Effect of Rice Harvest Time on Growth Characteristics and Forage Productivity of Paddy Field Sown Italian Ryegrass Very Early Maturing Variety Early Maturing Variety ‘Greenfarm’ in Middle Region of Korea

Abstract

This study evaluated the growth characteristics and forage productivity of Italian ryegrass (Lolium multiflorum Lam.) in response to different rice harvest times after sowing the Italian ryegrass into stands of growing rice. The study was conducted over three consecutive years in Cheonan, located in central Korea. The extremely early maturing variety ‘Greenfarm’, was sown into an experimental paddy field in late September, before the rice harvest. The rice was harvested 10 (treatment 1), 20 (treatment 2), and 30 days (treatment 3) after sowing of the Italian ryegrass. The delay led to reduced number of tillers and plant length before winter, the winter survival rate, and the dry matter yield of the ‘Greenfarm’ plants. The pre-winter tiller number decreased by 32% and 52% in treatments 2 and 3, respectively, compared to treatment 1. The delay also reduced the winter survival rate by 8% (treatments 2 and 3), and the dry matter yield by 6% (treatment 2) and 7% (treatment 3). The Italian ryegrass heading date was different across the three years, but same for all three treatments in each year. There was little difference in the plant length at the time of the Italian ryegrass harvest in spring. These study findings suggest that when cultivating Italian ryegrass ‘Greenfarm’ by sowing it into stands of growing rice in paddy fields, the rice should be harvested as soon as possible after sowing to increase the forage productivity of this variety.