English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Water is an economical source of heat to prevent cold damage to certain crops; however, ways to reduce the quantity of this limited resource required for cold protection need to be developed. Rapidly rotating (6 rpm) wedge-drive impact sprinklers (conventional practice) were compared with a rotary action spray head and patented slow-rotating stream sprinklers for cold-protecting a subtropical crop {leatherleaf fern [ Rumohra adiantiformis  (Forst.) Ching]} growing in shadehouses. Treatments were applied in a 3 × 3 latin square design to nine 29 × 29-m post- and-cable shadehouses covered with woven polypropylene shade fabric designed to provide 73% shade. Temperatures in each shadehouse were monitored 45 cm above the soil surface using four constantan–copper thermocouples. Ambient temperatures and wind speeds were monitored using additional thermocouples and an anemometer at a nearby weather station. All sprinklers had 2.8-mm orifices, were operated at 0.25 Pa, and applied 0.5 (rotating stream, rotary) or 0.54 (wedge-drive) cm·hr –1  of water. During an advective freeze with windspeeds up to 19 m·s –1  and temperatures to –2°C, there were no temperature differences due to treatments. During a radiational freeze with readings below –2°C for over 12 hr and a low of –5°C, all three irrigation systems maintained thermocouples at about –1°C. No significant damage to mature fronds were detected. Percentage of immature fronds damaged was not affected by treatments and ranged from 11% for rotary to 43% for the wedge-drive sprinkler treatments. The two newer sprinkler designs (rotary action spray head and patented slow-rotating stream) provided satisfactory protection equivalent to the industry standard (wedge-drive) while using about 10% less water.

Comparison of Three Sprinkler Designs for Cold Protection in Shadehouses