Effects of fertilizer doses on yield and quality of gandaria (Bouea oppositifolia (Roxb.) Meisne.) grown in Binh Minh town, Vinh Long province, Vietnam

Abstract

ABSTRACTThis study, conducted from May 2016 to June 2017, was aimed to investigate the effect of different fertilizer doses on yield and quality of gandaria (Bouea  oppositifolia (Roxb.) Meisne). Experiments were arranged in randomized complete block design, in which the 5 investigated treatments corresponded to the five fertilizer doses, viz 1, 2, 3 and 4 kg/tree/year and no fertilization as the control. Fertilizers doses were obtained by mixing and adjusting the proportions of mono (Urea, KCl, Diammonium phosphate -DAP) and compound (20-20-15) fertilizer. Every treatment had 10 replications, each of which equalled to one tree. The fertilizer doses were divided into three times of application, i.e. post-harvesting (50% of the investigated doses, at the N-P2O5-K2O ratio of 4:3:2), 30 days after fruit set (AFS) (25% of the investigated doses, at the N-P2O5-K2O ratio of 1:1:1), and 60 days AFS (25% of the investigated doses, at the N-P2O5-K2O ratio of 2:2:3). Leaf and soil samples were collected for further analysis to determine the content of some nutrient elements before and after fertilizer applications. Results of the present study showed that fertilizer application at the dose of 3-4 kg/tree/year resulted in higher yield (2.3 times higher than that of the control treatment) which was due to the increase in number of inflorescence per shoot, number of fruit per bunch and fruit set ratio. The treatment also prolonged flowering duration (79.4 days) as compared to that of the control treatment (39.0 days). Fruit sweetness was also improved by the application of 3-4 kg of fertilizer per tree per year.