Lentil Performance in Response to Weather, No-Till Duration, and Nitrogen in Saskatchewan

Increased soil N in no-till (NT) systems can interfere with biological dinitrogen fixation (BNF), stimulate vegetative biomass, and affect harvest index (HI) and yield of lentil (Lens culinaris L.). In the black soils of Saskatchewan, the effects of short-term (5-7 yr: ST) and long-term (28-30 yr: LT) NT practices on lentil were investigated in two experiments from 2006 to 2008. One trial tested the effects of NT duration on plant N and yield of five cultivars; the second examined the response of a late-maturing cultivar to NT duration at four rates of N fertilization. In both studies, average grain yield in 2006 and 2007 (warm seasons) was 2196 greater than in 2008 (cool season), although total rainfall and plant N content was similar in 2007 and 2008. Average soil available N over the years was 23% greater in LT than ST, but the cultivars had 33% less N and 28% less yield in LT than ST in a dry year (2006), and similar performance in LT and ST in the wet years (2007 and 2008). The 60 kg N ha(-1) treatment in the second trial diminished the yield difference between LT and ST in 2006. The only BNF measurement in 2008 showed that the cultivars fixed 10% less atmospheric N-2 in LT than ST in this year. Overall, cool and wet growing conditions stimulate vegetative biomass and lower HI and yield of lentil, whereas a possible reduction of lentil BNF in NT systems is less likely to affect lentil yield.