The Ameliorating Effect of Alkaline Industrial Byproducts in the Presence of Exogenous Low-Molecular-Weight Organic Acids on an Acidic Brown Soil from Jiaodong Peninsula of China

It has been proposed that the quality of acidic soils can be improved in the presence of alkaline byproduct amendments containing silicon (Si), calcium (Ca), magnesium (Mg), and potassium (K). In the present study, we aimed to explore the effect of byproduct amendments on ameliorating acidic soil in Jiaodong Peninsula of China in the existence of different types of low-molecular-weight organic acids (LOAs, such as malic acid, citric acid, oxalic acid, and succinic acid) that are usually excreted by plant roots. Therefore, a 60-day incubation test was carried out to assess the effect of byproduct amendments and LOAs on soil physicochemical properties, soil available Mg and Ca, cation exchange capacity (CEC), soil respiration, and enzyme activities. The results showed that in the presence of LOAs, the byproduct amendments could still increased the soil pH and decreased the soil exchangeable acid and exchangeable Al3+. Compared with the control group (CK), all byproduct amendment-containing treatments could increase soil available Mg and Ca, soil CEC, soil respiration, and soil sucrase (S-SC) activity. The addition of byproduct amendments could significantly improve the chemical and biological properties of the acidic brown soils in Jiaodong Peninsula of China. However, LOAs, especially the LOAs that could precipitate with Ca in byproduct amendments, negatively impair the ameliorating effect on acidic soil compared with byproduct amendments alone treatment. When using byproduct amendments to ameliorate acidic soil, the type of LOAs secreted by plant roots was an influencing factor that must be considered.