地下滴灌影响要素及其敏感性分析

An Experimental Study on Influencing Factors Under Subsurface Drip Irrigation

地下滴灌是一项具有广阔应用前景的高效节水灌溉技术之一。为分析不同影响因素对地下滴灌滴头流量的影响机制,以PLASSIM滴头、和平滴头2种滴头为研究对象,利用有机玻璃桶(直径40cm,高40cm)内埋设滴头(表层20cm下)系统分析了滴头工作压力(60,100,150,200,250,300,370kPa)、土壤初始含水量(12%,18%)及土壤容重(1.25,1.40g/cm^3)对地下滴灌滴头流量的影响及其敏感性。结果表明:工作压力是地下滴灌滴头流量的主要影响因素,且随工作压力增大,滴头流量增大;土壤初始含水率和容重对供试的滴头流量均起制约作用,其中对轻砂土的制约作用更为明显;土壤质地对各影响因素的敏感性存在差异,其中轻砂土最敏感,粉壤土居中,轻粘土最弱。PLASSIM滴头、和平滴头的敏感性指标均随工作压力、土壤初始含水率、容重的增加而降低。通过系统分析多种土壤物理特性对地下滴灌滴头流量的影响及其敏感性分析,将为设计经济、高效而又节水的地下滴灌系统,制定合理的地下滴灌制度提供理论依据。

Subsurface drip irrigation（SDI）,which has a wide application prospect,is one of the high-efficiency water-saving irrigation techniques.Because the emitters are buried in the soil,the hydraulic characteristics of SDI subunit pipe network are often affected by soil physical properties,and the research present on these problems are inadequate.In the paper,laboratory tests were carried out to investigate the influencing factors of hydraulic factors under subsurface drip irrigation,the treatments included work stress（60,100,150,200,250,300,370kPa）,soil initial moisture contents（12%,18%）,and soil bulk densities（1.25,1.40g/cm^3）.In addition,the sensitivity was also analyzed.In this study,PLASSIM emitters and Heping emitters were used.The main results were as follows：The work pressure was the main factor that affected the emitter discharge in all three soil samples,and the SDI emitter discharge was larger under higher work pressure.Soil bulk density and initial soil water content could limit the discharge,especially in sandy soil.Significant differences in the sensitivities of emitter discharges for different soil samples were obtained.The sensitivity was larger in the sandy soil,while it was smaller in the loamy soil and smallest in the clay soil.Three kinds of sensitive indicator of the PLASSIM emitter declined with the increase of work pressure,soil initial moisture content,and soil bulk density.The results obtained in this study could provide scientific instructions on irrigation program and efficient irrigation system.