Resistance of a Red Latosol to Penetration: Comparison of Penetrometers, Model Adjustment, and Soil Water Content Correction

Abstract

Penetration resistance can be determined directly in the field or in the laboratory. However, data obtained using the two methods are not directly comparable. Considering soil moisture influences penetration resistance, penetration resistance data obtained using the two methods can be corrected based on common moisture values. To enable comparison of the data, the measured data should be adjusted using mathematical models. Consequently, the objective of the present study was to compare soil penetration resistance values measured in a Red Latosol using a static penetrometer and a bench-top electronic penetrometer. The comparison was carried out using samples collected from different soil layers, based on moisture levels ranging from 0.15 to 0.28 kg kg-1. In addition, the reliability of some mathematical models was compared using benchpenetrometer data. Finally, the Busscher method and a new proposed method for moisture correction were tested. According to the comparison of results between the equipment, it is necessary to correct data using a linear type equation. The Jakobsen & Dexter (1987) model had the optimal performance (R 2 : 0.89; RMSD: 0.70). The new proposed corrected method was tested using several reference moisture values and it presented minor (< 0.30 RMSD) and stable errors.

Sensing and Mapping the Effects of Cow Trampling on the Soil Compaction of the Montado Mediterranean Ecosystem

“…This aspect is very important, since the vegetative cycle of dryland pastures normally begins in September (after the first autumn rains), an important phase in plant root development [ 42 ]. This trend towards higher CI values as SMC decreases, or vice versa (exponential relationship), confirms the results of other studies [ 15 , 18 ] and is attributed to the reduction in the cohesive forces between clay particles [ 43 ]. It should be noted, however, that this relationship between the CI and SMC restricts direct comparisons of CI values among same soils with different moisture contents [ 15 ].…”

“…The degree of compaction of the sub superficial layers of the soil can be measured through soil penetration resistance, or the resistance of the soil against mechanical penetration (Cone Index, CI, in kPa), which consists of quantifying the resistance observed against the penetration of a body of a certain shape, usually a cone [ 18 , 19 ]. The field penetrometer is a rapid and easy-to-use tool when compared to the more conventional soil determinations, such as soil bulk density [ 19 ].…”

“…The CI, utilised to quantify the mechanical impedance of the soil, is considered one of the key indicators for the diagnosis of the most restrictive soil layers for root growth at depth [ 19 ]. Such evaluations offer essential information about the ease or difficulty of the growth of crop root systems [ 18 ]. According to Donkor et al [ 13 ], Krajco [ 16 ] and Debiasi et al [ 20 ], if the CI is higher than 2 MPa, this may lead to restrictions on root penetration and growth.…”

“…However, measurements of the CI values are highly influenced by diverse soil factors: intrinsic (e.g., soil moisture, bulk density, texture and structure) and extrinsic (e.g., management system) [ 19 ]. Moreover, the results of field penetrometers depend on user operating speed (penetration rate), which is often challenging to standardise; a change in operating speed alters the force the users apply to insert the equipment rod, which, in turn, changes the result [ 15 , 18 ]. On the other hand, the characterisation of this and other soil properties is a difficult process due to the high soil spatial variability [ 14 ] and the interaction and combination of the factors involved, particularly in silvopastoral systems [ 1 ].…”

VARIAÇÃO ESPACIAL DOS ATRIBUTOS FÍSICOS E ESTOQUES DE CARBONO DO SOLO EM PLANTIO DE Schizolobium amazonicum NA AMAZÔNIA

“…Oliveira et al (2015) indicaram que valores de RP acima de 2000 kPa podem oferecer limitação ao crescimento e desenvolvimento radicular. A RP é diretamente proporcional aos teores de argila, ou seja, quando se aplica pressão em solos argilosos, a transmissão da resistência à penetração é maior nas camadas mais profundas (DUARTE et al, 2020). A estrutura do solo influencia nos valores de RP, sendo assim, solos argilosos com estrutura adequada, tendem a apresentar melhores condições para o desenvolvimento radicular, com menores valores de DS e RP (CORTEZ et al, 2018).…”