Hien Huu Nguyen1*
and Somsak Maneepong2
1 Faculty of Agriculture, Forestry and
Fisheries, Vinh University, Nghe An, Vietnam
2 School of Agricultural Technology, Walailak University,
Nakhon Si Thammarat, Thailand
*Corresponding email: huuhiendhv@gmail.com
ABSTRACT
Potassium
(K), Calcium (Ca), and Magnesium (Mg) are important nutrients for pummelo
growth and production. However, these nutrients are strongly antagonistic to
each others. This study aims to examine the effects of different K, Ca, and Mg
ratios in soil on nutrient uptake. Soil samples were collected under pummelo
canopies at a depth of 0 cm to 20 cm. Leaf samples of 3 to 5 month olds were
obtained from the same trees. The soil chemical properties and nutrient
concentrations in the leaves were determined. The results showed that the P
uptake was inhibited by a high Ca concentration in soil. High K/Mg ratio in
soil (0.52 ± 0. 27) positively affected on K uptake. Low K/Mg ratios in soil
(0.42 ± 0.20) negatively affected on K uptake, although exchangeable K in soil
was much higher than optimum ranges. The K/Ca mole
ratio in the leaves was higher than that in the soil,
therefore the uptake of K was better than that of Ca, despite the lower
concentration of K in the soil. Moreover, the uptake of K was better than that
of Mg, because the K/Mg ratio in the leaves higher than that in the soil. However,
the leaf K concentration in Pakapanang orchard was slightly lower than its
optimum ranges, because high exchangeable Mg in soil inhibited the uptake of K.
Low exchangeable Ca negatively affected on Ca uptake, although Ca/Mg mole ratio
in soil was high (2.77
± 1.18).
Keywords:
Nutrient uptake, Plant nutrition, Pummelo, Cation ratios
File: hien_huu_nguyen_bai_bao.doc