alternative summer fallow cropping rotation in cold regions of iran

in order to adapt the results of previous researches on annual forage legumes in zanjan province to cold regions condition of iran, yield and quality characters of two outstanding species namely grass pea (lathyrus sativus l.) and common vetch (vicia sativa l.) were evaluated in summer fallow cultivation condition for one year in 28 locations over 11 provinces of the country. in the variance analysis of regions, although no significant difference was observed between grass pea (5.33 and 1.31 t ha-1) and common vetch (5.64 and 1.19 t ha-1) in terms of average dry matter and crude protein yields. for the reason of higher nitrogen accumulation in the above ground organ tissues of grass pea (3.96 gr/100gr dry matter), the average crude protein yield of this species was 10% higher than common vetch. range of average dry matter and protein yield was variable from 2.48 to 8/78 and 0.61 to 2.16 t ha-1 for grass pea and from 1.76 to 11.73 and 0.39 to 2.56 kg ha-1 for common vetch, respectively. in conclusion, planting of grass pea and common vetch was successfully confirmed as an alternative to summer fallow in cold regions of the country.