Effect of Biochar Application and Arbuscular Mycorrhizal Inoculation on Root Colonization and Soil Chemical Properties

Field experiment was carried out in 2013 and 2014 to investigate the effects of biochar application and arbuscular mycorrhizal (AM) inoculation on AM root colonization and selected soil chemical properties of two tomato genotypes. The experiment was laid out in a split-split plot arrangement with two tomato genotypes in the main plots, five rates of biochar applied in the sub plots and two levels of AMF inoculation in the sub-sub plots. Data were subjected to analysis of variance and significant means separated using Duncan's Multiple Range Test (P<0.05). The results indicated that mycorrhizal inoculation had little or no influence on AM root colonization, soil organic carbon, soil pH and available phosphorus. Application of 20 t ha-1 of biochar significantly increased (P< 0.05) soil pH and available P compared with the control while 10 t ha-1 and 15 t ha-1 of biochar produced higher organic carbon than other rates. In conclusion, biochar increased soil pH but was not high enough as to have detrimental effect on soil properties. It is, therefore, recommended that biochar with very strongly alkaline pH should only be used in soil with low pH for improvement of soil chemical and AM root colonization.