土壤物理特性对地下滴灌毛管灌水质量的影响

压力水头偏差率和滴头流量偏差率是评价微灌灌水质量的重要指标。该文建立了地下滴灌毛管水力计算数学模型，利用该模型，分析了土壤物理特性对地下滴灌毛管水力特性分布规律和灌水质量的影响。结果表明，由于土壤物理特性对地下滴灌毛管滴头流量的制约作用，致使地下滴灌毛管压力水头与滴头流量偏差率比地表滴灌的要小；土壤物理特性对毛管灌水质量指标的影响不显著，但土质较重、土壤体积质量和初始含水率较大时，毛管压力水头与滴头流量偏差率较小，灌水质量较好。说明地下滴灌毛管灌水质量优于地表滴灌，土壤物理特性有利于毛管灌水质量的提高。计算与分析结果可为进一步研究地下滴灌田间管网水力特性及地下滴灌技术应用提供参考。

Effects of soil physical properties on irrigation quality of lateral in subsurface drip irrigation

Pressure head deviation rate and emitter flow deviation rate are two important indexes to evaluate irrigation quality of micro-irrigation system. The mathematical model for lateral hydraulic calculation in subsurface drip irrigation (SDI) was established. The model was used to study influences of soil physical properties upon hydraulic characteristics and irrigation quality of lateral in SDI. The results showed that pressure head deviation rate and flow deviation rate of lateral in SDI were lower than these two indexes in drip irrigation (DI) due to restrictive effects of soil physical properties on emitter discharges in SDI. The effects of soil texture, soil bulk density and initial soil moisture on irrigation quality of lateral in SDI were not significant. But the finer soil texture, higher soil bulk density, higher initial soil moisture was, the lower pressure head and flow deviation rates, and the better irrigation quality were. So irrigation quality of lateral in SDI was better than that of lateral in DI, and soil physical properties were advantageous to irrigation quality of laterals in SDI. These results can provide reference for studying hydraulic characteristics of field pipe network system in SDI and SDI technology application.