Climate variations in greenhouse cultivated with gerbera and relationship with external conditions

Aderson S De Andrade Júnior,Lisânea M O Damasceno,Cristiane Guiselini,Nildo Da S Dias,Hans R Gheyi

doi:10.1590/s0100-69162011000500003

Abstract

Black meshes used in greenhouses provide shade to plants, affecting photosynthesis and presenting certain properties that change the microclimatic conditions in these environments. The objective of this study was to evaluate the variation in climate elements in greenhouse cultivated with gerbera (Gerbera jamesonii, Vr. Rambo) in relation to external conditions and the reference evapotranspiration (ETo) at Teresina, State of Piauí, Brazil. The measurements were obtained from July to October 2007 by an automatic data acquisition system installed inside and outside the greenhouse. The global solar radiation, evapotranspiration, precipitation, temperature, relative humidity, and wind speed were estimated. The results showed that major effect of the shading occurred on the mean air temperature during the 120 days, making it higher than the external environment. Inside the greenhouse, mean values of relative air humidity, reference evapotranspiração, global solar radiation and wind speed were lower compared to those outside the greenhouse.

Highlights

The cultivation of flowers may be carried out in the open or in greenhouses covered with black meshes
When comparing crops under protected cultivation with those cultivated in the open, we find that evapotranspiration is generally lower in protected environments than in the field, basically due to the partial opacity to solar radiation of the plastic cover, and wind reduction, which are major factors of the evaporative demand of the atmosphere, the temperature and relative air humidity, at times, can be respectively higher and lower in the protected environment than in the exterior, depending on the climate conditions (FARIAS et al, 1994)
The average air temperature inside the greenhouse was 8.5% higher than the external environment in the warmer months of the year, especially September and October. This difference between the environments was confirmed with the results obtained by SOUSA et al (2002)

Summary

Introduction

The cultivation of flowers may be carried out in the open or in greenhouses covered with black meshes. Plants cultivated in the open field are susceptible to weather, especially heavy rainfall and sunlight. There generally is a significant increase in production and product quality, providing more guarantees of good yields to the farmer (GOMES et al, 2006; FERNANDES et al, 2006; BACKES et al, 2007). Greenhouse cultivation of ornamental plants can be performed at different periods of the year, allowing producers to make better use of soil, optimize management and, above all, provide better market price (BOUERI & LUNARDI, 2006). Chances are high for economic success, because specific technologies are used for each type of flower and climate adaptability of the cultivated species (GOMES et al, 2006)

Objectives

Methods

Results