Calcium Lactate Amendment Improves Saline Soil Properties and Enhances Pepper Resistance Under Short-Term Waterlogging Conditions

Saline soils subjected to short-term waterlogging are a constraint on the sustainable production of protected vegetables, triggering soil structural degradation, salt accumulation, and oxidative damage in plants, which seriously damages crop yield and quality. Calcium-based amendments have attracted considerable attention for improving soil conditions and enhancing plant stress tolerance. However, the effects of calcium lactate amendment on saline soil improvement and pepper physiological responses under short-term waterlogging conditions remain insufficiently understood. Different application rates of calcium lactate were applied to saline pepper croplands under waterlogged conditions. The effects on soil physicochemical properties, nutrient availability, plant antioxidant physiology, fruit yield, and quality were analyzed. Calcium lactate improved the physicochemical properties of waterlogged soil and increased the available nutrients in the soil, with the content of available phosphorus and available potassium increasing by 565–855% and 1.60–35.54%, respectively. It enhanced the activities of superoxide dismutase, peroxidase, and catalase, reduced malondialdehyde accumulation (up to 39% compared with CK), and increased proline content (up to 54.62% compared with CK), thereby promoting plant physiological adaptation under short-term waterlogging conditions and improving pepper yield and fruit quality. Higher doses of calcium lactate exhibit better ameliorative effects. Correlation analysis and partial least squares path modeling suggested that calcium lactate application was associated with improved pepper yield and quality through pathways related to soil improvement and plant physiological regulation. This study provides insights into the potential application of calcium lactate for saline soil improvement and sustainable pepper production under short-term waterlogging conditions.