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

Edison Aparecido Mome Filho,Fernando Henrique Setti Gimenes,Getulio Coutinho Figueiredo,André Cesar Vitti,Alvaro Pires Da Silva

doi:10.1590/s0100-06832014000300006

Abstract

Modern agriculture techniques have a great impact on crops and soil quality, especially by the increased machinery traffic and weight. Several devices have been developed for determining soil properties in the field, aimed at managing compacted areas. Penetrometry is a widely used technique; however, there are several types of penetrometers, which have different action modes that can affect the soil resistance measurement. The objective of this study was to compare the functionality of two penetrometry methods (manual and automated mode) in the field identification of compacted, highly mechanized sugarcane areas, considering the influence of soil water volumetric content (θ) on soil penetration resistance (PR). Three sugarcane fields on a Rhodic Eutrudrox were chosen, under a sequence of harvest systems: one manual harvest (1ManH), one mechanized harvest (1MH) and three mechanized harvests (3MH). The different degrees of mechanization were associated to cumulative compaction processes. An electronic penetrometer was used on PR measurements, so that the rod was introduced into the soil by hand (Manual) and by an electromechanical motor (Auto). The θ was measured in the field with a soil moisture sensor. Results showed an effect of θ on PR measurements and that regression models must be used to correct data before comparing harvesting systems. The rod introduction modes resulted in different mean PR values, where the "Manual" overestimated PR compared to the "Auto" mode at low θ.

Highlights

Sugarcane (Saccharum officinarum L.) is responsible for two main Brazilian commodities - sugar and ethanol
The selection criteria of the areas was based on the increasing mechanization of the areas during sugarcane cultivation, since at a higher degree of mechanization, the soil is more likely to be affected by compaction
Several studies demonstrated that mechanization increases bulk density (BD) (Jorajuria & Draghi, 1997; Yavuscan, 2000; ShaferLandefeld et al, 2004)

Summary

Introduction

Sugarcane (Saccharum officinarum L.) is responsible for two main Brazilian commodities - sugar and ethanol. 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). With the advent of mechanization, measuring the compaction degree of soils under sugarcane (Souza et al, 2006) as well as the development of techniques that may improve the compaction management have become crucial. The physical problems for plant growth caused by soil compaction consist of negative effects on root elongation, giving the soil a massive appearance due to reduced porosity (Oliveira et al, 2010). Soil penetration resistance (PR) has been prioritized in soil management and studies on soil physics (Blainski et al, 2008; Assis et al, 2009, Souza et al, 2010; Medeiros et al, 2011; 2013), due to the ease and speed of measurement (Busscher et al, 2000.)

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