نشریه تحقیقات کاربردی خاک
سال یازدهم شماره 2 (تابستان 1402)

Improper use of ammonium fertilizer could cause this type of pollutant to enter the aquatic ecosystem and enriches water resources. In this research, ammonium adsorption by green synthesized iron oxide nanoparticles with Eucalyptus globulus (EL-Fe NPs) as innovative, inexpensive, and eco-friendly method, was investigated. Characterization of nanoparticles was determined by transmission electron microscopy (TEM), X-Ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). The effect of time (0-120), pH (3-11), and KCl salt as ionic strengths on ammonium adsorption by EL-Fe NPS was investigated. Also, kinetics models were fitted with ammonium adsorption data. The results showed iron oxide nanoparticles encapsulated by polyphenols from Eucalyptus globulus extract and have an irregular nanoparticulate structure with a size range between 50-100 nanometers. Ammonium adsorption by EL-Fe NPS was equilibrated at pH≈3.7 after 30 min and 11/86% ammonium was removed from 10 mg/L of initial concentration. Based on the results, this reaction is affected by pH and ionic strength (KCl). By increasing pH, Ammonium removal increased and at pH=7.8 maximum amount of pollutant (76.9%) was removed. Moreover, ionic strength had a contrary effect on ammonium adsorption. In the ionic strengths 0, 0.001, 0.01, and 0.1 ammonium adsorption 76.9, 64.2, 28.2, and 5% was decreased, respectively. These results depict ammonium and potassium compete for adsorption sites of EL-Fe NPs. The pseudo-second-order kinetic model provided a good description for ammonium adsorption (r2=0.998). Considering the effect of increasing the ionic strength in reducing the absorption rate and also the dependence of ammonium absorption on pH, it is expected that the reaction between ammonium and EL-Feb NPs is most likely through electrostatics. In general, it seems that Ammonium adsorption by EL-Fe NPs is influenced by solution chemistry.

Most of the soils of sugarcane fields in the Khuzestan province are calcareous and have little organic matter. The availability of nutrients such as phosphorus and the efficiency of phosphorus fertilizer application are low in these soils. In calcareous soils, a significant part of phosphorus fertilizers, becomes insoluble after entering the soil and are out of reach of plants. This study aimed to evaluate the application of phosphorus fertilizers, based on their acidic solution, in order to evaluate the status of nutrients and quantitative and qualitative yield of sugarcane. For this purpose, treatments of 0, 10, 20 and 40 kg ha-1 of urea phosphate fertilizer were applied in 100 m2 square plots of cultivated sugarcane cultivar with second regrowth age (R2). The results showed that the application of phosphorus fertilizer compared to the control, significantly (P≤0.05) increased the quantitative and qualitative yield of sugarcane, so that the highest yield of millable cane was observed in 20 kg ha-1 of urea Phosphate treatment (61.3 ton ha-1 with 18.2% increase). However, applying of 40 kg ha-1 of urea phosphate, only a 10.5% increase was observed compared to the control. On the other hand, the negative effect of high phosphorus concentrations on nitrogen concentration in leaves was evident, especially in the early growth period. The leaf ratio of nitrogen to phosphorus (N:P), regardless of the type of treatment, averaged 1:6.9. But the average leaf ratio of nitrogen to potassium (N/K) was 2.7:1, which was significantly different from the optimal values required for maximum growth of sugarcane. In general, the results showed that urea phosphate application in available phosphorus-deficient soils, depending on soil and plant conditions, has a significant role in increasing sugarcane yield. On the other hand, disturbtion of the balance of nutrients by deficiency or excess of nutrients in the plant, leads to a significant reduction in growth and quantitative and qualitative yield in sugarcane.

Soil color is one of the obvious characteristics of soil that usually has much to do with other soil properties. The NixTMPro color sensor can detect different amounts of soil color and allow you to check different soil properties. This sensor is less sensitive to the user's environmental and mental conditions than the conventional method of Mansell manual to determine the color of the soil, and it is effortless to use. Therefore, in this study, NixTMPro color sensor was used for fast and cheap estimation of different soil properties. For this purpose, 150 soil samples were collected from the semi-arid study area of Qazvin province. Values related to each soil characteristic were measured in the laboratory. Then, using this color sensor, the spectra of each color system were recorded for each soil sample. Two methods were used for this purpose. In the first method, by examining the correlation between the variables of the color system, an attempt was made to introduce a standard color system with the highest correlation coefficient with all soil properties. In the second method, all variables of different color systems were examined by the method of recursive feature elimination, which selects the features that have the highest accuracy by choosing the most important features. According to the results of both methods and to introduce a standard color system, in this study, CIEL*a*b color system was used to estimate soil properties. Because this system showed the highest degree of correlation with different soil properties. Then, using the random forest algorithm, the values related to each soil feature were estimated. Soil properties include sand, silt, clay, salinity, calcium carbonate (CaCO3), organic matter and soil bulk density. According to the results of random forest forecast, the amount of root mean square error (RMSE), mean error (ME), ratio of performance to interquartile distance (PRIQ), and the value of correlation coefficient (r) for each soil feature were determined. For sand, silt and clay particles, the amount of RMSE was 10.07, 6.28, 7.26%, and the correlation was 0.70, 0.49, and 0.77, respectively. PRIQ statistics for sand particles (2.09), clay (2.37), and calcium carbonate (1.78) are at an excellent and acceptable level. The RMSE values of organic matter, calcium carbonate and soil bulk density were 0.57, 0.02, 0.11%, and the correlation coefficient were 0.55, 0.58, and 0.70, respectively. Based on these results, it can be said that the spectra obtained from the NixTM Pro color sensor can be helpful in the rapid prediction of soil properties.

The most soils of Khuzestan province are calcareous with different degrees of salinity, however, they play a significant role in the country agricultural production. One of the new methods to deal with environmental stresses is the use of plant growth stimulants. The aim of this study was to investigate the effect of application of growth stimulants on wheat yield components in saline soil, environmental and climatic conditions of Khuzestan province. Experiment was performed in three replications as randomized complete block design with soil salinity of 8 dS m-1 and water salinity of 3-4 dS m-1 under seven different treatments consisting of control, free amino acid, seaweed, seed treatment, humic acid, fulvic acid and combination in 2018 for two years. The use of seaweed, humic acid and amino acid caused a significant increase 30, 25 and 24 % of grain yield as compared to control treatment (p ≤0.05). The results of economic analysis showed a significant advantage of the humic acid application in increasing wheat yield (profit to cost ratio = 13.38). Application of plant growth stimulants on the macro and micro nutrients concentration in wheat leaves was not significant in almost all stages of plant growth compared to the control (p ≤0.05). In addition, the application of growth stimulants in calcareous soils of Khuzestan due to high soil buffering capacity did not have a significant effect on soil salinity, pH and sodium uptake ratio. Therefore, it is recommended that in wheat fields of Khuzestan province with saline and calcareous soils, in addition to basic fertilizers, humic acid be used as foliar application in two growth stages of tillering and booting to increase stress plant resistance and improve crop yield.

Rill erosion rate and particle size of eroded material can be affected by rill length. This study was conducted investigated the effect of furrow length on the rill erosion rate and sediment grain size. Field experiments were done in a rainfed field with a 10% slope gradient with six furrow lengths (2, 6, 10, 14, 18, and 22 m) in a randomized complete block with three replications. The experiments were performed in the furrows with 20 cm width and 5 cm depth using a simulated flow with 3 l min-1. The initiation time of rill erosion and sediment grain size were determined in each furrow/rill at 5-min intervals for 60 min. Based on the results, rill erosion varied in the furrows over time and mainly increased to 45 min. Rill erosion didn’t occur the 22-m furrow, which is related to water infiltration along the rill and the loss of flow power. Rill erosion in furrows with 2, 6, 10, 14, and 18 m were 0.02136, 0.003232, 0.00225, 0.0150, and 0.00235 mg m-2 s-1, respectively. A decreasing linear relationship was found between rill erosion rate and furrow length (R2= 0.54). The grain size distribution of sediment was significantly affects by furrow length. With increasing furrow length, the selectivity of silt increased, whereas the selectivity of sand was limited in the long rills. The selectivity of clay didn’t affect by furrow length. Application of conservation tillage in rainfed lands can increase water infiltration and control rill erosion in the furrows.

Cyanobacteria are one of the main components of soil biocrusts in arid and semi-arid regions that grow in the surface layer of the soil. They actively participate in the cycle of elements by secreting polysaccharides and play an important role in improving soil quality and fertility. Accordingly, they have been used in soil and water resources conservation issues in recent years through cultivating and producing the required biomass in laboratory conditions and inoculating at the soil surface. However, the proper media for optimal growth of the soil microorganisms have not been reported comprehensively. The present study was conducted to select the optimal culture medium for the growth of cyanobacteria in experimental conditions. For this purpose, the performance of three culture media viz. BBM, BG11 and CHU10 was compared during the one-month growth period of soil cyanobacteria. In this regard, the types of grown microorganisms as well as the number of cyanobacteria present during the growth period of one-month and on average once every 4 days were examined. The results showed that soil cyanobacteria in BBM culture medium had better growth than the other two culture media and at the end of the growth period, the number of cyanobacteria grown in BBM, BG11 and CHU10 medium was 91790, 48638 and 1491, respectively, per milliliter. Therefore, BBM culture medium is proposed as the optimal culture medium for use in preparing the biomass required by cyanobacteria for inoculation at the soil surface.

To investigate the effects of paclobutrazol, calcium (Ca), and temperature treatment (cold) on resistance to chilling of pistachios seedlings (Akbari cultivar), a factorial greenhouse experiment was carried out in a completely randomized design with three replications. The treatments included paclobutrazol (0, 75, and 150 mg.-1), Ca (0, 3, and 6 g.l-1 of calcium chelate source) and temperature (0,-2, and -4 in the greenhouse and 0, -2, and +4 °C in the garden). The results showed that with decreasing temperature, total chlorophyll, carotenoids decreased, but the combined use of paclobutrazol and Ca increased the amount of these parameters compared to the control. Also, with decreasing temperature, the amount of electrolyte leakage increased, while using of paclobutrazol and Ca reduced the amount of this parameter compared to control seedlings. Measurement of osmotic regulatory parameters showed that the concentration of starch and soluble protein in leaves decreased with decreasing temperature. However, with the combined use of paclobutrazol (150 mg.l-1) and Ca (6 g.l-1) at -4 ° C, the concentration of proline, total phenol, soluble sugars, starch and soluble protein were increased compared to the control by 112, 28, 20, 80, and 196% respectively. The results of the garden experiment also showed that with decreasing temperature, the amount of ion leakage, in the control fruits increased. Application of paclobutrazol and Ca treatments reduced electrolyte leakage, so that the lowest percentage of electrolyte leakage was observed at -4, 0, and -2 °C when paclobutrazol and Ca were used simultaneously and at the highest levels and the electrolyte leakage rate decreased by 27, 12, and 38% compared to control fruits, respectively. Finally, the results of this study showed that the combined use of Ca and paclobutrazol can reduce the damage caused by chilling in seedlings and pistachio trees.

Soil quality is affected by land use and slope gradient, and soil quality assessment is important in determining sustainable land-use and soil-management practices. This study was conducted to assess soil quality in different land uses and slope gradients at Babolrood watershed, south of Mazandaran province. The studied factors included five levels of land uses (natural forest, rangeland, paddy field, citrus orchard and farmlands) and five levels of slope classes (0-2%, 2-5%, 5-8%, 8-12% and above 12 %). A total of 89 soil samples were collected in the upper layer of topsoil (depth 0-20 cm). The seventeen soil properties were used in a total data set (TDS). These properties included pH, EC, organic carbon (OC), clay, silt, sand, water dispersible clay (WDC), soil bulk density (BD), soil porosity (Pr), mean weight diameter (MWD), geometric mean diameter (GMD), macro aggregates, micro aggregates, total neutralizing value (TNV), organic carbon pool (OCpool), particulate organic carbon (POC), and mineral-associated organic carbon (MOC). Using the principal components analysis (PCA) method, five soil properties (OCpool, macro aggregates, EC, silt and clay) were selected for the minimum data set (MDS). The soil quality was evaluated by additive soil quality index (SQIa) and weighted additive soil quality index (SQIw) in two data sets of soil properties including MDS and TDS. The eight soil quality indices showed that the forest has the best soil quality with a good and very good grade and the paddy field has the poorest soil quality. Also, among the evaluated SQIs, only SQIw-TDS-NL showed a decrease in soil quality with increasing slope gradients. Moreover, the correlation coefficients were 82% and 89% between the two sets of MDS and TDS in SQIa and SQIw using nonlinear scoring methods, respectively. Because of the good correlation between TDS and MDS, the MDS set is better to determine soil quality indices in the study area. The correlation coefficient between SQIw-MDS-NLwith OCpool was higher (0.85) than all SQIs. So, SQIw-MDS-NL is suggested to evaluate soil quality in the study area.

Municipal wastewater is a rich source of phosphorus. Due to the limited non-renewable resources of phosphate in the world, the recovery of phosphorus from wastewater in the form of struvite or magnesium ammonium phosphate (MgNH4PO4.6H2O) as slow release fertilizer has been considered worldwide. In this study, phosphorus removal from sewage sludge with digestion-absorption process with H2SO4 (0.2 N) and the molar ratio of magnesium/ ammonium/ phosphorus in 2:1:1 at pH=8.5. The struvite and struchar precipitation were performed in different ratio of grape biochar to struvite including 0:100, 25:75, 50:50 and 75:25 and some of their physicochemical properties were identified. Kinetic Phosphorus release of samples were investigated at 24 hr, 3, 5, 10, 14, 28, 42, 56 and 84 days in distilled water, citric acid (20g/L) and HCl (0.5 M). The release of phosphorus, magnesium and nitrogen in the samples increased with increasing contact time. The results showed that the phosphorus-cumulative-release of composites in water and 20 gram per liter critic acid good fitted to the first-order kinetic model (R2 =0.97-0.99), whereas it followed the Elovich model (R2 =0.98-0.99) in 0.5 mole per liter hydrochloric acid. In addition, the analysis of samples showed that the concentration of heavy metals studied in this study, increased in the presence of biochar but were less than the allowable concentration in fertilizers. In XRF analysis, P2O5 has the highest composition of the obtained sediments. By increasing percentage of biochar the release of phosphorus, nitrogen and magnesium increased in water, citric acid 20 g/L and HCl 0.5 M and the maximum solubility of phosphorus was obtained in the ratio of 75:25 biochar to struvite. Therefore, the use of waste grape pruning biochar in the struvite deposition process increases phosphorus removal, solubility and phosphorus release rate.

In the situation where Iran is severely suffering from the lack of freshwater resources and the water resources crisis is a serious issue, paying attention to non-conventional water sources is an unavoidable necessity, in which case environmental tensions will occur. Especially salinity becomes important. To investigate the effects of salinity stress in German chamomile with the use of different culture media, factorial research was carried out in the form of a completely randomized design with three replications. In this experiment, two factors of salinity stress (Sa) (0, 50, 100, and 150 mM) and different percentages of culture medium (perlite 100%, cocopit 25%+perlite 75%, cocopit 50%+perlite 50%, cocopit 75%+perlite 25%, and cocopit 100) %) was investigated. The investigated morphological and physiological traits included fresh and dry weight of root and shoot, stem diameter, amount of chlorophyll a and b and total chlorophyll. The results showed that all investigated traits were subjected to salinity stress and showed a significantly decrease compared to the control. The culture medium containing 75% cocopeat and 25% perlite increased the fresh weight of roots by 22.11% compared to the culture medium containing 25% cocopeat and 75% perlite. Also, the control treatment had a 96.08% increase in root fresh weight compared to salt stress with a concentration of 150 mM. Regarding the amount of total chlorophyll, the results showed that Co50Pe50+Sa0, and Co75Pe25+Sa0 treatments were the most (3.93 and 4.01 mg per gram of fresh tissue, respectively) and Co0Pe100+Sa150, Co25Pe75+Sa150, Co50Pe50+Sa150 treatments. Co100Pe0+Sa150 had the lowest (respectively 2.01, 2.02, 2.06, and 2.19 mg per gram of fresh tissue). In general, it can be said that the German chamomile plant in the culture medium containing 75% cocopeat + 25% perlite can withstand severe salt stress and have acceptable growth.