effect of different sources and rates of nitrogen fertilizer on the growth and biomass production of purslane (portulaca oleracea)

in order to evaluate the effect of different sources and rates of nitrogen the growth and biomass production of purslane, a randomized complete block design was conducted with three replications at the agricultural research farm of shahrekord university in 2012. fertilization treatments were consisted of control (no n amendment), 30 and 90 kg n ha-1in the form of urea fertilizer, 30 and 90 kg n ha-1 in the form of cow manure, 60 kg n ha-1 as urea fertilizer+ cow manure in 2:1, 1:1 and 1:2 ratios. the results showed that the greatest leaf area index was observed from the second cutting with integrated treatments and 90 kg n ha-1 as cow manure. in the first cutting, the greatest aboveground fresh weight (76.04 mg ha-1) was obtained in 90 kg n ha-1 as cow manure and it didn’t have a significant difference with that of the integrated treatment (1:1). in second cutting, aboveground fresh weight in integrated treatment (1:1) has a significant decline compared to that of the 90 kg n ha-1 as urea and/or cow manure. the leaf fresh weight from the first cutting was significantly greater than that of the second cutting. in general, the application of combined organic and chemical fertilizer (1:1) is effective in reducing nitrogen of single cutting of purslane production and future research should focus on top dress nitrogen for or increasing production of purslane second cutting treated with integrated fertilizer.