Studies on the Grassland Managementin Late-Autumn and Early-Spring II. Effect of fertilization application time in spring on growth, crude protein content and yield of grasses for grazing

월동전후 초지관리에 관한 연구 II. 봄철 방목이용초지에서 이른봄 추비시용시기가 목초의 생육과 조단백질함량 및 수량에 미치는 영향

This field experiment was carried out to determine the effects of fertilizer application time in spring on the growth, crude protein (CP) content and dry matter (DM) yield of gasses for grazing Application times of fertilizer were on March 10, March 20, March 30, April 9 and April 19, and control (non-fertilized) plot was involved. All fertilized plots were also treated with single and compound fertilizer. The first harvesting date for grazing was on April 30, and the regrowth soiling yield was investigated on June 9, 1988. In all fertilized plots, the growth, DM yield, CP, CP yield and nigrogen recovery of grasses were significantly increased compared with control, especially on the plot of March 30. The regrowth yield on March 30, April 9 and April 19 were shghtly hig!!a than those of the others. And there were not significant differences of grass growth, CP content, and DM yield between single-and compound fertilizer treatment. On March 30 which was the best time of fertilizer application in spring, the accumulated temperature was 116.6^{\circ}C.$ and the subsoil temperature at 10 cm depth was 8.1 - 8.6^{\circ}C.$. Considering the average meteorological condition in Suwon area, the optimum application time of spring fertilizer for grazing may be recommended on March 30-April 3 (accumulated temp.; 100-125^{\circ}C.$, subsoil temp.; 8-9^{\circ}C.$).