نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم و مهندسی خاک، دانشکده مهندسی آب و خاک، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران.
2 گروه مدیریت مناطق بیابانی، دانشکده مرتع و آبخیزداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران.
3 گروه باستان شناسی، دانشکده علوم انسانی, موسسه آموزش عالی معماری و هنر پارس، تهران، ایران.
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
One of the widely used elements that plays an important role in sustainable agricultural production is potassium.The potassium in the surface soil of the playa originates from the potassium present in the underground water. As a result, there is a correlation between the surface soil potassium and the potassium grade of the groundwater. The aim of this research is to utilize a combination of the random forest (RF) algorithm and satellite imagery to establish the relationship between soil surface potassium and remote sensing indicators. This will enable the prediction of the potassium grade of the underground in Khoor and Biabank playa in Isfahan province. For this purpose, 60 soil samples were taken from the 0-5 cm layer to measure potassium in the surface layer(dependent variable). In order to determine the sampling coordinates, the Latin supercube method was used. Twelve boreholes were drilled to extract and measure the potassium grade of underground saline water. The 12 bands of the Sentinel-2 satellite and four main mathematical operations were used to define the index (independent variables) to model the potassium content of the surface soil layer and ultimately estimate the rate of potassium grade in the underground saline water. The data were categorized into two groups: 70% for calibration (training) and 30% for validation (testing). The data were modeled using the RF algorithm in the Google Colab environment and implemented with the Python programming language. The results of this algorithm were obtained with R2, MSE, RMSE and MAE statistical indices of 0.51, 0.0179, 0.1338 and 0.1130 respectively. The results of this research confirm the effectiveness of remote sensing data and machine learning algorithms in predicting the potassium grade of saline groundwater.
کلیدواژهها [English]
Estimating the potassium grade of saline underground water using Sentinel satellite images and random forest algorithm
(case study of Khoor and Biabank playa, Isfahan province)
EXTENDED ABSTRACT
In recent decades, with the increase in population growth and the growing need to produce more food, today more than 90% of potassium production is used as fertilizer. One of the main sources of potassium fertilizers is saline water underground. One of the main mineral elements in saline water underground is potassium, which is found in the playa. Due to the environmental conditions of the playa, there is a lot of evaporation and it leads to the precipitation of soluble solutes on the surface. By examining these sediments, it is possible to determine areas with grade high potassium levels for extracting salt water underground in the playa but the complex climatic conditions that govern it make field measurements to estimate the grade of difficult. One of the new methods to estimate mineral resources is the combined use of machine learning algorithm and remote sensing.
The main purpose of this research is to use remote sensing and random forest algorithm to estimate the surface potassium of playa soil and to evaluate the relationship between potassium, and index of satellite images to estimate the grade potassium saline water underground , which is the innovation of this research compared to other previous researches.
In this research, the use of remote sensing and random forest algorithm was used to estimate the surface potassium of playa soil and to evaluate the relationship between potassium, and the index of satellite images to estimate the potassium grade of underground saline water.For this purpose, 60 samples of surface layer potassium (dependent variable) were sampled from the 0 - 5 cm layer using Latin hypercube method. Also, in 12 drilling boreholes, the potassium grade of saline water was measured in December 1400. because there was no related satellite index that has a high correlation with soil surface potassium. By using 4 basic arithmetic operations (addition - subtraction - multiplication and division) between SENTINEL 2 satellite image bands and by writing a new code (specific to the study) 61 million times, the code was executed with different combinations to produce new index. A regression model was used to estimate potassium grade of underground saline water , which was converted to the potassium grade of underground salinewith a potassium equation of the surface layer.The Sentinel 2 satellite image and the resulting indicators from this satellite (independent variables) were used to predict the potassium of the surface layer and finally estimate the potassium grade of underground saline water Also, Permutation Feature Importance (PFI) method was used in the RF model to prioritize and select parameters for modeling. The data were divided into two categories: 70% for calibration (training) and 30% for validation (testing) and were implemented in the random forest model in the Python programming environment.
results of the actual measured values and the predicted values of surface potassium with the RF model is based on the statistical indicators of the evaluation of the ML models including R2, MSE, RMSE and MAE The results of the model showed that the calibration data with R2 equal to 0.88 and MSE, RMSE and MAE equal to 0.0039, 0.0624 and 0.0460, respectively, as well as statistical indicators of R2, MSE, RMSE and MAE for the validation data of the model It is 0.51, 0.0179, 0.1338 and 0.1130 respectively. The results show that Index 3, Index 2, Index 4, Index 5 have the greatest effect on the estimation of soil surface potassium and potassium grade of saline water and Index 15, Index 14, Index 11 and Index 12 have the least effect.
Random forest algorithm by combining remote sensing technology with prioritizing effective indicators and finding meaningful relationships between variables and specifying important parameters as an efficient tool for extensive mapping of large areas for cases where predicting an important variable in the traditional way due to Spatial diversity. And when it is difficult and expensive to predict them, it will be very efficient and it will make it very easy to determine the parameters and prepare the map with a short period of time and spending much less money. Considering that there are many playas in the country that have potassium resources, determining the most important parameters with machine learning technology and remote sensing is a useful tool in managers' decision making in order to invest in drilling in promising areas for saline water underground extraction It has an effective role. Since the conditions of the playa in the are not very different, it is possible that the results of this research can be generalized to other playas in the desert to determine the potassium grade of saline water in the desert, in which case it is possible to estimate the potassium grade of saline water in the will be playa using satellite images.