مجله تحقیقات آب و خاک ایران
سال پنجاه و چهارم شماره 9 (پیاپی 93، آذر 1402)

Indiscriminate use of nitrogen fertilizers causes the accumulation of nitrate in agricultural products, especially vegetables. The high concentration of nitrate in vegetables can threaten the health of society. The purpose of this study is to investigate the status of nitrate as one of the characteristics of product quality and to estimate the daily uptake and determine the hazard quotients (HQ) of the non-cancerous diseases. Sampling of soil and fruit from a greenhouse (cucumber and strawberry) and a field (cucumber and tomato) in Jiroft was done in 2019. Nitrate concentration was measured by the distillation method.The average concentration of nitrate in strawberries, tomatoes, greenhouse cucumbers and field cucumbers was 55.23, 16.86, 64.16 and 44.39 mg/kg of fresh weight, respectively which were less than the standard limit of nitrates based on the Russian and Iran national standards. The calculated daily uptake was lower than the permitted level (3.7 mg/kg BW). HQ in all products was less than 1, of which the lowest amount was found in strawberries for girls under 6 years old (0.00086) and the highest amount was found in greenhouse cucumbers for girls under 6 years old and for boys 7-14 years old (0.0615). Therefore, strawberry has the least and the greenhouse cucumber has the most health threat potential for the health of consumers. According to the risk index of less than 1 for all age groups, there is no possibility of encountering non-cancerous diseases caused by nitrates through the consumption of vegetables in Jiroft region.

To investigate the release of nitrogen. Phosphorus and potassium elements from biochar, an experiment was conducted in a completely randomized design in three replications. Biochars were used by 2% in weight (W/W). The experimental treatments included control soil (CS), Soil+ Grape waste biochar (GSB), Soil + wheat straw and stubble (WSB) + brown walnut shell biochar (NSB) and Soil. The samples were incubated for about four months and sampling was done at days of 0, 7, 14, 28, 42, 56, 88 and 120. The results showed that the biochar addition significantly increased the concentrations of nitrogen, phosphorus and potassium in all biochar-amended soils compared to the control soil. Nitrogen concentration ranged from 766.6 mg kg-1 in control (average of sampling times) to 1272.2, 1366.7, and 1488.9 mg kg-1 in GSB, WSB and NSB treatments, respectively. Phosphorus concentration enhanced from 44.5 mg kg-1 in control (time-average of sampling) to 79.1, 67.1, and 70.8 mg kg-1 in GSB, WSB and NSB, respectively, and the concentration of potassium in the control increased from 103 mg kg-1 to 656.5, 293.8, and 125.6 mg kg-1 in the GSB, WSB, and NSB treatments, respectively. The WSB and NSB treatments released an average of 52% and 50.5% of their nitrogen content, respectively during 120 days, increased while GSB released only 28.6% of its total nitrogen on average. The order of nitrogen release rates in biochar were as follows: WSB≥ NSB> GSB. Regarding the release of phosphorus, NSB was considered to be the most efficient biochar, which was able to release 5% of its phosphorus during 4 months, while, GSB was the lowest effective biochar releasing only 0.5% of its phosphorus during the corresponding time. The order of phosphorus release from biochar treatments was as follows: NSB > WSB > GSB. The amount of available potassium in GSB was 2.3 to 6.7 times higher than the other treatments. The order of potassium release from biochar treatments was as follows: GSB > WSB > NSB. The results of infrared spectroscopy showed that the dissolution of amides containing nitrogen is the main mechanism of N release. The decrease in pH caused by nitrification, probably facilitated Ca-P dissolution from biochar and led to a higher phosphorus release.

To investigate the release of nitrogen. Phosphorus and potassium elements from biochar, an experiment was conducted in a completely randomized design in three replications. Biochars were used by 2% in weight (W/W). The experimental treatments included control soil (CS), Soil+ Grape waste biochar (GSB), Soil + wheat straw and stubble (WSB) + brown walnut shell biochar (NSB) and Soil. The samples were incubated for about four months and sampling was done at days of 0, 7, 14, 28, 42, 56, 88 and 120. The results showed that the biochar addition significantly increased the concentrations of nitrogen, phosphorus and potassium in all biochar-amended soils compared to the control soil. Nitrogen concentration ranged from 766.6 mg kg-1 in control (average of sampling times) to 1272.2, 1366.7, and 1488.9 mg kg-1 in GSB, WSB and NSB treatments, respectively. Phosphorus concentration enhanced from 44.5 mg kg-1 in control (time-average of sampling) to 79.1, 67.1, and 70.8 mg kg-1 in GSB, WSB and NSB, respectively, and the concentration of potassium in the control increased from 103 mg kg-1 to 656.5, 293.8, and 125.6 mg kg-1 in the GSB, WSB, and NSB treatments, respectively. The WSB and NSB treatments released an average of 52% and 50.5% of their nitrogen content, respectively during 120 days, increased while GSB released only 28.6% of its total nitrogen on average. The order of nitrogen release rates in biochar were as follows: WSB≥ NSB> GSB. Regarding the release of phosphorus, NSB was considered to be the most efficient biochar, which was able to release 5% of its phosphorus during 4 months, while, GSB was the lowest effective biochar releasing only 0.5% of its phosphorus during the corresponding time. The order of phosphorus release from biochar treatments was as follows: NSB > WSB > GSB. The amount of available potassium in GSB was 2.3 to 6.7 times higher than the other treatments. The order of potassium release from biochar treatments was as follows: GSB > WSB > NSB. The results of infrared spectroscopy showed that the dissolution of amides containing nitrogen is the main mechanism of N release. The decrease in pH caused by nitrification, probably facilitated Ca-P dissolution from biochar and led to a higher phosphorus release.

Recently, with the advancement of technology, extensive facilities have been provided for monitoring climate data with different resolution. Therefore, the aim of this research is to investigate the combination of precipitation databases and simultaneous monitoring of meteorological and hydrological droughts on a monthly time scale using the Combined Drought Index (CDI) at sub basins of Iran. To this end, observational data (100 synoptic stations on a daily scale) and global precipitation and runoff databases including ERA5, MRRRA2, GRUN, GLDAS and TERRA (with different spatial resolution on a monthly scale) were collected and extracted during the period of 1987-2019. Then, based on the aridity index, the climatic classification of the stations and sub basins has been done and the entropy weight method (EW) was employed to combine databases and indices. The accuracy of the datasets was assessed based on Kling Gupta (KGE) and Standardized Mean Square Error (NRMSE) metrics. The results showed that the combination of precipitation databases in the Hyper-arid, Arid, Semi-arid and Humid climates reduced the error index by 32, 10, 24 and 26%, respectively, compared to individual databases. In the 3-month scale, the sub basin of Sefidroud, Lake Namak, and Talesh, and in the 12-month scale, the sub basin of Lake Urmia, Lake Namak, Sefid Rud, Hamon Jazmourian, Hamon Mashkel, South Baluchistan, and parts of Aras River have faced with drought with more severity, duration, and peak values of drought. It should be said that, on average, in both scales, the middle part of the country has less drought severity and duration. The extent of drought in the river basins of Hyper-arid, Arid and Semi-arid climates in the scale of 3 and 12 months on average is 45 and 53%, and 70 and 40% in Humid climates. Based on these findings, it can be concluded that the combining precipitation databases enhances the accuracy compared to using global single databases. Additionally, drought in the humid climate shows higher intensity, duration, and extent in the short-term scale compared to the long-term scale.

In order to manage application of saline water in irrigated lands and coping with crisis of water resources scarcity in arid and semi-arid regions, it is logical to obtain the optimum yield-salinity-water production functions for crops. In this way, a greenhouse experiment with three irrigation treatments including 100, 75 and 50 percent of water requirement and four salinity levels of irrigation water including 0.7, 4, 8, and 12 dS m-1, as a factorial in the form of a completely randomized block design with three replications was conducted in Kashmar region. The objective of this study was to determine the optimum yield-water-salinity production function of safflower. The crop production functions used in this study were linear, Cobb-Douglas, quadratic and transcendental functions. For assessing the accuracy and efficiency of these functions in predicting yield and yield components of safflower, the statistics of mean absolute error, normal root mean square error, determination coefficient, efficiency function and agreement index were used. Additionally, the plant salinity resistance threshold was determined by Mass-Hoffman linear model. The results showed among the applied functions, the quadratic function the lowest NRMSE and the highest R2, had the most efficiency in predicting yield and yield components of safflower in simultaneous salinity and drought stress conditions. According to Mass-Hoffman linear model, grain yield relative reduction by 10 percent, in salinity of 3.75 dS m-1 and grain yield relative reduction by 25 and 50 percent were occurred in salinity of 6.75 and 11.75 dS m-1, respectively. According to the findings of this research it can be concluded that the quadratic equation is recommendable as the best yield-water-salinity production function of safflower in pot conditions. Since, crop production functions are dependent to soil type, weather and climate conditions and water management in the field, more comprehensive studies should be done in the field conditions for determining the best yield-water-salinity production function of safflower.

More than 80% of Iran's area is arid and semi-arid. Arid and semi-arid soils have various problems and limitations. One of the most important factors limiting soil fertility and crop production in these areas is the lack of soil organic matter (SOM). In more than 60% of Iran's agricultural lands, the amount of SOM is less than 1%; While its optimal level in soils should be 2-3%. SOM, as one of the most important indicators of soil health, plays a vital role in soil fertility and crop production; So, by increasing the amount of SOM, the physical, chemical, and biological characteristics of the soil and crop yield can be improved. However, the stability and residual effects of the fertilizers and organic wastes in the soil are low. Nowadays, converting organic wastes and residues into biochar and adding them to the soil is one of the new methods of increasing soil organic carbon, which enhance soil fertility and crop yield and has high residual effects due to its high stability. However, due to the specific characteristics of the soils of arid and semi-arid regions, using biochar in these regions is associated with challenges and has received less attention. In this review article, while reviewing the positive effects of biochar on soil quality indicators and crop production, the challenges of using biochar in the soils of arid and semi-arid areas, especially in drylands, and the solutions to overcome these challenges have been reviewed.

The present research was conducted to investigate the effect of foliar application of Zargreen organic liquid fertilizer on the growth and chemical composition of tomatoes under drought stress in greenhouse conditions in the Faculty of Agriculture of Shiraz University on May 2022. Treatments consisted of four levels of foliar application of Zargreen amino acid fertilizer (with concentrations of 0, 2.5, 5, and 7.5 L/1000L), and three soil moisture levels (field capacity (without stress), 75 and 50% of field capacity, FC). During the growing season three times; 1.5 months (at the end of vegetative growth and beginning of flowering), 2.5 months (at the stage of fruit development), and 3 months (at the stage of fruit ripening) after planting, Zargreen organic liquid fertilizer solutions were used with the mentioned concentrations for foliar spraying. The interaction effect of Zargreen organic fertilizer and moisture levels showed that the highest greenness index was observed with the highest level of soil moisture stress and the highest level of applied organic fertilizer. Application of 2.5, 5, and 7.5 L/1000L of Zargeen fertilizer increased the mean value of plant height by 8, 9, and 14%, respectively, compared to the control. The lowest shoot fresh weight was obtained without application of the organic fertilizer at the highest level of applied moisture stress. While at the same stress level, the highest shoot fresh weight was observed with the addition of 7.5 L/1000L of the organic fertilizer. The highest shoot zinc and copper concentrations were obtained in the plants grown at the highest moisture stress and the highest level of organic fertilizer application. It can be concluded that adding organic compounds improves the plant's tolerance to environmental stresses by modifying the physiological processes of the plant.

Roughness coefficient is an effective factor on water velocity and discharge in drain pipes. Roughness coefficient in experimental box model with dimensions of 100×41×56cm was evaluated with two pipes of smooth and corrugated in a diameter of 63 and 56mm by three series of independent tests. The first set was done on pipes with mineral envelop, the second set on pipes with synthetic materials and the third one on pipes without envelop. The mean values of "n" Manning’s in the smooth pipe with synthetic and mineral envelope and non-envelop materials were measured 0.0106, 0.0111, 0.011, and for the corrugated pipe 0.0088, 0.009, 0.0091. The mean values of "n" Ganguillete-Kutter’s in the smooth pipe with synthetic and mineral envelop and non-envelop materials were obtained 0.0048, 0.0048, 0.0048, and for the corrugated pipe 0.0041, 0.0042, 0.0042. The "n" values from the Reynolds-Darcy Weissbach combination formula in the smooth pipe with synthetic and mineral envelop and non-envelop materials were calculated to be 0.0050, 0.0050, 0.0049 and for the corrugated pipe 0.0048, 0.0048, 0.0049. Two evaluation indexes (R2 and RMSE Error Value) indicated a better result for n value obtained by Ganguillet-Kutter formula. The flow inside the drainage pipes is a turbulent and spatially variable which is affected by the small flows entering the pipe through holes. This flow pattern, while disrupting the uniform distribution of the transverse velocity of the flow, caused flow inhibition and increased Manning's roughness coefficient in the first 30 cm due to the flow rate and low flow speed compared to the second 30 cm. The negligible difference between "n" Manning’s with "n" Ganguillete-Kutter’s is not important and applying 0.011 for Manning coefficient in smooth pipe and 0.009 for corrugating pipe with envelop is satisfactory. 

One of the effective and necessary factors during plant growth period is plant nutrition and management of fertilizer resources. Nowadays, the use of nanotechnology in the preparation of nanofertilizers is popular. This research aims to investigate the effect of spraying nanofertilizers of potassium and boron on the growth and yield of mungbean (Vigna radiate L.). For this purpose, a factorial experiment based on randomized complete blocks design with three replications in 2021-2022 was conducted in a field experiment at the Misan University of Iraq. The factors were three levels of boron (0, 1 and 2 mg liter-1) and three levels of potassium (0, 4 and 8 mg liter-1). The results showed that the use of nanoboron and potassium spraying led to an improvement in crop growth parameters of mungbean. So that potassium spraying with 2 and 8 mg liter-1 led to a significant increase in the number of branches plant-1, the number of pods per plant, and grain yield in the plant compared to the control treatment. Furthermore, the application of boron in the plant at the highest concentration (2 mg liter-1) increased the grain yield per hectare, the number of seeds per pod, pod length and protein yield significantly compared to the control treatment (no boron spraying). In general, it can be said that the simultaneous spraying nanofertilizers of potassium and boron on the mungbean plant showed a more significant effect on growth and plant yield, compared to the application of nanopotassium and nanoboron alone.

Due to surface water limitations, groundwater reservoirs are known as the main source of supplying water requirements in most arid countries. Recently, owing to these aquifers’ over-exploitation, in order to apply optimal management of these resources, reliable water table forecasting exceeded in importance. This study is aimed to Determine the best scenario for combining input data in Hamedan-Bahar plain water table forecasting using the wavelet-support vector regression (WSVR) hybrid model. In the first step, Rainfall, temperature, evaporation, and the groundwater level data of seventeen piezometers in 26 years (1991-2017) were collected and completed. Nine scenarios with different lags and combinations were considered to select the model inputs and their lag numbers. Modeling performance in each scenario was evaluated using statistical parameters such as the Pearson correlation coefficient (r), standard error (SE), and root mean square error (RMSE), and using the best scenario, the water table of the area was predicted for ten years ahead. Based on the obtained results, the scenario in which each of the four input parameters was used, with one and two lags, had the highest accuracy. Additionally, the predicted results, using the best scenario, illustrated a noticeable downward trend in the water table of the region in the future. Therefore, concerning the high sensibility of this plain because of supplying the water demands in drinking water, agriculture, and industry of Hamedan and Bahar, as well as the necessity of more water harvesting in the future, deciding more favorable groundwater management is highly imperative in this area. کلیدواژه‌ها [English] Support vector machines Water table prediction Wavelet transport WSVR hybrid model