Degradation processes and nutrient constraints in sodic soils

TLDR

Excess sodium in sodic soils disrupts ion balance, lowers pH, destabilizes soil structure, degrades hydraulic properties, and induces nutrient imbalances that ultimately reduce crop growth and yield. The study aims to elucidate the mechanisms of sodic behavior—including clay slaking, swelling, dispersion, and nutrient constraints—to guide long‑term sustainable soil management practices. With increasing use of poor quality water and soils, sodic soil problems are projected to rise in the future. © 2002 John Wiley & Sons, Ltd.

Abstract

Abstract Accumulation of excess sodium (Na + ) in a soil causes numerous adverse phenomena, such as changes in exchangeable and soil solution ions and soil pH, destabilization of soil structure, deterioration of soil hydraulic properties, and increased susceptibility to crusting, runoff, erosion and aeration, and osmotic and specific ion effects on plants. In addition, serious imbalances in plant nutrition usually occur in sodic soils, which may range from deficiencies of several nutrients to high levels of Na + . The structural changes and nutrient constraints in such soils ultimately affect crop growth and yield. The principal factor that determines the extent of adverse effects of Na + on soil properties is the accompanying electrolyte concentration in the soil solution, with low concentration promoting the deleterious effects of exchangeable Na + even at exchangeable sodium percentage (ESP) levels less than 5. Consequent to an increase in the use of poor quality waters and soils for crop production, the problems of sodic soils can be expected to increase in future. The mechanisms that explain sodic behaviour can provide a framework in which slaking, swelling and dispersion of clay together with nutrient constraints in sodic soils may be assessed so that the practices to manage such soils can be refined for long‐term sustainable agriculture. Copyright © 2002 John Wiley & Sons, Ltd.