Evaluation Effect of Arbuscular Mycorrhiza Fungi, Biochar and Nitrogen Fertilizer on Important Root Characteristics and Grain Phosphorous Absorption of Wheat cv. Chamran

Plant nutrition with nitrogen, biochar, and bacteria leads to the improvement of soil quality, enhanced nutrient supply and facilitated root growth, all of which play a significant role in increasing agricultural productivity and improving crop yields. To investigate the yield reaction of Chamran cultivar wheat and root properties to mycorrhiza and biochar at different levels of nitrogen, an experiment was conducted during two crop years (2017-18) in the southwest of Iran. The experiment was designed as a factorial study using a randomized complete block design (RCBD) with four replications. The experimental factors included four levels of nitrogen (applied as urea with 46% nitrogen): 0, 50, 100, and 150kg.N.ha-1, two levels of Rhizophagus Irregularis inoculum (without and with application), and three levels of biochar: 0, 4, and 8 ton.ha-1. The results of the analysis of variance demonstrated significant effects of urea fertilizer, mycorrhiza and biochar on root length, root diameter and root colonization. In this research, the combined use of biochar and urea fertilizer in plants inoculated with mycorrhiza fungi showed better effects on all investigated traits compared to the use of biochar, nitrogen, and mycorrhiza alone. The highest values for root length, root diameter, root dry weight, root volume and root surface density were obtained from the application of 100 and 150 kg.N.ha-1 of nitrogen, along with 4 and 8 ton.ha-1 of biochar and mycorrhiza. In plants inoculated with mycorrhiza fungi at a biochar level of 4 ton.ha-1, there was a significant increase in root length (24%), root colonization rate (9%), root volume (22%) and root surface density (35%) compared to the control plants. This increase was attributed to the improved ability to absorb nutrients and enhance plant growth. According to the results of this research, the application of 100 kg.N.ha-1 of nitrogen and 4 ton.ha-1 of biochar in plants inoculated with mycorrhiza fungi played a vital and effective role in promoting wheat growth and increasing yield by improving the root system.