Soil acidification has become increasingly serious due to anthropogenic activities (e.g., fertilization) throughout the world. Examining the effects of soil acidification on bacterial and fungal communities in acidic crop soils provides valuable insights for revealing the potential role of microbes in soil quality and crop yield. Here, a total of 18 samples with pH varied from 4 to 7 were collected from agricultural regions in the Jiaodong Peninsula, Shandong Province, China. High-throughput sequencing analysis was used to determine the composition and diversity of the bacterial and fungal communities. The results revealed that the α-diversity of the bacterial community was significantly decreased as the soil acidification increased, while that of fungal communities exhibited little response to soil acidification, thus indicating that bacteria rather than fungi respond sensitively to soil acidification. Principal component analysis (PCA) and canonical correlations analysis (CCA) further corroborated that pH is an essential predictor for controlling the distribution of microbial communities, and it also could alter other exchangeable base cation (e.g., EH⁺, EAl³⁺, EK⁺, ENa⁺, ECa²⁺, and EMg²⁺) contents to further drive the microbial community patterns.

Foxtail millet (Setaria italica L.) is an important cereal for managing future water scarcity and ensuring food security, due to its strong drought and salt stress resistance owing to its developed root system. However, the molecular responses of foxtail millet leaves to salt stress are largely unknown. In this study, seeds of 104 foxtail millet accessions were subjected to 0.17 mol·L⁻¹ NaCl stress during germination, and various germination-related parameters were analyzed to derive 5 salt-sensitive accessions and 13 salt-tolerant accessions. Hong Gu 2000 and Pu Huang Yu were the most salt-tolerant and salt-sensitive accessions, respectively. To determine the mechanism of the salt stress response, transcriptomic differences between the control and salt-treated groups were investigated. We obtained 2019 and 736 differentially expressed genes under salt stress in the salt-sensitive and salt-tolerant accessions, respectively. The transcription factor families bHLH, WRKY, AP2/ERF, and MYB-MYC were found to play critical roles in foxtail millet’s response to salt stress. Additionally, the down-regulation of ribosomal protein-related genes causes stunted growth in the salt-sensitive accessions. The salt-tolerant accession alleviates salt stress by increasing energy production. Our findings provide novel insights into the molecular mechanism of foxtail millet’s response to salt stress.

Water cadmium (Cd) pollution has widely aroused concerns due to high Cd toxicity in water bodies and its serious health risks to humans. Adsorption has been identified as an effective and widely utilized technology for water purification with heavy metal pollution. To develop a newly identified adsorbent of modified zeolite that can easily and effectively purify Cd-polluted water, NaOH modification (JZ), high-temperature modification (HZ), humic acid modification (FZ), Na₂S modification (SZ), and ultrasonic modification (CZ) zeolites were developed, and their appearances and adsorption and desorption characteristics were investigated. The results showed that the adsorption capacity of Cd by JZ and SZ were improved by 68.87% and 32.06%, respectively, relative to that by natural zeolite (NZ); however, HZ, FZ, and CZ decreased the adsorption capacity. JZ had a higher adsorption capacity than SZ and could remove 99.90% Cd at an initial concentration of 100 mg/L. The dominant adsorption mechanism of Cd by JZ was the chemisorption of the monolayer. The preferred temperature and pH that enhanced Cd adsorption by JZ were 25–35 °C and 4–8, respectively. With an equilibrium adsorption capacity of 9.37–9.74 mg/g at an initial concentration of 280 mg/L, JZ reached its maximum saturated adsorption capacity; compared with SZ and NZ, the adsorption capacity increase was 27.83–68.81%. The R² fitted by JZ’s Langmuir model and quasi-second-order dynamics model were both above 0.93. In summary, JZ was recognized as a novel absorbent for Cd-polluted water purification.

Globally, soil acidification is becoming a serious environmental and ecological concern, posing a major threat to ecosystem functions and services. In order to clarifying the acidification mechanism, evaluating acidification risk, and reconditioning soil acidification, the effects of acidification on clay mineral composition and soil surface properties should be evaluated. In this study, the surface charge, specific surface area (SSA), species and content of clay minerals were investigated using the ion adsorption method, methylene blue method, and X-ray diffraction (XRD) for brown soil samples, which collected from Muping, Shandong Province, China. The results showed that the clay mineral species and content varied with the degree of acidification. A small amount of montmorillonite was found in weakly acidic soils, and gibbsite was found in strongly acidic soils. Furthermore, although illite, kaolinite, vermiculite, and chlorite were commonly found in soils with different acidification degrees, their content differed. The negative charge (CEC₈.₂), permanent negative charge (CEC_P), variable negative charge (CEC_V), and SSA values decreased with increasing acidification, while anion exchange capacity values (AEC) decreased. The change of CEC_V was caused by soil organic matter, and the change of CEC_P was caused by illite content, which accounted for the largest proportion in clay minerals of brown soil.