Water Application Methods - Practices of Irrigation and On-farm Water Management - page 50

Fig. 2.8 Center pivot sprinkler system
have been developed specifically for use on these machines to better match water
requirements, water application rates, and soil characteristics. Since the center pivot
irrigates a circle, it leaves the corners of the field unirrigated (unless additions of
special equipment are made to the system). Center pivots are capable of irrigating
most field crops but have on occasion been used on tree and vine crops. Linear move
systems are similar to center pivot systems in construction, except that neither end
of the lateral pipeline is fixed. The whole line moves down the field in a direction
perpendicular to the lateral.
Continuous Move Laterals
These systems are well adapted to apply to small and frequent irrigations.
LEPA Systems
Low Energy Precision Application (LEPA) systems are similar to linear move
irrigation systems but are different enough to deserve separate mention of their
own. The lateral line is equipped with drop tubes and very low pressure orifice
emission devices discharging water just above the ground surface into furrows.
This distribution system is often combined with micro-basin land preparation for
improved runoff control (and to retain rainfall which might fall during the sea-
son). High-efficiency irrigation is possible but requires either very high soil intake
rates or adequate surface storage in the furrow micro-basins to prevent runoff or
nonuniformity along a furrow.
2.3.4.3 Capabilities and Limitations of Sprinkler System
Soil Type
Sprinklers adapt to a range of soil and topographic conditions. Light sandy soils
are well suited to sprinkler irrigation systems. Most soils can be irrigated with the