A study on sowing techniques of Medicago sativa in Longdong dry land

A study on sowing date, sowing density and sowing methods of the newly introduced alfalfa (Medicago sativa) varieties was carried on in arid and semiarid areas of Longdong during last 2-3 years. The results show that: 1) in yield, the autumn sowing gave the best performance with the average yield of 0.772 kg·m-1 and the summer sowing followed with the average yield of 0.700 kg·m-1. Compared with spring sowing, the yields of autumn and summer sowing increased by 10.29%（P＜0.05） and 4.79% （P＜0.05）, respectively. Compared with Longdong alfalfa, the yields of Alfaking, Sanditi, Goldenmpress and Gannong No.1 increased by 13.08%（P＜0.05）, 3.54%, 2.22% and 7.53%（P＜0.05）, respectively. 2) In the sowing density, there were higher yields at 720 and 480 plants·m-2, which had significant differences（P＜0.05） comparing with the density of 960 and 240 plants·m-2, with the average yield of 0.72 and 0.66 kg·m-1, respectively. Among the tested varieties, Alfaking and Goldenmpress had higher yields than than Phabulous（P＜0.05）. 3) In sowing methods, there were no significant difference on germination rate, overwintering rate and hay yield bewteen plastic film beside furrow and ordinary furrow sowing, and there was no obvious difference compared with the mechanical drilling. 4) Overall, different sowing date, sowing density, sowing methods and varieties had great influences on alfalfa growth and yields in the first to second growth years, and no significant effect at the third year. According to the trial, the alfalfa should be sown in autumn by ordinary furrow sowing method and the optimum density was 480 to 720 plants·m-2 (15.0-22.5 kg·ha-1). Alfaking showed significant yield increases in the experiments and should be aggressively promoted in Longdong arid and semiarid areas.