بررسی عوامل موثر در تثبیت پتاسیم و آمونیوم در خاک، کانی‌های رسی و نقش آن-ها در مصرف کودهای پتاسیمی

نوع مقاله: علمی ترویجی

نویسندگان

1 دانشیار گروه خاکشناسی، دانشگاه کشاورزی و منابع طبیعی رامین خوزستان.

2 دانش‌آموخته سابق کارشناسی ارشد گروه خاکشناسی، دانشگاه کشاورزی و منابع طبیعی رامین خوزستان.

چکیده

تثبیت از مهم‌ترین فرآیندهایی است که بر قابلیت دسترسی عناصر غذائی پتاسیم و آمونیوم خاک برای گیاه اثر می‌گذارد. نوع و چگالی بار لایه‌ای کانی‌های‌ رسی، پتانسیل اکسیداسیون و احیاء، درجه اشباع بین‌ لایه‌ای کانی‌های رسی 2:1 لایه با پتاسیم و آمونیوم، غلظت یون‌های پتاسیم و آمونیوم در فاز محلول خاک، تناوب خشک و تر شدن، مقدار رطوبت، پ‌ها‌ش و مقدار مواد آلی خاک از جمله مهم‌ترین عوامل تأثیر گذار بر فرآیند تثبیت پتاسیم و آمونیوم در رس‌ها و خاک‌ها به شمار می‌روند. این دو کاتیون به دلیل دارا بودن شعاع یونی مشابه دارای رفتار مشابهی برای تثبیت هستند، لذا می‌توان با کاربرد توام کود پتاسیم و آمونیوم بر افزایش قابلیت جذب آن‌ها اثر گذاشت. قرار گرفتن یون‌های آمونیوم در بین‌ لایه‌های کانی‌های رسی موجب می‌گردد تا ظرفیت تثبیت پتاسیم در بین‌ لایه‌ها کاهش یافته و قابلیت جذب آن برای گیاه فزونی یابد و برعکس. این موضوع از نظر اقتصادی و مدیریت مصرف کود اهمیت کاربردی فراوانی دارد به ‌طوری‌ که به هنگام محاسبه مقدار کودهای نیتروژن و پتاسیم مورد نیاز گیاه باید به‌ طور کامل مورد توجه قرار گیرد. با اطلاع از عوامل اثر گذار بر تثبیت یا رهاسازی یون‌های پتاسیم و آمونیوم و هم چنین بررسی عوامل اثر گذار بر رقابت آن‌ها می‌توان برای مدیریت تغذیه‌ای گیاهان برنامه‌ریزی نمود. در این راستا با افزایش کودهای آمونیومی همچون اوره می‌توان بر رهاسازی پتاسیم از کانی‌ها اثر گذاشته و نیاز گیاه به این عنصر غذایی را تأمین نمود. در این مقاله تلاش گردیده است که فرآیند تثبیت پتاسیم و آمونیوم در خاک و نقش عوامل موثر بر آن بررسی و راهکارهایی برای استفاده صحیح از این دو عنصر کودی در مدیریت تغذیه‌ای گیاهان ارائه شود.

کلیدواژه‌ها


عنوان مقاله [English]

Study of Factors Influencing Potassium and Ammonium Fixation in the Soil, Clay Minerals and its Roles in Potassium Fertilizer Consumption

نویسندگان [English]

  • s j 1
  • m p 2
چکیده [English]

Potassium and ammonium fixation is one of the most important factors that influence the availability of these ions in the soil. Type of clay minerals, charge density, potassium and ammonium saturation percentage, concentration of potassium and ammonium ions in soil solution, wetting and drying cycles, soil moisture content, soil pH and the amount of soil organic matter are the most common and important factors affecting the fixation of potassium and ammonium in clays and soils. These cations have the same ionic radius and, therefore have same behavior to be fixed by clay minerals. Application of ammonium and potassium fertilizers together can decrease fixation capacity of these ions, and improve uptake of these ions by plants. Application of ammonium ions can decrease potassium fixation in the soil and, therefore it can increase potassium availability for plants and reversible. This result has important effect on economic and management of fertilizers application, and should be considered for the application of nitrogen and potassium fertilizers. Therefore, study the attribute factors on NH4+ and K+ fixation and its competitions can lead us to better management for these components and can help for selection of best program for fertilizer management and could be used for a good program for effect of clay mineral fixation. According to this, by application of NH4+ fertilizers, such as urea, K+ release from clay mineral will be increased. Therefore, K+ for plant uptake will be provided. We attempt to elaborate a review for evaluation of K and NH4+ fixation and affected factors on this process in soil. Finlay strategy for the optimum usage of these elemental fertilizers in plant nutrition will be proposed. 

کلیدواژه‌ها [English]

  • Ammonium
  • Fertilizer
  • Fixation
  • Potassium
  • Clay minerals
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