Effects of interconnections and ridge widths on soil properties at the paddy field-ridge transition zones

【Objective】Paddy field-ridge transition zones serve various functions in paddy fields. This paper investigates the effects of different interconnections and ridge widths on soil properties in these transition zones.【Method】Four interconnection types: field-ridge-field (TGT), field-ridge-ditch (TGg), field-ridge-pond (TGA), and field-ridge-river (TGH), were compared to study their combined effects with ridge width on the physical and chemical properties of the soil. Both in situ field experiments and laboratory analyses were used to assess the soil properties.【Result】Compared to TGT, TGg, TGA, and TGH reduced soil bulk density and sand content in the ridge. The interconnections also influenced the variation in soil texture along the soil profile. Soil bulk density peaked at depths of 40-60 cm under TGg, while in the other interconnections, it peaked at depths of 20-40 cm. At these depths, saturated soil water content, field capacity, and saturated hydraulic conductivity were lower compared to other soil layers. Additionally, increasing the ridge width reduced both soil bulk density and field capacity.【Conclusion】Considering soil compaction and water movement, TGg, TGA, and TGH ridge treatments resulted in water loss. When the ridge width was 50 cm, the soil exhibited the highest compaction, which favored water and nutrient retention.