كليدواژه :
آبياري , الگوي كاشت , نسبت برابري زمين , كلروفيل
چكيده فارسي :
به‌منظور بررسی اثر نسبت‌های مختلف كشت مخلوط بر عملكرد و اجزای عملكرد ارزن و سویا تحت شرایط تنش كم‌آبی، آزمایشی در مزرعه تحقیقاتی دانشكده كشاورزی دانشگاه بوعلی‌سینا در سال زراعی 95-1394، به‌صورت كرت‌های خردشده در قالب طرح پایه بلوك‌های كامل تصادفی با سه تكرار اجرا شد. كرت اصلی شامل كم‌آبیاری در سه سطح (آبیاری پس از 60، 90 و 120 میلی‌متر تبخیر تجمعی آب از تشت تبخیر كلاس A) و كرت‌های فرعی نسبت‌های كشت مخلوط جایگزینی در پنج سطح 33 درصد ارزن+ 67 درصد سویا، 50 درصد ارزن+ 50 درصد سویا،67 درصد ارزن+ 33 درصد سویا و تك‌كشتی سویا و ارزن بودند. صفات مورد بررسی شامل غلظت كلروفیل، ارتفاع بوته، اجزای عملكرد و عملكرد دانه ارزن معمولی و سویا بودند. نتایج نشان داد كه با اعمال تنش كم‌آبی، غلظت كلروفیل برگ ارزن و سویا كاهش یافت. غلظت كلروفیل برگ سویا و ارزن در نسبت‌های كشت مخلوط بالاتر از كشت خالص آن‌ها بود. بیشترین تعداد خوشه در بوته و تعداد دانه در خوشه ارزن در نسبت‌های (50 درصد سویا: 50 درصد ارزن) و (67 درصد سویا: 33 درصد ارزن) در شرایط عدم تنش كم‌آبی و كمترین میزان آن‌ها در كشت خالص ارزن تحت شرایط تنش شدید كم‌آبی مشاهده شد. تنش كم‌آبی موجب كاهش معنی‌دار تعداد غلاف در بوته، تعداد دانه در غلاف و وزن صد دانه سویا شد. نسبت كاشت (50 درصد سویا: 50 درصد ارزن) تعداد غلاف در بوته و تعداد دانه در غلاف سویا را افزایش داد. نسبت كاشت (50 درصد سویا: 50 درصد ارزن) تحت شرایط تنش شدید كم‌آبی، بیشترین نسبت برابری زمین 14/1 را به خود اختصاص داد. به‌طور كلی، می‌توان نتیجه گرفت كه بهترین نسبت كشت مخلوط برای به‌دست آوردن حداكثر عملكرد دانه ارزن و سویا نسبت كشت (50 درصد سویا: درصد 50 ارزن) در سطوح مختلف كم‌آبیاری بود.
چكيده لاتين :
Introduction
Drought is one of the major abiotic stress limiting plants growth and productivity across the world. Intercropping increased the efficiency of water utilization. In arid and semi-arid regions, intercropping can improve water use efficiency and water conservation in soil. Because intercropped plants use water efficiently and caused increasing of water use efficiency. Intercropping of legumes and cereals compared with corresponding sole cropping is common and might be beneficial in semi-arid regions particularly in resource limiting conditions. Do and Goutan (1987) reported that millet can be planted in mixture with some plants such as cowpea, sorghum, peanut and soybean. The aim of the investigation was to study the impact of intercropping on the growth and yield of millet and soybean under deficit irrigation.
Materials and Methods
The experiment was carried out as a split-plot based on a randomized complete block design with three replications, at the Research Farm of Agricultural Faculty of Bu-Ali Sina University in 2015. The main factor included three levels of deficit irrigation (irrigation after 60 (well-watered), 90 (mild stress) and 120 (severe stress) mm by using of class A evaporation pan) and five levels of replacement intercropping consisted of monoculture of soybean, monoculture of millet, 67% soybean+ 33% millet (67S:33M), 50% soybean+ 50% millet (50S:50M) and 33% soybean+ 67% millet (33S:67M) as subplot.
Results and Discussion
Water stress decreased chlorophyll concentration of millet and soybean. In all intercropping ratios, the chlorophyll concentration of soybean was higher than its monoculture. The rate of increase in chlorophyll concentration in (67S:33M), (50S:50M), and (33S:67M) ratios compared to monoculture of soybean, were 8.43, 8.57 and 8.76 percent respectively. The highest total chlorophyll content of millet was obtained in (50S:50M) and (33S:67M) ratios, that was 12.34 and 12.09 percent higher than monoculture of millet, respectively. The highest number of panicles per plant of millet was obtained from (50S:50M) and (67S:33M) ratios under well-watered, and the lowest one was observed in monoculture of millet under severe water stress. The highest number of seed per panicles of millet was observed at intercropping of 33S:67M, 50S:50M and 67S:33M treatments under well-watered, and the lowest value was measured in monoculture of millet under sever water stress. Water stress decreased number of pods per plant, number of seeds per pod and 100-seed weight of soybean, compared to well-watered. Number of pods per plant, number of seeds per pod and 100-seed weight of soybean reduced in severe water stress were about 50.58, 33.68 and 26.09 percent, respectively, compared to well-watered. The number of pods per plant of soybean plants in all intercropping patterns was higher than monoculture of soybean. The rate of increase in number of pods per plant in (67S:33M), (50S:50M), and (33S:67M) ratios, were 6.38, 11.63 and 7.75 percent respectively, compared to monoculture of soybean. The highest seeds per pod of soybean was obtained in (50S:50M) ratio by 13.78 percent higher than monoculture of soybean. Water stress reduced grain yield of millet and soybean by 46.8 and 50.05 percent, respectively. Under well-watered condition, the highest yield of millet was obtained in (67S:33M) and (50S:50M) ratios. The highest actual yield of soybean was observed in (50S:50M) ratio by. Maximum value of LER (1.14) was achieved in (50S:50M) ratio intercropping in severe stress.
Conclusions
The best planting pattern to obtain maximum yield of millet and soybean was (50S:50M) ratio. The difference in rooting millet with soybean and better use of water in different soil depths could be reason to the high yield under water stress, the show millet and soybean intercropping were complementary.
