Читать книгу Handbook of Ecological and Ecosystem Engineering - Группа авторов - Страница 29

Description of the marginality factor: Soil surface acidity can reduce nutrient availability in soil solutions, increasing the concentration of heavy metals (especially aluminum) and their toxic effects on decomposition and nitrogen fixation microbial communities [61, 117, 118]. The occurrence of toxicity caused by aluminum depends on the interaction of this element with other limiting factors such as nitrogen, phosphorus, pH, and iron [119].

Revitalization strategy: According to Zhao and collaborators [119], three proposals can be applied to acidic soils to improve plant growth: (i) combined application of lime and nutrients, depending on the type of soil and plants; (ii) identification and development of tolerant plant species of multiple stressors; and (iii) inoculation of plants with beneficial microorganisms.

Revitalization by ecosystem engineering: Plants can reduce the toxicity of aluminum ions by exuding compounds that can chelate aluminum or sequester aluminum in plant cells through complexes with organic acids [120]. Other plants also develop associations with arbuscular symbiotic mycorrhizal fungi, increasing the plants' resistance to soil acidity and phytotoxic levels caused by aluminum in soil [121]. Bioenergy crops like A. donax can adapt to a sub‐severe pH threshold (5–5.5): performance is optimal between pH 6 and 7, moderate between pH 7 and 8, and poor between pH 4 and 5 [61]. Switchgrass tolerates acidic soils in all the growth and development phases, from seedling to adult; its roots can tolerate a pH of 3.7 and show excellent growth in soils with a pH between 6 and 7 [61]. Other bioenergy crops tolerant of acid soils include soybean [122, 123] and Jatropha curcas [124]. Adjusting the pH and adding fertilizers to the soil can also improve phytoremediation efficiency technology, as discussed in the following subsection [125].