Zhu Xiaoxu, Zhao Shengchen, Lin Siqi, Wang Jihong, Leng Su
College of Resource and Environmental Science, Jilin Agricultural University, Changchun, Jilin, China.
PLoS One. 2025 Apr 16;20(4):e0318417. doi: 10.1371/journal.pone.0318417. eCollection 2025.
The excessive utilization of chemical fertilizers, particularly nitrogen fertilizers, is leading to decline in the pH level of the black soil in Jilin Province. Acidification of black soil leads to reduced salt base saturation, decreased organic matter content, and increased soil degradation, which, in turn, leads to diminshed aggregate stability and poor soil structure, negatively affecting soil fertility. As a result, the sustainability of food production and farmland ecosystem stability are at risk. The precise relationship between alterations in cementing substances and changes in soil aggregate stability during the acidification of black soil remains unclear, and the ultrasonic thermal difference method allows for the quantitative description of changes in soil aggregate stability. Therefore, this study employed the ultrasonic thermal difference method to investigate the impact of acidification on the stability of black soil aggregates and their cementing substances through a simulated fertilizer drenching experiment, thus elucidate the relationship between primary cementing materials and the stability of aggregates under varying degrees of black soil acidification, and to provides theoretical basis and data for alleviating and preventing acidification of black soil in Jilin Province. The results disclosed a gradual decline in soil organic carbon (SOC) levels during the acidification experiment, while water-soluble organic carbon (WSOC) first increased and then decreased. After 25 years of simulated leaching, SOC decreased by 1.34% and WSOC declined by 15.63%. Acidification has a minimal impact on Fe-Al bonded organic carbon but significantly reduces calcium-bonded organic carbon by 17.07% over 25 years. The content of exchangeable Ca2+ and Mg²⁺ decreases as acidification intensifies. After 25 years, exchangeable Ca2+ and Mg²⁺ decreased by 9.42% and 7.00%, respectively. The acidification of the test soil resulted in a 46.5% reduction in the aggregate stability energy (E) of water-stable microaggregates, with an average decrease of 14.04 J/g for every 0.1 unit decrease in pH. Additionally, the soil critical stabilization energy (Ecrit) exhibited a 51.48% reduction. The results demonstrated that a decrease of 0.32 J/g in E was associated with a 0.1 unit decrease in pH on average. Furthermore, the multivariate linear regression analysis revealed that the reduction in soil organic carbon (SOC) content contributed the most to the decline in E, followed by Calcium bond-bound soil organic carbon (Ca-SOC). Notably, Ca-SOC exerted the greatest influence on the reduction in sand grain Ecrit, followed by SOC.
化肥，尤其是氮肥的过度使用，正导致吉林省黑土的pH值下降。黑土酸化导致盐基饱和度降低、有机质含量减少以及土壤退化加剧，进而导致团聚体稳定性下降和土壤结构不良，对土壤肥力产生负面影响。因此，粮食生产的可持续性和农田生态系统稳定性面临风险。黑土酸化过程中胶结物质变化与土壤团聚体稳定性变化之间的确切关系尚不清楚，而超声热差法能够定量描述土壤团聚体稳定性的变化。因此，本研究采用超声热差法，通过模拟肥料淋溶试验，研究酸化对黑土团聚体及其胶结物质稳定性的影响，从而阐明不同程度黑土酸化下主要胶结物质与团聚体稳定性之间的关系，为缓解和预防吉林省黑土酸化提供理论依据和数据。结果表明，在酸化试验过程中，土壤有机碳（SOC）水平逐渐下降，而水溶性有机碳（WSOC）先增加后减少。经过25年的模拟淋溶，SOC下降了1.34%，WSOC下降了15.63%。酸化对铁铝键合有机碳影响最小，但在25年内钙键合有机碳显著减少了17.07%。随着酸化加剧，交换性Ca2+和Mg²⁺含量降低。25年后，交换性Ca2+和Mg²⁺分别下降了9.42%和7.00%。试验土壤酸化导致水稳性微团聚体的团聚体稳定能（E）降低了46.5%，pH每降低0.1个单位，平均降低14.04 J/g。此外，土壤临界稳定能（Ecrit）降低了51.48%。结果表明，E平均每降低0.32 J/g与pH降低0.1个单位相关。此外，多元线性回归分析表明，土壤有机碳（SOC）含量的降低对E的下降贡献最大，其次是钙键合土壤有机碳（Ca-SOC）。值得注意的是，Ca-SOC对砂粒Ecrit的降低影响最大，其次是SOC。
