Combined Effect of Ceramsite and Nitrogen on Soil Salinization Management and Sunflower Yield Improvement in Highly Saline Soil
摘要
Reclaiming highly saline soils is crucial for land use efficiency, yet few studies have investigated recycled amendments like ceramsite, especially in the Hetao Irrigation District, China. Combining ceramsite with nitrogen to reduce salt and boost yield needs deeper understanding, and the optimal pattern requires further exploration. This study investigated salt reduction under different particle size (P1, < 5 mm; P2, 5–10 mm, and P3, > 10 mm) and amount of additive (C1, 700 kg ha− 1; C2, 1400 kg ha− 1; and C3, 2100 kg ha− 1) through soil column experiments, and then used various amounts of nitrogen (N1, 120 kg N ha− 1; N2, 180 kg N ha− 1; and N3, 240 kg N ha− 1) in the field. Ceramsite with a particle size of P1 and an addition amount of C2 or C3 improved salt reduction. Field experiments further demonstrated that ceramsite combined with nitrogen contributed to lower soil electrical conductivity [EC, 1:5 (w/v) soil: water] and higher sunflower yield. Furthermore, the soil EC1:5 was controlled to be lower than 1.1 dS m− 1, which was the critical value of highly saline soil in this area. In particular, N2C2 resulted in a salt reduction rate of 66.48% and a net income of 38,080 Chinese yuan ha− 1 year− 1, which was higher than that with no-ceramsite application or other treatments. Applying ceramsite combined with an appropriate amount of nitrogen could effectively reclaim highly saline soil in the Hetao Irrigation District, China.