Effect of irrigation frequency on cashew nut yield in Northeast Brazil

Abstract

The study was carried out in Ceará, Brazil, with the goal of evaluating the response of three dwarf cashew clones to different irrigation frequencies. Cashew trees were evaluated during seven consecutive seasons, from the 2nd to the 8th year after planting. Four irrigation treatments were used: no irrigation, and irrigation when accumulated evaporation on a class “A” pan equaled 10 mm (T10), 30 mm (T30), and 50 mm (T50). The sub plot treatments were three cashew clones (CCP 09, CCP 76, and CCP 1001). Seasonal irrigation rates were the same for all irrigated treatments, and ranged from 400 to 500 mm per year for fully developed plants (6–8 years old). Response to irrigation varied among cashew genotypes. Irrigation had a significant effect ( P < 0.05) on nut yield of cashew clones CCP 76 and CCP 09. The highest nut yield was obtained with cashew clone CCP 09, irrigated when accumulated pan evaporation reached 10 mm. Cashew trees trended to alternate years of high nut yield and years of low yield, even when irrigation was applied. Irrigation did not influence nut weight of clones CCP 76 and CCP 09.