Nitrogen Partitioning in Lentil Under Varying N Fertility Regimes.

Lentil seed yield is affected by both biomass and harvest index (HI) and because of the association of plant nitrogen (N) with HI and yield any effort to improve yield selection of cultivars should consider biomass and N distribution in the plant. The application of three fertility treatments (inoculant, 50kg Nha^-1 and an untreated control) in Saskatchewan altered the weight and N content of lentil leaf, stem and pod materials. As available N increased in the soil with fertilizer or rhizobia, leaf, stem and pod mass increased compared to the control. Average pod weight was 1.61^a, 1.59^a and 1.37^b g plant^-1 for inoculated, fertilized and the control plots, respectively. Fertilizer N produced more stem mass than the inoculated and control plots, although stem N content was similar for the treated plots. These results, along with lower pod N concentration (%) in the fertilized treatment, showed that higher available N at the beginning of the season in fertilized plots could produce more biomass with lower N concentration. Influence of N treatment on dry matter allocation among plant organs indicated the importance of N on dry matter distribution among the lentil organs. During the growing seasons (2006, 2007), the average leaf weight was increased by time but total leaf N was significantly higher in the mid-pod stage compared with both maturity and vegetative growth stages. The reason is either leaf loss in final stages of growth or N remobilization from leaves.  The stems did not lose weight or N during pod formation instead pod weight and pod N content were increased over time.