نوع مقاله : مقاله پژوهشی

نویسندگان

• کسری آهیخته ¹
• مریم نوابیان ²
• محمد حسن بیگلویی ¹

¹ گروه مهندسی آب، دانشکده علوم کشاورزی، دانشگاه گیلان، رشت، ایران

² گروه مهندسی آب، دانشکده علوم کشاورزی، دانشگاه گیلان، رشت، ایران و عضو وابسته پژوهشی گروه مهندسی آب و محیط زیست پژوهشکده حوضه آبی

چکیده

این پژوهش، با هدف ارزیابی عملکرد محیط‌زیستی‌ سامانه زهکش لانه‌موشی برای زهکشی میان‌ و پایان‌فصل برنج در اراضی شالیزاری انجام شد. براین اساس آزمایشی به‌صورت کرت‌های یکبار خرد شده در قالب طرح بلوک‌های کامل تصادفی با سه تکرار برای سال‌های زراعی 1401-1402 در مزرعه تحقیقاتی دانشگاه گیلان در شهر رشت انجام شد. به‌طوری‌که عامل اصلی، زهکشی در دو سطح؛ سامانه زهکش لانه‌موشی سنتی (بدون گراول) و سامانه زهکش لانه‌موشی با گراول و عامل فرعی، مدیریت آبیاری در دو سطح؛ غرقاب دائم و تناوبی اجرا شد. در طول این پژوهش، سطح ایستابی و پارامترهای کیفی زه‌آب مورد پایش قرار گرفتند. نتایج نشان داد که بیش‌ترین مقدار در میانگین اسیدیته و نسبت جذب سدیم به‌ترتیب 99/6 و 65/4 میلی‌اکی‌والان بر لیتر در میان‌فصل برای سامانه زهکش لانه‌موشی با گراول و آبیاری غرقاب دائم بود. همچنین بیش‌ترین غلظت آمونیوم و نیترات برای زهکشی میان‌فصل به‌ترتیب با 20 و 21/0 میلی‌گرم بر لیتر و بیش‌ترین میانگین هدایت‌الکتریکی برای زهکشی پایا‌ن‌فصل به‌ترتیب 3845 میکرو‌زیمنس بر سانتی‌متر در سامانه زهکش لانه‌موشی سنتی و آبیاری غرقاب دائم مشاهده شد. نتایج تجزیه آماری نشان از عدم معنی‌داری تیمارهای مورد بررسی برای مقادیر هدایت‌الکتریکی و نیتریت زه‌آب داشت. نتایج نشان داد متوسط مقادیر هدایت‌الکتریکی، نسبت جذب سدیم، سدیم، آمونیوم، فسفات، سولفات و کلراید زه‌آب برای میان و پایان‌فصل زهکشی در سامانه زهکش لانه‌موشی با گراول نسبت به سامانه سنتی کم‌تر بود اگرچه با تفاوت 9 درصدی سامانه زهکش لانه‌موشی سنتی در کنترل سطح ایستابی موفق‌تر عمل کرد. از دیدگاه محیط‌زیستی، زهکشی لانه‌موشی با گراول قابل توصیه است.

کلیدواژه‌ها

• بافت خاک سنگین
• سطح ایستابی
• زهکشی میان و پایان‌فصل
• کیفیت زه‌آب

موضوعات

• مهندسی زهکشی

عنوان مقاله [English]

Evaluation of environmental performance of mole drain on rice cultivation in paddy fields

نویسندگان [English]

• Kasra Ahikhteh ¹
• Maryam Navabian ²
• Mohamad Hasan Biglouei ¹

¹ Water Science and Engineering, Faculty of Agricultural Sciences, University of Guila,, Rasht, Iran

² Water Science and Engineering, Faculty of Agricultural Science, University of Guilan, Rasht, Iran & Dep. of Water Eng. and Environment, Caspian Sea Basin Research Center, University of Guilan, Rasht

چکیده [English]

It is possible to effectively control water in paddy fields, prevent flooding problems, and create optimal conditions for the growth of agricultural products with simultaneous and correct management of irrigation and drainage. Due to the high initial cost of the construction of subsurface drainage, Mole drainage is a suitable and more economical alternative in clay soils. Constructing the mole drain at a critical depth and passing the water through the cracks, improves the soil conditions and removes excess water from the soil surface. Mulqueen (1985), reported that gravel mole drain is a suitable alternative to traditional mole drain. Considering the limited studies in the field of mole drainage, the purpose of this study is to evaluate the performance of low-cost mole drainage for draining excess water from paddy fields and its environmental effects. Therefore, the effect of traditional mole and gravel mole drain on drainage water quality and control of the water table of paddy fields in the mid and end of rice season was investigated.

Materials and Methods

The experiment was conducted in the agricultural year of 2022-2023 in the research farm of the Faculty of Agricultural Sciences, University of Guilan (IRAN). The split-plot experiment was implemented in a randomized complete block design in three replications under the main drainage treatment on two levels: (1) Traditional mole drain (without gravel) and (2) Gravel mole drain and the sub-treatment of irrigation method in two levels: (1) Flood irrigation and (2) Alternative irrigation. In the stages of tillering and harvesting, mid and end season drainage were done respectively. During the drainage period, the water table was measured with a piezometer. By sampling the drainage water, its quality parameters including acidity, electrical conductivity, nitrate, nitrite, phosphate, sulfate, chloride, total suspended and dissolved solids, sodium, calcium, magnesium, and ammonium were measured. The results of the investigated treatments were statistically analyzed using SAS software.

Results and Discussion

With the start of mid season drainage, after one day, the water table reached the middle of the soil profile and more than half of the root development depth was in anaerobic conditions. Five days after the drainage in the traditional mole drain, the depth of root development was in aerobic conditions. The highest value in average acidity and sodium adsorption ratio was 6.99 and 4.65 meq/l respectively in mid season in gravel mole drain and flood irrigation. The highest concentration of ammonium and nitrate in mid season drainage was 0.20 and 0.21 mg/l, respectively, and the highest average electrical conductivity and total dissolved solids at the end season were 3845 µS/cm and 2475 mg/l, respectively, in traditional mole drain and flood irrigation. In mid and end season drainage, the amount of total suspended solids in the mole drain with gravel was 60% and 88% higher than the traditional mole drain, respectively. The highest concentration of nitrite was obtained in the gravel mole drain and flood irrigation with a value of 6.75 mg/l during mid season drainage. The average concentration of phosphate and sulfate in gravel mole drain compared to the traditional mole in mid and end season decreased by 25 and 30%, respectively, and sulfate by 3 and 5.5%. Also, the average concentration of chloride in the gravel mole drain was lower than the traditional one.

Conclusion

The comparison of results indicated that the average amounts of electrical conductivity, total dissolved solids, sodium adsorption ratio, sodium, ammonium, phosphate, sulfate, and chloride of drainage water in mid and end season were lower in gravel mole drain than the traditional one. The results of statistical analysis showed that the treatment of drainage, irrigation, and time at the level of one and five percent were effective on most of the parameters, while the values of electrical conductivity, total dissolved solids, and nitrite of the drainage water showed that their difference was not significant. The traditional mole drain was more successful in controlling the water table. A comparison of the quality parameters of drainage water with the standard of the Iranian Environmental Protection Organization for the discharge of drainage water into surface waters showed that most of the parameters, except for ammonium and total suspended solids, were within the permissible limits.

کلیدواژه‌ها [English]

• Drainage water quality
• Heavy soil texture
• Mid and end season drainage
• Water table