Response of chickpea's yield and yield components to double inoculation with mycorrhiza and rhizobium under split application of nitrogen

The utilization of advantageous microorganisms as a biofertilizer has gained significant importance in the agricultural industry due to their potential contribution to food safety and the sustainable cultivation of crops. To evaluate the effect of nitrogen (N) fertilizer and co-inoculation with arbuscular mycorrhiza and rhizobium on the yield and yield component of chickpea (Cicer arietinum L.), a 2-year field experiment was conducted in 2020–2021 at the Agricultural Research Station of Ferdowsi University of Mashhad, Iran. The experiment was designed as a randomized block trial in factorial design with three replicates. The treatments included two levels of inoculation (noninoculated and inoculated with rhizobium and mycorrhiza) and application of different levels of N fertilizer (0, 25, or 50 kg ha⁻¹) at three growth stages (sowing, flowering, pod filling) as follows; F0 (0,0,0), F1 (25,0,0), F2 (25,25,0), F3 (25,25,25), F4 (50,0,0), F5 (50,50,0) and F6 (50,50,50), respectively. The results showed that seed inoculation and split N fertilization significantly increased yield and yield components in chickpea (Cicer arietinum L.). Seed inoculation showed the highest values for all traits studied compared to the noninoculated treatments. Moreover, among the fertilizer treatments, the highest values for plant height (41.8 cm), number of branches (9.1), number of grains per plant (17.8) and 100-grain weight (30.4 g) from F6 through the F3 treatment, were statistically similar. The results show that the effect of inoculation is more significant when a lower amount of N fertilizer is applied. Due to the health and environmental problems associated with chemical fertilizers, double inoculation and split application of N fertilizers at lower doses can be recommended.