Use of manufacturer-specified value of greenhouse film transmissivity to estimate solar radiation and crop evapotranspiration in a hoop house
presentationposted on 05.05.2016, 00:00 by Daniel Adamson
Hoop houses are becoming increasingly important for food production, and as these systems cover larger areas, their efficient use of resources becomes more critical. Weather-based irrigation scheduling provides potential for conserving water, but its use in hoop houses is complicated by the altered microclimate inside. Weather-based irrigation scheduling in hoop houses would be made more accessible if the need to purchase expensive instruments, such as those that measure solar radiation (Rs), could be eliminated. This study examined the use of a manufacturer-stated value for Rs transmissivity of greenhouse film to estimate crop evapotranspiration (ETc) in a hoop house. The results showed that the use of Rs corrected with the manufacturer's transmissivity factor overestimated ETc by 4.8% because film transmissivity in the field is lower than that stated by the manufacturer. However, the use of a manufacturer stated transmissivity factor could still be a practical solution to avoid the need for expensive instruments inside a hoop house if it is adjusted to improve accuracy.