Puddling intensity, sesquioxides, and soil organic carbon impacts on crack patterns of two paddy soils

• Published in: Geoderma 2016-01, Vol.262, p.155-164
• Main Authors: Zhang, Z.B., Zhou, H., Lin, H., Peng, X.
• Format: Article
• Language: English
• Subjects: Aggregate size distribution; Paddy soil cracks; Puddling; Sesquioxides; Soil organic carbon
• ISSN: 0016-7061; 1872-6259
• DOI: 10.1016/j.geoderma.2015.08.030

Paddy soils subjected to puddling are easily cracked under wetting and drying cycles. This phenomenon has implications for water loss and chemical leaching in paddy fields. We hypothesized that crack patterns in such paddy soils result from aggregate size distribution created by puddling under submerged condition. Soil organic carbon (SOC) and sesquioxides are main binding agents of aggregation while puddling is a disruptive force of aggregates. In this study, our aim was to investigate the effects of puddling intensity, SOC, and sesquioxides on cracking in two paddy soils — one cultivated for 20years (YPF soil) and the other cultivated for over 100years (OPF soil). The puddling intensity was simulated by ultrasonic dispersion at applied energy of 0–800Jml−1. The soils were treated chemically by water as a control as well as by oxalate, dithionite-citrate-bicarbonate (DCB), or by H2O2. The aggregate size distribution and crack patterns were determined after the simulated puddling and the chemical treatments. The results showed that the simulated puddling and the chemical treatments increased clay- (