The current research aims at producing high kohlrabi knob yield with better quality traits using nano-chitosan-urea (versus urea) as a foliar spray in presence of mycorrhiza (AMF) as plant inoculants either solely or in combinations with each other. This investigation was carried out under the field conditions for two successive seasons (2015/2016 and 2016/2017). In this concern, microrrhizal inoculations were set up in the main plots whereas the foliar application of nano-urea was arranged in the sub-plots, comprising 5 treatments, i.e. spray with water, spray with ordinary urea at a rate of 1500 mg N L-1, spray with nano-urea at rates of 500 mg N L-1, 1000 mg N L-1, and 1500 mg N L-1 (designated U0, U1, U2, U3, and U4 respectively). Generally, spraying kohlrabi plants with different urea forms increased significantly the studied vegetative growth parameters as well as the yield quantity and quality traits in the following order U4>U1=U3>U2>U0. Likewise inoculating plants with AMF improved significantly the investigated growth parameters and yield components. It seems that inoculating plants with AMF did not affect significantly the above-mentioned growth parameters and yield components when plants sprayed with nano-chitosan-urea at a rate of 1500 mg N L-1. Thus, spraying plants with 1000 mg N L-1 as nano chitosan-urea together with plant inoculation with AMF (U3M1) is the recommended solution to cut off the inputs of chemical N fertilizers by 33.3% as this integrated treatments recorded comparable results with the ones attained for the application of the full dose of urea |
