Comparison of estimation methods of soil strength in five soils

Abstract

In agriculture, the soil strength is used to describe the susceptibility to deformation by pressure caused by agricultural machine. The purpose of this study was to compare different methods for estimating the inherent soil strength and to identify their suitability for the evaluation of load support capacity, compaction susceptibility and root growth. The physical, chemical, mineralogical and intrinsic strength properties of seven soil samples, collected from five sampling pits at different locations in Brazil, were measured. Four clay (CS) and three sandy clay loam (SCL) soils were used. The clay soils were collected on a farm in Santo Ângelo, RS (28 ° 16 ' 16 '' S; 54 ° 13 ' 11 '' W 290 m); A and B horizons at the Universidade Federal de Lavras, Lavras, MG (21 ° 13 ' 47 '' S; 44 ° 58 ' 6'' W; 918 m) and on the farm Sygenta, in Uberlandia, MG (18 ° 58 ' 37 '' S; 48 ° 12 ' 05 '' W 866 m). The sandy clay loam soils were collected in Aracruz, ES (19 ° 47 ' 10 '' S; 40 ° 16 ' 29 '' W 81 m), and on the farm Xavier, Lavras, MG (21 ° 13 ' 24 '' S; 45 ° 05 ' 00 '' W; 844 m). Soil strength was estimated based on measurements of: (a) a pneumatic consolidometer, (b) manual pocket (non-rotating) penetrometer; and (c) automatic (rotating) penetrometer. The results of soil strength properties were similar by the three methods. The soil structure had a significant influence on soil strength. Results of measurements with both the manual pocket and the electric penetrometer were similar, emphasizing the influence of soil texture. The data showed that, to enhance the reliability of predictions of preconsolidation pressure by penetrometers, it is better to separate the soils into the different classes, rather than analyze them jointly. It can be concluded that the consolidometer method, although expensive, is the best when evaluations of load support capacity and compaction susceptibility of soil samples are desired.

Toward Improving Global Estimates of Field Soil Water Capacity

“…Different values of such pressure have been used in different countries, e.g., -5 kPa in United Kingdom (White, 2006) and France (Le Bas et al, 1997), -6 kPa in Brazil (Ajayi et al, 2009), -10 kPa in Australia (White, 2006) and Sweden (Kätterer et al, 2006), and such values can vary among different researchers in the same country. In the United States, the recommended value of such pressure is -33 kPa (Kirkham, 2005).…”

Assessment of the physical and mechanical properties of the soils in the different agroecological zones of Benin

“…However, the use of a simpler and portable penetrometer is one of the means for rapid collection of soil characteristics (Dexter et al 2007, Lenoble andMartinaud, 2003). Indeed, resistance to soil penetration is one of the most common indicators of soil physical properties in agronomic assessment (Daniel et al 2015, Ajayi et al 2009. Several studies have shown the penetrometer's ability to distinguish spatial variations in mechanical properties in natural soils (Steve and Caroline, 2017 ;Lepetit et al 2000).…”

Portable penetrometer for agricultural soil: sensitivity test to identify critical compaction depth

“…So, determining compacted soil layers with simpler and portable penetrometers would be an adequate and cheap alternative. Similarly, various equipments have been tested to evaluate soil load support capacity (Ajayi et al, 2009). …”