EFFECT OF STRAW MULCHING ON MAIZE (ZEA MAYS L.) PRODUCTIVITY IN SALT-AFFECTED SOIL IN THE MEKONG RIVER DELTA, VIETNAM

Straw mulching has become a common agricultural practice in the Mekong River Delta (MRD) of Vietnam. This study evaluated the effects of straw mulching on soil moisture content, soil electrical conductivity (ECe), maize productivity, and economic benefits in saline soils. The experiment was conducted using a randomized complete block design with four straw mulching rates (0, 3.5, 7.0, and 10.5 t ha⁻¹) and three replicates. The results showed that rice straw mulching significantly improved soil moisture content at 45 days after sowing (DAS) but did not significantly affect soil moisture retention at other crop stages. In addition, soil ECe showed no significant differences among mulch rates of 0, 3.5, 7.0, and 10.5 t ha⁻¹ at both the initial and harvest stages in the 2021 and 2022 seasons. However, the application of straw mulching (3.5–10.5 t ha⁻¹) significantly improved plant height, leaf length, leaf width, leaf area, and fresh biomass compared to the nomulch treatment. Maize yield in the treatments receiving 3.5–10.5 t ha⁻¹ of straw mulching was significantly higher than in the treatments without straw mulching in both 2021 and 2022, by 0.58– 1.82 t ha⁻¹. Furthermore, straw mulching at rates of 7.0–10.5 t ha⁻¹ also significantly increased net benefits by 182–184% in 2021 and 133–147% in 2022 compared with the no-mulch treatment. Based on these findings, the application of straw mulching at rates of 7.0–10.5 t ha⁻¹ is recommended for maize cultivation in salt-affected soils in the Vietnamese Mekong Delta.