Impact of Mounting Height and Working Water Pressure on the Performance of Micro-sprinkler Irrigation System for Seedling Beds

Abstract

【Objective】 Micro sprinkler irrigation is often mounted on the top of seeding beds to nurture crop seedlings. The purpose of this paper is to study the impact of the mounting height and working water pressure on performance of the irrigation system. 【Method】 We compared three mounting heights: 0.5, 0.6 and 0.7 m, and four working water pressures: 200, 250, 300 and 350 kPa. In each treatment, we measured the spatial distribution of water droplets. Based on the mass balance, we derived a model to calculate the water distribution sprayed from the nozzle, and converted constant water distribution measured from a single sprinkler to dynamic water distribution. We also measured the uniformity coefficient of water in all treatments and linked it to water pressure and the distance between adjacent nozzles. 【Result】 Increasing the installation height from 0.5 to 0.7 m improved uniformity of the water distribution and reduced the maximum irrigation intensity; the average intensity of single sprinkler increased with water pressure. When the working pressure was the same, the uniformity coefficient decreased first and then increased before declining again as the distance between adjacent nozzles increased. When the installation height was the same, the uniformity coefficient of water distribution did not show noticeable change with the working water pressure. For all treatments we compared, the optimal working conditions were as follows: installation height, 0.5 m, working water pressure, 300 kPa, space between adjacent nozzles, 0.5 m. These gave a uniformity coefficient as high as 98.08%. 【Conclusion】 Raising the mounting height of the system increased the uniformity coefficient of water distribution and the area that the water could cover, and reduced the maximum water intensity. Increasing the working water pressure increased water irrigation intensity. For the system we studied, the optimal installation height, working water pressure and nozzle spacing were 0.5 m, 300 kPa and 0.5 m, respectively.

Keywords

• seedling bed nozzle
• installation height
• working pressure
• combination spacing
• uniformity coefficient