Manejo da irrigação com déficit hídrico controlado no cultivo orgânico da cenoura (Daucus carota)

Abstract

The crop simulation models are tools used to assist in the management of the available resources. For the carrot crop, few studies have examined the effect of irrigation with deficits in their performance and quality of crops. The optimization of the regulated deficit irrigation strategy (ORDI), which integrates the economic optimization model for irrigation water management (MOPECO), determines the level of deficit to be achieved at each stage of crop development in order to maximize the performance for a given level of deficit. The study was conducted in 2013 and 2014 in the Integrated Agroecological Production - SIPA, located in Seropédica-RJ, Brazil. It was used drip irrigation system with a line for each two lines of cultivation, emitter spacing of 10 cm and flow rate of 4 L h-1 m-1. Two deficit irrigation application methods were evaluated (constant water deficit - CHD and ORDI). For both methods were applied 5 different levels of global deficit (90, 80, 70 and 60% of crop evapotranspiration (ETm), and without irrigation), besides the treatment with 100% ETm. In the two years evaluated no statistically significant differences were obtained in total yields between ORDI and CHD, for the same level of deficit used. However, a high percentage of the roots obtained from the CHD strategy had shortcomings in terms of quality (defects, improper size, cracks, etc.) provided decrease in commercial production. Therefore, for the same volume of water applied, irrigation management made by ORDI was more efficient, reaching 50% and 24% more commercial productivity in the treatment ETm 0.6 and other treatments, respectively