Changes of Plant Nutrients Concentration in Soils and Trees of Mangosteen (Garcinia mangostana L.) during the Fruit Development

Abstract

Translucent flesh disorder (TFD) and gamboge disorder (GD) are major problems limiting marketable yield of mangosteen (Garcinia mangostana L) in Thailand. The imbalance or deficiency of essential nutrients in soils and plants may cause poor fruit quality. To classify this issues, the pattern of plant nutrient accumulation and nutrient requirement in soils and mangosteen trees during fruit development period were investigated. An experiment was established in a mangosteen orchard with 2 main factors: 1) Fruit positions in the canopy of mangosteen trees (outer and inner canopy fruits) and 2) concentration of plant nutrients in soils and trees. Soil sampling was taken at 2 depths; 0-15 and 15-30 cm from soil surface, around the middle of the tree canopy in blooming and harvesting periods and analyzed for some important chemical and physical properties. Leaves and fruits sampling were taken during fruit development period, every 2 weeks from blooming to harvesting, and analyzed in relation to the changes of soil nutrients. Results indicated that the soil textures varied from sandy loam to sandy clay loam, and the natural soils in the mangosteen orchard was very extremely acid to moderately acid (pH 4.86-5.61, soil: water=1: 5). Most of the soils in the mangosteen orchard had very low level essential nutrients for plant growth. Mangosteen fruit qualities were not significantly different between the outer and inner canopy fruits. Likewise, most of the plant nutrients accumulation in mangosteen leaf, peel and flesh were not significantly different between two fruit positions. It was remarkable that nutrient accumulation in the fruit decreased from blooming to harvesting period. Mangosteen (leaf, peel and flesh) required higher amounts of N, P, K, Ca and Mg for growth in the early stage of fruit development period (from bloom to 6^th week after bloom) and S and B in the late stage of fruit development period (from 6th week after bloom) compared with other growth periods. Potassium and Ca contents in the peel of normal fruits (NF) were higher than TFD and GD fruits, whereas P and Mg contents in the flesh of TFD fruits were higher than NF and GD fruits.