The effect of land use changes on soil properties(case study: Mazdaran watershed)

Subject Areas : Agroecology Journal

seyedeh samereh pirzadeh ¹ , عباس احمدی ² , ali mohammad i torkashvand ³ , Abolfazl Moeini ⁴ , ابراهیم پذیرا ⁵

1 - agriculture
2 -
3 - Associate Professor, Department of Soil Science, Science and Research Branch, Islamic Azad
4 - Associate Professor, Department of Soil Science, Science and Research Branch, Islamic Azad University, Tehran,
5 - استاد دانشگاه آزاد اسلامی واحد علوم تحقیقات تهران

Received: 2022-11-22 Published : 2025-09-09

Keywords: Vegetation, land use change, deforestation, soil chemical properties, soil physical properties,

Abstract :

The conversion of forests and pastures to agricultural land is one of the major concerns regarding environmental degradation and global climate change. This study aimed to investigate the changes in physical and chemical properties of soil under different land uses. Accordingly, a topographic map at a scale of 1:25000 was provided by the Iran mapping organization, and the boundaries of the catchment area were determined. Then, a land use map was prepared using satellite images and aerial photographs. Points for digging profile holes were determined for each of the desired uses, resulting in a total of 19 profiles. In the area, some soil characteristics, such as depth and color, and so on, were determined and a description map for each profile was filled in. Samples were collected from each horizon for further analysis, and 52 samples were sent to the laboratory. A laboratory test was performed to determine the percentage of clay, sand, silt, organic matter percentage, pH, and EC. Ultimately, a one-way analysis of variance was performed to determine the relationship between soil properties and land use. Duncan's test was used to compare the means at a significant level of 5%. According to the results, defforestation, destruction of pastures, and subsequent continuous cultivation of these lands destroy some of the optimal physical and chemical properties of the soil. The results of this study indicate that changes in land use can lead to a decrease in soil organic carbon and soil porosity, followed by a decrease in soil hydraulic conductivity, leading to soil degradation and making it susceptible to erosion. Overall, it can be concluded that land use changes cause undesirable soil properties through soil degradation, increased erodibility, and decreased fertility

Full-Text:



اثر تغییرات کاربری اراضی بر ویژگی‌‌های خاک

 (مطالعه موردی: حوزه آبخیز مزداران)

 

سیده سامره پیرزاده1، علی محمدی ترکاشوند2 *، عباس احمدی3، ابوالفضل معینی4، ابراهیم پذیرا2

 

1- دانشجوی دکتری فیزیک و حفاظت خاک، گروه خاکشناسی، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی، تهران، ایران. 

2- استاد گروه خاکشناسی، گروه خاکشناسی، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی، تهران، ایران.

3- دانشیار گروه علوم و مهندسی خاک، دانشکده کشاورزی، دانشگاه تبریز، تبریز، ایران.

4- استادیار گروه آبخیزداری، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی، تهران، ایران.

 

([e-mail]*  : نویسنده مسئول)

چکیده

تغییر کاربري اراضی جنگلی و مرتعی به کشاورزي، به یکی از نگرانی‌‌هاي قابل‌توجه در سطح دنیا در زمینه تخریب محیط‌‌زیست و تغییر اقلیم جهانی، تبدیل شده است. هدف از این پژوهش، بررسی تغییرات خصوصیات فیزیکی و شیمیایی خاک در کاربری‌های مختلف بوده است. بدین منظور ابتدا نقشه توپوگرافی 1:25000 از سازمان نقشه‌‌برداری کشور تهیه و مرز حوضه، مشخص شد. سپس با استفاده از تصاویر ماهواره‌‌ای و عکس‌‌های هوایی، نقشه کاربری اراضی تهیه و در هر یک از کاربری‌های مورد نظر، نقاطی به‌منظور حفر پروفیل تعیین و در مجموع 19 پروفیل حفر شد. برخی خصوصیات خاک نظیر عمق‌، رنگ و غیره در منطقه تعیین و کارت تشریح برای پروفیل‌‌ها تکمیل گردید و از هر افق، نمونه‌‌ای برای سایر آزمایش‌‌ها برداشته‌شده و 52 نمونه به آزمایشگاه، ارسال گردید. در آزمایشگاه، فاکتورهای درصد رس، درصد شن‌، درصد سیلت، درصد مواد آلی، pH و EC تعیین گردید. نتایج نشان داد که جنگل‌تراشی و تخریب مراتع و به‌‌تبع آن کشت و کار مداوم در این اراضی، منجر به تخریب برخی از ویژگی‌‌های بهینه فیزیکی و شیمیایی خاک می‌‌شود. با توجه به نتایج این پژوهش، می‌‌توان اظهار داشت که تغییر کاربری اراضی می‌‌تواند سبب کاهش کربن آلی و تخلخل خاک و بدنبال آن، کاهش هدایت‌هیدرولیکی خاک شود. این تغییرات، سبب تخریب خاک شده و آن‌ را مستعد فرسایش می‌‌سازد. بنابراین، تغییر کاربری با تخریب خاک، افزایش فرسایش‌‌پذیری و کاهش حاصلخیزی، سبب ایجاد خصوصیاتی نامطلوب در خاک می‌‌شود.

 

کلیدواژه ها: پوشش‌‌گیاهی، تغییر کاربری اراضی، جنگل‌‌تراشی، شیمی خاک، فیزیک خاک

 

 

 

 

 

 

 

 

The effect of different land uses on characteristics of the soil

(case study: Mazdaran watershed)

 

Seyede Samereh Pirzadeh1, Ali Mohammadi Torkashvand*2, Abbas Ahmadi3, Abolfazl Moeini4, Ebrahim Pazira2

 

1- Ph.D. Student, Department of Soil Science, Science and Research Branch, Islamic Azad

University, Tehran, Iran.

2- Professor, Department of Soil Science, Science and Research Branch, Islamic Azad

University, Tehran, Iran.

3- Associate professor, Department of Soil Science, University of Tabriz, Tabriz, Iran.

4- Assistant Professor, Department of Soil Science, Science and Research Branch, Islamic Azad University, Tehran, Iran. 

 

* [e-mail] (Corresponding author)

 

Abstract

The conversion of forests and rangelands to agricultural land is one of the major concerns regarding environmental degradation and global climate change. This study aimed to investigate the changes in physical and chemical properties of soil under different land uses. Accordingly, a topographic map at a scale of 1:25000 was provided by the National Cartography Center of Iran (NCC), and the boundaries of the catchments area were determined. Then, a land use map was prepared using satellite images and aerial photographs. Points for digging profile holes were determined for each of the desired uses, resulting in a total of 19 profiles. In the area, some soil characteristics, such as depth and color, and so on, were determined and a description map for each profile was filled in. Samples were collected from each horizon for further analysis, and 52 samples were sent to the laboratory. A laboratory test was performed to determine the percentage of clay, sand, silt, organic matter percentage, pH, and EC. According to the results, deforestation, destruction of rangelands, and subsequent continuous cultivation of these lands destroy some of the optimal physical and chemical properties of the soil. The results indicate that changes in land use can lead to a decrease in soil organic carbon and soil porosity, followed by a decrease in soil hydraulic conductivity, leading to soil degradation and making it susceptible to erosion. Overall, it can be concluded that land use changes cause undesirable soil properties through soil degradation, increased erodibility, and decreased fertility.

 

Keywords: Deforestation, Land use change, Soil chemistry, Soil physics, Vegetation

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