A. H Nasrolahi, M. Behzad, S. Bromand Nasab, M. Heydariniya,
Volume 17, Issue 66 (winter 2014)
Abstract
Drip irrigation is a new method of irrigation that is rapidly growing in different countries. The emitters are the most important parts of a drip irrigation system. Many factors such as physical, chemical and biological clogging, pressure, water temperature affect the emitter´s uniformity of water emission. In this study, to investigate pressure effect on the hydraulic performance of emitters, 7 kinds of compensating emitters in the market were selected and studied in laboratory conditions. For this purpose, a drip irrigation system was designed in irrigation laboratory in faculty of water sciences engineering, Shahid Charm University, Ahwaz. Average flow of emitters, Manufacturer´s coefficient of variation of emitter(CV), emission uniformity(EU), Christiansen coefficient of uniformity(CU) and Flow Variations for all types of emitters at pressures of 5, 10, 15 and 20 meters were calculated and compared. Also, in order to compare the pressure compensating capacity, for every emitter the equation of Flow- pressure was extracted. Results showed that the D-type emitter has the best hydraulic performance from among the emitters tested. Therefore, to achieve higher efficiency and also to use it on slopes and uneven lands this emitter is recommended as the best. However, performances of other emitters are also acceptable.
F. Alizadeh, A. H. Nasrolahi, M. Saeedinia, M. Sharifipour,
Volume 25, Issue 1 (Spring 2021)
Abstract
In areas with high rainfall distribution, proper irrigation management, including complementary irrigation, is one of the effective strategies to increase crop production. In order to investigate the effect of supplementary irrigation in different growth stages on the yield and water productivity of Autumn rapeseed, an experiment in the form of a complete randomized block design with five irrigation management treatments including rainfed (I1), single irrigation at flowering stage (I2), single Irrigation at pod filling stage (I3), two irrigation at pod filling stage and flowering (I4), three irrigation at flowering, and pod filling and grain Filling stages (I5) was carried out at Lorestan University Research Field. Results showed that there was a significant difference between the effects of different irrigation treatments at 1% level. The lowest grain yield, biological yield and oil yield were obtained in I1 treatment with 44.62%, 50.95% and 53.58% decrease, as compared to I5 treatment. The results also showed that by applying irrigation at pod filling stage, grain yield and oil yield were increased by 13.22% and 20.23%, as compared to I1 treatment. The highest total productivity for the grain yield and oil yield was obtained in I5 treatment with 0.252 and 0.073 kg / m3. In general, due to the fact that drought stress in rapeseed calving stages reduces yield, the higher the number of irrigations in rapeseed calving stages, the more the yield.
