به‌منظور بررسی تاثیر میزان و تقسیط کود نیتروژن بر عملکرد و جذب عناصر در برنج رقم هاشمی مطالعه ای در طول دو فصل زراعی در موسسه تحقیقات برنج کشور به صورت آزمایش فاکتوریل در قالب طرح بلوک های کامل تصادفی در سه تکرار انجام شد. تیمارها عبارت بودند از مقادیر کود نیتروژن از منبع اوره در چهار سطح (30، 60، 90 و 120 کیلوگرم در هکتار) و تعداد تقسیط کود در سه سطح (یک، دو و سه تقسیط) در مراحل نشاکاری، ابتدای پنجه‌زنی و اواخر دوره پنجه‌زنی و قبل از گل دهی. نتایج نشان داد مقدار و همچنین تقسیط کود نیتروژن (به جز سال دوم) در طول دوره رشد بر عملکرد دانه اثر بسیار معنی‌داری داشت (P<0.01). میزان کاربرد نیتروژن تأثیری بر میزان درصد فسفر جذب شده در دانه نداشت. افزایش دفعات بکارگیری نیتروژن در سه تقسیط باعث افزایش درصد جذب نیتروژن در دانه شده است (سال اول P<0.01). نتایج همچنین نشان داد افزایش عملکرد ناشی ‌از مصرف نیتروژن اضافی به میزان 30 کیلوگرم در هکتار، معادل افزایش یک مرحله در تعداد تقسیط می‌باشد. تفاصيل المقالة

In order to calibrate and validate the PILOTE model for rice in a humid climate, this study was carried in a randomized complete block design with three replications on a popular local variety, Hashemi, during 2001, 2002, 2005, 2006 and 2007 crop seasons. This research was done at the Rice Research Institute of Rasht, Iran. Evaluation of simulated and measured grain yield and dry matter values was done using Nash-Sutcliffe efficiency (EF), Root Mean Square Errors (RMSE) and normalized root mean square errors (NRMSE) indices. The results revealed that RMSE for validation and calibration were 0.69 and 0.72 Mg.ha-1, respectively. NRMSE for calibration was 9.5% and for validation was 14.1%. NRMSE for grain yield and dry matter were 8.74 and 13.37%, respectively. EF values were between 0.84 and 0.98. The results showed that the PILOTE model can be used to manage properly rice irrigation in different regimes. Scenario analysis showed that the best irrigation regime was intermittent irrigation with 8-day interval. تفاصيل المقالة

About 20% of the electricity produced in the world is consumed in rotary equipment for conveying fluids such as water, gas, air, and other liquids, while the loss of energy consumption in this sector is more than 60%. The aim of this study is to evaluate different efficiencies in the pumping stations in the pressurized irrigation systems to address low energy efficiency issues in the pump stations, and then finding proper solutions to increase it. In this regard, the electrical efficiency, hydraulic efficiency, and mechanical efficiency were determined in the studied pump stations. The total efficiency of each pump station was determined using those efficiencies. Pump station assessment tool (PSAT) software was used for modeling each station and predicting annual energy consumption costs; furthermore, the potential of increasing the efficiency was calculated. Results showed that the total efficiency of the studied pump stations ranged from 13 to 32% and averaged 24%. Factors, such as improper design, disproportion in terms of the operation conditions, and the design and improper operation caused a drop in efficiency of pump stations, and addressing these issues can improve the productivity of the energy consumption in the pump stations from 24 to 49%. تفاصيل المقالة