saleh mahmoom salkovyeh
Abstract
Introduction: Deficit irrigation is a management strategy for increasing water productivity. The yield loss can be compensated by saving water consumption under deficit irrigation. Increasing water productivity is a key factor in removing the biggest challenge facing the agricultural sector in water-limited ...
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Introduction: Deficit irrigation is a management strategy for increasing water productivity. The yield loss can be compensated by saving water consumption under deficit irrigation. Increasing water productivity is a key factor in removing the biggest challenge facing the agricultural sector in water-limited areas, which means less water production. In order to achieve this, awareness of the relationship between water and yield, known as production functions, can be of great help in this regard.
Materials and Methods: An experiment was carried out on a plot of 96 × 30 × 30 m2 based on a plot in a factorial arrangement in three replications. The main treatments consisted of six main hydrothermal treatments (0%, 33%, 66%, 85% 100% and 125% water requirement) and sub-treatments including four levels of fertilization (0%, 33%, 66% and 100% fertilizer requirement), and two cultivars named Golestan and B 557. Furthermore, the irrigation planning based on soil moisture discharge ranged from 5% to 70%. In this experiment, single branch sprinkler irrigation system was used, therefore 144 plots (6 water × 4 fertilizers × 2 digits × 3 repeats) were, created on the sides of the pipeline. On each cropping line, 20 cm spacing on each row and at a row spacing of 75 cm were cultivated. For each plot, the dimensions were 2.5 × 2.3 m (2.5 m in the direction of irrigation, and 3 m along the irrigation line). Soil samples were collected from each depth of 0-5, 20-20, 20-40 and 40-60 cm before each irrigation. The moisture content was determined by weighing method. Based on the physical properties of the soil (bulk density, percentage of moisture content in field capacity and wilting point), effective depth of root and field management (MAD) 60-70% (based on previous studies), the depth of irrigation water was calculated. 40% of N-fertilizer application was carried out prior to sowing and the remaining N-fertilizer was applied from flowering stage with first irrigation and based on different treatments. The irrigation time was determined by dividing the irrigation water depth by the intensity of the sprinklers. 6I treatment due to the close proximity to the sprinklers received the largest amount of water and treatment 1I received the lowest amount of water (rain) as it was situated outside of the spray nozzle radius. From the beginning of planting, the irrigation program was carried out according to the amount of soil moisture at the irrigation time of the 5I treatment (100% water requirement). Therefore, it is expected that treatment 6I has received water more than water requirement. The total amount of water received by each row of crops during the growth period was measured by placing a water collecting canal mounted on a tripod to a height of 1 meter. After irrigation, by using cylinders the depth of water collected in the cans was measured. Due to wind blowing during the day, irrigation was carried out at night, to maintain the uniformity of water distribution. The final harvesting operation was performed for all treatments and replicates on first and second of November. a relationship and the corresponding regression coefficients were obtained between the irrigated yield and the each cultivar and fertilizer level separately, .
Results and Discussion: The quadratic relationship was determined between the yield and the applied water. The coefficients values of the quadratic equation of production function were calculated for each fertilizer application and cultivars and were showed in Tables 5 and 6. The yield functions of cotton cultivars versus applied water were in the form of a second-order quadratic with a downward contraction. Initially, the gradient of the graph was high and then its intensity decreased indicating that water efficiency is much higher in irrigation. In addition, by increasing the amount of irrigation, the amount of the product reached to the peak value, and since then, a yield reduction was observed as applied water amount increased owing chiefly to N-leaching. The sensitivity coefficients for Golestan cultivars and 557 B were calculated at four levels of fertilizer according to the Doorenbos and Kassam formula. The average sensitivity coefficient for Golestan and B-557 was 1.18 and 1.27, respectively.
Conclusions: It can be concluded that the Golestan cultivar is less sensitive to water shortage as compared with B-557. These results can be used to optimize water use under water constraints.
A. Kiani; A. Hezarjaribi; T. Dehghan; M. Khoshravesh
Abstract
Introduction: Water scarcity is one of the major problems for crop production. Using drip irrigation as an effective method in the efficient use of water is expanding in arid and semi-arid regions. One of the problems in under pressure irrigation during use of saline, unconventional and waste is emitters ...
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Introduction: Water scarcity is one of the major problems for crop production. Using drip irrigation as an effective method in the efficient use of water is expanding in arid and semi-arid regions. One of the problems in under pressure irrigation during use of saline, unconventional and waste is emitters clogging. There are several ways to prevent particle deposits in pipes and clogging of emitters. Generally, conventional methods are divided into two categories: physical and chemical methods. In physical method, suspended solids and inorganic materials are removed using particles sediment sand and disc filters. In the chemical method the pH drops by adding acid to water resulting in the dissolution of carbonate sediments. With chlorine handling, organisms (i.e. algae, fungi and bacteria) that are the main causes of biological clogging are destroyed. However, the application of these methods is not successful in all cases. It has been observed that the emitters have gradually become obstructed. Magnetic water is obtained by passing water through permanent magnets or through the electromagnets installed in or on a feed pipeline. When a fluid passes through the magnetized field, its structure and some physical characteristic such as density, salt solution capacity, and deposition ratio of solid particles will be changed. An experimental study showed that a relatively weak magnetic influence increases the viscosity of water and consequently causes stronger hydrogen bonds under the magnetic field.There exist very few documented research projects related to the magnetization of water technology and its application to agricultural issues in general and emitter clogging in drip irrigation method, in particular. This technology is already used in some countries, especially in the Persian Gulf states. This research was designed and implemented aimed at increasing knowledge about the application of magnetic technology and its effects on emitters clogging in the drip irrigation system.
Materials and Methods: A field experiment was carried out in 2011 in Gorgan Agricultural Research Station to study emitter clogging in drip irrigation using magnetic, non-magnetic and acidic water under salinity condition. The geographical location of the farm was 36° 55′ N, 54° 25′ E and 13.3 m above mean sea level with annual rainfall 400-450 mm. The experiment was laid out with a split plot in a complete randomized block design with three replications. The treatments included three treatments of the management of emitters clogging including, magnetized water (M), non-magnetized water (N) and acidic water (A) plus using three water quality levels namely, well water (S1), saline waters 7 (S2) and 14 (S3) dS m-1. Two methods were simultaneously used to magnetize water. In the first method, an electromagnet was installed around the sub-main pipe before the flow of water to the laterals. The amount of power required to magnetize the irrigation water was 0.03 kW-h of electricity per m3 of water. In the second method, the permanent magnets (ceramic magnets) were installed around the sub-main pipe before the laterals. In the second method the power requirement was 0.3 Tesla. To assess the emitter clogging, discharge and its variations as a function of time, emission uniformity, uniformity coefficient, and coefficient of variation were estimated and analyzed.
Results and Discussion: The results of variance analysis showed that the effect of different irrigation management in irrigation system (N, M and A treatments) and different levels of water quality on all parameters were significant. Statistical comparison showed that in all cases there were no significant differences between magnetized water and non-magnetized water treatments. However, acidic water was statistically different from the two types of water mentioned. Both magnetic and conventional indices were examined in this study. However, no significant difference was observed. But in all cases, using magnetic water is advantageous compared with using non-magnetized water. The overall results have shown that the use of magnetized water in this study, in the non-saline water condition, does not offer a relatively higher advantage compared to the use of non-magnetized water.
Conclusion: For saline water, insignificant differences were observed between magnetic and non-magnetic water treatments, however magnetic water was slightly preferable. Most of the indicators that were assessed showed that acid water treatment was significantly different from magnetic and non-magnetic water treatments. Thus, acid water treatment is not preferable. Emitter clogging with increase of time and the salinity level of irrigation water increased; the greatest difference between the treatments occurred in S3 and the last irrigation treatments. Magnetic water up to salinity level of 7 dS m-1, had no effect on the flow rate and thus on the emitter clogging. However, when using saline irrigation water and also with the increase of time, emitter clogging in magnetic water treatment was lower compared with non-magnetic treatment.
Keywords: Emitters clogging, Magnetized water, Saline water
A. Hezarjaribi; F. Nosrati Karizak; K. Abdollahnezhad
Abstract
Cation Exchange Capacity (CEC) is an important characteristic of soil in view point of nutrient and water holding capacity and contamination management. Measurement of CEC is difficult and time-consuming. Therefore, CEC estimation through other easily-measurable properties is desirable. The purpose ...
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Cation Exchange Capacity (CEC) is an important characteristic of soil in view point of nutrient and water holding capacity and contamination management. Measurement of CEC is difficult and time-consuming. Therefore, CEC estimation through other easily-measurable properties is desirable. The purpose of this research was to investigate CEC estimating using easily accessible parameters with Artificial Neural Network. In this study, the easily accessible parameters were sand, silt and clay contents, bulk density, particle density, organic matter (%OM), calcium carbonate equivalent (%CCE), pH, geometric mean diameter (dg) and geometric standard deviation of particle size (σg) in 69 points from a 1×2 km sampling grid. The results showed that Artificial Neural Network is a precise method to predict CEC that it can predict 82% of CEC variation. The most important influential factor on CEC was soil texture. The sensitivity analysis of the model developed by using of Artificial Neural Network represented that clay%, silt%, sand%, geometric mean diameter and geometric standard deviation of particle size, OM% and total porosity were the most sensitive parameters, respectively. The model with clay%, silt%, sand%, geometric mean diameter and geometric standard deviation of particle size as inputs data was selected as the base model to predict CEC at studied area.
Hossein Sharifan; P. Mokhtari; A. Hezarjaribi
Abstract
By considering the shortage of water resources in our country and dominant share of agriculture in making use of these resources, economizing and saving in this sector and using management practices for raising the efficiency of water consumption is necessary and essential. Super absorbent polymers, ...
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By considering the shortage of water resources in our country and dominant share of agriculture in making use of these resources, economizing and saving in this sector and using management practices for raising the efficiency of water consumption is necessary and essential. Super absorbent polymers, polymer gel, Are hydrophilic and are able to absorb a vast amount of water, Salt water, or physiological solutions and enhance the act of saving water in soil. Using super absorbent polymer is one of the methods that enhances the utilization of water that not only provide conditions which makes quality performance better, it also considerably increases the water use efficiency. In this research we examined the effect of super absorbent on the infiltration equation parameters (Kostiakov _ Lewis) through the advance time calculated and the effects of superabsorbent on these equations also were examined. The experiment were performed in the educational farm of the university of natural resources and agriculture in a no cultivation conditions.in this research four combinations of superabsorbent polymer A200 with soil which were composed of 0,7,11,16gr of polymers in square at a depth of 25cm and the electric current was 0.75 liter per second were considered. The experiment were performed four times. The results indicated that by adding polymers A200 to the soil, advance time and rollback time were increased. also therefore the Infiltration and the cumulative soil Infiltration were increased.
M. Ghabaei Sough; A. Mosaedi; M. Hesam; A. Hezarjaribi
Abstract
Abstract
Process of evapotranspiration (ETo) is a major component of the hydrologic cycle that its accurate estimation plays an important role to achieve sustainable development in water balance, irrigation system design and planning and management of water resources. Being a function of different metrological ...
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Abstract
Process of evapotranspiration (ETo) is a major component of the hydrologic cycle that its accurate estimation plays an important role to achieve sustainable development in water balance, irrigation system design and planning and management of water resources. Being a function of different metrological parameters and their interactions, evapotranspiration is a complex, nonlinear phenomenon. Preprocessing input parameters to select appropriate combinations is complex when modeling nonlinear systems. Using these methods reduce steps by trial and error by recognizing most important parameters for modeling by intelligent methods. In this study, two methods of stepwise regression (FS) and gamma test (GT) were used for preprocessing input parameters in multi layer perceptron neural network (MLP) to estimate daily estimation of ETo at Shiraz synoptic station. To evaluate the effect of Input parameters preprocessing in artificial neural networks using different statistical error criteria, ANN-FS and ANN-GT both with pre-processed parameters were compared against each other and also with ANN model without pre-processed parameters. The results showed that all three models have a high degree of accuracy to estimate daily ETo. ANN-GT model represented a determination coefficient (R2) of 0.9995 and the root mean square error (RMSE) of 0.0483. For ANN-FS and ANN models R2 values were 0.9984 and 0.9994 respectively and RMSEs were 0.0874 and 0.0548 respectively. Although the accuracy of ANN-GT model was slightly greater than ANN, but the ability of determination of importance of input parameters, education and recognition of the best combination of input parameters with 800 data in this study, makes this model a useful tool for fast preprocessing input parameters to model evapotranspiration.
Keywords: Potential evapotranspiration, Artificial neural networks, Gamma test, Stepwise regression, Shiraz synoptic station
