Growth analysis and yield of chickpea (Cicer arietinum L.) in relation to organic and inorganic nitrogen fertilization

Abstract

Growth analysis is still the most simple and precise method to evaluate the contribution of different ecological processes in plant development. In order to study the effects of organic and inorganic nitrogen on growth indices and yield components of chickpea (Cicer arietinum L.) cv. ILC 482, a spilt plot experiment based on randomized complete block design with four replications was conducted at the Experimental Farm of the Agriculture Faculty, University of Mohaghegh Ardabili, Ardebil, Iran. Experimental factors were comprised of inorganic nitrogen fertilizer at four levels (0, 50, 75 and 100 kg ha^–1 ) in the main plots applied in the urea form, and two levels of inoculation with Rhizobium bacteria (with and without inoculation) as sub plots. Application of N and Rhizobium inoculation continued to have positive effect on growth indices and yield components of chickpea. Lower levels of nitrogen application and non-inoculated plants showed less growth indices including total dry matter (TDM), leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR) and net assimilation rate (NAR) while the highest values of these indices were observed at the high levels of nitrogen application and inoculated plants. The highest plant height, number of primary and secondary branches, number of pods per plant and number of grains per plant were obtained from the highest level of nitrogen fertilizer (100 kg urea ha^–1 ) and Rhizobium inoculation. Application of 75 and 100 kg urea ha^–1 showed no significant difference in these traits. Moreover, the highest grain yield was recorded in the inoculated plants that were treated with 75 kg urea ha^–1 . The results indicated that the application of suitable amounts of nitrogen fertilizer (i. e. between 50 and 75 kg urea ha^–1 ) as a starter can be beneficial in improving growth, development and total yield of inoculated chickpea.