Responses of Low-Quality Soil Microbial Community Structure and Activities to Application of a Mixed Material of Humic Acid, Biochar, and Super Absorbent Polymer

Abstract

Low-quality soil with little human disturbance is used in mine soil reclamation in China, such as in deep tillage and soil replacement operations [1]. However, it has extreme texture with high density, low porosity, low water capacity, and poor fertilizer conservation [2]. The low-quality of guest soil is closely related to soil microbial diversity and activity [3, 4]. In recent years, more attention has been paid to the use of organic materials like humic acid, biochar, and super absorbent polymer for mine soil reclamation. Humic acid could effectively improve the physical, chemical, and biological properties of soil and promote plant growth. Maji et al. [5] found that humic acid could promote plant growth and increase available nutrient content, while dry weight increased 59.49% as compared to control. Super absorbent polymer could increase soil water retention, which could in turn promote fertilizer conservation, improve plant supply capacity, and increase crop yield [6, 7]. Moreover, super absorbent polymers with high water absorption and water retention ability could also promote aggregate formation [8]. Biochar application in soil is beneficial for carbon (C) sequestration, soil fertility, and ecosystem functioning [9, 10]. Lehmann et al. [11] and Zhu et al. [12] found that the addition of biochar benefited soil microorganisms that play important roles in soil nutrient cycling, carbon exchanges, soil buffering capacity, and soil ecosystem stability. A recent study showed that biochar could improve soil microbial activity, nutrient availability, and plant growth in arid soil [13]. Madhavi et al. [14] found that the combined application of humic acid, biochar, and some chemical fertilizers could significantly enhance acid phosphatase activity. Microorganisms regulate several characteristics like soil organic matter, soil nutrient cycle, soil ecosystem Low-quality soil for land reuse is a crucial problem in vegetation quality and especially to waste disposal sites in mining areas. It is necessary to find suitable materials to improve the soil quality and especially to increase soil microbial diversity and activity. In this study, pot experiments were conducted to investigate the effect of a mixed material of humic acid, super absorbent polymer and biochar on low-quality soil indexes and the microbial community response. The indexes included soil physicochemical properties and the corresponding plant growth. The results showed that the mixed material could improve chemical properties and physical structure of soil by increasing the bulk density, porosity, macro aggregate, and promote the mineralization of nutrient elements in soil. The best performance was achieved by adding 3 g•kg-1 super absorbent polymer, 3 g•kg-1 humic acid, and 10 g•kg-1 biochar to soil with plant total nitrogen, dry weight and height increased by 85.18%, 266.41% and 74.06%, respectively. Physicochemical properties caused changes in soil microbial diversity. Acidobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Firmicutes, Nitrospirae,...

Effects of coal-derived compound fertilizers on soil bacterial community structure in coal mining subsidence areas

“…The purpose of soil reclamation in coal mining subsidence area is to reconstruct productive, healthy and sustainable ecosystem of land use after mining. Increasing soil nutrients and enriching microbial population through fertilization is an effective method for ecological restoration in mining areas ( Mummey et al, 2002 ; Cao et al, 2020 ; Li et al, 2020 ; Yan et al, 2021 ). In our study, soil nutrient and bacterial community diversity increased significantly after 4 years of reclamation.…”

Superabsorbent polymer and its effect on maize germination, emergence and genetic diversity of rhizosphere microorganisms

“…Since in these groups, there were also control samples without the use of SarB from their experiment it follows that the addition of either a peat substrate or maize straw than a SarB had a greater impact on bacterial diversity. Li et al (2020) detected that SaP (containing linear anionic polyacrylamide + humic acid + biochar), nine mixtures of different concentrations, affected soil bacterial communities. From the cluster analysis of the bacterial community composition at the OtU level, they found that the control samples showed the greatest similarity with treatments e1 (0.5 g/kg SaP + 3 g/kg humic acid + 5 g/kg biochar) and e5 (1 g/kg SaP + 6 g/kg humic acid + 5 g/kg biochar).…”

Effect of Humic Amendment on Selected Hydrophysical Properties of Sandy and Clayey Soils

“…Humic compounds offer a range of benefits, including enhanced biological activity, nutrient availability, cation exchange capacity, pH buffering, carbon sequestration, and soil-water relations [37][38][39][40]. Their capacity to promote plant stress tolerance by influencing hormonelike effects and micro-organism activity has also been noted [41][42][43].…”