Species, Cultivar and Seasonal Effects on Nodulation and Nitrogen Utilization of Spring Mediterranean Grain Legumes

Information on nitrogen economy of grain legumes during seed filling is critical for their sustainable cultivation in rainfed agroecosystems, but a comparable assessment of different legumes under the same growth conditions is lacking. The purpose of this study was to examine species, cultivar and seasonal effects on nodulation and nitrogen accumulation, remobilization, and utilization. Five grain legumes [common vetch ( Vicia sativa L.), red pea ( Lathyrus cicera L.), lentil ( Lens culinaris Medik), chickpea ( Cicer arietinum L.), and field pea ( Pisum sativum L.)], each represented by two cultivars, were grown for two years in a semiarid Mediterranean environment. There were considerable environmentally induced differences among species in nodulation, with chickpea maintaining a sufficient number of nodules (16 nodules plant ‒1 ) and nodule dry weight (57 mg plant ‒1 ) even in the drier year (2015). Pre-podding nitrogen accumulation varied among species, particularly in the wetter year (2014). Nitrogen translocation from vegetative parts to seeds was correlated with pre-podding nitrogen accumulation (r = 0.99, P < 0.01 in 2014 and r = 0.98, P < 0.01 in 2015). Interspecific differences in nitrogen translocation efficiency were enlarged under drought, with red pea exhibiting the highest (84%) and lentil the lowest value (72%). Chickpea produced the highest seed nitrogen accumulation in both years and had the highest nitrogen utilization efficiency (21 kg seeds per kg N) the drier year. Nitrogen utilization efficiency was positively correlated with nitrogen harvest index and negatively with nitrogen concentration in vegetative parts at maturity. Most trait differences were less evident within species than between species. Overall, chickpea was found to outperform other legumes in semiarid Mediterranean conditions in terms of nitrogen accumulation in seeds and nitrogen utilization efficiency.