Compressive properties and least limiting water range of plough layer and plough pan in sugarcane fields

• Published in: Soil use and management 2021-07, Vol.37 (3), p.533-544
• Main Authors: Lima, Renato P., Rolim, Mário M., Dantas, Daniel da, Silva, Anderson R., Mendonça, Edwardo A. S., Cornelis, Wim
• Format: Article
• Language: English
• Subjects: Compaction; Compressibility; Compressing; Compression; Compression index; Compression tests; Compressive properties; Constraining; Penetration; Penetration resistance; Plows; precompression stress; Properties; Soil; Soil compaction; Soil compressibility; Soil layers; Soil resistance; soil strength; soil water availability; Soils; Specific volume; Sugarcane; Tillage; Water depth
• ISSN: 0266-0032; 1475-2743
• DOI: 10.1111/sum.12601

In this work, we aimed to investigate changes in compressive properties and least limiting water range (LLWR) of the plough layer and plough pan induced by successive years of sugarcane cultivation. Undisturbed soil samples were collected in a sugarcane field at the plough layer and below tillage depth (plough pan). Uniaxial compression tests were performed for a water tension (h) range of 30 to 15,000 hPa for calculations of the compressive parameters N (the specific volume at 1 kPa), λ (compression index) and κ (recompression index), besides the precompression stress (σp). The LLWR was examined through the water retention and penetration resistance curves. σp linearly increased with the increase in the compaction state (plough pan) and h, whereas κ decreased with the increase in the h with no significant effect of compaction level. N and λ presented peaks at intermediate h values (100–2,000 hPa). Considerable reductions in the LLWR were observed from the plough to plough pan layer, which was induced by the increase in the soil penetration resistance. These results suggest that the residual plough pan induced by the successive years of intensive use of machinery for field operations in sugarcane areas originates a soil layer of lower compressibility and higher strength that further increases as the soil dries in response to h. Moreover, the consequent increase in the soil penetration resistance from the plough to plough pan is the main factor negatively affecting the LLWR.