Climate risk zoning for gladiolus in the state of Rio Grande do Sul, Brazil

Abstract

The objective of this work was to develop a climate risk zoning for the gladiolus (Gladiolus x grandiflorus) crop in the 497 municipalities of the state of Rio Grande do Sul, Brazil. The PhenoGlad model was used to simulate crop development and the occurrence of damages. The model was run for four developmental cycles of gladiolus over 34 years and in 23 locations in the state. The probabilities of 10, 20, and 30% damages due to low and high temperatures were used to define periods suitable for planting. Rio Grande do Sul is adequate for growing gladiolus during most of the year. In the coldest areas of the state, the inadequate planting dates are from March until mid-May due to frost damage. In the hottest regions, the inadequate planting dates are greater from October to January due to heat damage. Because it is stricter, the 10% level of damage is considered more appropriate to define the periods recommended for planting.

Climate risk zoning for gladiolus production under three climate change scenarios

“…The current climate risk zoning in RS (Uhlmann et al, 2020) was developed using a high-resolution meteorological data set of minimum and maximum daily air temperatures of 34 years proposed by Xavier et al (2016). These data were used because of the low density of meteorological stations across the state.…”

“…The 497 municipalities of the RS State were grouped into 23 homogeneous regions (Figure 1) regarding the influence of macroclimatic factors, such as altitude, latitude, continentality, oceanity, and relief (Uhlmann et al, 2020), and each region was represented by a meteorological data grid point. The PhenoGlad model was run for daily planting dates from 01 January to 31 December, for the current period and for each climatic scenario and, the four gladiolus developmental cycles (Early, Intermediate I, Intermediate II and Late), which vary in their developmental cycle from 69 to 121 days for early cultivars and from 85 to 148 days for late cultivars (Becker et al, 2021), for the 23 regions of the State.…”

“…The recommended planting dates were considered when the PhenoGlad model identified the occurrence of high and low temperature damage in less than 10% of the evaluated years. The 10% limit was considered in this study as being stricter and consequently more adequate to define the climatic risk zoning of an ornamental plant such as gladiolus (Uhlmann et al, 2020). The results were presented on maps using QGIS software and the future climate risk zoning was compared with the current climatic risk zoning for the crop.…”

“…Changes in temperature may cause major losses in ornamental plants because the market requires that flowering must occur within a rather narrow time window to meet market demand (Snipen et al, 1999;Fisher & Lieth, 2000;Munir et al, 2015), and heat stress or frost may cause injuries on the floral stem, killing plants or reducing flower quality (Uhlmann et al, 2017;Schwab et al, 2018). The climatic risk zoning is a tool to assist farmers in defining the best periods for the production of quality floral stems, considering damage by high and low temperatures in the floral stem (Uhlmann et al, 2020).…”

Irrigation and soil mulching can improve the quality of flower stems of gladiolus

“…Marketed mainly as a cut flower for interior decoration (Khanam & Patra, 2015), gladiolus can also be used in landscaping such as in mixed borders, and for ornamenting events or other special dates (Schwab et al, 2018; Tomiozzo et al, 2019). In Brazil, it is among the 10 most produced cut flowers (Becker et al, 2020; Ibraflor, 2018) and, in the Rio Grande do Sul state, a great increase in demand for gladiolus was verified over the years, mainly among small landholders through the Extension Project ‘Flowers for All’ (Streck & Uhlmann, 2021; Uhlmann et al, 2019, 2020).…”