sowing and N fertilizer rates needed to increase profitability of Italian ryegrass seed production alongside preventing N loss. However, further research will be necessary to elucidate on increasing seed quality and stability of cultivation under various environmental conditions.

Relation between IRG seed yield and nitrogen fertilization rates according to the regression curve in the Saemangeum reclaimed tidal land.