Daily Evapotranspiration of Guzmania ‘Irene’ and Vriesea ‘Carly’ Bromeliads Produced in a Shaded Greenhouse

Abstract

Additional index words. actual evapotranspiration (ET A ), bromeliad daily water use, daily water requirements, ornamental foliage plants, water need index (WNI)Abstract. Bromeliads are important ornamental foliage plants, but until now, their daily water use during production was unknown. Using a canopy closure model developed for container-grown woody ornamental plants, in this study we investigated actual evapotranspiration (ET A ) of Guzmania 'Irene' and Vriesea 'Carly' from tissue-cultured liners grown in 15-cm containers to marketable sizes in a shaded greenhouse. The mean daily ET A of Guzmania 'Irene' ranged from 4.02 to 66.35 mL per plant, and the mean cumulative ET A was 16.66 L over a 95-week production period. The mean daily ET A of Vriesea 'Carly' varied from 3.98 to 59.89 mL per plant, and the mean cumulative ET A was 15.52 L over the same production period as the Guzmania cultivar. The best-fit models for predicting daily ET A of the two bromeliads were developed, which had correlation coefficients (r 2 ) of 0.79 for Guzmania 'Irene' and 0.68 for Vriesea 'Carly'. The success in the model of ET A for both bromeliads suggested that the canopy closure model was equally applicable to container-grown ornamental foliage plants produced in greenhouse conditions. The daily ET A and cumulative ET A values represent researchbased information on water requirements, and, when applied, could improve irrigation practices in bromeliad production. This study also showed that roots per se of the two epiphytic bromeliads were able to absorb water and nutrients from a peat-based container substrate and support their complete life cycles.

Daily Water Requirement of Container Grown Davallia bullata and Nephrolepis exaltata and Implication in Irrigation Practices

“…Interestingly, the mean cumulative ET A for both crops was 9.4 L. Additionally, the two crops exhibited a similar water requirement pattern, i.e., initially low in water requirement and then gradually increased with plant growth regardless of seasonal variation ( Figure 2B). This pattern is different from D. bullata, Guzmania and Vriesea [21], Asplenium nidus [20], and Calathea [22]. Due to the difference in production time, Boston fern crop 1 took an extra 10 days to reach marketable size with a water use efficiency of 2.4 g/L, lower than crop 2 (3.3 g/L).…”

“…Various irrigation methods have been adopted for improving irrigation, including time clock based, climate monitoring, soil or substrate monitoring, and phyto-sensing [8]. However, a consensus is that the best irrigation practice is to water plants based on their requirements [8,21,22,40]. Thus, daily ET A of each important species of container plants should be established.…”

“…The canopy closure model probably represents an easy and convenient way of quantifying daily ET A of plants of interest. This method has been used to quantify daily ET A and cumulative ET A of Acer rubrum from liner to 8 m tall trees over 4.75 years [41], Ilex x 'Nellie R. Stevens' from liners to 4 m tall trees for 5.75 years [42], and Quercus virginiana to 7.2 m tall trees in five years [43] as well as this and previous studied container-grown greenhouse plants [20][21][22]. Thus, ET A values for the other container plants should also be able to quantify using this or other reliable methods.…”

“…Plants from over 100 genera are produced as foliage plants [2,19]. However, there has been little information on daily water requirement of those cultivated foliage plants until three recent publications where daily water use of Chamaedorea elegans and Asplenium nidus [20], Guzmania and Vriesea [21], and Calathea and Stromanthe [22] were quantified, which provide important information on revising irrigation practices for foliage plant production.…”

“…Based on the relationships of ET A , ET O , and PCA of a given species, a plant factor (PF) [25] was calculated. PF is also known as Water Need Index (WNI) [20][21][22] or crop coefficient (Kc) [26]. Kc is dimensionless.…”