[Effects of activated coke on soil properties and growth of two plant species in saline alkali soil in northern Shanxi Province, China]

Solid waste-based improver is one of the effective means to improve properties of saline-alkali soil. As a kind of porous waste, activated coke is expected to improve soil properties and alleviate salt-alkali stress. In order to understand the improvement effect of activated coke on saline alkali land in northern Shanxi Province, we examined the effects of different addition rates of activated coke (CK, 0 g·kg^-1; A₁₀, 10 g·kg^-1; A₂₀, 20 g·kg^-1; A₅₀, 50 g·kg^-1) on the properties of saline alkali soil and the growth of two plant species. The results showed that activated coke addition could increase the content of water soluble soil aggregates, reduce soil salt content, soil pH, and the electrical conductivity (EC). Compared with CK, the mean weight diameters of the aggregates for the saline-alkali soils grown with Puccinellia distans and maize were increased by 5.1%-32.2%, soil pH was decreased by 0.4%-4.1%, sodium adsorption ratio (SAR) was decreased by 4.8%-18.7%, and the EC was decreased by 7.4%-8.2%. Applying appropriate amount of activated coke could promote plant growth through reducing the plasma membrane damage of plant cells, increasing plant chlorophyll and Ca²⁺ contents. The biomass of Puccinellia distans and maize both reached the maximum under the A₂₀ treatment. It suggested that the application of 20 g·kg^-1 activated coke (A₂₀) in saline alkali soil could improve soil quality in the rhizosphere soil, increase plant selective Ca²⁺ absorption, thereby reducing salt damage to plant cells and promote plant growth in saline-alkali habitat.