در این پژوهش با استفاده از روش زمین آمار پراکنش مقادیر کربن آلی، فسفر و پتاسیم قابل استفاده در اراضی زراعی منطقه جلگه رخ از توابع شهرستان تربت حیدریه واقع در استان خراسان رضوی مورد ارزیابی قرار گرفت. به این منظور تعداد بالغ بر ۱۰۰ نمونه خاک در سال ۱۴۰۰ از مزارع منطقه تهیه شد. مقادیر پارامترهای مذکور برای هر نمونه در آزمایشگاه خاکشناسی اندازه گیری گردید. معیارهای ارزیابی در این مطالعه، میانگین خطا مطلق و ریشه دوم میانگین مربعات خطا باقیمانده با استفاده از روش اعتبارسنجی ارزیابی متقابل بودند. تغییر نما برای کلیه عناصر ترسیم شد. پس از تعیین مدل نیم تغییر نما، اعتبار سنجی الگوی برازش داده شده بوسیله خطای تخمین بررسی گردید. پس از تأیید صحت واریوگرام، روش درون یابی کریجینگ انتخاب و نقشه پراکنش عناصر غذایی تولید شد. نتایج نشان دادکه عناصر دارای پراکنش مکانی متفاوت می باشند. بطوریکه در ۹۰ درصد اراضی میزان کربن آلی خاک کمتر از نیاز گندم، پتاسیم و فسفر قابل جذب به ترتیب در 32/2 و ۴۶ درصد اراضی بیش از حد بحرانی برای گندم بود. در مجموع تهیه نقشه پراکنش عناصر غذایی می تواند نشان دهنده کمبود و یا بیش بود عناصر غذایی در خاک و از آن در بهینه سازی مصرف کودها استفاده گردد. تفاصيل المقالة

Background and objective: Information concerning the spatial and temporal characteristics of vegetative drought is essential for decision-making in environmental and agricultural practices. The present study is a comprehensive Spatio-temporal analysis of vegetative drought over thirty years of observations.Materials and Methods: The data obtained from NOAA/AVHRR (National Oceanic and Atmospheric Administration/ Advanced Very High-Resolution Radiometer) to reveal the vegetative drought patterns across Khorasan-e-Razavi province, northeast of Iran from 1990 to 2019. Three satellite-based drought indices including the Vegetation Condition Index (VCI), Temperature Condition Index (TCI), and Vegetation health index (VHI) as well as NDVI were used to characterize the dynamics of drought severity conditions and their fluctuations in the study area.Results and conclusion: It was found a strong correlation between land surface temperature (LST), and TCI with VHI which indicates a definite influence of thermal stress on vegetation health in the study area. The analysis of Pearson (R), and the correlation between vegetative drought indices over the 1990–2019 period in Khorasan-e-Razavi province revealed no significant differences among drought indices except P-values. Analyzing long-term drought indices in the study area showed high thermal stress, very poor vegetation condition, and mainly weak VHI in most years of the study. Results from this study highlight the potential for including satellite-based drought indices in agricultural decision support systems (e.g. agricultural drought early warning systems, crop yield forecasting models, or water resource management tools) complementing meteorological drought indices derived from precipitation grids. تفاصيل المقالة

Background and objective:Inappropriate land use due to changing requirements and pressures leads to the destruction of land resources and increases poverty and other social problems.Materials and methods: The present study evaluated the land suitability for the spatial development of the Shandiz urban region, northeast of Iran based on the analytical hierarchy process (AHP) and geographical information system (GIS).Results and conclusion: On this basis, the land suitability of the study area for spatial development was estimated and revealed that 12 land uses (22.5% of the region) have high and moderate suitability for spatial development. Our results indicated that the regions with higher suitability for the spatial development of the Shandiz urban region are located in the middle and east parts of the study area. In contrast, the north, south, and west parts of the region have low suitability for spatial development. Our study presents a map of land suitability for the spatial development of the region, which will aid in appropriate planning, quick and safe mitigation measures, and future development strategies based on identifying the environmental factors affecting land suitability in the region. We developed a systematic regional planning approach to identify geographic priorities for on-ground natural resource management actions that most cost-effectively meet multiple natural resource management objectives. تفاصيل المقالة