Effects of Different Peat Application Methods on Water and Salt Migration in a Coastal Saline Soil

Peat can be used as a soil amendment to ameliorate saline soils. This study explored the effects of different peat application methods on soil infiltration, phreatic evaporation, and salt accumulation in a coastal saline soil. One-dimensional vertical infiltration and phreatic evaporation experiments were carried out for 3 and 21 days, respectively. Columns were prepared using a moderately saline silty loam soil without peat amendment (control), soil mixed with peat (MP), soil containing a buried peat layer (BP), and soil containing a buried soil-peat mixture (BSP). Compared with the control, the infiltration rate was significantly reduced by 68.3% under the BP treatment. At the end of the infiltration stage, the 0-20 cm soil water content was increased by 11.9% and 10.3% under the BP and BSP treatments, respectively; however, no significant increase occurred under the MP treatment (2.9%) compared with that of the control. After evaporation, significant reductions (44-45%) were observed in the cumulative evaporation amount under the BP treatment compared with that of the control. The 0-20 cm soil water content and electrical conductivity of the BP treatment were also reduced by 47.7% and 84.2%, respectively. There were no significant differences in the soil water and salt distributions of 0-20 cm depth under the BSP and MP treatments compared with that of the control. These findings indicate that burying a peat layer in the saline soil is an effective method to reduce infiltration in the upper soil layers and simultaneously inhibit phreatic evaporation, thereby controlling salt movement in the deeper soil layers.

Automated summary

Peat can be used to improve saline soils, with burying a peat layer being an effective method to reduce infiltration and inhibit phreatic evaporation in the upper soil layers. This study found significant reductions in infiltration rate and evaporation amount under the buried peat layer treatment, leading to decreased soil water content and electrical conductivity. Soil water and salt distributions at a depth of 0-20 cm showed no significant differences under the buried soil-peat mixture and peat mixed treatments compared to the control.