Effects of sowing date and sowing rate on yields and agronomic traits of grass pea intercropped with citrus

A consecutive two-year split-plot experiment was carried out to study the effects of different sowing date and sowing rate on fresh grass yield, seed production and agronomic traits of grass pea (Lathyrus sativus) intercropped with citrus. The results showed that sowing date and rate had significant effects on fresh grass yield and seed yield of grass pea (P<0.05), and the effect of sowing rate was greater than that of sowing date. Fresh grass yield and seed yield of grass pea decreased prominently as the sowing date postponed (P<0.05). The highest fresh grass yield (29 406.0 kg·ha-1) and seed yield (1 616.1 kg·ha-1) were obtained from sowing on 20th and 30th September, respectively. The agronomic traits including plant height, branch number per plant, nodule number per plant, ripening rate and thousand seed weight with the treatment sowing on September were better than those with the treatment sowing on October. Maximum yields occurred with an intermediate sowing rate of 45 kg·ha-1, and the effect of excessive sowing rate on agronomic traits and yields of fresh grass and seed were negative. In general, the most suitable sowing date was September and sowing rate was 45 kg·ha-1 for grass pea. intercropped with citrus in Xichong County, Sichuan Province