The way of irrigation water supplied to the crop root zone is called as irrigation method. In determining the irrigation method for use, soil and topographic features of the land, plant type, irrigation water supply, labor and technical skills conditions, facilities and operating costs and climatic data of region are factors that are needed to be considered. Basically, there are two groups as surface irrigation methods and pressurized irrigation methods. Surface irrigation methods are evaluated amongst the traditional irrigation methods and transmission of water is carried out with the help of energy provided through geographic height difference completely between the source and target parcels. The basin, furrow, border and uncontrolled flooding irrigation methods are also involved in the surface irrigation method.
The purpose of Irrigation planners is to re-increase the optimum level the decreasing water levels in the root zone with a minimum of irrigation water by using an efficient irrigation system. The pressurized irrigation methods are preferred than surface irrigation methods because of its need more less water and staff per unit area. In pressurized irrigation methods, water is transmitted via the pipe system from the source to the relevant parcels under a certain pressure. A pressurized irrigation system that will be installed in general, is composed of pump unit, control unit, the main pipe line, sub main pipe line, manifold, lateral and water emitters (Phocaides, 2007) (Figure 1).
2.4 Sprinkler irrigation
This method is the systems which water is supplied from the source such as stream, lake, dam, or drinking water system in the form of droplets sprayed through atmospheric air to the plant with the help of sprinklers (Ingels, 2003). These types of systems which are high degree-uniform-water distribution can be supplied with proper planning in all kinds of soil conditions and slope and rough terrains. Sprinkler irrigation is the most suitable and common method for landscape irrigation. It is suitable for irrigation by using any type of water source on the condition of using appropriate equipment. Sprinkler irrigation elements: water supply, pumping unit, control unit, the main canal, sub main canal, manifold, lateral and sprinkler heads. Sprinkler irrigation method is the most preferred method in landscape irrigations. Advantage and disadvantage of sprinkler irrigation method are given below.
The advantages of sprinkler irrigation method
– The larger areas can be irrigated with smaller quantity of water than the method of surface irrigation.
– In problematic areas from topographic aspect, the desired performance can be achieved through appropriate design and arrangement.
Fig. 1. Main components of pressurized irrigation systems
– High uniform distribution of water can be provided,
– Irrigation efficiency is high,
– Fertilizing can be applied during irrigation,
– Frost protection can be achieved.
– Irrigation labor is less than in surface irrigation.
– Its initial investment cost is lower than the drip irrigation.
– It prevents the salt deposit in the root zone of plants by the effect of leaching
The disadvantages of sprinkler irrigation method
– The realization problems of uniform distribution of water are experienced especially in windy conditions.
– Blasts may occur in the leaves in applications during sunny conditions
– It leads the occurrence of an illness (crown gall) or spread of disease in the wet foliage
– The evaporation loss is occurred at noon.
Components of sprinkler irrigation system are given below.