平移式喷灌机行走速度及喷灌均匀度试验研究

Study on translocating speed and water distribution uniformity of lightweight lateral move irrigation system

为研究低压喷灌下喷灌机行走速度合理取值以及喷灌均匀度对土壤含水率均匀度的影响,以自行研制的轻小型平移式喷灌机为研究对象,通过室内单喷头试验和田间喷灌试验,探究了特定灌水定额下喷灌机的工作压力与行走速度关系,并对其水量分布、喷灌均匀度以及土壤含水率均匀度随时间变化进行了分析.结果表明：通过确定灌水定额能够计算出平移式喷灌机的行走速度和工作压力：当灌水定额分别为10,15,20 mm时,40~120 kPa喷灌压力下喷灌机行走速度最小为17.27 m/h,最大为58.65 m/h;增大喷灌压力能小范围提高均匀度,40 kPa工作压力均匀度为0.696,60~120 kPa喷灌压力下均匀度变化范围为0.731~0.788,喷灌水在土壤中的二次分布均匀度明显高于地表喷灌均匀度,40 kPa喷灌压力下喷后6 h土壤含水率均匀度达到0.906,24 h后达到0.953,可相应降低喷灌均匀度设计值以降低运行成本,节约能耗.

In order to identify a reasonable translocating speed of lateral irrigation system and effects of water distribution uniformity on soil water content under a low operating pressure, a relationship between operating pressure and translocating speed at a rated irrigation quota is established through indoor and field experiments by employing the lightweight lateral move irrigation system developed in house, in addition, the variations in water distribution and uniformity as well as soil water content uniformity are analyzed in terms of time. It is clear that the relationship can estimate the translocating speed and operating pressure accurately under a given irrigation quota. The lowest and highest translo- cating speeds are 17.27, 58.65 m/h under 40 - 120 kPa operating pressure at 10, 15 and 20 mm irrigation quotas, respectively. An increasing operating pressure can improve water distribution uniformity slightly, for instance the uniformity is 0. 696 for 40 kPa operating pressure, but for 60 - 120 kPa pres-sure it is increased to 0. 731 - 0. 788. Note that the water distribution uniformity is quite better in soil than on land surface at low working pressure. Particularly, the soil water content uniformity is 0. 906 after 6 h since irrigation, but it can be as high as 0. 953 after 24 h under 40 kPa working pressure. This suggests that the design specification on water distribution uniformity can be loosened properly by moving the irrigation system faster to reduce operating cost and energy consumption.