Reasons of sprinkler freezing and rotational irrigation for frost protection in tea plantations

Abstract

Sprinkler irrigation can effectively reduce the rate of frostbite on cash crop buds and young fruits. In this study, we propose applying the rotational irrigation method in frost protection to achieve water conservation, simplify the sprinkler system and expand the frost protection area. The freezing test of various sprinklers in a frosty environment (approximately −4.0°C) was conducted to determine the maximum duration of sprinkling cessation for the microsprinkler, butterfly‐shaped sprinkler, impact sprinkler and MegaNet sprinkler. The results indicate that the butterfly‐shaped sprinkler and impact sprinkler freeze after 4 and 3 min, respectively. In contrast, the microsprinkler and MegaNet sprinkler do not freeze even after 10.0 min. The temperature increase amplitude and rate of the microsprinkler are significantly greater. At an ambient temperature of −4.0°C, three areas were irrigated with microsprinklers. Each sprinkler had a rotation interval of 3.0 min of spraying followed by 6.0 min of stopping. This ensured that the canopy temperature was maintained at approximately −1.0°C. The water consumption was only one‐third of that used in continuous sprinkler irrigation. This sprinkler irrigation method for frost protection is more water efficient than traditional continuous sprinkler irrigation and easier to operate and maintain than existing automatic sprinkler irrigation methods.