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اثر سامانه‌های زهکشی شالیزار بر افت گسیل گاز گلخانه‌ای متان | ||
| تحقیقات آب و خاک ایران | ||
| مقاله 1، دوره 44، شماره 1، فروردین 1392، صفحه 1-10 اصل مقاله (474.52 K) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22059/ijswr.2013.36120 | ||
| نویسندگان | ||
| علی بخت فیروز1؛ محمود رائینی سرجاز* 2 | ||
| 1دانشجوی کارشناسی ارشد هواشناسی کشاورزی | ||
| 2دانشیار گروه مهندسی آب دانشگاه علوم کشاورزی و منابع طبیعی ساری | ||
| چکیده | ||
| گرمایش جهانی، پیامد انباشت گازهای گلخانه‌ای، تأثیرات زیست‌محیطی بسیاری دارد. گاز متان، پیامد تجزیة بی‌هوازی کربن آلی، در شرایط غرقابی شالیزارها فراوان تولید می‌شود. هدف این پژوهش بررسی اثر زهکش میان‌فصلی شالیزار در کاهش گسیل متان است. این پژوهش با سه تیمار زهکش سنّتی، سطحی و زیرزمینی در طرح بلوک‌های کامل تصادفی در تابستان 1390 در ساری انجام شد. نمونه‌برداری گاز هر هفته، یک هفته پس از نشاکاری تا برداشت شالی، انجام گرفت. نهال‌های برنج در فاصلة 25 × 25 سانتی‌متری نشا شد. بیست‌و‌پنج روز پس از نشاکاری، آبیاری به مدت یک هفته قطع شد، که سبب افت سطح ایستابی در زهکش‌های زیرزمینی، سطحی و سنّتی، به‌ترتیب، تا ژرفای 7/0، 1/0 و 03/0 متری شد. گسیل متان هم‌سو با افت سطح ایستابی کاهش یافت. کاهش گسیل و دورة بازگشت به مقدار پیش از زهکشی در زهکش زیرزمینی بیشتر از دو تیمار دیگر بود. کمینة گسیل متان در هفتة دوم پس از زهکشی میان‌فصلی با افت 25، 45 و 315 درصدی، به‌ترتیب، در زهکش‌های سنّتی، سطحی و زیرزمینی رخ داد. بر پایة یافته‌های این پژوهش، افت سطح ایستابی بر افت گسیل گاز متان از شالیزار اثر معنا‌داری داشت. | ||
| کلیدواژه‌ها | ||
| زهکشی میانفصل؛ سطح ایستابی؛ شالیزار؛ گاز گلخانه‌ای؛ متان | ||
| عنوان مقاله [English] | ||
| The Effect of Drainage Systems on Methane Emission Reduction from Paddy Fields | ||
| نویسندگان [English] | ||
| Ali Bakht Firooz1؛ Mahmood Raeini Sarjaz2 | ||
| 1Global warming, as a consequence of greenhouse gases accumulation, has exerted significant impacts on biosphere. Methane, a product of reduction processes of organic carbon in anaerobic conditions, is mainly emitted from paddy fields. The aim followed in this research is to evaluate the impact of midseason drainage on methane emission from paddy fields. The research was conducted with three treatments of traditional, surface, and subsurface drainages in a CBD in Sari region. Gas sampling was done weekly following the first week of transplanting till harvest time. Twenty five days after planting, irrigation was ceased for a week, which caused lowering of water table depth to 0.03, 0.1, and 0.7m for traditional, surface, and subsurface drainages, respectively. Methane emission decreased as subsurface water table dropped. Gas emission reduction and the return period to before drainage practice were significantly higher in subsurface drainage. The lowest methane emission occurred two weeks after midseason drainage, as compared with the other two. where emission was reduced by 25, 45 and 315 percent in traditional, surface, and subsurface drainages, respectively. In conclusion, based on the obtained results, water table drawdown, and thus change in anaerobic conditions of root zone to an aerobic one could reduce methane emissions from paddy fields. | ||
| 2Global warming, as a consequence of greenhouse gases accumulation, has exerted significant impacts on biosphere. Methane, a product of reduction processes of organic carbon in anaerobic conditions, is mainly emitted from paddy fields. The aim followed in this research is to evaluate the impact of midseason drainage on methane emission from paddy fields. The research was conducted with three treatments of traditional, surface, and subsurface drainages in a CBD in Sari region. Gas sampling was done weekly following the first week of transplanting till harvest time. Twenty five days after planting, irrigation was ceased for a week, which caused lowering of water table depth to 0.03, 0.1, and 0.7m for traditional, surface, and subsurface drainages, respectively. Methane emission decreased as subsurface water table dropped. Gas emission reduction and the return period to before drainage practice were significantly higher in subsurface drainage. The lowest methane emission occurred two weeks after midseason drainage, as compared with the other two. where emission was reduced by 25, 45 and 315 percent in traditional, surface, and subsurface drainages, respectively. In conclusion, based on the obtained results, water table drawdown, and thus change in anaerobic conditions of root zone to an aerobic one could reduce methane emissions from paddy fields. | ||
| چکیده [English] | ||
| Global warming, as a consequence of greenhouse gases accumulation, has exerted significant impacts on biosphere. Methane, a product of reduction processes of organic carbon in anaerobic conditions, is mainly emitted from paddy fields. The aim followed in this research is to evaluate the impact of midseason drainage on methane emission from paddy fields. The research was conducted with three treatments of traditional, surface, and subsurface drainages in a CBD in Sari region. Gas sampling was done weekly following the first week of transplanting till harvest time. Twenty five days after planting, irrigation was ceased for a week, which caused lowering of water table depth to 0.03, 0.1, and 0.7m for traditional, surface, and subsurface drainages, respectively. Methane emission decreased as subsurface water table dropped. Gas emission reduction and the return period to before drainage practice were significantly higher in subsurface drainage. The lowest methane emission occurred two weeks after midseason drainage, as compared with the other two. where emission was reduced by 25, 45 and 315 percent in traditional, surface, and subsurface drainages, respectively. In conclusion, based on the obtained results, water table drawdown, and thus change in anaerobic conditions of root zone to an aerobic one could reduce methane emissions from paddy fields. | ||
| کلیدواژه‌ها [English] | ||
| Greenhouse Gases, methane, midseason drainage, Paddy field, water level | ||
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