JOURNAL OF WATER AND SOIL RESOURCES CONSERVATION
Year:2019 | Volume:8 | Issue:4 |Papers Count:9

Evapotranspiration (ET) is one of the key parameters in water and energy balance equation. According to FAO 56, crop evapotranspiration (ETc) is calculated from multiplying reference evapotranspiration (ET0) by crop coefficient (Kc). But, due to excessive simplification of Kc curve in the FAO approach, potential evapotranspiration (ETp) would be miscalculated. Therefore, accurate estimates of ETp entail improving Kc estimates. In this study, Kc curves of early-and late-planted fodder maize and sugar beet were obtained based on two main satellite-based methods: (1) ratio approach (2) vegetation indices (VIs) approach. In the ratio approach, basal crop coefficient (Kcb) and single crop coefficient (Kc) was directly calculated from the ratio of potential transpiration (Tp) to ET0 (using SWAP) and ETp to ET0 (using SWAP and the Priestly-Taylor equation), respectively. The VI approach makes use of Landsat 7 (ETM+) and 8 (OLI) and also MODIS imagery in order to extract soil adjusted vegetation index (SAVI). The Kcb curves were evaluated against field measured leaf area index (LAI) in 2012 growing season. After each Kc curve was modeled, net irrigation requirement (NIR) was calculated on daily and season basis. Results showed that the SWAP approach was weak in estimating the Kcb and Kc curves especially at late-season stage. The VI approach could properly detect changes in vegetation cover during an entire growing season. But, when it came to Kc curve modelling, the VI approach was limited to the values given in FAO 56. However, the Priestly-Taylor approach compensated for the aforesaid limitation; therefore, yielded more sensible trends in Kc curves. Therefore satellite-based approaches derived from more realistic Kc curves during the entire growing season. Overall, making use of the satellite-based approaches could improve water management on regional scales.

In this research, effect of irrigation water crossing from fixed magnetized field on tape nozzle clogging and hydraulic properties of tape irrigation system as well as yield and water use efficiency in maize cv. Maxima were studied. The research was done from June to October in Research Farm of Zanjan University based on the complete randomized blocks in three replications with two treatments, irrigation water crossing and no crossing from field magnetic. Magnetic field was created by wire-tube method with an intensity of 0. 1 Tesla. At the end of the growing season, drip irrigation system was evaluated. In addition, yield and yield components of maize were measured. Based on the results, at no magnetic irrigation system, mean of a q, u E, C U and u D decreased as 18%, 3%, 2% and 3% (respectively) and v C increased 3% compared with magnetic irrigation system (significant differences). Calcite deposits in tape nozzles and their clogging caused it. Using magnetized water for maize watering increased total wet weight, total dry weight and leaf area (as 11%, 10% and 13%, respectively) comparing no magnetized watered crops and the differences were statically significant. As same water used for both magnetic and no magnetic treatments (5193 cubic meter per hectare), increasing of maize total wet weight in magnetic water caused significant increasing in water use efficiency as 1. 7 kg/m3 (11%).

One of the effective factors to identify the problems of watersheds is the daily suspended sediment load. Due to the lack of sufficient data in direct measurement of daily suspended sediment, intelligent models like the Genetic Expression Programing model (GEP) can be used to estimate it. In this research, the data of the machine hydrometric station was used in the Rood Zard watershed with a statistical period of 36 years (1977-2012). The input variables of the GEP model include instantaneous flow discharge (Q), average daily flow discharge (Qi) and average daily precipitation (Pi) with three steps of time delay and output variable to the model includes daily suspended sediment load. In order to reduce time and cost, pre-processing of input data into the GEP model was obtained using gamma test method and entered the GEP model along with non-preprocessing combinations of the test and error method. The results of comparison between all models showed that the best combination of input variable from gamma test with the lowest standard error is zero, gamma statistic is 0. 000092 and Vratio statistic is 0. 012 and the combination of variables including average daily flow discharge with two steps of time delay and average daily precipitation with three steps of time delay, had the most accurate and correct estimate for suspended sediment load. This model had the lowest value of RMSE=1671. 90 (ton/day) and MAE=475. 68 (ton/day) and the highest value of R2=0. 99 and NSE=0. 99 compared to other models. Therefore, the use of gamma test method as a data preprocessing method, by selecting combinations of appropriate input variables to models, an average of up to 40% of the estimated error (RMSE) of daily suspended sediment load compared to the inputs from the test and reduce the error and increase the performance of the GEP model in estimating the suspended sediment load by increasing the similarity between the values of observational data with computational data.

Soils from the industrial areas in the south of Bandar Abbas County are susceptible to contamination by the export terminal, metal and non-metallic industries. In this research, the concentrations of selected potentially toxic elements in order to determine the contamination level, source and assessment of ecological risk index, also health risk assessment to determine the quantity of potential carcinogenic and non-carcinogenic risks of the elements in the soil of this area was investigated So that a total of 66 soil samples were collected. The Enrichment Factor (EF) and Ecological Risk Index were calculated to measure the contamination level. Principle component analysis (PCA) was used to determine the sources of heavy metals pollution, and also the health risk assessment was used in three ways: ingestion, inhalation and dermal contact. Results indicated that the average of EF for studied elements decreased in the order of Cu, Cd, Pb, Zn, As, Ni and Cr. The mean value of the ecological risk of Cu and Cd indicates medium and high ecological risk, respectively. The Hazard index for all selected elements through ingestion, inhalation and dermal contact in children is higher than that of adults. The results of EF and PCA indicate that the As, Cd, Cu, Pb and Zn have been affected by anthropogenic sources. As, Cr and Cd were regarded as the priority pollutants and Cancer risks in soils were within tolerable risk to human health.

The main objective of this study was to investigate the effect of possible non-structural management schemes with no need of changing irrigation systems and optimal use of agricultural water at the farm level, including improving irrigation water efficiency, changing planting dates and deficit irrigation with preserving the composition and area under cultivation in the region, . Management interventions were designed based on present irrigation management (amount, number of irrigation, etc. ). The main goal was to improve the optimum use of water in the agricultural sector to prevent the continuation of excessive withdrawal of groundwater resources. The information was collected directly from 158 farms, which represents the distribution of the existing conditions of the whole region, and the scenarios for improving the efficiency of irrigation were based on improving available higher efficiency in the region The results showed that improvement of irrigation efficiency for dominant crops in two regions of Dorodzan and Korbal, leads to savings in water allocation by 131. 5 (11. 2%) and 33. 8 (10. 83%) million cubic meters, respectively. Management scenarios of change in planting date using AquaCrop model simulation showed that upto 31. 6 (2. 7%) and 9. 17 (2. 94%) million cubic meters of water in the two regions of Dorodzan and Korbal can be saved. At the same time, different levels of deficit irrigation can reduce water consumption by 85. 5 (7. 3%) and 26. 2 (8. 4%) million cubic meters respectively. . All in all the results of this study show that in many cases, significant amount of water can be saved with minimal operation costs and preserving the existing structural conditions, even without changing the pattern of cultivation.

Although the use of fertilizers in poor soils is necessary to increase soil fertility and optimal plant growth, but in recent years, the use of chemical fertilizers has caused a lot of environmental damage, The aim of this study was to investigate the effect of different levels of modified biochar sugarcane bagasse and potassium zeolite as natural and environmentally friendly fertilizers on some physical and chemical properties of soil in a completely randomized design with four replications for three months per year 2018 was conducted at the Faculty of Water Engineering, Shahid Chamran University of Ahwaz. The levels of biochar and zeolite use included three levels of 0, 2 and 5 grams per kg of soil (0, 0. 2 and 0. 5 wt%). The results showed that the 2 and 5 grams biochar per kg of soil increased the total porosity by 3. 7% and 9. 2% respectively, 9. 6% and 19% moisture content of crop capacity, 1 and 1. 5% moisture content of wilting point, 9. 8% and 21. 3% organic carbon, 9% and 18% of absorbable phosphorus, 8% and 22% of nitrogen, 6. 5% and 27. 9% of electrical conductivity, 3. 3% and 8% respectively of bulk density and 0. 26% 0. 92 percent soil acidity. The levels of 2 and 5 grams of zeolite per kilogram of soil also increased 2 and 6 percent bulk density, 2. 33% and 3. 89% specific gravity, 10. 1% and 26. 5 percent moisture content, 1. 1% And 6. 3% moisture content of wilting point, 0. 65 and 1. 05% of acidity, 9. 1% and 33. 5% of electrical conductivity, 0. 09% and 3. 4% of total porosity, 0. 26% and 0. 92% respectively Soil acidity was not significant and did not have a significant effect on specific gravity, organic carbon, absorbable phosphorus and soil nitrogen. In general, the results indicate superiority of biochar treatment to zeolite treatment is due to the improvement of physical and chemical properties of loamy soil.

The lack of water and soil resources and their salinity are important points in the agricultural sector. Investigating the interactions between salinity and irrigation on plant yields is important in order to improve soil management and water use in arid and semi-arid regions. The purpose of this study was to study and evaluate the production functions of Basilicum L. in Mazandaran mass cultivar under simultaneous stress conditions of water and salinity. For this purpose, an experiment was conducted on a hectare research site in the Dushantepheh research center of Tehran. In this study, we used microplate weight-drainage to determine the rate of evaporation-transpiration of basil plant. Factorial experiment was conducted in a completely randomized design with four irrigation treatments including complete irrigation (FI), irrigation with 40 (DI40%), 60 (DI60%) and 80 (DI80%) water requirements of the plant and three subsoil treatments Irrigation water with a conductivity of 175/1 (S1), 3 (S2) and 5 dS / m (S3) for two consecutive years of 1395 and 1396 was carried out. The results showed that the basal plant yield reduction was 3. 1 dS / m for irrigation water salinity and 10% for grazing line slope. Also, the highest amount of fresh leaf with 3080 and 3076 kg / ha, the highest leaf area index with 85840 and 85537 kg / ha, the highest yield of material was 5998 and 5966 kg / ha, and the highest dry matter yield was 3782 and 3698 kg ha-1 was obtained in full irrigation treatments in 1395 and 1396 respectively. In the case of production functions, the results also show that the exponential production function has a higher accuracy for performance estimation.

Over the past decades, several rainfall-runoff models including global hydrological model (GHMs) and land surface models (LSMs) have been developed for simulation of hydrological variables. One of the most important problems that limits the using of such models is that these models require a huge amounts of inputs and providing them is almost impossible, especially in data-limited regions. The main objective of this study is to assess the performance of Earth2Observe's GHMs and LSMs reanalysis models in estimating runoff at the outlet of Sefidrood river basin (SRB). In addition, for better evaluating the efficiency of Earth2Observe uncalibrated models, the VIC-3L land surface model is implemented over the SRB and calibrated using observed discharges. Results showed that, based on CC and NS statistics, the performance of SURFEX-TRIP model in both daily and monthly time scales is the best one and it led to the same results as well as VIC-3L calibrated model. The values of CC and NS statistics, at daily time scale, in the case of SURFEX-TRIP model are 0. 75 and 0. 55, respectively, while at the monthly time scale these values are 0. 86 and 0. 73, respectively. As an overall, findings indicate that LSMs performs better than GHMs in simulating runoff and this may be due to the ability of LSMs in considering both water and energy budgets and they can exchange energy and mass between land surface and atmosphere. Therefore it is highly recommended to use the results of reanalysis models as an appropriate guidance, particularly in the cases of ungauged catchments or data restricted areas.

The comprehensive management of a watershed requires basic informations such as land use and land cover. The aim of this study is to conduct accuracy analyses of land use/land cover classifications derived from Landsat-8 data, and to reveal that which kind of land use and land cover can be estimated more accurately. Tarom Basin and its near surrounding (Zanjan, Guilan, Ardebil and East Azerbaijan) was selected as study area for this case study. Landsat-8 the data, acquired on 8 August 2017, were utilized as satellite imagery in the study. The RGB (RED, Green, Blue) and NIR (Near Infrared) bands were used for classification and comparison the results with ground samples. Required pre-processing and control of georeferenced of images were performed. After performing the required atmospheric corrections, using the FLAASH algorithm, classification maps were generated. LULC images were generated using 3 pixel-based supervised classification method method, Maximum Likelihood (MLC), Support Vector Machine (SVM) and Artificial Neural Network (ANN). As a result of the accuracy assessment, kappa statistics and overall accuracy for MLC method were 0. 88 and 91. 55 respectively. The obtained results showed that Landsat-8 OLI data, presents satisfying LULC images in water body, mountain and rock, bare land, Vegetation and forest classes. In addition, according to the obtained results, it can be stated that all three methods of classification in a region with heterogeneous (in terms of elevation elevation between 280 and 3000 m and land use and variety of vegetation) Such Tarom, can have good results. Among these methods, Classification with MLC method, had higher speed and lower complexity for execution, than two other methods in achieving the required maps.