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A SALINE SOIL BETWEEN MELIORATION AND RENATURATION

Daniela Răducu

Abstract

The paper emphasizes the ecological restoration (renaturation) of the natural conditions of a saline soil, which was previously under long term melioration. The soil is a Salinic Pelic Alluvic Sodosol with relict gleization, covering an Alkali soil (according to SRTS-2012). The site is located in Moldova Tableland, where Tma is 584.6?C and Pma is 9.5 mm. The depth of the groundwater table is about 1.80 m, with frequent seasonal fluctuations and weak-moderate mineralization. The soil had a polyphasic evolution, both as parent material (being the result of several depositional phases), and subsequently as soil (sequences). Currently, as a result of the short time evolution, the soil profile consists of two soil sequences: 1) the first sequence (0-119 cm) represents an Entic-Salinic-Pelic-Alluvic Solonetz with relict gleization; 2) the second sequence (119-215 cm) consists of a buried Alkali soil with gleyic properties. In the 1980s, a long term melioration experience was established, including drainage, deep loosening, amendments application to remove Na+ effect, as well as washing out the salts from the soil. At present, as a result of melioration abandonment, Na+ re-invaded the adsorption complex and salts tend to re-accumulated into the soil profile. As a result, the values of the sodium adsorption ratio (SAR) are ranging from 26.4 ? 77.3 in the upper (0-119 cm) to 49.1 ? 69.5 in the deeper (119-215 cm) soil profile. The micromorphological observation showed that gypsum occurs as: big gypsum lenticular crystals in the largest voids (channels, chambers and cracks) and sporadically into the soil matrix either singular or as clusters; and anhedral crystals (lacking specific crystallographic faces) in the smallest voids. Salt efflorescences (more easily soluble than gypsum) are also present throughout the soil horizons.

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