TROCAS GASOSAS E PRODUTIVIDADE DE TOMATEIRO INDUSTRIAL EM RESPOSTA A DIFERENTES FORMAS DE UTILIZAÇÃO DE COBERTURA COM AGROTÊXTIL E IRRIGAÇÃO POR GOTEJAMENTO

Abstract

The objective of this work was to evaluate the physiological changes in gas exchange and productivity of tomato plants grown under localized irrigation systems associated with different colors and management of agrotextile covers, under field conditions in the Cerrado do Sul Goiano region. The experiment was installed in a randomized block design, with four replications, in a split-plot scheme (2 x 5). In the plots, two localized irrigation systems were used (Surface Drip and Underground Drip), where both received equal irrigation depths. The subplots were composed of five treatments with agrotextile coverage: T1 – open, without the use of agrotextile; T2 – uninterrupted coverage with white agrotextile; T3 – coverage with white agrotextile removed in the interval between 30 to 60 days after transplanting (DAT); T4 – uninterrupted coverage with red agrotextile; T5 – covering with red agrotextile removed within 30 to 60 DAT. Each subplot consisted of three rows of 6.0 m long plants, spaced 1.1 m apart. The eight plants of the central line were considered the useful area of the plot, the other borders. Plants were evaluated for photosynthetic rate (A, - µmol m⁻² s⁻¹); transpiration rate (E, mmol m⁻² s⁻¹); stomatal conductance (gs, - mol m⁻² s⁻¹); internal and external carbon concentration ([Ci/Ca]); electron transport rate (ETR, µmol m⁻² s⁻¹); and water use efficiency (WUE, µmol CO2 mmol-1 H2O). No significant differences were found regarding the use of irrigation systems in any of the evaluations carried out. The use of red-colored agrotextiles promoted lower values of transpiration rate and stomatal conductance at 80 DAT. The highest average yields were measured in the open treatment, followed by white, red, white (30-60), and red (30-60) treatments.