The experiment was conducted to determine the effects of nitrogen fertilizer levels on seed production of Italian ryegrass (Lolium multiflorum Lam.) in mountainous regions of Gangwon Province. The 'Green Call' variety of Italian ryegrass was sown in Pyeongchang, Gangwon in September 2021. The experiment consisted of three nitrogen application levels (100, 120, and 140 N kg/ha) and was arranged in a randomized complete block design with three replications. Harvest was carried out on June 28. The plant height was tallest in the 140 N kg/ha treatment, but the difference was not statistically significant. Lodging resistance, disease resistance and winter hardiness showed no significant differences among treatments, although severe lodging occurred in all plots. The average spike length was 54.77 cm, with no significant difference among treatments, while the number of seeds per spike was highest in the 100 N kg/ha treatment. Seed yield increased with higher nitrogen levels, with an average of 2,820 kg/ha (based on air-dry weight). The average dry matter content of seeds and straw was 56.70% and 38.80%, respectively, with no significant differences among treatments. The average dry matter yield of residual straw after seed harvest was 4,144 kg/ha, with the highest yield observed in the 120 N kg/ha treatment. Meanwhile, the feed value of the harvested straw did not differ significantly among treatments. The average contents of ADF, NDF, CP, IVDMD, and TDN were 43.04%, 70.63%, 8.65%, 52.77%, and 54.88%, respectively. In conclusion, the optimal nitrogen fertilization level for Italian ryegrass seed production through autumn sowing in the mountainous areas of Gangwon Province was found to be 120 N kg/ha.

This study was conducted to investigate the changes in seed productivity of Italian ryegrass (Lolium multiflorum Lam.) according to harvest time after heading in a mountainous area of Gangwon Province. The Italian ryegrass variety ‘Greencall’ was sown in the fall of 2021 in the Pyeongchang region of Gangwon and harvesting was performed every 10 days from 30 to 60 days after heading.. The treatments consisted of four seed harvest times (30, 40, 50, and 60 days after heading), arranged in a randomized complete block design with three replications. Plant height reached its maximum (93.0 cm) at 30 days after heading and subsequently declined with delayed harvest. Lodging resistance, disease resistance, and winter hardiness did not differ significantly among treatments, but lodging became more severe with time (rated 8∼9). Diseases were also more prevalent in the plots harvested 50 and 60 days after heading. The length of the spike was longest at 40 days after heading (54.33 cm), while the number of seeds per spike was lowest in the 60-day harvest plot (76 seeds/spike). The 1,000-seed weight was highest at 50 days after heading but decreased at 60 days. Seed dry matter content increased with delayed harvest, and dry seed yield increased up to 50 days after heading (3,742 kg/ha) but decreased at 60 days (2,442 kg/ha). The dry matter content of seed straw peaked at 50 days after heading, followed by a slight decline at 60 days, which was attributed to rainfall during the harvest period. Dry matter productivity was highest in the 50-day harvest plot. The feed value of seed straw decreased with delayed harvest, with an average Relative Feed Value (RFV) of 83. In conclusion, the optimal harvest time for fall-sown Italian ryegrass for seed production in the mountainous areas of Gangwon is 50 days after heading.

This study was conducted to investigate changes in the productivity of Italian ryegrass seeds according to the timing of harvest after heading in the southern region. The Italian ryegrass variety ‘Greencall’ was sown in Jinju, Gyeongsangnam-do, in the fall of 2022. Four harvest timings were tested (30, 40, 50, and 60 days after heading), with a randomized complete block design and three replicates. Sowing in the test plots took place on October 10, 2022, and harvesting was carried out from 30 days after heading on May 18 to 60 days. The plant height was the longest (99.1 cm) in the plot harvested 30 days after heading and decreased as the harvest was delayed. No significant differences were observed among treatments in terms of lodging resistance, disease resistance, and cold resistance. However, lodging severity increased over time after heading (7∼9). Disease incidence was also higher in plots harvested 50 and 60 days after heading. The length of the spike was shortest (38.76 cm) in the plot harvested 50 days after heading, and the number of seeds per spike was the lowest (42 seeds/spike) in the plot harvested 60 days after heading. The dry matter content of seeds increased with the delay in harvest, while dry matter yield decreased, with the lowest yield observed in the plot harvested 40 days after heading (3,031 kg/ha, p<0.05). The dry matter content of seed straw was highest at 75.73% in the plot harvested 50 days after heading and dropped to 34.99% 60 days after heading due to rainfall. The dry matter productivity of the seed straw was the lowest in the plot harvested 40 days after heading. The feed value of the seed straw also decreased with delayed harvest, with an average RFV (Relative Feed Value) of 91. In conclusion, the optimal harvest timing for fall-sown Italian ryegrass intended for seed production in the southern region appears to be 30 days after heading.