Mapping of penetrometer resistance in relation to tractor traffic using multivariate geostatistics

Abstract

The traffic of agricultural machines can cause soil compaction and high variability of soil structure, both along normal lines and along those parallel to the field plane. The aim of this work was to investigate the potential of an electronic penetrometer, a GPS, a GIS and geostatistical techniques for mapping soil compaction.In July 2003 soil cone penetrometer resistance was measured using a semi-automatic electronic penetrometer in a sandy-silt soil (Vertic Xerochrept) of inland Sicily where a three-year rotation wheat (Triticum durum Desf.)-wheat-tomato (Solanum lycopersicum L.) was practiced. The measurements were carried out along three parallel 3-m long transects, from the soil surface to a depth of 0.70 m.A multivariate geostatistical approach, including exploratory analysis, variography, stochastic simulation and post-processing of simulations, was applied to produce thematic maps of penetrometer resistance and probability exceeding a critical value, in correspondence of a different number of tractor passes. Penetrometer resistance variation resulted erratic at the surface but showed high spatial correlation between data measured at different depths. The probabilistic maps of compaction risk showed that the soil volume, exceeding the penetrometer resistance of 2.5 MPa, critical for root growth, at the probability level of p N 0.40 increased from 20% to 40% after five tractor passes.

Spatial prediction of soil penetration resistance using functional geostatistics

“…The predicted curve was similar to the behavior pattern of the observed data, which suggested that the soil does not present limitations for crop root growth for this zone (Carrara et al, 2007;Utset and Cid, 2003). At depths greater than 15 cm, compaction levels were greater than 2 MPa PR, which is the critical limit for root growth (Chan et al, 2006;Hakansson and Lipiec, 2000;Hamza and Anderson, 2005).…”

Multi-criteria characterization of recent digital soil mapping and modeling approaches

“…Only 27.7% (N: 25) of the investigated DSMM studies sampled multiple soil layers/horizons (soil databases are not considered in these numbers). Only one paper by Carrara et al (2007) provided threedimensional (3D) soil representations and one paper by Zhang et al (2008a) used an explicit 3D Geographic Information System (GIS)-based tabulation of soil data.…”

Compared performance of penetrometers and effect of soil water content on penetration resistance measurements

“…The area of sugarcane plantations in the 2011/2012 growing season was 8.4 million hectares, of which 52.6 % (4.4 million hectares) in the state of São Paulo (CONAB, 2012). From planting to harvest, sugarcane cultivation is a highly mechanized process (Ceddia et al, 1999;Paulino et al, 2004), and the increase of machinery traffic has caused soil physical degradation, creating obstacles for root growth (Carrara et al, 2007). Therefore, with the advent of mechanization, measuring the compaction degree of soils under sugarcane as well as the development of techniques that may improve the compaction management have become crucial.…”

“…The main difference is related to the insertion speed of the rod into the soil, which can be constant or interfere with the results of the in situ measurements, according to the operator (Herrick & Jones, 2002). The reliability of data generated by hand penetrometers is directly related to the control of the rod speed during insertion into the soil, although maintaining a constant speed is almost impossible (Carrara et al, 2007). So, when the speed is not constant, neither is the applied force (Herrick & Jones, 2002); if the rod insertion speed is accelerated, the force is increased, and decreased in the case of deceleration (Sun et al, 2006).…”