2.2 Land use and management history
The Tiaozini reclamation area had no documented history of cultivation until 2015, and paddy rice and winter wheat rotation was employed in this area (Fig. 1). Paddy rice was initially planted in the cropland to leach soil salinity as the salt levels of the newly-reclaimed farmland exceeded the salt-tolerant thresholds for most agricultural crops. Brackish water with the average electrical conductivity of 3.6 dS/m, as drawn from the river near the site, was used for paddy rice irrigation, and water was supplied using flood irrigation during the rice season. The growing season of paddy rice was from late-June to mid-October and that of rainfed winter wheat was from early November to mid-June. Conventional soil fertility and pest management practices were used and no organic matter inputs were made. Poor soil aggregate structure, soil nutrient pools and microbial activity, as induced by soil salinization, are known as significant limitations to soil productivity in the coastal saline area (Zhang et al., 2014; Shahid et al., 2018), resulting in an annual yield depression of 30~50% in the experimental site.