Effect of deficit irrigation, mycorrhiza and nitrogen nutrition system on some chemical properties of soil, oil content and biological yield of Purslane (Portulaca oleracea L.)

To investigate the effect of integrated nitrogen fertilizers (manure and urea) resources and mycorrhiza under water deficit stress on soil chemical properties and biological yield of Purslane, an experiment was conducted in Qom during 2015-2016 growing seasons. Treatments were arranged as a factorial split plot in a randomized complete block design with three replications. A factorial combination of two levels of irrigation (Irrigation at 50% and 70% of available water) and two treatments of mycorrhizal (inoculated and non-inoculated) were assigned as the main plots. The subplots consisted of six different sole and integrated combinations of fertilizers consisting of manure (sheep and chicken) and urea fertilizer (control, without fertilizers, 100% manure, 75% manure+25% urea, 50% manure+50% urea, 25% manure + 75% urea, and 100% urea). Results showed that water deficit stress increased oil content and decreased the electrical conductivity, total nitrogen, phosphorous, potassium of soil, mycorrhiza colonization (30.3% and 15.3 %( and biological yield (21.3% and 17.7 %( of purslane in first and second year, respectively. Also, manure in combination with urea fertilizer and mycorrhiza increased the biological yield (50% Manure+50% urea) and oil content (25% Manure+75% urea) in purslane leaf and reduced the consumption of urea fertilizer by modifying the negative effects of water deficit stress and increasing the availability of nutrients. Decomposition of halophyte purslane plant residues in soil increased the electrical conductivity and potassium content of the soil. Due to the key role of potassium in fertility and osmotic regulation of soil, it could produce acceptable biological yield in water stress conditions.