Effect of different nitrogen nutritional systems on yield and competition ability of fennel (Foeniculum vulgare Mill.) against mallow (Malva spp.)

A field experiment was conducted at agricultural college, Islamic Azad University, Shoushtar Branch in 2013-2014 to determine the effect of different nitrogen nutritional systems on yield and competition ability of fennel (Foeniculum vulgare Mill.) against mallow (Malva spp.). The treatments were consisted of N1 or control (Uniformly spreading urea fertilizer in the plot, 50% at planting time and 50% at stem elongation), N2 (Uniformly spreading 50% of urea fertilizer in the plot at planting time and spraying the other 50% of urea fertilizer at stem elongation on fennel foliage), N3 or cow manure, N4 or biofertilizer (Inoculation of fennel seeds with Azotobacter and Azospirillum), N5 or Integrated-1 (Cow manure uniformly spreading urea fertilizer in the plot at stem elongation), N6 or Integrated-2 (Cow manure inoculation of fennel seeds with Azotobacter and Azospirillum) were applied to the main plots. Three mallow densities consisting of: 1. MD1 (0 plant m-2), 2. MD2 (30 plant m-2) and 3. MD3 (60 plant m-2) were applied to subplots. Based on the results, N2, the treatment in which urea spraying were used, could produce the highest fennel yield in any mallow density with the average of 74.73 g m-2. Besides, this treatment succeeded to gain the highest AWC (Ability to Withstand Competition) and the lowest yield loss, however the highest crop equivalent (CE) was obtained from the integrated-1 treatment.