Fisiologia e produção de plantas de coqueiro anão sob diferentes níveis de irrigação

Abstract

In the Brazilian Northeast, coconut cultivation has been under serious threat due to the severe water crisis in this region. Because it is a crop with a high demand of water, it is generally necessary to use irrigation to meet the hydric need of the crop and it is important to make an efficient use of it. Hence, the present study had as objective to evaluate the physiological and productivity responses of the coconut to irrigation with different water . The experiment was conducted in Boa Esperança farm of the company Ducoco Alimentos S.A., in the municipality of Camocim, Ceará, under randomized block design, in a 4 x 6 factorial scheme, with five replications, each replicate being composed of 4 plants. The first factor consisted of the application of different fractions of the coconut evapotranspiration (50%, 75%, 100% and 125% of the ETPc) and the second factor was the months of evaluation of the plants (September 2016 to February 2017). The plants were irrigated by micro sprinkler, with one emitter per plant and daily rule shift. Physiological variables such as leaf water potential, stomatal conductance, transpiration, photosynthesis and total soluble carbohydrates in the leaves were analyzed, as well as production variables such as the number of fruits produced, the average fruit weight, the volume and solids content of fruit water and productivity from water. Plant water potential, gas exchange and foliar soluble carbohydrate contents were not influenced by the application of water. The fruit production varied between the months, without great influence of the amount of water applied. The fruits were heavier in the months of September and February, without any influence of the applied water. The water content of the fruit was positively influenced by the water levels applied, with the highest values found in the ETPc lamina of 125% and, similar to the weight, the highest water volumes were found in the months of September and February. The water productivity based on the fruit water volume decreased as the amount of water applied to the plants increased.