MORPHOLOGICAL AND CHEMICAL CHARACTERISTICS OF SOIL PROFILES FOR RICE CULTIVATION IN LONG MY TOWN, HAU GIANG PROVINCE

Abstract

The study was performed with an aim to determine morphological and chemical features of the soil profiles for rice growth in Long My town, Hau Giang province. The morphological description was based on the Munsell soil colour chart comparison table under the field condition, and the analysis of soil chemical properties of 5 profiles for rice soil was performed under the laboratory condition. Based on the morphological characteristics, the soil for growing rice was suitable for rice development, with extremely deep acid sulfate-bearing materials (>100 cm below the surface). The profiles belonged to the alluvial soil series, and had the Mollic horizon. The soil name, according to the classification of FAO-WRB (2006), was Molli Gleysols (Bathi Proto Thionic) - Glmo(dtip). The chemically analytic results showed that pH_KCl at the surface of the 5 profiles fluctuated roughly 3.01 - 6.15, and was considered to be at the acidic threshold. The total nitrogen content (0.126 - 0.406%) was moderate, and the total P content (0.014 - 0.042%) was considered poor threshold. The available nitrogen content and the soluble P content were determined as 43.9 - 264.3 mg NH₄⁺ kg^-1 of soil, and 0.11 - 25.6 mg P kg^-1 of soil, respectively. The toxicity of Fe²⁺ and Al³⁺ was up to 88.0 mg Fe²⁺ kg^-1 of soil and 3.38 meq 100 g^-1 of soil, respectively. The organic matter content was moderately high, while the cation exchange capacity was low.