Articles
Potential to improve current mist irrigation control practices by young plant operations in the U.S.
Article number
1409_36
Pages
275 – 280
Language
English
Abstract
Past research has shown a range in volume of applied and leached mist irrigation among commercial ornamental propagation facilities, indicating a need to optimize irrigation for improved water use efficiency.
Large-scale ornamental young plant growers in the U.S were surveyed to identify (a) current practices for scheduling mist irrigation for cutting propagation, and (b) their level of integration of inline sensors with environmental control systems (ECS). Twelve greenhouse facilities in five U.S. states were visited in 2022. Spot measurements in 61 compartments were made using hand-held climate sensors.
Seven of 12 growers used time clocks only to control irrigation.
Five growers used vapor pressure deficit (VPD), with VPD sensors as components of irrigation boom systems or the ECS. All 12 growers monitored air temperature and relative humidity, while 10 growers measured substrate or floor temperature, and four measured photosynthetic photon flux density (PPFD). Indoor short-wave radiation (SW) was not measured, and leaf temperature was only estimated by four growers.
Two growers had converted temperature and humidity-controlled germination chambers to vertical indoor propagation (VIP) facilities using light-emitting diodes (LEDs). Humidity was higher (88±7% (mean ± st.dev.) vs. 72±11%), and VPD was lower (0.3±0.2 vs. 0.8±0.4 kPa) in VIP compared to the greenhouse.
Daytime PPFD was similar between the two environments (154±15 vs. 146±84 µmol m-2 s‑1) but light provided for 24 h d‑1 in VIP, likely resulting in a higher daily light integral.
Substrate surface temperature was closely correlated (R2=0.95) with leaf temperature indicating potential for connecting IR inline sensors to the ECS for evapotranspiration (ET) models to estimate leaf and substrate surface temperature.
Opportunities to modernize irrigation control from time clock and subjective decisions include greater adoption of ET models (air VPD, irradiance, and possibly leaf temperature), climate sensors, integration of irrigation booms with ECS, fog humidification of greenhouses and VIP systems.
Large-scale ornamental young plant growers in the U.S were surveyed to identify (a) current practices for scheduling mist irrigation for cutting propagation, and (b) their level of integration of inline sensors with environmental control systems (ECS). Twelve greenhouse facilities in five U.S. states were visited in 2022. Spot measurements in 61 compartments were made using hand-held climate sensors.
Seven of 12 growers used time clocks only to control irrigation.
Five growers used vapor pressure deficit (VPD), with VPD sensors as components of irrigation boom systems or the ECS. All 12 growers monitored air temperature and relative humidity, while 10 growers measured substrate or floor temperature, and four measured photosynthetic photon flux density (PPFD). Indoor short-wave radiation (SW) was not measured, and leaf temperature was only estimated by four growers.
Two growers had converted temperature and humidity-controlled germination chambers to vertical indoor propagation (VIP) facilities using light-emitting diodes (LEDs). Humidity was higher (88±7% (mean ± st.dev.) vs. 72±11%), and VPD was lower (0.3±0.2 vs. 0.8±0.4 kPa) in VIP compared to the greenhouse.
Daytime PPFD was similar between the two environments (154±15 vs. 146±84 µmol m-2 s‑1) but light provided for 24 h d‑1 in VIP, likely resulting in a higher daily light integral.
Substrate surface temperature was closely correlated (R2=0.95) with leaf temperature indicating potential for connecting IR inline sensors to the ECS for evapotranspiration (ET) models to estimate leaf and substrate surface temperature.
Opportunities to modernize irrigation control from time clock and subjective decisions include greater adoption of ET models (air VPD, irradiance, and possibly leaf temperature), climate sensors, integration of irrigation booms with ECS, fog humidification of greenhouses and VIP systems.
Authors
P.R. Fisher, C. Gómez, S. Gómez
Keywords
evapotranspiration, LED, propagation, vertical farming, VPD
Online Articles (64)