Mucilage effects on the soil water characteristics curve, mechanical consistency, and penetration resistance of compacted heavy and light texture soils.

Abstract

Aims This study aimed to investigate the effects of mucilage on soil mechanical properties and the soil water characteristic curve(SWC). Methods Six soil samples with a wide range of physical and chemical properties were taken and then SWC, soil penetration resistance(SR), and the Atterberg limits were measured at compaction pressures of 100, 200, 300, 400, and 600 kPa, and mucilage(extracted from chia seed)concentrations of 0, 0.1%, 0.3%, and 0.5%. Based on their texture and consistency, the studied soils were divided into two groups: sandy to loamy and clayey soils. Results Results showed that the effect of mucilage, especially at 0.1%, on the Atterberg limits was more significant for clayey soils. The mucilage reduces the compaction potential of light-texture soils and improves penetrability, especially when the soil is dry and under a high compaction pressure. This results in more water retention, especially at low matric suction. Mucilage causes fine-texture soils to be more prone to compaction. The inconsistent effects of mucilage on heavy and light-texture soils may be due to mucilage arrangement and concentration of the solution within fine and coarse pores. Conclusion It is concluded that the increase in water retention would be significant as long as the compressibility is not amplified due to the presence of the mucilage, especially under high compaction energy. The mucilage can improve water retention and penetrability, but tillage or any disturbance should be conducted with care for intensively cultivated soils, which may have higher root exudate concentration and compressibility than bare and fallow soils.