Web Based Program for Estimating Evapotranspiration, Crop Water Requirements and Irrigation Water Demand A A Alazba and N A Alrdyan Alamoudi Water Research Chair, King Saud University
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ASABE International Symposium on Evapotranspiration Challenges in Measurements and Modeling from Leaf to Landscape Scale and Beyond Raleigh, North Carolina, U.S.A April 7-10, 2014 Abstract A software program running via the Internet has been developed to assess water requirements for irrigation. The research is divided into two main parts, one relating to calculations aspects and the other with software. Calculations aspects cover three parts: estimating evapotranspiration of reference by several mathematical models chosen by the user. This stage requires a number of climatic and geographic data entered by user, and then estimating evapotranspiration of the crop which requires a number of crop data entered by user, and then assessing water requirements for irrigation that requires a number of field data entered also by user. The user will be in front of three options for data entry method which are entered either directly from the keyboard, or by uploading a prepared file in advance with the option of saving the results in the personal computer of the user, or by downloading a prepared file in advance with the option of saving input data as well as the results that exist in the server which can be referenced at any time for modification or update. This software uses virtual values of climatic and geographic data as well as crop and field data, ensuring the initial operation. Software aspects include algorithms, flowcharts of mathematical models and flow charts Of mathematical models, software computer, computer programming of mathematical models and designing of input and output screens. This allows the estimate of requirements for irrigation water, depending on the data entered by the user and the user is given three options for: the review of the results only or printing or saving them on his personal computer or in the database according to whether user-type is a subscriber or normal user.
Introduction Our contemporary world is making rapid steps, shortening distances and time in the fields of technology, information, means of communication and networking in all aspects of life. Undoubtedly, the revolution of information and communications has re-shaped our world virtualizing a new mentality to deal with the new reality. The world is experiencing a qualitative change in economy, politics, culture, public relations and all other aspects of life. Furthermore, the modern means of communication provided opportunities that were not available to the previous generations, and the Internet have the lead within the world of information and communications technology and terminated the dominance of traditional means of communication which is an amazing way of development and transition of a modern technology to another one more sophisticated, in a way that allows a more quick transmission of information across the network. Computers and wireless monitoring devices will play a central role In the transmission of information. It is likely that the mobile phones, satellite communications, Internet technology will, increasingly, have the main role in the management of irrigation systems (Hoffman et al., 2007). Today's world faces a great challenge in harmonizing the requirements of food, clothing, which increase steadily due to the increase in the census, and the rationalization of the use of water. Filling this demand led to an increase in the agricultural area and, resulted, in turns, in increasing the reclamation of land and demand for water. The world at present is facing a water crisis, especially for the agricultural sector is being the largest consumer among other sectors, and in order to rationalize the water, the employment of modern techniques has to be optimized. The internet is one of those modern techniques that come in the most important place in the present day and using it in the estimate of water requirements for irrigation, which is of the most basic steps in the rationalization of water used in agriculture.
In this research, a software program running via the Internet has been developed to assess water requirements for irrigation. The research is divided into two main parts, one relating to calculations aspects and the other with software. Calculations aspects cover three parts: estimating evapotranspiration of reference by several mathematical models chosen by the user. This stage requires a number of climatic and geographic data entered by user, and then estimating evapotranspiration of the crop which requires a number of crop data entered by user, and then assessing water requirements for irrigation that requires a number of field data entered also by user. User will be in front of three options for data entry method which are entered either directly from the keyboard, or by uploading a prepared file in advance with the option of saving the results in the personal computer of the user, or by downloading a prepared file in advance with the option of saving input data as well as the results that exist in the server which can be referenced at any time for modification or update. This software uses virtual values of climatic and geographic data as well as crop and field data, ensuring the initial operation. Software aspects include algorithms, flowcharts of mathematical models And flow charts Of mathematical models, software computer, computer programming of mathematical models and designing of input and output screens. This allows the estimate of requirements for irrigation water, depending on the data entered by the user and the user is given three options for: the review of the results only or printing or saving them on his personal computer or in the database according to whether user-type is a subscriber or normal user.
Objectives This research aims to developing a software program running under the Internet environment to estimate water requirements for irrigation, in addition to the estimate of : Reference evapotranspiration and Crop evapotranspiration.
Materials and Methodology The work in this research covers two main sections, which are the section on calculation aspects, including mathematical calculations and the preparation of mathematical models, and the section concerned with the programming aspects including mathematical models programming and designing of input and output screens . Calculation Aspects This phase requires a range of materials including mathematical models to calculate the (reference evapotranspiration, crop evapotranspiration and water requirements for irrigation) in addition to a set of inputs data of climate and geography to complete the calculations for estimating reference evapotranspiration, and field data to complete the calculations to estimate crop evapotranspiration and water requirements estimate for irrigation. Programming Aspects Working on this phase requires a computer to complete the programming operations and computer softwares such as Excel and the PHP (Programming language for the Internet) in addition to a printer. Methodology
Calculation Aspects Water requirements are estimated for irrigation via three basic steps: (A) estimate of the reference evapotranspiration, and (B) calculating crop evapotranspiration, and (C) determination of water requirements for irrigation. A- Estimation of Reference Evapotranspiration Several mathematical models to estimate reference evapotranspiration have been used, the most important of which are Penman- Monteith Model, in its general form which is the best mathematical models to estimate referential evapotranspiration (Allen et al., 1998) so that reference
evapotranspiration can be estimated on the basis of grass or clover by reference entered crop. Calculations to estimate reference evapotranspiration require a group of Climatic and geographic data that differ from one model to another as shown in Table ( 3 ), and the user will give an opportunity to enter this data by the three options (1) either directly via the keyboard and this option is for the data of one day or limited data, (2) or downloading a preset file and giving a chance to the user to save the results in his personal computer, (3) or downloading a preset file and save the input data and results on a server so that the user can refer to his data at any time later time. B- Estimation of Crop Evapotranspiration: Evapotranspiration is the actual need of water amounts required for crops during the growth period, and the amount of water lost via the process of evaporation from leaf gaps. Given the difficulty of directly estimating evapotranspiration (ETc), it has been replaced by the reference evapotranspiration (ETref) and crop coefficient (Kc) . Applying this scientific concept, crop evapotranspiration is equal to reference evapotranspiration, multiplied by crop coefficient. The crop coefficient is the ratio between evapotranspiration for a particular crop under ideal or standard conditions (availability of water, plant free from diseases, good management) to reference evapotranspiration for reference crop of the same ideal conditions for specific crop intended to identify its needs. C- Estimation the Requirements of Irrigation Water Last calculations needs to estimate water requirements for irrigation (IWR) taking into account leaching requirements (LR), water losses during transport and during the addition expressed by the irrigation efficiency (Ei). For the requirements of washing requirements and the efficiency of irrigation system, user will be given an opportunity to enter the appropriate values and selection of irrigation method used, which can be calculated by the end user using the following mathematical equations (Allen et al., 1998: )
Default values for input data Been using a set of default values in the program to ensure the initial operation, divided the default values into three groups, namely (1) climate data and geography of the Kingdom of Saudi Arabia - Riyadh region and are in the process of estimating evapotranspiration of Reference, as well as the percentage of conversion results of evapotranspiration reference to the basis of clover to the grass would be 1.15 (clover / grass) ( Jensen et al., 1990 ), And (2) Data crop for estimating evapotranspiration of the crop will be taken from the Book of FAO 56 is to harvest lemons, and (3) requirements Algusalah and efficiency of irrigation (sprinkler irrigation) to estimate water requirements for irrigation and will be 0.10, 0.75, respectively.
Results The estimate water requirements for irrigation and the program works online environment does not require any installation on your PC and what is needed is to connect to the Internet and access the link program (URL: http://i-water.co). The program is a user friendly ad self-learning. Below, a number of snap shots are presented. Figures 1 and 2 are a snap shoot of the flow chart of the program algorithm and the home-page of the program, respectively.
Data Entry Methods
Start
The user selects one of the three options for data input via (Data Entry Methods) screen as shoen in Fig. 3. The three options are: From Keyboard; the data are manually entered via the keyboard. From File; the data can be entered by downloading the Excel file (Fig. 4) containing preset data necessary to complete the calculation, and the way in which the third and final (From Server Data Base) Means the data is retrieved via the databases of the device server that previously the user to save the data, but this method is available only to registered users as members of the program. The details will come later each method separately and how they work. And the picture number (12) describes the methods of data entry.
Go to URL:………………....
Select a reference crop
Programming Aspects This work is divided into three main sections, namely, (a) making logarithms and flowcharts, (b) computer programming, and (c) design input and output screens. a- Logarithms and Flowcharts Flowcharts has been made for all mathematical models to explain the functioning of calculations within each mathematical model, then a flowchart has been made for the program as a whole describes the functioning of the work in this program. b- Computer Programming There are Many of programming languages used in the world of programming and PHP was used (PHP: Hypertext Preprocessor) for several reasons Of which they are considered the most important languages of the most powerful existing due to its easy use and spread the great widespread as well as being a language free of charge and can be downloaded from its official website. c- Design input and output screens Input and output screens are designed via several programs such as Photoshop and front page, flash and other to be simple and easy to use and contains screen input to choose a mathematical model to estimate the reference evapotranspiration and entering of climate and geographic data and field crop to estimate reference evapotranspiration and then estimate crop evapotranspiration and then estimate water requirements for irrigation, and there is an option for the user to start the calculations. For screen output, user will just give several options, either a review of results only or printing them or saving them to the personal computer or in database according to his user account whether is it subscriber or normal user.
Figure 2. Program Homepage
Select the Model (s) to be Used for the Calculation of ETref
Select Data Entry Methods for the Calculator ETref
Is Select From Keyboard ?
Is Select From File ?
Upload the Data File
Figure 3. Data Entry Options Upload the Data File
Enter the Data in the Boxes
Preview the Result
Save the Report
Preview the Result
Print the Report Save the Report
Print the Report Send Report by Email
End
Figure 4. Excel File Format Figure 1. Program Flow Chart
