A study on optimized sowing date of seasonal cultivation alfalfa along Huai River region

In order to explore the optimum sowing date of alfalfa (Madicago sativa) in seasonal planting system in Huai River region, effects of autumnal sowing date on growth characteristics and forage yield were investigated in field experiments at Funan and Huaian from September 2009 to June 2011. The results showed that in the seasonal planting system (autumn sowing and twicecutting in next spring), growth characters and forage yield reduced gradually with the autumn sowing date delayed. The average plant height at the early bloom stage in the first cutting was 91.91 cm for the sowing date of September 6, which was near double that of October 22 (42.90 cm) on the Huaian experiment site. Accordingly, the forage yield on the sowing date of September 6 was the highest, 4.37 kgm-2 in fresh weight and 1.05 kgm-2 in dry matter. Forage yield was positively correlated (P0.01) to plant height, shoot number and dry weight per plant (P0.01). According to the path analysis results, plant height and dry weight per plant were the most primal factors for alfalfa forage yield. The results implied that the earlysowing in autumn improved the dry matter yield of alfalfa by increasing the plant height and dry weight per plant. The optimum sowing date of alfalfa for seasonal cultivation along Huai River region should be in September to early October.