JWSS - Journal of Water and Soil Science

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In order to study the effect of various amounts of nitrogen (N) and Iranian natural zeolite on the quantitative and qualitative forage yield of winter canola (Brassica napus L.) in light soil, a field experiment was conducted on research farm of Tarbiat Modares University, Tehran, during 2006-2007. Treatments were arranged in the form of RCBD with 3 replications. The experimental treatments were based on factorial various levels of zeolite (0, 3, 6 and 9 t.ha^-1) and nitrogen (90, 180 and 270 kg ha^-1) in urea form. Seeds of canola (Brassica napus L. cv. Okapi) were sown on October 2, and fresh forage was harvested at the time of silique formation (170 DAP). Results showed that the effect of N and zeolite on forage quantitative attributes including biomass, leaf and stem dry weight and leaf area index were statistically significant. In addition, forage qualitative traits including crude protein percentage and calcium percentage in plant mass were significantly affected by N and zeolite. Increasing application of N fertilizer caused increase in N leaching, and with increasing zeolite application, N leaching reduced. The interaction of two factors for all parameters was not significant. The most increasing effects on forage yield and quality were gained using 270 kg N ha^-1 in combination with 9 t. Zeolite ha^-1. More detailed studies are strongly recommended to investigate the effects of integrated application of chemical fertilizer and natural zeolite.

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The objective of this study was to investigate the effect of potassium zeolite on ammonium ion sorption and retention in a saturated sandy loam soil in laboratory conditions with four treatments of 0, 2, 4 and 8 g zeolite per kg soil. The study was conducted as a completely randomized block design. Simulation of ammonium ion leaching was performed using Hydrus-1D model in the soil columns. Ammonium nitrate fertilizer with a concentration of 10g per liter was added to soil columns and then leaching was performed. Results of the study showed that adding potassium zeolite to soil causes reduction in the mobility of ammonium ion and increase in the retention of ammonium in soil. Also, the results of the Convection- Dispersion (CDE) and Mobile- Immobile (MIM) models investigation indicated that the ammonium ion sorption by soil followed the Freundlich isotherm model. Absorption isotherms and diffusion and dispersion coefficients were determined using the inverse modeling technique. Based on the results obtained, optimized values of Freundlich isotherm of model were much less than the observed amounts. This shows that the Hydrus-1D model is not able to predict the ammonium ion mobility in soil macropores, and as a result, reduces greatly the amount of absorption parameters. Because the soil was disturbed, CDE model estimation was closer to the observed values in all four treatments

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Nitrogen (N) loss from irrigated cropland, particularly sandy soils, significantly contributes to nitrate contamination in surface and groundwater and increases N applications to crops. This is because negatively charged nitrate normally does not have much affinity to soil particles. To retard the movement of nitrate, materials should have high affinity for anions, which most naturally occurring minerals do not have. The cation-exchange properties of natural zeolites can be exploited to modify their surface chemistries so that other classes of compounds, particularly anions and non-polar organics are retained. In this study, the ability to remove nitrate from aqueous solutions with different Cl- concentrations using Iranian zeolite (Semnan) modified by hexadecyltrimethylammonium bromide in millimeter and nanometer particle sizes was determined and the equilibrium isotherms were characterized. The nitrate release as affected by time and ionic strength was also evaluated. It was demonstrated that SMZ is capable of adsorbing more than 60 mmol kg-1 and 80 mmol kg-1 nitrate in millimeter and nanometer sizes, respectively, and adsorbed nitrate can be easily released under different ionic strengths. The millimeter and nanometer-sized SMZ showed 26.7% to 82.3% and 37.8% to 85.5% nitrate removal efficiency, respectively. The average of nitrate released by millimeter-sized SMZ was 6.92 mmol kg-1 in deionized water while it was 14.68, 22.71, and 34.91 mmol kg-1 in releasing solutions with ionic strengths of 0.03, 0.1, and 0.3 M, respectively

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There chemical and organic matter content in garbage leachate that may affect soil physical and hydraulic properties. The main objective of this study was to evaluate the influences of the leachate of Isfahan Organic Fertilizer Factory (IOFF) on some soil physical and hydraulic properties in a soil chemically enriched by Zeolite. The treatments include two soil textures (clay loam and sandy loam) and three levels of zeolite (0, 5 and 10 percent). The treatments were applied on lysimeters scale. The results showed that irrigation with the leachate caused a reduction of infiltration and hydraulic conductivity in the clay loam soil. The hydraulic conductivities in clay loam soil without zeolite (B0) before and after irrigation with leachate were 1.73 and 0.36 m/day, respectively. In contrast, there were no changes in the sandy loam soil’s infiltration and hydraulic conductivity. The hydraulic conductivities in the sandy loam soil with 5 percent zeolite (A5) before and after irrigation with leachate were 3.17 m/day. Furthermore, zeolite had a decreasing effect on those processes. The results show that irrigation with leachate caused reduction of bulk density in two types of soil and all levels of zeolite.

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Water management in cracked paddy soils is an important issue in rice cultivation. In order to study organic matter and zeolite effect and their interaction on moisture conditions and hydraulic and physical properties of paddy soils, the organic matter (rice straw) at four levels (0, 8, 16 and 24 tons per hectare), zeolite at four levels (0, 0.5, 1 and 1.5 percent ), and also moisture stages of soil at 5 levels were selected. This experiment was conducted in Rice Research Institute of Iran. Randomized Complete Block Design (RCBD) was used to study the effect of treatments on different subjects. The amount of moisture, bulk density and the distance of soil from the wall of container were measured in a 4-month period. The obtained results showed that the interaction effects of organic matter and zeolite on soil moisture content were statistically significant at one percentage level. Addition of plant residues caused an increase in soil moisture weight and reduction in bulk density compared to the control treatment. It was also found that soil moisture content and bulk density were highly correlated. Bulk density of control treatment ranged from 0.75 to1.7 gr/cm3, while with addition of 1.5 % crop residue the bulk density ranged from 0.7 to 1.3gr/cm3. Overall results show that crop residues are effective in reduction of crack parameters of soil , but zeolite cannot be effective although it causes more maintenance of soil moisture.

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Zeolites are substances that have been renowned for their remarkable nitrogen adsorption capacity resulting of decrease in leaching rate of soil nitrogen. This research was conducted to study the effect of the zeolite dosage, zeolite particle size and the method of application on the nitrate leaching of the soil irrigated by treated wastewater (TWW). All of the adsorption tests were carried out in a 27 PVC columns with 11 cm diameter and 60 cm length. The experiments were consisted of 9 treatments and 3 replications including 2 zeolite application method (mixed and layered), 2 zeolite’s grain size (63-125 and <63 micrometer) and 2 zeolite dosage (2 and 4 percent). Zeolite powders were added to the soil in mixed or layered fashion. The soil columns were irrigated 13 times with TWW in a weekly period. In the 4th, 9th and 13th irrigation event, three samples were taken from input and output TWW introduced to columns to measure the change in nitrate concentration. The results were shown that nitrate absorption rate was increased by average of 164.3% and 350.7% in mixed and layered treatments, respectively compared to the control. The result showed that zeolite application method, irrigation event, zeolite’s grain size and dosage were statistically significant on nitrate absorption efficiency (P<0.01). It shows that as the zeolite size decrease the soil nitrate adsorption increases significantly. It increases when the zeolite percentage increases. The result show that the soil nitrate adsorption decreases as the irrigation event increase and soil adsorption potential degraded with irrigation events.

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Zeolite is widely used for removing heavy metals from aqueous solutions. The objective of this study was to assess three sizes of zeolite in removing lead, nickel and cadmium from wastewater. A splite-plot experimental design was employed with 45 treatments and three replications at Shiraz University Lab in 2011. The treatments were five different concentrations of the pollutant and three sizes of zeolite (0.075, 0.2 and 0.425mm). The concentrations for lead were: 40, 250, 500, 1000 and 1250 mg/l and 4, 6, 15, 20 and 40 mg/l for nickel and cadmium. The results showed that the effect of concentrations of pollutant was significant, and by increasing the concentration of pollutant, absorption of heavy metals by zeolite increases linearly. Maximum lead absorption occurred at 1250 mg/l with 59.97 mg and minimum absorption of lead was related to the concentration of40 mg/l with 1.82 mg for 1 grams of zeolite. Maximum and minimum nickel absorptions were related to the concentration of 40 and 4 mg/l with 1.92 and 0.16 mg for 1 grams of zeolite, respectively. The values were 1.87 and 0.18 mg for 40 and 4 mg/l for cadmium, respectively. The effect of size of zeolite on the pollutant adsorption was not significant.

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In this study, the effect of clinoptilolite zeolite, as a soil amendment, on the parameters related to water and nitrogen movement in soil was investigated. Parameter and uncertainty estimation in the unamended (control) and amended soil (Z), was performed using the sequential uncertainty fitting algorithm (SUFI-2) which is linked to LEACHN (in the LEACHN-CUP software). The goodness of prediction uncertainty was judged on the basis of P-factor and R-factor. P factor, R-factor, and Nash-Sutcliffe coefficient (NS) was obtained 0.71, 0.76, and 0.92, respectively, in the prediction of the accumulated drainage from control. The results in prediction of the accumulated drainage from Z treatment using hydraulic parameters obtained in control were satisfactory (P-factor = 0.87, R-factor = 0.78, and NS = 0.87). P-factor, R factor, and NS were 0.87, 1.36, and 0.91, respectively, in the prediction of NO3-N leaching at control. According to the P-factor and R-factor values (P-factor = 1, R-factor = 2.46), application of the control parameter ranges in the prediction of NO3-N leaching at Z treatment produced a large uncertainty. By adjusting the parameters in control for zeolite amended soil, the estimated values for denitrification rate, distribution coefficient, and soil/solution NO3-N nitrification rate were greater in zeolite-amended soil compared to control.

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Although addition of amendment materials to soil is not for changing of soil K status, secondary effects of these materials can be important in K distribution among soluble, exchangeable and non-exchangeable forms. In this research, effect of addition of 2% zeolite, 2% vermicompost and 1% zeolite+ 1% vermicompost on 10 calcareous soils of Fars province belonging to five orders was investigated. The experiments were done as a randomized complete block with three replicates. Samples were incubated at 22±2 °C and 50% of saturated moisture content for 90 days. Then different forms of K were determined in the samples. Zeolite application induced 279 mg kg-1 increase in exchangeable K and 24 mg kg-1 decrease in non-exchangeable K, but it had not a significant effect on soluble K. Although vermicompost application increased soluble and exchangeable K, its effect was more sensible for soluble K (139 mg kg-1). Zeolite+vermicompost application increased all forms of K. Increase in soluble K with vermicompost application may increase risk of K leaching but zeolite application can preserve K in exchangeable phase and inhibit K leaching and fixation.

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Sorption hysteresis in soil constituents has important environmental implications such as pollutant transport and bioavailability. This research was carried out to study sorption reversibility of cadmium (Cd) on natural zeolite. Sorption isotherms were derived by sorption of Cd (П) from solutions containing different concentrations of Cd in the range of 1 to 10 mg L-1 using a 24h batch equilibration experiment. Desorption of Cd(II) was studied with the clay samples initially treated with the metal loadings of 50 and 100% maximum sorption capacity (SCmax) during the sorption study. Sorption isotherms of Cd were well described by the Freundlich and Coble-Korrigan models (R2=0.96). Desorption isotherms of Cd from zeolite showed little deviation from sorption data indicating reversible sorption. On the other hand, the results revealed no hysteresis. The average amount of 71.75 % of the initially sorbed Cd was desorbed from zeolite after five successive desorption steps. Release of such a relatively high proportion of sorbed Cd indicates that zeolite is an effective sorbent for the repeated purification of polluted water and wastewater.

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Removal of boron from aqueous environments (soil and water) is difficult, because it is present as B(OH)3 and B(OH)4- species. This research was done to study the sorption of boron by HDTMA-modified zeolite. The sorption of B on modified zeolite was studied as a function of pH (B concentration: 1 and 10 mg L-1) in the range of 6-9.5, and as a function of ionic strength (0.03 and 0.06 M Ca(NO3)2 or Mg(NO3)2) at a constant B concentration of 5 mg L-1. Sorption isotherm was performed for the solutions containing initial B concentration in the range of 1-15 mg L-1 using a 24h batch equilibration experiment. The results revealed that surfactant-modified zeolite exhibited the best performance at pH 9.5, and sorption of B increased with the increase of suspension pH. Greater B adsorption in the Ca system over the Mg system was clearly observed for the modified zeolite. Sorption isotherm of B were well described by the Freundlich and Langmuir models but the Freundlich sorption model described the interaction between B and the mineral material better than the Langmuir model. Maximum sorption capacity (qmax) of the sorbent was 120 mmol kg-1. The experimental data showed that HDTMA-modified zeolite used in this study had a reasonable sorption capacity for B.

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In this work, the effect of raw and modified bentonite and zeolite with trivalent iron on the stabilization of water-soluble and adsorbed arsenic in a calcareous soil was studied. Raw and modified bentonite and zeolite were added to the soil in different weights in a completely randomized block design with three replications and kept to field capacity soil moisture content of 80% for 8 weeks. The concentrations of water-soluble and adsorbed arsenic, water-soluble and absorbed phosphorus in soil and soil pH were measured. Treatments significantly affected the mobility of arsenic and phosphorus in soil. Raw zeolite and bentonite in different levels increased arsenic mobility (about 107 to 325 % and 259 to 350% respectively). Despite the change in surface properties of zeolites modified with iron, this treatment at different levels increased arsenic mobility in soils by about 124 to 246%. Bentonite modified with iron had the greatest effect on reducing arsenic mobility in soil (about 91%). Phosphate mobility was similar to arsenic in different treatments.

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Current study conducted to evaluate the effects of vermicompost and zeolite on the kinetics of nickel (Ni) fixation. Treatments consisted of a factorial combination of two vermicompost levels (zero and 2 w/w percent), three zeolite levels (zero and 4 w/w percent of zeolite of Firoozkoh, and Semnan) and two soil textures (clay and sandy loam) in three replications. All treatments were spiked with 50 or 100 mg Ni kg-1. DTPA extractable Ni was determined after 5, 10, 20, 30, 60 and 90 days. Ni availability was higher in sandy loam texture. Vermicompost application increased Ni availability in sandy loam texture in all the designated times. Zeolite application had no significant effect on Ni availability. The trend of Ni availability decrease was composed of two distinct stages with high and low Ni fixation rates. In the first step which continued up to 30 d, the available Ni fixation rate was high and then decreased sharply. Ni fixation data was suitably prescribed using simple Elovich and exponential equations. It seems that vermicompost has a greater effect to prevents Ni fixation and to retain it in available form in light texture soils. On the other hand, it seems that zeolite does not have any considerable effect on Ni fixation in calcareous soils.

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One of the major problems associated with petroleum-contaminated soils is water repellency, especially in arid regions of the world. Hence, a variety of methods such as clay addition has been proposed to improve the hydrophobicity of soils. This research was conducted to evaluate the influence of zeolite application on water repellency of an oil-contaminated soil from Khuzestan Province under various treatments including initial soil moisture content (0, 10, 20, and 30 weight %), the amount of applied zeolite (2, 4 and 8 weight %), size (25-53 and <2 μm), and exchangeable cation (Sodium and Calcium). The hydrophobicity of soil sample was determined using Water Drop Penetration Time (WDPT) method. The results showed that by increasing the amount of applied mineral WDPT decreased, where the application of 2 percent of zeolite led to the reduction of WDPT by about 27 percent less than the control. The results also indicated that soils treated with sodium-saturated zeolite had less WDPT than the calcium-treated samples, where the average of WDPT in sodium and calcium treatments decreased by 23% and 5% compared with the control, respectively. The initial moisture content of 30 percent showed the best performance with the decreasing WDPT of about 67 percent. Furthermore, the effect of mineral particle sizes showed a meaningless reduction in WDPT.

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Water scarcity forced farmers to use wastewater as water source, without considering its effects on environment and resultant contamination of soils and plants especially with heavy metals. The objectives of this study are to evaluate the application effects of zeolite as soil amendments on the uptake of Cd by spinach (Spinach Oleares L.) irrigated with wastewater (containing 10 ppm Cd). Different levels amounts of zeoilte (0, 1% and 5% w/w) were added to the soil and the experiment was conducted as a completely randomized design in a green house with 3 replications. The results indicated that, the addition of zeolite 1% (w/w) in soil treated with wastewater reduced cadmium concentration in plant, and consequently the percentage of extractable Cd using DTPA was decreased. However, application of zeolite 5% (w/w) increased the soil salinity, and as a result increased Cd concentration in the plant but this increase was not statistically significant, comparing with control. Spinach biomass did not differ significantly under irrigation with wastewater, but the Cd available in wastewater caused a decrease in Spinach biomass yield.

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