5750

5365

كارشناسي ارشد

مكانيك ماشين هاي كشاورزي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي

1389

نوزده،179ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

سيدجليل رضوي، رسول امير فتاحي

مهدي قيصري،شمس اله ايوبي

27/1/90

عباس همت، جهانگير عابدي

مهندسي كشاورزي

ID5365

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

180 Abstract Water shortage as demand for more stable water sources increases has become an important issue given the fact the agriculture sector is the highest consumer of water resources in any country More efficient ways of water consumption therefore must be devised in order not to hamper the chain of food production in the country Irrigation planning and choice of the proper method or system for irrigating farms might be an important management solution In Iran use of pressurized irrigation systems such as center pivot and linear because of small farm lands and topography may not be possible For this reason solid set irrigation system with removable sprinkler has become popular and fit with farmers farming conditions To improve water use efficiency in solid set systems more than ever a variable rate sprinkler working based on site specific soil moisture measurements by sensor was designed and evaluated under laboratory set up Information related to land slope soil texture soil moisture content at field capacity FC plant permanent wilting point PWP and root development depth Z were given to a controller The soil moisture sensor was from the type of FDR which transmitted data via wireless system The controller and the sensor were designed based on AVR Based on the data collected flow and duration of irrigation would be determined automatically Two variable rate sprinklers were designed and fabricated one from brass which was tested with 3 levels of flow and second one equipped with an electric valve with 7 flow levels Laboratory evaluation of the sprinkler with electrical valve showed that nozzle combination would result in a change in spray pattern from triangular to trapezoid pattern This resulted in better performance of the sprinkler indices and meanwhile an increase in laterals distances which would lower initial investments in sprinkler irrigation systems Use of different combinations of nozzles would improve uniformity of distribution Maximum distribution coefficient of 89 3 for triangular spray pattern was obtained with lateral and sprinkler spacing Sm Sl for 8 6 4 nozzle combination at 4 Bar pressure However considering economic aspect of system installation the best performance for this sprinkler with same combination was obtained at 4 5 Bar with 40 30 meter spacing The performance indices for 8 6 4 nozzle combination distribution coefficient distribution uniformity and application efficiency were 80 1 80 14 and 69 32 respectively Distribution coefficient for nozzle combinations of 8 6 8 4 and 6 4 at 4 5 Bar pressure and overlapping of 26 70 26 70 and 6 55 were 83 5 86 4 and 66 5 respectively The brass made sprinkler did not have nozzle combination but its performance was evaluated with three nozzle sizes of 6 8 and 10 mm This sprinkler had a triangular spray distribution pattern so the distribution uniformity would increase only when sprinkler distances were reduced On average highest uniformity of 86 5 was obtained with nozzle size 10 at 4 Bar with 100 overlapping 22 5 22 5 m However looking at other performance indices for all three nozzles a pacing of 30 30 is suggested Overlapping for 6 8 and 10 mm nozzles were 57 62 and 78 respectively while the uniformity coefficient were 69 77 5 and 86 4 respectively Keywords Site Specific Irrigation Variable Rate Sprinkler Uniformity Coefficient

سيدجليل رضوي، رسول امير فتاحي

مهدي قيصري،شمس اله ايوبي

عباس همت، جهانگير عابدي