Phosphorus effects on four lentil cultivars grown on alkaline Mediterranean soil

Lentil, a major grain legume in the Mediterranean region, grows under rainfed conditions, on alkaline, P-poor soils where cultivar and rhizosphere microbes may determine nutrient uptake and seed yield (SY). Four cultivars (‘Samos’, ‘Thessaly’, ‘Ikaria’, ‘Flip’) were grown under four P rates (0, 13.1, 26.2, 39.3 kg P ha −1 ) for two growing seasons to determine optimum P rates and traits determining SY. Rates up to 26.2 kg P ha −1 increased SY via increasing aboveground biomass at full bloom (DW), P concentration and number of pods/plant. Phosphorus affected alkaline phosphatase activity (ALPase) but not N 2 -fixation (%N dfa ), arbuscular mycorrhizal colonization (AMF) and acid phosphatase activity (APase). The early-maturing cv. ‘Flip’ outperformed escaping thermal and water stress during reproduction and allocating more biomass to reproduction, thus showing increased number of pods/plant and harvest index. ‘Flip’ had high N (41.2) and P (2.88 mg kg −1 ) concentrations, but low DW (289.7 g m −2 ), %N dfa (63.6%), AMF (39.6%) and ALPase (257.50 PN μg g −1 h −1 ). In the wetter and cooler growing season of 2015, SY (434.56 g m −2 ), yield components and AMF (49.4%) were higher, but ALPase (258.00 PN μg g −1 h −1 ) and APase (131.45 PN μg g −1 h −1 ) were lower than 2014. After removal of lentil straw at harvest, soil residual NO 3 -N and P-Olsen did not differ among cultivars, however, in the wetter 2015 both were higher compared to 2014. Thus, application of 26.2 P ha −1 and an early-maturing cultivar increased SY due to increased fruiting without compromising %N dfa , AMF and APase.