Effect of Fertigation on Nutrient Uptake, Growth, Yield and Quality of Longan

Abstract

A field trial was conducted during 1999-2000 season consecutively in the mature Sichompoo longan orchard established on Hangchat Soil Series (clayey, mixed isohyperthermic Oxic Paleustults) at hangchat horticultural Experiment Station, Lampang province. The objective of the experiment was to evaluate the efficient use of water soluble fertilizers through the irrigation stream (fertigation) using a simple and inexpensive injextion pump operated by Venturi principle. The longan trees were irrigated with minisprinklers wetting 75% of the under-canopy area. There rates of fertigaion, 300-125-375, 600-250-750 and 900-375-1125 g N-P2O5-K2O /tree/year were compared with broadcasting of 900-375-1125 g N-P2O5-K2O /tree/year. Nutrient distribution through the soil profile, nutrient uptake, growth, yield and quality of longan were recorded. Results showed that fertigation rate of 600-250-750 g N-P2O5-K2O /tree/year produced significantly high yield, number of leaf per tree, uptake of nitrogen, phosphorus and potassium over broadcasting fertilizer of 900-375-1125 N-P2O5-K2O /tree/year. Fertigation rate of 900-375-1125 g N-P2O5-K2O /tree/year had the highest ammonium content in the soil. In this study, fertigation at rates tended to promote better leaf carbohydrate and yield quality of longan as compared to that of broadcasting fertilizer.