Potassium supply and adsorption capacity changes in a Chinese subtropical paddy soil chronosequence

• Published in: Archiv für Acker- und Pflanzenbau und Bodenkunde Vol. 69; no. 2; pp. 290 - 303
• Main Authors: Han, Guang-Zhong, Cao, Xiao-Ming, Han, Bang-Shuai, Yang, Fan, Huang, Lai-Ming, Wu, Yun-Jin
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 28.01.2023; Taylor & Francis Ltd
• Subjects: Adsorption; clay mineral; Crop yield; Cultivation; Fertilizers; Grain cultivation; Leaching; Organic matter; Organic soils; Paddy soil chronosequence; Potassium; potassium adsorption; quaternary red clay; Rice fields; Soil fertility; Soil organic matter; Soil properties; Soils; Sorbents
• ISSN: 0365-0340; 1476-3567
• DOI: 10.1080/03650340.2021.1985109

An accurate assessment of the effect of long-term rice cultivation on K-supplying capacity and adsorption characteristics of paddy soils has theoretical and practical significance for rational application of K fertilizers. We measured changes in basic soil properties and K adsorption isotherms in a representative subtropical paddy soil chronosequence in Southern China. Results showed that mean water dissolvable K and non-exchangeable K contents of paddy soils (27.0 and 184.8 mg kg −1 ) were higher than those of original soils (15.5 and 169.5 mg kg −1 ), but the mean exchangeable K contents showed the opposite trend (paddy soils, 37.1 mg kg −1 ; original soils, 52.5 mg kg −1 ). Long-term paddy cultivation caused reduced K-supplying capacity and K + adsorption capacity of paddy soils in the red soil regions, which was attributed to the rapid loss of sorbents (e.g. Fe d and clay) by leaching and the competitive occupation of sorption sites by the accumulated soil organic matter. The promotion of sustainable and balanced K fertilizer inputs and appropriate increase in short-term applications of K fertilizer (K fertilizer input > K output from harvest) during application of N and P fertilizers to paddy soils were necessary to maintain the K-supplying capacity of soils and the crop yield.