نوع مقاله : مقالات پژوهشی
نویسندگان
دانشگاه شهید چمران اهواز
چکیده
ماده آلی خاک از مهمترین عوامل ارزیابی کیفیت خاک است و ارتباط نزدیکی با ویژگیهای فیزیکی، شیمیایی و بیولوژیکی خاک دارد. از طرفی، ترسیب کربن در زیتوده گیاهی و خاکهای متأثر از آن هستند، سادهترین و به لحاظ اقتصادی عملیترین راهکار ممکن جهت کاهش خطرات دیاکسید کربن اتمسفری است. اطلاعات کمی در ارتباط با تأثیر مدیریت قرق بر ترسیب و مدیریت کربن در خاکهای مراتع استان خوزستان وجود دارد؛ لذا این مطالعه با هدف بررسی تأثیر مدیریت قرق بر میزان و تغییرات ترسیب و مدیریت کربن خاک و با دیدگاه اقتصادی در برخی خاکهای مراتع دشت پنتی ایذه و منطقه دیمه رامهرمز در استان خوزستان انجام شد. چهار مرتع با مدیریتهای مختلف (قرق شده و تحت چرا) در اطراف ایذه و رامهرمز انتخاب و سپس از 15 نقطه به صورت تصادفی و از دو عمق سطحی و زیرسطحی (با توجه به مرز تفکیک افقها) نمونهبرداری صورت گرفت. نتایج حاصل از ترسیب و شاخص مدیریت کربن در این مطالعه نشان دهنده بازیابی کربن خاک و بهبود کیفیت آن طی قرق میباشد. از طرفی، برآورد ارزش اقتصادی ترسیب کربن طی قرق در مراتع مطالعاتی بسیار قابل توجه بوده و موجب افزایش 17 و 7/12 درصدی ارزش ترسیب کربن در منطقه ایذه و رامهرمز گردیده است. از این رو ضروری به نظر میرسد که تیمار قرق بهعنوان یکی از برنامههای اصلی در طرحهای منابع طبیعی تجدید شونده مد نظر قرار گیرد.
کلیدواژه‌ها
عنوان مقاله [English]
Carbon Sequestration and Estimation of its Economic Value in Selected Pastures of Khuzestan under Grazing and Grazing Exclusion
نویسندگان [English]
- Alireza Owji
- Ahmad Landi
- Saeed Hojati
Shahid Chamran Univ. of Ahvaz
چکیده [English]
Introduction: Soil is a key resource that contributes to the earth system functioning as a control and manages the cycles of water, biota and geochemical and as an important carbon reservoir. Soil organic matter is one of the most important factors in soil quality assessment and having relationship with physical, chemical and biological properties of soil. Carbon sequestration in plant biomass and soils is the simplest and the most economically practical solution to reduce the risks of atmospheric carbon dioxide. Little information is available about the effects of grazing management on sequestration of carbon in Khuzestan Province pastures. Therefore, this study was conducted to evaluate the effects of grazing exclusion on the amount and forms of carbon management and carbon sequestration with economic view in some pasture soils from Peneti Plain of Izeh area and Dimeh regions of Ramhormoz in Khuzestan Province.
Materials and Methods: This study was conducted in two regions including Izeh and Ramhormoz representing different climates, vegetation and soil types of southwestern Iran. We selected two grazing treatments including ungrazed and grazed pastures in each region. The first area includes rangeland ecosystem in Izeh city between 31° 57ʹ 8ʺ to 31° 58ʹ 20ʺ N and 49° 41ʹ 11ʺ to 49° 42ʹ 33ʺ E. The region has a typical temperate continental climate, characterized by dry summers and cold winters. The mean annual rainfall is 623mm. The mean annual temperature (MAT) is 19.2 °C, and the mean monthly air temperature varies from -0.6 °C in January to 42.4 °C in July. The second area (Ramhormoz) is located between 31° 7ʹ 44ʺ to 31° 9ʹ 11ʺ N and 49° 29ʹ 13ʺ to 49° 28ʹ 52ʺ E. The mean annual rainfall is 200 mm and the mean annual temperature (MAT) is 27.2 °C, and the mean monthly air temperature varies from 4.2 °C in January to 51.6 °C in July. For each climate region, grazed and ungrazed sites were located on the same soil series with similar aspect and slope. Then, random soil samples were taken from the surface and subsurface in 15 points. After air drying the soil samples and passing them through a 2 mm sieve, physical, chemical properties of the soils were measured.
Results and Discussion: The soil of both studied regions are non-saline, calcareous, and alkaline and have relatively heavy texture. The results showed that the studied characteristics in four study areas had low and moderate coefficients of variation. This suggests that the contribution of edaphic and environmental factors to explain variation in the data is not high. Also, grazing management has increased soil organic matter of surface and subsurface soil, but despite the increase in organic matter contents of subsurface soils the difference was not statistically significant. The effect of management practices, in order to have a significant effect to lower parts of the soil, it requires a longer period management. Comparing the biomass upon non-grazing (405 and 42 gm-2 in Izeh and Ramhormoz respectively) and grazed (117 and 17 gm-2) areas, indicates a good condition of vegetation in the non-grazing and the effectiveness of enclosure in rehabilitation of pastures in the study area. However, due to more rainfall rates, the amount of biomass produced in Izeh is higher.
Conclusion: The carbon management index in the study areas, as well as the depths of the study is high, indicating recovery of soil carbon and improving its quality. Also, based on carbon sequestration in the study area, non-grazing was one of the most proper and efficient management practices, which improved soil quality. Accordingly, it seems that non-grazing practices should be considered as one of the major programs in renewable natural resources plans. On the other hand, estimation of the economic value of carbon sequestration in the pastures has been remarkable, and increased 17 and 12.7% of the value of carbon sequestration in Izeh and Ramhormoz regions under the management of the exclusion. Therefore, the management of rangelands should be directed to allow for their ecologic performance and capacity considering the environmental economy of rangelands so that in broad terms, the justification for the enhancement and maintenance of the economic equilibrium can be viewed as a guaranty of implementing the range managements resulting in sustained development.
کلیدواژه‌ها [English]
- Carbon management index
- Carbon sequestration
- Economical
- Grazing exclusion
- Pasture
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