center pivot irrigation system is used as a modern irrigation method in different parts of iran. unfortunately due to lack of proper design and hydraulic shortcomings of the system in several agricultural lands in iran, the efficiency of the center pivot irrigation system is low or unacceptable. low system efficiency results in non-uniformity of water distribution along the lateral and on the c...

27 28 The simulation of center-pivot performance has been the subject of research 29 efforts since the 1960s. Center-pivot models frequently use empirical equations 30 relating pressure and sprinkler radial application pattern. Individual, stationary 31 water application patterns are overlapped and the resulting water application is 32 mapped in the field. Such models use constant tower angular...

Abstract Nowadays, the development of irrigation is increasingly recognized as a necessary factor in agriculture, primarily because global warming. Depending on field conditions, most commonly used method sprinkler irrigation. The spray uniformity sprinklers installed equipment can be characterized by Christiansen-uniformity coefficient (CUc%) and distribution (DU%). Our investigations were car...

according to the irrigation systems design standards, allowed pressure variation in lateral pipes is 20 percent. reasons for this rate selection, which since the 60's is performed, are not known. the increased changes in allowed pressure tubes to lateral pipes design, the increased sprinkling system required pressure and the increased nonuniform sprinkler distribution, so energy supply cos...

In recent years, bean common bacterial blight (CBB) caused by Xanthomonas axonopodis pv. phaseoli (Xap) has caused serious yield losses in several countries. CBB is considered mainly a foliar disease in which symptoms initially appear as small water-soaked spots that then enlarge and become necrotic and usually bordered by a chlorotic zone. Xap epiphytic population community has a critical role...

Impact of drip and overhead sprinkler irrigation on the persistence of attenuated Escherichia coli O157:H7 in the lettuce phyllosphere was investigated using a split-plot design in four field trials conducted in the Salinas Valley, California, between summer 2007 and fall 2009. Rifampicin-resistant attenuated E. coli O157:H7 ATCC 700728 (BLS1) was inoculated onto the soil beds after seeding wit...

Use of the double ring infiltrometer to measure soil water infiltration in center pivot irrigation systems isn’t an accurate approach because the real conditions of infiltration under center pivot sprinklers is different from what happens in the double ring. In this study the infiltration parameters were evaluated in real conditions of a center pivot system. For this purpose a single ring...