Effect Of Straw Mulching On Soil Moisture, Salt Accumulation, And Beetroot Growth On Saline Soil Under Greenhouse Condition

Abstract

Saltwater intrusion has increasingly impacted soil quality and crop productivity in the Mekong River Delta (MRD), Vietnam. This study investigated the effects of rice straw mulching on mitigating salinity accumulation, conserving soil moisture, and improving the yield of beetroot (Beta vulgaris) under greenhouse conditions. The experiment was designed with two factors: three irrigation salinity levels (S1: 0‰, S2: 2‰, and S3: 4‰ of NaCl) and four rates of straw mulch application (M1: 0, M2: 3.5, M3: 7.0, and M4: 10.5 tons ha⁻¹).The results showed that rice straw mulching significantly enhanced soil moisture retention by up to 25% compared to the non-mulched control. Applying rice straw mulch at a moderate rate (M3) reduced salt accumulation, exchangeable Na⁺, exchangeable sodium percentage (ESP), and sodium adsorption ratio (SAR), while improving plant growth, beetroot yield, and water use efficiency. However, excessive mulching (M4) temporarily increased soil salinity, possibly due to ion release from straw decomposition. Therefore, applying straw mulch at a moderate rate (M3) is recommended as an effective soil management practice to enhance beetroot growth, productivity, and soil quality in salt-affected areas of the MRD