Programa de Pós-Graduação em Recursos Hídricos, Universidade Federal de Lavras, Departamento de Recursos Hídricos, Campus Universitário, Aquenta Sol, 37200-900, Lavras, MG, Brazil.
An Acad Bras Cienc. 2021 Mar 31;93(1):e20191338. doi: 10.1590/0001-3765202120191338. eCollection 2021.
To achieve a better SDI system design, the emitters' hydraulic characteristics and the flowrate uniformity along lateral lines under backpressure influence must be known. The objective of this study was to evaluate the effect of backpressure on the maximum length of irrigation laterals using two types of emitters (pressure-compensating and nonpressure-compensating) in different situations. Data from a field experiment combined with information obtained from a previously published paper was used, that tested driplines hydraulics behavior influenced by backpressure. The lateral dripline design technique based on statistical approach developed by Anyoji & Wu 1987 was used to calculate the maximum length. The variables that most influenced the maximum length of the laterals were the terrain slope and permissible flowrate variation. For nonpressure-compensating emitters, the maximum length of the irrigation laterals is up to 5% greater in subsurface applications than in surface applications. For pressure-compensating emitters operating under the influence of backpressure, there is an increase in the discharge exponent due to the small difference in flowrate between the surface and subsurface conditions, which also increases the influence of pressure variations on the flowrate thus, the surface laterals are up to 8% longer than the subsurface ones.
为了实现更好的 SDI 系统设计，必须了解发射器在背压影响下的水力特性和沿侧线的流量均匀性。本研究的目的是评估两种类型的发射器（压力补偿和非压力补偿）在不同情况下背压对灌溉侧线最大长度的影响。该研究使用了来自田间试验的数据以及先前发表的论文中获得的信息，测试了受背压影响的滴灌线水力行为。Anyoji 和 Wu 1987 开发的基于统计方法的侧线滴灌设计技术用于计算最大长度。对侧线最大长度影响最大的变量是地形坡度和允许的流量变化。对于非压力补偿发射器，地下应用的灌溉侧线最大长度比地面应用长 5%。对于在背压影响下运行的压力补偿发射器，由于地表和地下条件之间的流量差异较小，流量指数会增加，这也增加了压力变化对流量的影响，因此，地表侧线比地下侧线长 8%。
