نوع مقاله : مقالات پژوهشی
نویسندگان
1 دانشگاه تبریز
2 دانشگاه تهران
3 دانشگاه گیلان
چکیده
افزایش عملکرد گیاهان زراعی تحت تأثیر عوامل مختلفی از جمله ویژگیهای خاک همچون عناصر غذایی موجود در آن است. تعیین درجه حاصلخیزی خاک برای مشخص کردن میزان کوددهی بسیار مهم بوده و بدون توجه به این موضوع، مصرف کودهای شیمیایی، نه تنها باعث افزایش عملکرد محصولات کشاورزی نمیشود، بلکه باعث تحمیل هزینههای اضافی، به هم خوردن تعادل عناصر غذایی در خاک و مسائل زیست محیطی میگردد. بنابراین تهیه نقشه حاصلخیزی و تعیین درجه آن ضروری به نظر میرسد. از طرفی منطق فازی برای تهیه نقشهها در علوم مختلف به ویژه علوم خاک بهطور گسترده مورد استفاده قرار میگیرد. لذا انتظار میرود باعث افزایش کارایی نقشههای حاصلخیزی خاک برای محصولات کشاورزی مختلف گردد. در این مطالعه تلاش شده است تا با تهیه نقشه حاصلخیزی خاک در نواحی مرکزی استان گیلان، با استفاده از منطق فازی و فرآیند تحلیل سلسله مراتبی در محیط نرم افزار ArcGIS وضعیت منطقه از نظر حاصلخیزی برای گیاه برنج ارزیابی شده و دقت نقشه مربوطه با استفاده از این روشها نسبت به روشهای سنتی افزایش یابد. جهت نیل به اهداف، مقادیر کربن آلی، فسفر و پتاسیم خاک که از 117 نقطه مورد مطالعه اخذ شده بود، وارد مدل شدند. ابتدا درونیابی این نقاط برای هر سه پارامتر با استفاده از روش کریجینگ در محیط GIS4 انجام شد. سپس برای هر یک از پارامترهای مورد مطالعه با تعریف تابع عضویت S شکل، نقشه فازی تهیه گردید. پس از تعیین تابع عضویت، نقشههای مربوط به هر سه پارامتر با استفاده از AHP5 وزندار شده و از روی هم اندازی لایهها، نقشه حاصلخیزی خاک تهیه شد. مقایسه نقشه فازی و نقشه تهیه شده به روش بولین با استفاده از مقادیر پارامترها در نقاط نمونهبرداری مجدد برای کنترل دقت نقشهها نشان داد که منطق فازی با AHP میتواند با افزایش دقت و کارایی نقشه، در استفاده بهینه از کودها مؤثر باشد. همچنین مقادیر معیارهای واریانس نسبی و ضریب توجیهپذیری نشان داد که نقشه فازی، تغییرات پارامترها را به خوبی تفکیک کرده است.
کلیدواژهها
عنوان مقاله [English]
Increasing Efficiency of Soil Fertility Map for Rice Cultivation Using Fuzzy Logic, AHP and GIS
نویسندگان [English]
- javad seyedmohammadi 1
- leila esmaeelnejad 2
- Hassan ramezanpour 3
1 University of Tabriz
2 University of Tehran
3 University of Guilan
چکیده [English]
Introduction: With regard to increasing population of country, need to high agricultural production is essential. The most suitable method for this issue is high production per area unit. Preparation much food and other environmental resources with conservation of biotic resources for futures will be possible only with optimum exploitation of soil. Among effective factors for the most production balanced addition of fertilizers increases production of crops higher than the others. With attention to this topic, determination of soil fertility degree is essential tobetter use of fertilizers and right exploitation of soils. Using fuzzy logic and Analytic Hierarchy Process (AHP) could be useful in accurate determination of soil fertility degree.
Materials and Methods: The study area (at the east of Rasht city) is located between 49° 31' to 49° 45' E longitude and 37° 7' to 37° 27' N latitude in north of Guilan Province, northern Iran, in the southern coast of the Caspian sea. 117 soil samples were derived from0-30 cm depth in the study area. Air-dried soil samples were crushed and passed through a 2mm sieve. Available phosphorus, potassium and organic carbon were determined by sodium bicarbonate, normal ammonium acetate and corrected walkly-black method, respectively. In the first stage, the interpolation of data was done by kriging method in GIS context. Then S-shape membership function was defined for each parameter and prepared fuzzy map. After determination of membership function weight parameters maps were determined using AHP technique and finally soil fertility map was prepared with overlaying of weighted fuzzy maps. Relative variance and correlation coefficient criteria used tocontrol groups separation accuracy in fuzzy fertility map.
Results and Discussion: With regard to minimum amounts of parameters looks some lands of study area had fertility difficulty. Therefore, soil fertility map of study area distinct these lands and present soil fertility groups for better management of soil and plant nutrition. Weight of soil parameters was0.54, 0.29 and 0.17 for organic carbon, available phosphor and potassium, respectively. Fuzzy map of study area includes five soil fertility groups as: 22.9% very high fertility, 27.7% high fertility, 35.53% medium fertility, 10.48% low fertility and 3.39% very low fertility. Consequently, a separated map for soil fertility prepared to evaluate soil fertility of study area for rice cultivation. Toinvestigatethe efficiency of fuzzy model and AHP in increasing the accuracy of soil fertility map, soil fertility map with Boolean method prepared as well. Boolean map showed 58.88% fertile and 41.12% unfertile.15 soil samples from different soil fertility groups of study area were derived fromcontrol of maps accuracy. 13 renewed samples of 15 and 9 soil samples have matched with fuzzy and Boolean map, respectively. Comparison of parameters mean in fuzzy map fertility groups showed that parameters mean amounts of very high and high fertility groups are higher than optimum level except potassium that is a few lower than optimum level in high fertility group, therefore, addition of fertilizers in these groups could not be useful to increase rice crop production. Phosphorus parameter amount is lower than the critical level in very low, low and medium fertility groups, then in these groups phosphorus fertilizer should be added to the soil toincreaserice production. The amount of potassium parameter is higher than the critical level and lower than optimum limit in very low, low, medium and high fertility groups, then in these groups addition of potassium fertilizer will results in theincrease of production. Organic carbon amount is lower than optimum level in very low and low fertility groups. With regard to the relation between organic carbon andnitrogen and phosphorus, therefore, the addition of organic carbon fertilizer could compensate deficit of nitrogen and phosphorus in these groups as well. Attention to the presented explanations and comparison of fuzzy and Boolean maps using parameters amounts in renewed sampling points for control of maps accuracy, it is distinct that fuzzy logic could influencetheoptimum using of fertilizers with increasing map efficiency and accuracy. In addition, relative variance and correlation coefficient amounts showed that fuzzy map has separatedquite wellparameters changes.
Conclusion: Effective parameters in soil fertility, includingorganic carbon, phosphorus and potassium were used topreparesoil fertility map for rice cultivation. With regard to the minimum amounts of parameters looks some lands of study area had fertility difficulty. Therefore, soil fertility map of study area distinct these lands and presents soil fertility groups tobetter management of soil and plant nutrition. Fuzzy and Boolean methods were used topreparesoil fertility map. Comparison of these two approaches showed that fuzzy method with AHP caused to increase theefficiency and accuracy of fertility map for rice. Separated and distinguish soil fertility groups in fuzzy map help suitable distribution and optimum use of fertilizers for rice production.
کلیدواژهها [English]
- Analytic Hierarchy Process
- Fertility map
- Fuzzy
- Geographic Information System
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