نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه خاکشناسی، دانشکده کشاورزی، دانشگاه زنجان، زنجان ایران

2 عضو هیئت علمی دانشگاه زنجان

3 گروه خاکشناسی، دانشکده کشاورزی، دانشگاه صنعتی شاهرود، شاهرود، ایران

4 گروه خاکشناسی، دانشکده کشاورزی، دانشگاه زنجان، زنجان ، ایران

چکیده

تخمین روند تغییرپذیری مکانی ویژگی‌های مختلف خاک، راهکاری سودمند برای دست‌یابی به مدیریت خاص مکانی کارا و هدفمند این جزء حیاتی اکوسیستم است. در این پژوهش، به‌منظور بررسی تغییرات مکانی ویژگی‌های خاک، 48 نمونه خاک از عمق صفر تا 25 سانتی‌متری به روش شبکه‌بندی منظم با فواصل 250 متری در اراضی دانشگاه زنجان جمع‌آوری شد. ویژگی‌های مختلف خاک نظیر وزن مخصوص ظاهری، مقدار آب قابل‌دسترسقابل‌دسترس، هدایت هیدرولیکی اشباع، میانگین وزنی قطر خاکدانه­ها، درصد رس، درصد شن، کربن آلی و کربنات کلسیم معادل اندازه‌گیری شد. پس از تشریح ساختار مکانی متغیرهای مختلف، مقادیر آن­ها با استفاده از تخمین‌گر کریجینگ معمولی برآورد شد و نقشه‌های پیوسته مکانی فراهم گردید. نتایج پژوهش گویای آن بود که بیش‌ترین ضریب تغییرات به ویژگی هدایت هیدرولیکی اشباع (28/43 درصد) و کم‌ترین آن به جرم مخصوص ظاهری (53/5 درصد) تعلق داشت. برای متغیرهای درصد کربن آلی و کربنات کلسیم معادل، مدل کروی و برای سایر متغیرها، مدل نمایی مناسب‌ترین برازش را بر الگوی تغییرات مکانی داشتند. کلاس هم‌بستگی مکانی برای ویژگی هدایت هیدرولیکی اشباع خاک، متوسط و برای سایر ویژگی‌های مورد مطالعه، قوی بود. بررسی نقشه‎های پهنه‌بندی حاکی از آن بود که با افزایش درصد رس از جنوب به شمال منطقه، مقادیر هدایت هیدرولیکی اشباع خاک کاهش و مقادیر آب قابل‌دسترس در خاک افزایش می‌یابند. این نتیجه گویای آن است که با توجه به جوان بودن خاک‌ها و عدم تکامل ساختمان در آن­ها، اغلب ویژگی‌های فیزیکی خاک تحت تأثیر بافت خاک هستند. هم‌چنین مشاهده شد که اختصاص یافتن اراضی واقع در بخش‌های جنوبی منطقه به کشت گیاهان زراعی و بخش‌های شمالی به باغ سیب، موجب افزایش درصد کربن آلی به بیش‌تر از یک درصد شده است که به‌نوبه خود، باعث افزایش قابل‌ملاحظه میانگین وزنی قطر خاکدانه‌ها در این مناطق شده است.

کلیدواژه‌ها

عنوان مقاله [English]

Spatial Variability of Some Soil Characteristics in Lands of Zanjan University

نویسندگان [English]

  • Hadiseh Shabani 1
  • Mohammad Amir Delavar 2
  • Yaser Safari 3
  • Parisa Alamdari 4

1 Soil Science, Agriculture Faculty, University of Zanjan, Zanjan, Iran

2 Associate Professor

3 Depth. Soil science, Agriculture faculty, Shahrood University of Technology, Shahrood, Iran

4 Depth. of Soil science, Agriculture faculty, University of Zanjan, Zanjan, Iran

چکیده [English]

Abstract
Assessing the spatial variability trend of various soil properties is a helpful procedure to access to the efficient site-specific management of this ecosystem vital component. Aimed to investigate the spatial soil variability in lands of Zanjan University, 48 topsoil (0-25) samples were collected based on a regular grid of 250 meter. Soil samples were analyzed for some physical properties, including bulk density, available water capacity, saturated hydraulic conductivity, mean weight diameter and clay, sand, organic carbon and equivalent calcium carbonate percentage. Identifying the spatial structure of selected properties, ordinary kriging was used to estimate the values of soil properties in un-sampled locations and continuous maps were prepared. The results showed that saturated hydraulic conductivity (43.28%) and bulk density (5.53%) had the maximum and minimum coefficients of variations, respectively. The spherical model was performed well to describe the spatial structure of organic carbon and carbonate calcium equivalent; whereas exponential model showed the best fit to the remained soil properties. Saturated hydraulic conductivity showed a strong correlation class; whereas spatial structure of other studied properties was moderately correlated. Interpolated maps revealed that increasing clay percentage from the south to the north of study area led to the decreased contents of saturated hydraulic conductivity and increased values of available water capacity. This observation indicated that considering soil youthfulness and less-developed soil structure, most of the soil physical properties are mainly influenced by soil texture. It is also observed that cultivated crops in the south of studied area and apple trees in the north, resulted in the soil organic carbon to be increased to more than 1%, in turn, led to the significant increase in mean weight diameter of soil aggregates in these areas.

کلیدواژه‌ها [English]

  • Spatial variability
  • Kriging
  • Geostatistics
  • Variogram
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