Performance of annual legume green manure crops at Saskatoon

Non-Peer ReviewedFour annual legumes, lentil (Lens culinaris cv. 'NEL-481'), field pea (Pisum sativum cv. 'Trapper'), faba bean (Vicia faba cv. 'Outlook'), Tangier flatpea (Lathyrus tingitanus cv. 'Tinga'), and one perennial, alfalfa (Medicago sativa cv. 'Moapa') were compared over three growing seasons for their suitability as annual green manure crops grown in the fallow year of a wheat-fallow rotation. As nitrogen-fixation usually declines after seed set, crop growth was stopped by cultivation or desiccation during early pod filling. This terminated further use of available soil moisture, conserving it for the following grain crop. Mean seasonal nitrogen fixation ranged from 2 to 40 kg/ha. However, the mean total nitrogen in the top growth at plow down, ranged from 15 to 114 kg/ha. The measured nitrogen fixation accounted for 13 to 42 % of the above ground nitrogen. There was little difference in water use among the legume crops