The Effect of Nanocellulose and Wetting-Drying Cycle on Water-Holding Capacity and State of Aggregation of Fine-Textured Soil

Abstract

     Soil drainage and aeration are critical problems faced when planting crops in fine-textured soils. The small particle size and flattened shape of the particles that make up fine-textured soils cause the soil to be easily compacted. These problems affect root growth and microbial activity. The promotion of granulation in fine-grained soils can enhance levels of drainage and the presence of air pores in the soil. This is generally done by adding organic matter or organic substances to the soil. These practices are effective but can take a long time. In this research, we used nanocellulose to improve the water-holding capacity and state of aggregation of fine-textured soil. The effect of wetting-drying (WD) cycles on these soil properties was investigated as well. Soil samples were mixed with nanocellulose at the ratios of 1, 1.3, 2 and 4 percent (nanocellulose : soil, % w/w). The mixtures were subjected to three wetting-drying cycles, and soil water-holding capacity (WHC), change in mean weighted diameter (CMWD), state of aggregation (SA), and pore-size distribution (after three WD cycles) mixtures were measured. The results showed that high content of nanocellulose (2 and 4 %) increased WHC to a higher degree than did low content (1 and 1.3 %). Moreover, more wetting-drying cycles also enhanced WHC. High nanocellulose content (2 and 4 %) promoted state of aggregation (high SA) and aggregate stability (low CMWD) to a higher degree than did low content of nanocellulose (1 and 1.3 %). Multiple WDs reduced soil aggregation. Moreover, a high content of nanocellulose enhanced drainage and level of aeration (> 30 mm).