The Amelioration of Reclamation on Physical andChemical Properties of Coastal Saline-Sodic Soils

Poor soil quality caused by salinity and sodicity is the main limitation on plant growth and crop production worldwide.This study focused on the change in the physicochemical properties of the coastal saline-sodic soils of Yellow River Delta with different histories of reclamation.Soil samples representing six different reclamation times (RTs) were collected in two soil profiles (0-20 cm and 20-40 cm).The results showed that soil soluble salts (SSs) significantly decreased with increasing reclamation time, and the change were 32.9%-67.6% in the 0-20 cm layer and 39.0%-73.2% in the 20-40 cm layer, respectively.Based on non-liner fitting, the change regulation of SS with RT was expressed by the following functions:(R 2 = 0.93, p<0.01) in the 0-20 cm layer and SS = (R 2 = 0.97, p<0.01) in the 20-40 cm layer, respectively.The other soil properties, such as bulk density, total carbon, total nitrogen, the ratio of carbon and nitrogen, soil organic matter, available phosphorus, and available potassium significantly improved with increasing RT, but EC and pH had the opposite trend.The change in the physical and chemical properties of saline-sodic soil was higher at 0-20 cm soil depth than at the 20-40 cm soil depth, indicating that the effect of reclamation on salinesodic soils occurs mainly in topsoil.In conclusion, reclamation has been shown to be an effective human activity in terms of improving fertilizer and inhibiting the salinity of saline-sodic soils.