تأثیر دی اکسیدکربن و نیتروژن بر تجزیه بقایای گندم (Triticum aestivum L.) و یونجه (Medicago sativa L.) در دو خاک آهکی و غیر آهکی

نوع مقاله : علمی - پژوهشی

نویسندگان

گروه علوم خاک، دانشکده کشاورزی، دانشگاه فردوسی مشهد، ایران

چکیده

استفاده از بقایای گیاهی درسیستم های کشاورزی پایدار به منظور حفظ حاصلخیزی خاک اهمیت زیادی دارد. کیفیت مواد آلی، غلظت دی اکسیدکربن و میزان نیتروژن خاک از جمله عواملی هستند که بر تجزیه بقایای گیاهی تأثیر بسزایی دارند. در این مطالعه تأثیر دو سطح دی اکسیدکربن (360 و700 پی پی ام) و دو سطح کود نیتروژن (صفر و 200 کیلوگرم کود اوره در هکتار خاک) ، در شش زمان (صفر، 10، 20 ، 40، 60 و 90 روز) با دو تکرار با آرایش فاکتوریل و در قالب طرح کاملاً تصادفی بر تجزیه بقایای گندم (Triticum aestivum L.) و یونجه (Medicago sativa L.) در دو خاک با درصد آهک متفاوت (66/32 و 4/3 درصد آهک ) در شرایط آزمایشگاهی مورد بررسی قرار گرفت. رطوبت نمونه های خاک (70 درصد ظرفبت زراعی) در طول آزمایش ثابت نگه داشته شد. میزان تجزیه بقایای گیاهی به عنوان شاخص ماده آلی خاک انتخاب گردید. نتایج نشان داد که میزان تجزیه بقایای گیاهی در هر دو خاک آهکی و غیرآهکی با افزایش غلظت دی اکسیدکربن افزایش یافت. نتایج همچنین نشان داد افزایش میزان نیتروژن در خاک سبب افزایش میزان تجزیه بقایای گندم و یونجه گردید. در تمام تیمارها میزان تجزیه بقایای گندم و یونجه در خاک آهکی بیشتر از خاک غیر آهکی بود.

کلیدواژه‌ها


عنوان مقاله [English]

The effect of elevated CO2 and N on decomposition of wheat straw and alfalfa residues in calcareous and non calcareous soils

نویسندگان [English]

  • Solmaz Razavi Darbar
  • Amir Lakzian
  • Akram Halajnia
  • Gholamhossein Haghnia
Department of Soil Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Iran
چکیده [English]

Incorporation of plant residue in soils is considered as an important agricultural practice for maintaining soil fertility in sustainable agricultural system. CO2 levels, nitrogen fertilization and plant residues are factors which highly affect decomposition of added organic matter to soil. In this research controlled chambers were used to investigate the effects of elevated atmospheric CO2 concentrations (350 vs. 760 CO2 ppm) under two N fertilization levels (0 vs. 500 kg N ha-1) and two replicates on decomposition of wheat and alfalfa residues in two calcareous (32.66 % CaCO3) and non calcareous soils (3.4 % CaCO3) at 6 times (0, 10, 20, 40, 60 and 90) under laboratory condition. Soil moistures were adjusted at 70% of field capacity. The results showed that elevated CO2 significantly increased decomposition of residues in both calcareous and non calcareous soils. In the samples that received N fertilizer, decomposition of wheat straw and alfalfa residues increased in both soils. From the obtained results, we concluded that in all treatments the amount of decomposition of wheat straw and alfalfa residues in calcareous soil were higher than non calcareous soils.

کلیدواژه‌ها [English]

  • Calcareous soils
  • CO2 enrichment
  • N fertilizer
  • Plant residue mineralization
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