Salinity threshold value of Quinoa (Chenopodium Quinoa ‎Willd.) at ‎various growth stages and the appropriate ‎irrigation method by saline ‎water

Salinity is one of the major agricultural problems in arid and ?semi-arid regions. Considering the variation of plant’s ?sensitivity to salinity during growth, a greenhouse study with completely randomized design? was conducted to determine the relative salinity tolerance of Quinoa (Chenopodium quinoa Willd.) at different growth stages from seedling establishment to maturity (establishment, flowering and seed filling) by evaluating the Salinity Threshold Value (STV). Eight levels of EC_i (i.e., Non-saline, 2, 4, 8, 12, 15, 20, 25 dSm^?1) with four replications and five levels (i.e., Non-saline, 10, 15, 20, 25 dSm^?1) with three triplications were applied at first and two last growth stages, respectively. A ?comparison was performed on some growth and yield parameters of plants irrigated by considering STV (T) and ?plants irrigated permanently by mentioned salinity levels regardless of STV (P) to choose ?which method (P or T) is better at each salinity level. The STV was ?evaluated 8, 20 and 15 dSm^?1 at each growth stage, respectively. Seedling of Quinoa was more sensitive to salinity than the mature plant. Therefore, after establishment Quinoa has the ?feasibility of irrigation by high-saline waters. The (P) ?method was suitable only if the freshwater was available during all growth period of the plant; otherwise at higher salinities irrigation should be performed by considering STV (T method) to minimize the intensity of growth and yield reduction and to prevent yield loss at very high salinities. To achieve this, if high-saline water is available it’s possible to ?use plant propagation techniques or cultivating Quinoa simultaneously with seasonal rainfall.?     

Stabilization of lead in two artificial contaminated calcareous soils using stabilized nanoscale zero-valent iron particles with/without chelating agents

Nanoscale zero-valent iron particles (nZVIs) have been used as the stabilizing materials for remediation of heavy metals (HMs). The usage of nZVIs in the presence of oxygen is a challenging task. When this material comes in contact to air, immediately oxide formation takes place. Thus, preparation of air-stable nZVIs is necessary for successful remediation process. Therefore, the present study has attempted to evaluate the effects of three kinds of synthesized nZVIs, including nZVI_EDTA (stabilized by ethylenediaminetetraacetic acid), nZVI_DTPA (stabilized by diethylenetriamine pentacetic acid) and nZVI (without chelating agent), to determine their ability to stabilize lead (Pb) in two Pb-spiked soils. Pb-spiked soils were separately incubated with additives at the rates of 0.5% and 2% (W/W) for 90 days. The efficacy of nZVIs was evaluated by desorption kinetic and chemical fractionation experiments. According to the results, addition of nZVI_EDTA, nZVI_DTPA and nZVI significantly decreased Pb release by 70.1–86.4%, 56.5–70.6% and 24.3–49.2%, respectively. Among the three kinds of nZVIs, nZVI_EDTA was the most effective treatment in decreasing desorption and mobility factor of Pb. In practice, all three kinds of nZVIs are effective in Pb immobilization, while application of nZVI_EDTA at the rate of 2% was the best treatment to immobilize Pb in polluted soils.