تاثیر روش‌های مختلف کم آبیاری بر صفات فیزیولوژیکی ذرت دانه‌ای (.Zea Mays L)

شیوه‌های نوین آبیاری ضمن افزایش راندمان مصرف آب، کمک به رفع مشکل کمبود آب مورد نیاز بخش کشاورزی مینماید. پژوهش حاضر به بررسی روش‌های مختلف کم آبیاری و تاثیر آن بر خصوصیات فیزیولوژیکی ذرت دانه‌ای می‌پردازد. بدین منظور آزمایشی در سال 1395در قالب طرح بلوک‌های کامل تصادفی با 18 تیمار و سه تکرار در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه بیرجند انجام شد. تیمارهای آزمایش شامل دو تیمار آبیاری کامل و پرآبیاری و 16 تیمار کم آبیاری در دو سطح 75 و 50 درصد نیاز آبی طی دوره رویشی و کل فصل رشد گیاه به روش‌های سنتی و خشکی موضعی ریشه با آبیاری یک درمیان ثابت جویچه‌ها و آبیاری متناوب جویچه‌ها به ترتیب بعد از یک و دو نوبت آبیاری بود .بالاترین میانگین‌های بدست آمده در صفات ارتفاع بوته، طول بلال، شاخص سطح برگ، هدایت روزنه‌ای و محتوای نسبی آب برگ، در تیمار پرآبیاری مشاهده شد. طول بلال در تیمار کم آبیاری به روش خشکی موضعی ریشه با جوی و پشته یک درمیان ثابت (ci75t) به میزان 14.7 سانتی متر، اختلاف معنی‌داری با تیمار آبیاری کامل نشان نداد. بیشترین افزایش شاخص سطح برگ طی رشد به ترتیب برای تیمارهای 2prd75v، 2prd50v و 1prd50v به میزان 33.20، 30.28 و 25 درصد بود. کمترین هدایت روزنه‌ای در تیمار 2prd75t مشاهده شد که در مقایسه با تیمارهای 125 و 100 درصد نیاز آبی به ترتیب 64.58 و 58.17 درصد بود. کمترین میزان محتوای نسبی آب برگ در تیمار آبیاری سنتی di50v مشاهده شد. بر اساس نتایج بدست آمده، اختلاف ناشی از اعمال تنش در تیمارهای کم آبیاری موضعی ریشه کمتر از این اختلاف در تیمارهای کم‌آبیاری سنتی (نسبت به آبیاری کامل) بود. بنابراین، استفاده از روش‌های کم آبیاری ضمن کاهش جزیی رشد محصول، راهکاری مناسب برای مقابله با معضل بحران آب در زراعت ذرت در بیرجند می‌باشد.

Effect of deficit irrigation methods on physiological characteristics of maize (Zea mays L.)

IntroductionMaize (Zea mays L.) is an annual crop belonging to poaceae family that compared to other cereals has high yield. After wheat and rice, maize dedicated largest cultivation area in the world. Drought stress is one of the most important abiotic stress that often affects many aspects of plant growth and it’s the main limitation factor for crop production especially in arid and semiarid regions. Low irrigation lead to drought stress, which affects the plant growth and development. Drought stress leads to growth reduction, delayed maturity and crop yield loss. The use of modern irrigation methods to increase water use efficiency could help solve the problem of water resources shortage that needed for agriculture. Partial root zone drying irrigation is one of the innovative techniques that enhance water use efficiency without a significant reduction in throughput product. The part of the plant root watering and the other part remains dry; this part of the roots that remained dry by sending a signal to aboveground respond to dry and causes Stomatal closure and reduction of plant water consumption. This study aimed to evaluate the effect of different traditional irrigation and partial root zone drying focuses on physiological characteristics of maize. Materials and methodsIn order to evaluate the effect of different traditional irrigation and partial root zone drying on physiological characteristics of corn, an experiment in complete randomized block design with 18 treatments and 3 replication was conducted in Birjand University Agricultural Research Station at 59 degree and 13 minutes of eastern longitudes and 32 degree and 56 minutes altitudes. Irrigation treatment concluding from over irrigation (at 125% water requirement), full irrigation (at 100% water requirement) and combined from traditional low irrigation, low irrigation with fixed furrows and variable furrows after one or two irrigation, that started one month after emergence and continued until the end of vegetative or growth period of plant. low irrigation treatments were applied at 50 and 75% of water requirement. For measuring the volume of irrigation water per plot first net irrigation requirement was measured and then To finetune the distribution of water between plots and distribution of water the pumps and water counter were used. Finally, plant height, ear length, leaf area index, Stomatal conductance and relative water content were measured. Results and discussionThe results showed that the effect of irrigation treatment on all treats was significant. The highest averages were observed in irrigation at 125% of water requirement and applying various methods of irrigation lead to reduced plant height, ear length, leaf area index, stomatal conductance and relative water content in all of low irrigation treatments were observed in maize plants, although this different was not statistically significant in some treatments. Although water stress was reduced in maize plants traits, but the difference caused by the stress at the partial root zone drying was less than traditional low irrigation compared to full irrigation. Partial root zone drying also increased the physiological characteristics compared to traditional low irrigation treatments. It has been reported that the use of partial root zone drying in cotton resulted in significant savings in water consumption, earliness and increase the quality of the product, this technique reduces water consumption by 50% and increase water use efficiency by 21 percent compared to conventional irrigation to full irrigation was 43 percent. ConclusionAccording to the results of this study can be recommended partial root zone irrigation at 75 percentages of maize plant water requirement by variable irrigated furrows after twice irrigation as the best treatment for water use reduction in maize seed production. This treatment is appropriate for solving the water crisis.