بررسي عملكرد و كارآيي نيتروژن و فسفر در كشت مخلوط رديفي گندم و كلزاي پاييزه

Assessment of Yield and Use Efficiency of Nitrogen and Phosphorus in Row Intercropping of Wheat and Canola

به‌منظور بررسی عملكرد و كارآیی نیتروژن و فسفر در كشت مخلوط گندم- كلزا، آزمایشی در سال زراعی 93-1392 در مزرعه تحقیقاتی دانشگاه فردوسی به‌صورت فاكتوریل در قالب طرح بلوك‌های كامل تصادفی با سه تكرار انجام شد. تیمارهای آزمایش شامل: كشت خالص گندم (ارقام الوند و فلات)، كشت خالص كلزا (ارقام اكاپی و زرفام) و كشت مخلوط كلزا و گندم به‌صورت ردیفی با نسبت‌های 1:1، 2:2 و 3:3 بودند. نتایج به‌دست آمده از این آزمایش نشان داد كه بیشترین عملكرد اقتصادی و بیولوژیك گندم و كلزا پس از كشت خالص، در تیمار كشت سه ردیفی مشاهده شد. همچنین بالاترین نسبت برابری زمین از تیمار الوند- اكاپی (3:3) به‌دست آمد. بالاترین كارایی فیزیولوژیك نیتروژن و فسفر گندم مربوط به كشت خالص رقم فلات بود و در مورد كلزا در تیمار فلات- زرفام 2:2 مشاهده شد. بیشترین كارایی مصرف نیتروژن و فسفر گندم بعد از كشت خالص الوند، در تیمار الوند- اكاپی 3:3 مشاهده شد. تیمارهای الوند- اكاپی 3:3 برای گندم و كشت خالص رقم اكاپی برای كلزا بیشترین كارایی جذب نیتروژن و فسفر را داشت. در مجموع با توجه به مشاهدات این آزمایش و از آن‌جایی‌كه بیشترین میزان كارایی جذب و مصرف عناصر در تیمارهای كشت سه ردیفی مشاهده شد، به‌نظر می‌رسد الگوی كشت مخلوط سه ردیفی گندم و كلزا شرایط مناسب‌تری برای استفاده بهتر از عناصری همچون نیتروژن و فسفر دارا می‌باشد.

<strong >Introduction </strong > Intercropping is one of the most effective approaches for developing sustainable agriculture which causes control of soil erosion, decreasing usage of agrochemicals, increasing biodiversity, yield in area unit, quantity and quality of the product and it finally makes stability in agronomical ecosystems. Many researchers consider the multiple cropping as the most important factor for increasing the diversity of cultures in agricultural ecosystems. Increasing crop diversity through intercropping can be effective to improve the ecological functions and ecosystem services. The aim of this study was to determine the best pattern of wheat and canola intercropping based on yield and nutrition use efficiency. <strong >Materials and Methods </strong > In order to study the effects of intercropping on yield and nitrogen and phosphorus use efficiency, a field experiment was conducted as randomized complete block design (RCBD) at Agricultural Research Station, Ferdowsi University of Mashhad, Iran, during 2012-2013 growing season. Experimental treatments were included planting patterns of wheat (Alvand and Falat cultivars) and canola (Ocapy and Zarfam cultivars) intercropping with ratios of 1:1, 2:2, 3:3 and sole cropping of them with three replications. The size of each plot was 6 m2 and distance between plots and blocks were 0.5 and 1 m, respectively. Planting of wheat and canola cultivars were done with densities of 320 and 80 plant per m2, respectively, at the same time. Nitrogen content of plant was determined by microkejeldal machine and wet digestion method. Phosphorus content was measured by spectrophotometer machine and Olsen method. Land equivalent ratio (LER) was used to evaluate the advantage of the intercropping. Analysis of variance was done with SAS ver 9.1 software and means were compared with Duncan’s test at the 5% level of probability. <strong >Results and Discussion </strong > The results showed that the highest economical yield was obtained from sole cropping of Alvand (4199.77 kg ha1). Treatment of Alvand-Ocapy intercropping (3:3) had the highest economical yield within different patterns of intercropping. The highest and lowest biological yield of wheat were revealed from sole cropping of Alvand and Falat-Zarfam intercropping (2:2), respectively. The sole cropping of Ocapy and Falat-Zarfam intercropping (2:2) had the highest (4034.54 kg ha-1) and lowest (1691.98 kg ha1) economical yield of canola. The highest and lowest amounts of canola biological yield were obtained from sole cropping of Ocapy and Falat-Zarfam intercropping (2:2), respectively. Land equivalent ratio (LER) in all different patterns of intercropping was more than one which shows advantage of the intercropping. The highest LER was obtained from Alvand-Ocapy intercropping (3:3). The highest nitrogen and phosphorus physiological efficiency were observed in sole cropping of Falat cultivar (wheat) and in the case of canola was obtained from Falat-Zarfam intercropping (2:2). The sole cropping of Alvand and Alvand-Ocapy intercropping (3:3) had the highest use efficiency of nitrogen and phosphorus, respectively. The highest amount of nitrogen and phosphorus uptake was obtained from Alvand- Ocapy intercropping (3:3) and sole cropping of Ocapy (respectively, for wheat and canole). <strong >Conclusions </strong > The results of this study indicated that treatment of Alvand- Ocapy intercrroping (3:3) had the highest economical yield, land equivalent ratio and also the highest amount of nitrogen and phosphorus uptake. This planting pattern can be suggested to obtain proper yield of wheat and canola as well as appropriate amount of nitrogen and phosphorus uptake.