ارزيابي دو سيستم آبياري قطره اي نواري (تيپ) و شياري تحت رژيم هاي مختلف رطوبتي

Evaluation of Tape and Furrow Irrigation Systems under Different Moisture Regimes

به طور كلي مناسب بودن يك روش آبياري به مقدار آب ذخيره شده در ناحيه توسعه ريشه، تلفات نفوذ عمقي در زير ناحيه ريشه، تلفات ناشي از رواناب سطحي و يكنواختي آب به كار برده شده در پروفيل خاك در هر نوبت آبياري بستگي دارد. اندازه گيري اين پارامترها در شرايط مزرعه و در حين كار طبيعي ارزيابي سيستم آبياري تعريف مي شود. اين پژوهش به منظور ارزيابي دو روش آبياري قطره‌اي و شياري، تحت رژيم‌هاي مختلف آبياري (50، 75 و 100 درصد نياز آبي) در دو سال زراعي (85 و 1386) در ايستگاه تحقيقات كشاورزي گرگان اجرا گرديد. مقايسه حجم آب مصرفي بين دو روش نشان داد كه آبياري قطره‌اي موجب كاهش 33 درصدي در مقايسه با آبياري شياري شده است. نتايج نشان داد كه عملكرد سويا تحت تاثير روش آبياري قرار نگرفت ولي رژيم‌هاي مختلف آبياري بر عملكرد محصول موثر بودند. متوسط راندمان يكنواختي پخش آب در آبياري كامل در روش آبياري قطره‌اي 96 درصد و آبياري شياري 95 درصد بوده است و راندمان كاربرد آب در روش قطره‌اي به طور قابل ملاحظه‌اي (84 درصد) بيشتر از روش شياري بدست آمد. بر اساس نتايج اين پژوهش قسمت عمده هدر رفت آب در روش آبياري شياري ناشي از تلفات رواناب سطحي (67 درصد در تيمار آبياري 100 درصد نياز آبي) مي‌باشد، در حالي كه اين تلفات در روش آبياري قطره‌اي مشاهده نشد.

Among the main causes of low water use efficiency are use of an improper irrigation method and applying excessive irrigation. To evaluate tape and furrow irrigation methods for soybean cultivation under different irrigation regimes, a field experiment was conducted in two years (2006-2007) at Gorgan Agricultural Research Station located in Golestan province in north of Iran. The experiment was laid out in a split plot design in the form of completely randomized blocks where each treatment was replicated three times. Irrigation systems of tape and furrow were set up as the main plots, and three irrigation regimes of 100%, 75% and 50% of total crop water requirement were allocated to the subplots. Comparison of water consumption (m3/ha) between the two systems showed that tape irrigation had 33 percent less water use than furrow irrigation. Results indicated that the soybean yield was not affected by irrigation systems. But, the different irrigation regimens had some impact on crop yield. Water use efficiency in the full irrigation (100 %) regime under drip tape irrigation was 1.6 times that of furrow irrigation system. In tape irrigation, mean water distribution uniformity (Ed) in full irrigation was 96% and in furrow irrigation it was 95%. Application efficiency (Ea) under tape irrigation was 84%, which was much higher than furrow irrigation. Also, based on the results, most of water losses in furrow irrigation systems were due to surface run off, while these losses were not observed in the tape irrigation. Overall, in drip tape irrigation, less water was consumed and water use efficiency increased compared to furrow irrigation