پایش سلامت خاک در بوم‌سازگان ناپایدار شهر گرگان

نوع مقاله : مقاله کوتاه

نویسنده

مربی، عضو هیئت علمی گروه مهندسی خاک، دانشکده آب و خاک، دانشگاه زابل، زابل، ایران

چکیده

افزایش جمعیت و فشار مضاعف به بوم‌سازگان جهت تأمین منابع غذایی، منجر به تغییرات گسترده در کاربری اراضی طبیعی جنگل‌های شمال کشور به اراضی زراعی شده است. این پژوهش با هدف مطالعه اثر تغییر کاربری بر‌ سلامت و کیفیت خاک اراضی شیب‌دار جنوب شهر گرگان انجام شد. نمونه‌برداری در تیرماه 1398 به­دلیل تخریب شدید اراضی تنها از 2 موقعیت شانه شیب و شیب پشتی و به‌صورت کاملاً تصادفی از عمق cm 20-0 خاک جنگل و زمین کشت‌شده مجاور انجام و سپس نمونه‌ها مورد تجزیه قرار گرفتند. خصوصیات مورد ارزیابی شامل درصد کربن آلی خاک، درصد اجزای بافت خاک (شن، سیلت و رس)، وزن مخصوص ظاهری خاک، درصد آهک معادل خاک، واکنش خاک، مقادیر عناصر پرمصرف (ازت، فسفر، پتاسیم) و ظرفیت تبادل کاتیونی به‌عنوان شاخص‌های کیفیت خاک بودند. نتایج نشان داد که بیشترین ضریب تغییرات در نتیجه تغییر کاربری مربوط به پارامتر درصد کربن آلی خاک بوده است. تجزیه واریانس و مقایسه میانگین حاکی از آن بود که تغییر کاربری از جنگل به کشاورزی موجب کاهش معنی‌دار کیفیت خاک در تمامی پارامترهای مورد ارزیابی به‌استثناء فسفر قابل‌جذب شده است. همچنین بررسی درصد کربن آلی خاک به‌عنوان مهم‌ترین شاخص کیفیت خاک نشان داد که این پارامتر با میانگین 07/6% در کاربری جنگل و میانگین 59/0% در کاربری زراعی با کاهش 90% در نتیجه تغییر کاربری روبرو شده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Evaluation of Soil Health in the Unstable Ecosystem of Gorgan City

نویسنده [English]

  • Abolfazl Bameri
Lecturer, Department of Soil Engineering, Faculty of Water and Soil, University of Zabol, Zabol, Iran
چکیده [English]

Introduction: Improving soil quality and stability leads to continued soil fertility, maintaining environmental quality and increasing plant and human health. Land use change is one of the main drivers of changing soil quality by changing the structure and performance of ecologists. Increased population and double pressure on the ecosystem to provide food resources, has led to widespread changes in the use of natural land in the northern forests of the country to agricultural land. Therefore, this study was conducted to assess the effect of land use change on the health and soil quality of sloping lands south of Gorgan.
Materials and Methods: In this study, two hills, one with forest use and the other with marginal agricultural land, which has more than 50 yr of cultivation history, were selected. Sampling was performed in July 2020 due to severe land degradation from only two positions of shoulder and back slope and completely randomly from a depth of 0-20 cm of forest soil and adjacent cultivated land and then samples were analyzed. Properties evaluated include soil organic carbon content (OC), percentage of soil texture components and bulk density of soil, percentage of lime equivalent soil, EC, pH, the amounts of high consumption elements (NPK) and CEC were as indicators of soil quality.
Results: The research showed the highest coefficient of variation as a result of land use change was related to the two parameters of OC. Based on the correlation matrix, the physical parameters of saturated mud percentage, total porosity percentage with the percentage of organic carbon and soil clay at the level of one percent (P <0.001) show a positive and significant relationship. Among the chemical variables, as expected, there was a significant positive correlation between cation exchange capacity, percentage of total nitrogen and potassium levels available with organic matter and percentage of clay at the level of 1%. Analysis of variance and mean comparison showed land use change from virgin forest to agriculture has significantly reduced soil quality in all parameters evaluated except absorbable phosphorus. The reason for this can be considered improper cultivation operations in arable lands, which causes the breakdown of aggregates and exposes the organic matter trapped in the aggregates to microbial decomposition. As a result, the surface horizon of the soil loses its original structure and is easily affected by erosion and physiographic processes of the hill.
Conclusion: the study of OC as the most important indicator of soil quality showed that this parameter with an average of 6.07% in forest use and an average of 0.59% in agricultural use with a 90% decrease as a result of land use change. High reduction of organic carbon and soil clay as the most important indicators for assessing soil quality in arable lands, indicates unstable use and highly unstable ecologists in the sloping lands of south of Gorgan. It is suggested that in future studies, the effect of land use change on erodibility and land production should be studied and evaluated, considering that the continuation of cultivation in this area causes an increasing decrease in soil quality.

کلیدواژه‌ها [English]

  • Golestan province
  • Land Use Change
  • Soil quality
  • Soil Organic Carbon
Abid, M. and Lal, R. (2008). Tillage and drainage impact on soil quality. Aggregate stability, carbon and nitrogen pools. Soil Till. Res., 100(1-2), 89–98. doi: 10.1016/j.still.2008.04.012
Adolfo Campos, C., Klaudia Oleschko, L., Jorge Etchevers, B. and Claudia Hidalgo, M. (2007). Exploring the effect of changes in land use on soil quality on the eastern slope of the Cofre de Perote Volcano (Mexico). Forest Ecol.  Manag., 248, 174–182.
Akinde, B. P., Olakayode, A. O., Oyedele, D. J. and Tijani, F. O. (2020). Selected physical and chemical properties of soil under different agricultural land-use types in Ile-Ife, Nigeria. Heliyon, 6(9), e05090. doi:10.1016/j.heliyon.2020.e05090.
Ashenafi, A., Abayneh, E. and Sheleme, B. (2010). Characterizing soils of Delbo Wegene watershed, Wolaita Zone, Southern Ethiopia for planning appropriate land management. J. Soil Sci. Environ. Manag, 1, 184–199.
Balesdent, J., Chenu, C. and Balabane, M. (2000). Relationship of soil organic matter dynamics to physical protection and tillage. Soil Till. Res., 53, 215-230.
Bryan, B. A., Gao, L., Ye, Y., Sun, X., Connor, J. D., Crossman, N. D., Stafford-Smith, M. and Wu, J. (2018). China’s response to a national land-system sustainability emergency. Nat., 559, 193–204.
Collazo, A. A. (2020). Land use planning, mobility and historic preservation in Aguascalientes city. Are cultural sustainability and circular economy possible?, Int. J. Sustain. Develop. Plann, 15 (5), 647–654.
Dang, V. M., Anderson, D. W. and Farrell, R. E. (2002). Indicators for assessing soil quality after long-term tea cultivation in Northern Mountainous Vietnam. 17th WCSS, Thailand. Pp:14-21.
Fu, Q., Li, B., Hou, Y., Bi, X. and Zhang, X. S. (2017). Effects of land use and climate change on ecosystem services in Central Asia’s arid regions: a case study in Altay Prefecture, China. Sci. Total Environ, 607–608, 633–646.
Karami, Z. and Sharifi, Z. (2020). Assessment effect of land use change from rangeland to rainfed wheat on soil physical and chemical properties using soil quality index. Appl. Soil Res., 8(2), 201-213 [In Persian].
Khormali, F., Ajami, M., Ayoubi, Sh., Srinivasarao, Ch. and Wani, S. P. (2009). Role of deforestation and hillslope position on soil quality attributes of loess-derived soils in Golestan Province, Iran. Agri. Ecosyst. Environ, 134, 178–189.
Kiani, F., A. Jalalian, A., Pashaee, A. and Khademi, H. (2004). Effect of deforestation on selected soil quality attributes in loess-derived landforms of Golestan province, northern Iran. Proceedings of the Fourth International Iran & Russia Conference, Pp:546-550.
Kogaa, N., Shimodab, S., Shiratoc, Y., Kusabaa, T., Shima, T., Niimi, H. and Yamane T. (2020). Assessing changes in soil carbon stocks after land use conversion from forest land to agricultural land in Japan. Geoderma, 377, 114487.
Lal, R. (2006). Enhancing crop yields in the developing countries through restoration of the soil organic carbon pool in agricultural lands. Land Degrad. Develop., 17, 197–209.
Lizaga, I., Quijano, L., Gaspar, L., Ramos, M. C. and Navas, A. (2019). Linking land use changes to variation in soil properties in a Mediterranean mountain agroecosystem. Catena, 172, 516-527.
Malakouti, M. J. and Homayi, M. (1994). Soil Fertility of Dry Areas, Tarbiat Modares University Press, Tehran [In Persian].
Martel, Y. A. and Mackenzie, A. F. (1980). Long-term effects of cultivation and land use on soil quality in Quebec. Can. J. Soil Sci, 60, 411-420.
Natural Resources Conservation Service (NRCS), USDA. (2001). Soil Quality Information Sheet. Soil Quality-Introduction.
Sadaghiani, M. H., Ghodrat, K., Ashrafi-Saeidlou, S., Jafari, M. and Khodaverdiloo, H. (2016). Evaluation of soil quality indicators in a deforested region of Northern Zagros (Case study: Oshnavieh-West Azerbaijan). J. Soil Manag. Sustain. Product., 6(3), 83-99. [In Persian]
Solomon, D., Lehmann, J., Mamo, T., Fritzsche, F. and Zech, W. (2002). Phosphorus forms and dynamics as influenced by land use changes in the sub-humid Ethiopian highlands. Geoderma, 105(1-2), 21–48.
Sun, Q., Qi, W. and Yu, X. (2021). Impacts of land use change on ecosystem services in the intensive agricultural area of North China based on Multi-scenario analysis. Alexandria Eng. J., 60, 1703–1716.
Wilding, L. P. and Dress, L. R. (1983). Spatial variability and pedology. In: Wilding, L. P., Smeckand, N. E. and Hall, G. F. (eds.). Pedology and Soil taxonomy. I. Concepts and interactions. Elsevier Science Pub. 83-116.
Zheng, Z., Simard, R. R., Lafond, J. and Parent, L. E. (2001). Changes in phosphorus fractions of a Humic Gleysol as influenced by cropping systems and nutrient sources. Can. J. Soil Sci., 81(2), 175–183. doi:10.4141/s00-666.