Canopy temperatures and accumulated degree days on cotton plants under water deficit.

• Autor(a) principal: ZONTA, J. H.
• Data de Publicação: 2018
• Outros Autores: MANIÇOBA, R. M., BRANDAO, Z. N., CARRILLO, M. A., BEZERRA, J. R. C.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice)
• Texto Completo: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1118705
• topic: Phenological cycle; Environmental conditions; Infrared thermometry; Stress; Irrigation

Canopy temperature is one of the best integrators of plant health and has been successfully used for irrigation scheduling. Therefore, the objective of this study was to evaluate the canopy temperature of cotton plants under water stress at different stages of the crop cycle and to determine the accumulated degree days based on canopy temperature. It was applied water deficit periods of 15 days at the following phenological stages: First Square, First Flower, Peak Bloom and Opening Bolls and control treatment. Canopy temperature was obtained using SmartCrop® wireless infrared temperature sensors. The results showed higher canopy temperatures during water deficit periods. For water deficit periods, canopy temperature values were always above the optimum temperature for cotton metabolism. As a result of the stress caused by water deficit, cotton yield was significantly reduced, with the higher yield loses recorded when applied deficit occurred during flowering stages (beginning and peak). Accumulated degree days also varied according to water stress, with a shortened phenological cycle for treatments with water deficit in comparison to the control without stress. The period for fiber thickening was also influenced by the variation in canopy temperature due to water stress, which may reflect decline in fiber quality.