Effect of humic acid and sulfur application with Thiobacillus bacteria on morphological characteristics of Magnolia

Iran is one of the arid and semi-arid regions of the world. Crop production at optimal yield levels in calcareous soils and high pH soils has always been problematic. An important part of these problems arises because in these soils, due to their high pH and high concentration of calcium ions, nutrients that are pH-dependent can become insoluble and unusable for plants. Adding these elements to the soil through chemical fertilizers will cause environmental problems and pollution. Therefore, in this study, the effect of sulfur combined with Thiobacillus and humic acid bacteria on soil pH and increase in soil organic matter was achieved. For this purpose, a factorial experiment was conducted in a completely randomized block design with 4 treatments in 3 replications and 2 replicates in each tree. Experimental treatments included garden soil, humic acid of organic origin (coal), and humic acid of plant origin (sugar beet) each at 3500 g / ha and 500 g of thiobacillus with 25 kg of sulfur per hectare. The traits tested were leaf dry weight, leaf area index, leaf number and stem length. Based on the results of this study, all morphological characteristics of magnolia trees were significantly improved compared to calcareous soil. It was also observed that thiobacillus treatment with sulfur was the most effective treatment for magnolia tree growth compared to other treatments