Ameliorants improve saline–alkaline soils on a large scale in northern Jiangsu Province, China

• Applying chemical ameliorants improve saline–alkali soil.
• We have developed a new ameliorant containing several effective components.
• Three ameliorants could improve soil properties greatly.
• The optimum combination (t/ha) was: the new ameliorant 45, gypsum 18, cow dung 300.

In order to improve the coastal saline–alkali soil in north Jiangsu Province, the effects of a newly-developed ameliorant was compared with gypsum and cow manure in field trials in coastal saline soil in Dafeng County, China. Measurements included soil electrical conductivity, pH, soil nutrients, the plant (Salicornia europea L.) growth and ion concentration in stems and roots. The three ameliorants and their combinations improved soil physical and chemical properties and increased the plant height and stem diameter in the order of cow dung > gypsum > new ameliorant. During the experimental period, the soil electrical conductivity of the optimum combination decreased initially and then increased, but was lower than that in the other treatments. Compared with the control,the pH value in the optimum treatment increased by 10.4%, 9.2% and 5.2% in 0–5, 5–20 and 20–40 cm soil layers, respectively. The content of soil organic matter in the three soil layers increased by 22%, 28% and 10%, respectively. The total potassium content in different soil layers increased by 23%, 26% and 26%, respectively. In the optimal treatment, the height of S. europea increased by 32% and stem diameter by 20% compared with control. The K+ and Ca2+ concentration in roots and stems of S. europaea was significantly higher in the optimum treatment compared with control. The optimum combination (in t/ha) was: the new ameliorant 45, gypsum 18 and cow dung 300.