Effects of soil physical and chemical properties on phosphorus adsorption-desorption in fluvo-aquic soil under conservation tillage

• Published in: Soil & tillage research Vol. 234; p. 105840
• Main Authors: Yang, Jiao, Xin, Xiuli, Zhang, Xianfeng, Zhong, Xinyue, Yang, Wenliang, Ren, Guocui, Zhu, Anning
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-10-2023
• Subjects: Adsorption and desorption capacity; Aggregate distribution; Chemical properties; Reduced tillage; Straw returning; Aggregate distribution; Adsorption and desorption capacity; Chemical properties; Straw returning; Reduced tillage
• ISSN: 0167-1987; 1879-3444
• DOI: 10.1016/j.still.2023.105840

Conservation tillage has been widely used in the North China Plain to improve the aggregate structure and promote soil organic matter (SOM) retention, which is closely associated with phosphorus (P) turnover. However, a quantitative description of how conservation tillage alters P adsorption and desorption characteristics via affecting soil physical and chemical properties remains lacking. Thus, we conducted a batch experiment using pilot soils that had experienced two tillage regimes (conventional/reduced tillage) and two types of straw management (straw returning/removal) for 13 years. The results indicated that the maximum adsorption capacity (Qm) and adsorption binding energy (KL) of reduced tillage decreased by 36.2% and 21.5%, respectively, and the average desorption rate (Dr) increased by 14.4% compared with conventional tillage. In addition, the Qm and KL of straw returning decreased by 40.5% and 51.9%, respectively, and the Dr increased by 25.2% compared with straw removal. The adsorption capacity of aggregates with different particle sizes showed the order of silt + clay > macroaggregate > / (≈) microaggregate, while the desorption capacity exhibited the opposite trend. Moreover, the Qm and KL depicted negative correlations with SOM, total P (TP), Olsen-P, and the mass proportion of macroaggregate. However, they exhibited positive correlations with free aluminum oxides (Ald), non-crystalline aluminum oxides (Alo), pH, specific surface area (SSA), and the mass proportion of microaggregate and silt + clay. The Dr was just the opposite with Qm and KL. The random forest results indicated that SOM, pH, SSA, TP, Ald, Olsen-P, and the mass proportion of macroaggregate were the key factors affecting the P adsorption and desorption. The physical and chemical properties collectively explained 80.8% of the total variance, and their interaction made the largest contribution. This study provides insights into how conservation tillage reduced P adsorption potential and promoted P desorption capacity from a physical and chemical perspective and emphasizes the importance of aggregate in the environmental behavior of P, which is of great importance for sustainable agricultural development and protecting food security.
●Conservation tillage decreased the adsorption and enhanced the desorption of P.●Straw returning had a greater impact on P adsorption-desorption than reduced tillage.●Increasing SOM and TP, while reducing SSA, pH, and Ald, contributes to weaken the adsorption action.●The macroaggregate has an essential impact on the P adsorption-desorption.●The interaction of physicochemical properties was the largest contributor to variance.