JWSS - Journal of Water and Soil Science

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Somatic embryogenesis is affected by several factors. In this research project, we studied the effect of explant size, wounding and desiccation treatments on somatic embryogenesis and their conversion into plantlet among three genotypes of soybean. The explants were sampled from immature embryos of soybean in three different sizes (3, 5 & 7 mm) with wounding treatment on half of each, and then were cultured on the somatic embryogenesis medium. In order to determine desiccation effect on conversion amount of embryos into plantlets, the produced embryos were affected by three levels of desiccation treatments (2, 4 & 6 days). The increase ratio of callus mean weight, percentage of embryogenic calli, embryo number per explant and percentage of embryo conversion to plantlet were used for treatment evaluation. Variance analysis of the data showed significant differences (P<0.01) between treatments regarding the variables. The results indicated that BP was a superior genotype with embryogenic capability (24.19 %) and the best explant size for somatic embryogenesis was immature embryo with 3 mm length. The six day desiccation treatment caused highest percentage of embryo conversion into plantlet (74.7 %). Wounding increased callus production on explants and number of embryos per explant (20.28), but it did not show any significant effect on percentage of embryogenic calli. Germinated somatic embryos were transferred to pots containing peat-moss. Somatic embryogenesis is an efficient method for the plant regeneration and genetic transformation. However, this method still offers low percentages of plant regeneration, and is perhaps related to the maturation process and high morphological abnormalities of the matured embryos. This study aimed to find some solutions for soybean somatic embryogenesis problems.

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Compost and sewage sludge contain high concentration of plant nutrients and, thus, have been used extensively as an inexpensive fertilizer. The objective of this study was to evaluate cumulative and residual effects of compost, sewage sludge and cow manure on nitrogen, phosphorus and potassium in soil and wheat. The experiment included compost, sewage sludge and cow manure, each applied at 3 rates (25, 50 and 100 Mg ha-1), a chemical fertilizer (250 kg ha-1 amonium phosphate + urea) and a control plot with 3 replications. The experimental design consisted in completely randomized blocks with treatments arranged in split plots. To study the cumulative and residual effects of the organic amendments, application was repeated on four fifths of each plot in the second year. Wheat was grown in the plots. The results showed that one application (residual effect) of organic amendments had not significant effect on total N in soil and wheat leaves and stem, but it led to significant increase of available phosphorus and potassium in soil and wheat leaves and stem. Cumulative effects of organic amendments significantly (P≤ 0.05) increased the total N (in 50 and 100 Mg ha-1 Cow manure and 100 Mg ha-1 Compost treatments), available P in all organic treatments and K (in all Compost and Cow manure treatments) in soil. Also, cumulative effects of organic amendments significantly (P≤ 0.05) increased the N (in 100 Mg ha-1 sewage sludge), P (in 100 Mg ha-1 compost) and K (in all organic treatments with the exception of 25 Mg ha-1 Compost) concentrations in leaves and stem.

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Discrimination function analysis is a method of multivariate analysis that can be used for determination of validity in cluster analysis. In this study, Fisher’s linear discrimination function analysis was used to evaluate the results from different methods of cluster analysis (i.e. different distance criteria, different cluster procedures, standardized and un-standardized data). Furthermore, Hotelling T2, CCC plot and multivariate analysis of variance were used to support the results. To achieve the goals, 8 rapeseed genotypes were planted in a randomized complete block design with three replications in Rice Research Institute of Iran, Rasht, durin 2005-2006, and 14 characteristics were measured. Analysis of variance based on the randomized complete block design showed significant differences between genotypes for all the studied traits. Comparison of means between genotypes indicated that the genotype Hyola401 for grain yield and most of the measured characteristics was better than the other genotypes. Evaluation of phenotypic and genotypic coefficient of variations showed that most of the traits had high variability in the population. Discrimination function analysis showed that the Euclidean distance criterion was better than others and a desirable clustering was obtained by this criterion. Also, all of the data standardization methods produced similar clusters and were better than un-standardized data. Based on evaluation of dendrograms derived from different methods of cluster analysis determined that the UPGMA, complete linkage and Ward’s minimum variance methods were better than the other methods, and grouped the genotypes into three clusters. Fisher’s linear discrimination function analysis showed that UPGMA and Ward's minimum variance methods with clustering validity of 87.5 percent, was more suitable than other cluster analysis methods however, discrimination analysis grouped genotypes into two clusters. Tests of Hotelling T2, CCC plot and multivariate analysis of variance supported the results from the discrimination function analysis. It seems that the UPGMA and Ward's minimum variance procedures based on Euclidean distance criterion of standardized data function better in grouping genotypes, yet, the use of discrimination function analysis is recommended to confirm the results and determine the actual groups.

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Daily solar radiation intercepted at the earth’s surface is an input required for water resources, environmental and agricultural studies. However, the measurement of this parameter can only be done in a few places. This has led researchers to develop a number of methods for estimating solar radiation based on frequently available meteorological records such as hours of sunshine or air temperature. In this study two empirical Angestrom and Hargreaves- Samani models, which are respectively based on air temperature and sunshine duration were calibrated and evaluated for estimating solar radiation in southeast of Tehran, Iran. Also, two neural networks models were presented using similar inputs and above-mentioned empirical models. The results showed that the both empirical and neural network models provided closer agreement with the measured values, but the models based on sunshine hours gave better estimates than the models based on air temperature. The neural network model based on sunshine hours with a R2 of 0.97 and a RMSE of 1.34 MJ m-2 d-1 provided the best results

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In this study, the remote sensing statistical approach was used to determine the global solar radiation from NOAA-AVHRR satellite data in southeast of Tehran. This approach is based on the linear correlation between a satellite derived cloud index and the atmospheric transmission measured by the clearness index on the ground. A multiple linear regression model was also used to convert the five AVHRR data channels and extraterrestrial radiation to global solar radiation. The results of this study showed that multiple linear regression model estimated the solar radiation with an R2 of 0.93 and a root mean square error (RMSE) of 5.8 percent, which was better than the statistical approach.

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Azotobacter chroococcum can improve mineral nutrition of plants through N2 fixation and plant growth promoting capabilities. Fourteen strains of A. chroococcum were isolated from rhizosphere of wheat plants grown in different field conditions around Tabriz, northwest of Iran. In a pot culture experiment with sterile soil, wheat plants (Triticum aestivum cv. Falat) were inoculated with 14 bacterial strains. Positive control received nitrogen fertilizer without bacterial inoculation and the negative control was left un-inoculated and without N- fertilizer. Totally, 16 trearments with four replications were arranged in a completely randomized design. The plant growth indices and N and P concentrations of shoot and root were determined at the harvest time. Results showed that the inoculation with Azotobacter strains caused a significant increase in shoot and root dry weights. Bacterial inoculation significantly enhanced the concentration and content of N in shoot and root. Phosphorus content was only enhanced (p<0.05) in the root. Translocations of N and P from root to shoot were markedly increased in bacterial treatments compared to the positive and negative controls. Moreover, strains 1 and 48 which showed relatively higher phosphate solubilizing capability and phosphatase activity in in-vitro assay also brought about higher P content and concentration in shoot and its translocation from root to shoot.

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In order to investigate the effect of vermicompost on physical and chemical properties of soil, an experiment was carried out in split plot based on complete randomized block design in three replications in Sari Agricultural Sciences and Natural Resources University. The physical and chemical properties of soil included bulk density, particle density, total porosity, water holding capacity, field capacity, permanent wilting point, available water capacity, pH, organic carbon and electrical conductivity in soil. Six levels of fertilizer treatments (T1= control, T2= chemical fertilizer, T3= 20 tons vermicompost + 1/2 T2, T4 = 20 tons / hac vermicompost + 1/2 T2 , T5= 40 tons vermicompost + 1/2 T2 and T6= 40 tons / hac vermicompost) and three levels of application years, one year of fertilization (1385), two consecutive years of fertilization (1385 and 1386) and three consecutive years of fertilization (1385, 1386, 1387). The results of the study showed that the application of these treatments in soil were significantly effective in increasing the total porosity, water holding capacity, field capacity, permanent wilting point, available water capacity, organic carbon electrical conductivity and in decreasing the bulk density, particle density and pH compared to control. In Contrast years of consumption of fertilizer did not have any significant effect on the physical properties of the soil except for FC, PWP, AWC, pH, OC and EC. The interaction between years of consumption of fertilizers were significantly different only in particle density and field capacity.

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Contamination of agricultural soils by heavy metals is a serious threat from both agricultural and environmental standpoints. Among heavy metals, cadmium (Cd) toxicity for humans and plants is of great concern due to its high mobility and phytoavailability in soil even at low concentrations. Opposite to Cd, Phosphorus (P) is an essential nutrient for plant growth. A greenhouse experiment was carried out in a completely randomized design to examine the influence of Cd, P and their interaction on the growth and chemical composition of spinach grown on a calcareous soil. Treatments consisted of four Cd levels (5, 10, 20 and 40 mg/kg soil as cadmium sulfate) and four P levels (0, 20, 40 and 80 mg/kg soil as mono-calcium phosphate) in three replicates. The results indicated that 40 mg Cd significantly decreased spinach dry weight by 47% but P application decreased detrimental effect of Cd on spinach dry weight. Also, phosphorus application significantly decreased Cd concentration in spinach aerial parts by 78%. Increasing Cd levels increased concentration of this element in spinach shoots. Addition of 40 mg Cd decreased P concentration by 21.5% in aerial parts. Zinc (Zn), manganese (Mn), calcium (Ca), and nitrogen (N) concentration significantly decreased with P application but increased concentration of sodium (Na). Cadmium application decreased Zn concentration but increased Ca, Na and N concentrations in spinach. Our tentative conclusion is that P application in P-deficient soils is probably effective in decreasing Cd concentration and the detrimental effect of Cd on spinach growth, indicating a negative interaction between these elements. Prior to any fertilizer recommendation, the results of this experiment should be verified under field conditions

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In this study, a completely randomized experiment was designed with four irrigation treatments and three replicates. The irrigation programs were raw wastewater, treated wastewater, a combination of 50% raw wastewater and 50% potable water and a combination of 50% treated wastewater and 50% potable water. The experiments were run within a greenhouse. The lysimeters were built up on September 2009 and they were filled with two layers of soil. The upper (0-30 cm in depth) and lower (30-70 cm in depth) layers were sandy loam and sandy clay loam, respectively. A total of eight watering programs with an interval of elevens-day were applied. After each irrigation program, intake wastewater and drainage water of each Lysimeter was sampled in order to analyse the transport of heavy metals (Cu, Zn, Fe and Mn, Ni, Cd and Pb). Results showed that the effect of water quality was significant on percentage of transport of heavy metals. The lowest transport percentage of heavy metals belonged to raw wastewater treatment. Also, the highest percentage of transport of Cu, Zn, Fe, Ni and Pb belonged to the combination of 50% raw wastewater and 50% potable water. In most cases, we observed that the transport percentage of these elements increased by continuing the irrigation

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This study was conducted on subsurface drainage network under operation in Behshahr. DRAINMOD model was used to simulate drainage system using measured data in 2006. The model was evaluated to estimate soil hydraulic conductivity by comparing the measured and predicted values of water table depth and drain discharge for different values of hydraulic conductivity. The results of this method were compared with the results of output drainage water method (as a baseline method). Use of water table depth simulation results in estimating hydraulic conductivity model resulted in considerable error, while the simulation results of drain discharge rate could be used with good accuracy for estimating it. There was a small difference between the output drainage water method and the inverse solution of DRAINMOD model to estimate soil hydraulic conductivity (2.3 and 2.5 cm/h, respectively). Thus, the comparison between the measured and predicted values of drain discharge could be a good criterion to estimate soil hydraulic conductivity using the inverse solution of the DRAINMOD model

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Reference evapotranspiration (ET0) is a necessary parameter for calculating crop water requirements and irrigation scheduling. In this study, a method was presented as ET0 is estimated with NOAA satellite imagery in the irrigation network. In this method, a pixel from a set of pixels within the irrigation network was chosen with the highest vegetation index, and its surface temperature (Ts) with extraterrestrial radiation parameter (Ra) was used as inputs of the model. The M5 model tree for converting Ta and Ra to ET0 was used as input variables. In this research, Gazvin irrigated area was selected as a case study. A total of 231 images of NOAA satellite related to irrigation season of the study area were used. The results obtained by the M5 model were compared with the Penman–Monteith results, and error values were found within acceptable limits. The coefficient of determination (R2), percentage root mean square error (PRMSE) and the percentage mean bias error (PMBE) were found to be 0.81, 8.5% and 2.5%, respectively, for the testing data set.

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In order to investigate the effects of municipal solid waste enriched with mineral fertilizers on some soil physical properties and lead (Pb) and chromium (Cr) concentration in plant organs of spinach, a field experiment was carried out in a factorial arrangement based on the randomized complete block design with three replications in 2008. The main plot included four levels of fertilizer, control without fertilizer, 20 tons of multiple solid waste + 50% chemical fertilizers and 40 tons of multiple solid waste + 50% chemical fertilizers per hectare and sub-plot consisted of a period of application in 3 levels of time (one, two and three years). The results showed that application of enriched municipal compost increased field capacity, soil porosity and moisture holding capacity, but particle and bulk density of soil decreased compared to the control. Also, the physical parameters in the two levels of emriched waste compost were higher than chemical fertilizer treatment. On the other hand, using for three-years the urban waste compost enriched fertilizer at all levels increased significantly (p 0.05) lead and chromium concentrations in spinach. The Pb and Cr accumulated in roots and shoots of spinach in urban using 40 tons of waste compost per hectare with 50 percent of chemical fertilizer for a period of three years and showed a significant increase. The amounts of fertilizer in all three levels were higher than the root element shoot.

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Riparian vegetation is a component of river system that performs certain basic functions including primary vegetative production, protecting stream banks from erosion, trapping sediments, promoting water quality, wildlife habitat and fisheris, forage for livestock, etc. In this research, spatio-temporal change of vegetation riparian area of Aghbolagh-river as an upstream of Karoon-river for 65-km was investigated using 1956, 1969, 1998 aerial photos and 2006 satellite images. Results showed a significant change in riparian area between different periods (kappa=26.55%). This change is the result of construction of dam in the upstream in 1993, alteration of riparian area to arabal land, exploitation of groundwater for agricultural usage, etc

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Management of organic and inorganic treatments may have positive or negative effects on soil quality, plant growth and human nutrition. The objectives of this study were to determine the effects of organic and inorganic zinc fertilizer application on soil quality indicators and wheat yield. This research was conducted at Agricultural Research Station Roudasht, Isfahan, Iran. Sewage sludge and cow manure (5 and 10 t/ha), ash rubber (1 t/ha), powder rubber (200 kg/ha), ZnSO4 (40 kg/ha) were applied and wheat was cultivated. Soil samples were collected at tilling and harvest stages. After taking samples and measurements of the soil parameters, we determined the critical limits for each category and class rating for the each soil parameters, and the soil quality index was calculated. The results showed sewage sludge and rubber ash were significantly effective in increasing soil bioavailable Zn compared to other treatments. Application of sewage sludge and cow manure at 10 ton/ha improved soil quality. The expanded soil quality index can help better understand the effect of fertilizers on soil. A positive and significant relationship between soil quality indicators and Zn uptake and wheat yields was also observed. Our results indicate that addition of 10 t/ha sewage sludge as fertilizer can significantly improve soil quality, supplying the necessary amount of Zn for wheat growth.

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The present study was conducted to increase phytoextraction efficiency of Festuca ovina L. in lead contaminated soil in the EDTA-assisted (0, 1.5, 3, 1.5+1.5, 3+3, 6 mmol kg&minus;1), assess the best time of plant harvesting to increase Pb uptake and method of EDTA application to reduce Pb leaching risk. The results revealed that the greatest Pb uptake was observed in 3EDTA treatment. Therefore, 3mmolkg-1 was used in the second step for assessing harvest time for 15, 30 and 45 days. Results showed that the concentration of Pb in plant tissues was increased with the passage of time and the best harvest time to achieve maximum removal of Pb was 60 days of the first harvest. In the third step to reduce leaching of Pb-chelate, 3mmolkg-1 EDTA in five ways of single, double, triple, quadruplet, quintuplet were added to the soil. The results indicated that under quintuplet application, Pb content reached its minimum concentration in the soil and in the plant organs, the Pb concentration was maximum and metal concentration in the plant organs did not vary significantly when triple, quadruplet and quintuplet dosages were added (p<5%). Overall, optimum phytoextraction of F. ovina L. and Pb leaching reduction were achieved when 3mmol kg&minus;1 EDTA was added in quintuplet dosage and the plant was harvested at the end of growth stage.

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Erosion and sedimentation as a river natural behavior lead to the loss of soil and cause irreparable damages to water development projects. Since the phenomenon of erosion and deposition is one of the most complex natural processes, the complete understanding of the effective factors involved in this phenomenon is really a big problem. This study was done to optimize the parameters affecting sediment yield and determine their sensitivity in the Doiraj river basin in the West of Iran, using SWAT, a semi-distributed model, and SUFI2 algorithm, and the monthly sediment yield from 1994 to 2004. In the first run of the model, coefficients R2, NS, and Br2 were respectively obtained as 0.43, 0.39 and 0.28. The results showed that performance of the model with the default data was not satisfactory and we needed to determine the used optimal values. Then, the optimal values of parameters were determined using SUFI2 algorithm and reverse modeling and the model was run with the new values. Based on the new results, coefficients R2, NS, and Br2 were respectively obtained as 0.75, 0.73 and 0.65 and performance of the model improved and its accuracy increased acceptably. In the next step, from among the studied 30 parameters, (CH_N2), (USLE_K), (USLE_P) and (OV_N) were identified as the important parameters effective in the output of the sediment yield from basin. Also, USLE_K as was diagnosed as the most sensitive parameter. Results of this survey can be used in the management of the effective parameters in sediment load. Determining exact values of the effective parameters in other studies can be helpful to improve the simulation results in similar basins, too.

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Determining the spatial distribution of different contaminants in soil is essential for the pollution assessment and risk control. Interpolation methods are widely used to estimate the concentrations of the heavy metals in the unstudied sites. In this study, the performances of interpolation methods (inverse distance weighting, local polynomials and ordinary Kriging and radial basis functions) were evaluated to estimate the topsoil contamination with copper and nickel in Golestan Province. 216 surface soil samples were collected from Golestan province, and their Cu and Ni concentrations were measured. Soil contamination was determined using different interpolation methods. Cross validation was applied to compare the methods and estimate their accuracy. The results showed that all the tested interpolation methods have an acceptable prediction accuracy of the mean content for soil heavy metals. RBF-IMQ and IDW1 methods had the lowest RMSE, whereas RBF-TPS method with the largest RMSE estimated a larger size for the polluted area. The greater the weighting power, the larger the polluted area estimated by IDW. Compared with the ‘‘sample ratio over the pollution limits” method, the polluted areas of Cu and Ni were reduced by 8.38% and 6.14%, respectively.

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The importance of decreasing the cost of soil structures due to the budget constraints makes engineers avoid handling large volumes of soil, thus making maximum use of local materials. Soil performance change in order to improve engineering applications of soil is called soil stabilization. Soil stabilization methods can be mechanical, electrical, thermal, chemical, etc. Gypsiferous soil including soils used in civil affairs and special structures in the vicinity of water needs to be established. This study is conducted to evaluate changes of shear strength of gypsiferous soil, using chemical method by addition of “A polyurethane Mastic”.  The studied gypsiferous soil was prepared from 3km north-west of Ramhormoz in Khuzestan province. Soil samples containing 0%, 1%, 2%, 3%, 5% and 7% of the said material additive were compressed with optimum moisture content obtained from standard Procter test, and finally, were tested under the direct shear test at shear rate of 0.5 mm per minute. After achieving cohesion parameters of soil, the best mix of the additive “A polyurethane Mastic” was found to be 5%.

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Precipitation is an important element of the hydrologic cycle and lack of this data is one of the most serious problems facing research on hydrological and climatic analysis. On the other hand, using satellite images has been proposed by many researchers as one of practical strategies to estimate precipitation. The present paper aims to evaluate the accuracy of satellite precipitation data, provided by PERSIANN and TRMM-3B42 V7 in Gorganrood basin, Iran. To achieve this aim, two sets of daily precipitation ground-based data, 2003 to 2004 and 2006 to 2007, from six stations of Gorganrood basin, named; “Tamer”, “Ramian”, “Bahalkeh-ye Dashli”, “Gorgan Dam”, “Ghaffar Haji” and “Fazel Abad” have been used in this paper. The evaluation indices have been calculated and analyzed in different time scales, including daily, monthly and seasonal. The results indicated that the two above mentioned satellite models are not accurate in daily scale. However, they showed reasonable accuracy in monthly and seasonal scales. The highest correlations between satellites and recorded data in daily and monthly scales, for TRMM-3B42 V7 in “Gorgan Dam” and “Bahlke Dashlei” stations, are 0.397 and 0.404, respectively. The comparison of measured and satellite data of winter showed better agreement for PERSIANN model. However, TRMM-3B42 V7 shows better correlation in other seasons. The results also indicated that while TRMM-3B42 data displays higher correlation with measured data, PERSIANN provids better results in predicting the number of rainy days. 

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In this study, two different approaches of infiltration parameters estimation in traditional, variable and fixed alternate furrow irrigation, with and without cutback inflow, were performed and compared. Four usual methods including two-point (Elliott and Walker), Valiantzas one-point, Mailapalli one-point and Rodriguez and Martos optimization methods, as approaches based on advance data, and multilevel optimization method as an approach based on the advance, storage and recession data, were considered. Surface irrigation model: WinSRFR was used to simulate irrigation phases and infiltration value in each method. 13 furrow irrigation field experiments, from two case studies: Karaj and Urmia, were used to perform different methods. Based on the results, the multilevel optimization method predicted the advance and recession phases and runoff-infiltration with high accuracy for traditional, variable and fixed alternate furrow irrigation. The multilevel optimization method for traditional furrow irrigation, showed more accuracy than variable and fixed alternate furrow irrigation in advance and recession phases and the average root mean square error (RMSE) for predicting advance phase for the three furrow irrigation methods was 1.37, 1.8, and 1.57 minutes and for the recession phase was 3.76, 5.0, and 3.03 minutes, respectively. Also the multilevel optimization method for cutback options indicated high performance to advance and recession prediction and the average RMSE of advance and recession prediction were obtained 3.57 and 2.13 minutes for cutback option and 3.8 and 1.3 minutes for no cutback option, respectively. The multilevel optimization method indicated high performance in storage phase, too. The average of relative error (RE) of runoff estimation for traditional, variable and fixed alternate furrow irrigation was calculated 0.5, 0.4 and 0.4 percent, respectively. The runoff average RE of multilevel optimization method with cutback and no cutback option were obtained 1.85 and 0.85 percent, respectively; that showed high performance of this method for no cutback option in comparison with the cutback option. Therefore, the use of data of all irrigation phases to estimate infiltration parameters shows better performance in the prediction of irrigation and water balance components. (run-off and infiltration).