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Journal of Nanomaterials
Volume 2016, Article ID 5403976, 11 pages
http://dx.doi.org/10.1155/2016/5403976
Research Article

Effects of Superabsorbent Polymers on the Hydraulic Parameters and Water Retention Properties of Soil

1State Key Laboratory of Simulation and Regulation of Water Cycles in River Basins, China Institute of Water Resources and Hydropower Research, Beijing 100048, China
2College of Water Conservancy and Civil Engineering, China Agricultural University, Beijing 100083, China

Received 30 January 2016; Revised 16 May 2016; Accepted 5 June 2016

Academic Editor: João Garcia

Copyright © 2016 Renkuan Liao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Superabsorbent polymers (SAPs) are widely applied in dryland agriculture. However, their functional property of repeated absorption and release of soil water exerts periodic effects on the hydraulic parameters and water-retention properties of soil, and as this property gradually diminishes with time, its effects tend to be unstable. During the 120-day continuous soil cultivation experiment described in this paper, horizontal soil column infiltration and high-speed centrifugation tests were conducted on SAP-treated soil to measure unsaturated diffusivity and soil water characteristic curves. The experimental results suggest that the SAP increased the water retaining capacity of soil sections where the suction pressure was between 0 and 3,000 cm. The SAP significantly obstructed water diffusion in the soil in the early days of the experiment, but the effect gradually decreased in the later period. The average decrease in water diffusivity in the treatment groups fell from 76.6% at 0 days to 1.2% at 120 days. This research also provided parameters of time-varying functions that describe the unsaturated diffusivity and unsaturated hydraulic conductivity of soils under the effects of SAPs; in future research, these functions can be used to construct water movement models applicable to SAP-treated soil.