## 2 Materials and Methods  
### Systems Designing  
The CPL system was set up in a 48 m \(\times\) 48 m farm in Guangxi province, China. Two irrigation system plans, one as traditional semi-permanent using 2 literals and another as CPL applying a single lateral, were designed. PVC pipes were used to simplify the installation and implementation process since CPL has different sprinkler distances and aluminum tubing have fixed length and fittings for sprinklers. The farm water supply was from the distribution network at the test center (provided from the nearest river) and had 5 L per second maximum discharge rate located at the southwest corner of the farm. The field was plain and had zero slope as shown in the below figure (Figure 2). In order to specify the soil infiltration rate (I), soil texture evaluation was carried out on the site. Based on the outcomes and soil texture triangle diagram, the farm soil type was identified as loam and the infiltration rate was accounted for 13 mm per hour. The Soil water holding capacity or SWHC [26] and other basic information used to design an irrigation system according to the site long term measured data are provided and calculated in Table 1 [27,28]. \"I\" was considered as the  
Figure 1: Schematic comparison of (**A**) semi-permanent split lateral (**B**) CHL and (**C**) CPL layout. Figure 2: Corner pivot lateral testing at irrigation test center. limiting margin in sprinklers or sprayer selection process in which they were elected to work at lower than the infiltration rate to prevent runoff. In contrast with ordinary semi-permanent layouts in which sprinkler distances are equal, in a CPL system the lateral irrigates a slice of the watering area at each cycle, therefore the sprinklers' distance of throw will increase toward the lateral to the outmost side. Since the farm corner is a smaller area, sprayers with minor throw distance were applied, however bigger radius sprinklers were used at the end of the line, the same as in the center-pivot technique [29]. The maximum allowable discharge rate for each sprinkler was calculated individually according to a modified formula (Equation (1)) [28]. Definitively for sprinklers the discharge rate is expressed as the volume of water per time i.e., liter per second dispersed on the farm. In an ordinary rectangular shape area among 4 sprinklers for semi-permanent, to calculate the maximum discharge rate, the infiltration rate is multiplied by area (sprinklers distance or \(S_{l}\) multiply by lateral distance or \(S_{m}\)). While in CPL, due to radial lateral moves, the area is more like trapezoid than rectangle shape. The conceptualized imbalanced overlapping has been illustrated below (Figure 3). Hence, the discharge rate for sprinklers in CPL is adjusted accordingly in which the lateral distance (\(S_{m}\)) would be the average distances of lateral in 2 continuous sprinklers that is additive along the lateral towards its end. Also the sprinkler distance would be the trapezium height (right angled c in Figure 3) between the 2 sides (a & b sides in Figure 3). With this we have replaced the rectangle area with trapezium in the below formula:  
\[q=\frac{I\times S_{l}\times S_{m}}{3600}=\frac{13\times 11.5\times 9.5}{3600}=0. 39\ L/S \tag{1}\]  
in this equation:  
\(I\) is the soil infiltration rate in millimeter per hour  
\(q\) is the sprinkler allowable discharge rate in liter per second  
\(S_{l}\) is the upright sprinklers distance or c in meter  
\(S_{m}\) is the average laterals distance in meter (a + b)/2  
An ordinary head to head sprinkler/sprayer design was customized to be implemented for CPL [21; 30]. In semi-permanent or solid set systems, the sprinklers interval is constant. This will consequently provide a uniform coverage pattern for these layouts. However, since the sprinklers radiuses are unequal in CPL, therefore the coverage pattern of an individual sprinkler/sprayer by the previous and next watering circle is imbalanced, as a function of sprinklers throw distance.