پديد آورندگان :
مومن، علي دانشگاه فردوسي مشهد - دانشكده كشاورزي - گروه زراعت , كوچكي، عليرضا دانشگاه فردوسي مشهد - دانشكده كشاورزي - گروه اگروتكنولوژي , نصيري محلاتي، مهدي دانشگاه فردوسي مشهد - دانشكده كشاورزي - گروه اگروتكنولوژي
كليدواژه :
بهينه سازي , كارايي تبديل , كارايي جذب , نياز آبي گياه
چكيده فارسي :
به منظور درك اثر متقابل آب، نيتروژن و فسفر بر عملكرد و كارايي مصرف عناصر غذايي ذرت آزمايشي به صورت كرت‌هاي خرد شده در دو سال 1393 و 1394 در قالب طرح بلوك‌هاي كامل تصادفي در مزرعه تحقيقاتي دانشگاه فردوسي مشهد به اجرا در آمد. آبياري در سه سطح 80 (ETc80)، 100 (ETc100) و 120 (ETc120) درصد نياز آبي گياه به عنوان كرت اصلي و تركيب فاكتوريل سه سطح صفر (N0)، 200 (N200) و 400 (N400) كيلوگرم نيتروژن در هكتار با صفر (P0)، 100 (P100) و 200 (P200) كيلوگرم فسفر در هكتار در كرت‌هاي فرعي در نظر گرفته شدند. نتايج نشان داد كه با افزايش هر يك از نهاده‌ها عملكرد دانه ذرت بهبود يافت. روند تاثير هر يك از اين نهاده‌ها بر عملكرد دانه به اين ترتيب N > ETc > P بود. اثر متقابل مصرف آب و نيتروژن نشان داد كه عملكرد و كارايي مصرف نيتروژن و فسفر در سطح N0 با افزايشETc نسبتا خطي افزايش يافت، اما اين صفات در تيمارهاي N200 و N400 با افزايش آبياري بيش از ETc100 به ترتيب بدون تغيير و روند كاهشي نشان دادند. بنابراين، ETc100N200 بهينه‌ترين تيمار در افزايش عملكرد و كارايي مصرف نيتروژن به طور همزمان بود. اثر متقابل نيتروژن و فسفر بر عملكرد و جذب عناصر غذايي مثبت و به صورت هم‌افزايي بود. نتايج آناليز مسير مشخص نمود كه در اغلب تيمارهاي آزمايش تاثير كارايي جذب نيتروژن و فسفر در مقايسه با كارايي تبديل آنها بر كارايي مصرف هر يك از اين عناصر غذايي بارزتر بود.
چكيده لاتين :
Introduction: Water and nutrient deficiency often restrict growth and production potentials of agricultural ecosystems in arid and semi-arid environments (Cao et al., 2007). It has been reported that the effects of nutrient supply and water regimes may interact significantly on plant growth (Hu and Schmidhalter, 2005). A simple assessment of the effect of each input may not show a complex interaction with the other inputs. Therefore, it is necessary to understand the interactive effects of soil water and nutrients on plant growth in the arid environments. Hence, the objectives of this study were to: (1) determine the interactive effects of ETc, nitrogen and phosphorus on yield and N-P efficiency indicators in maize crop and (2) evaluate the importance of uptake efficiency versus utilization efficiency of nitrogen and phosphorus on NUE and PUE. Materials and Methods: This study was carried out at the research farm of Ferdowsi University of Mashhad, Iran, located 10 km east of Mashhad at 36.16° North latitude, 59.36° East longitude, and height of 985 m above sea level in two growing years of 2014 and 2015. The experiment was conducted as split plot based on a randomized complete block design with three replications. The main plots consisted of three levels of 80 (ETc80), 100 (ETc100) and 120 percent (ETc120) of plant water requirement based on crop evapotranspiration, and the sub-plots included a factorial combination of three N levels (0, 200 and 400 kg ha-1) and three P levels (0, 100 and 200 kg ha-1). Combined analysis of variance was performed by SAS 9.4 software, and means of different treatments were compared by Tukey test at the probability level of 5%. Results and Discussion: Maize grain yield increased significantly as a result of the increase in the all inputs. However, effect of nitrogen on grain yield was more pronounced than the others. Application of 200 and 400 kg ha-1 N caused 24% and 38% increases in maize yield, respectively. The interaction effect of ETc and N for grain yield was significant, and the highest and the lowest maize yields of 9486.8 and 5836.4 kg ha-1 were respectively obtained with ETc100N400 and ETc80N0. When the applied water increased up to ETc100, all the nitrogen rates increased the maize yield but the use of water higher than this level resulted in the decreased grain yield in N400. It appears that under these conditions, leaching increases, which ultimately leads to the reduction of yield. According to these findings, irrigation higher than ETc100 decreased N uptake in this treatment. The trends of NUE and PUE in response to treatments were similar to that of grain yield. It has been reported that changes in each of the P use efficiency components are significantly dependent on plant yield (Fageria et al., 2014). The interaction of nitrogen and phosphorus showed that in N0, the effect of different levels of phosphorous on grain yield was not significant, while phosphorus application at nitrogen levels of N200 and N400 significantly increased maize grain yield. These observations suggest that the interaction of nitrogen and phosphorus on grain yield and nutrient uptake is synergistic. The results of path analysis indicated that in most of the treatments, the effect of N and P uptake efficiency was more conspicuous on the NUE and PUE as compared to that of their utilization efficiency. Conclusion: The results showed that maize grain yield improved with increasing the inputs. The magnitude of the effects of all inputs on yield was in the order of N > ETc > P. The interaction effect of ETc and N showed that ETc100N200 was the optimal treatment for the simultaneous improvement of maize yield and nitrogen efficiency. The interaction of N and P on the yield and nutrient uptake was found to be positive and synergistic. Overall, this study showed the importance of the interactive relationships between water and nutrients for achieving both the highest grain yields and nutrient use efficiency.
