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Mathieu Lamandé

Soil precompression stress, penetration resistance and crop yields in relation to differently-trafficked, temperate-region sandy loam soils

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Compaction of the subsoil due to heavy traffic in moist and wet soil is widespread in modern agriculture.
The objective of this study was to quantify the effects from realistic
field traffic on soil penetration
resistance and barley crop yield for three Luvisols developed from glacial till. Undisturbed soil cores were
used for quantifying the precompression stress (spc) of non-compacted soil. Tractor-trailer combinations
for slurry application with wheel loads of
6 and
8 Mg (treatments M3, M6, M8) were used for the
experimental traffic in the spring at
field-capacity. For one additional treatment (labelled M8-1), the soil
was loaded only in the
first year. A tricycle-like machine with a single pass of wide tyres each carrying
12 Mg (treatment S12) was included at one site. Traffic treatments were applied in a randomized block
design with four replicates and with treatments repeated in four consecutive years (2010–2013). After
two years of repeated experimental traffic, penetration resistance (PR) was measured to a depth of 1 m.
The yield of a spring barley crop (Hordeum vulgare L.) was recorded in all four years of the experiment. The
results did not support our hypothesis of spc as a soil strength measure predicting resistance to subsoil
compaction. The tyre inflation pressure and/or the mean ground pressure were the main predictors of PR
in the upper soil layers. For deeper soil layers, PR correlated better to the wheel load. The number of
wheel passes (M-treatments vs the S12 treatment) modified this general pattern, indicating a very strong
impact of repeated wheel passes. Our data indicate that a single traffic event may mechanically weaken
the soil without inducing major compaction but with influence on the effect of subsequent traffic even
after as long an interval as a year (treatments M8 vs M8-1). Crop yields were much influenced by
compaction of the plough layer. Due to the repeated wheel passes for the M-treatments, significant yield
penalties were observed, while the single-pass treatment with 12 Mg wheel load in S12 did not have
significant effects on crop yield. Our hypothesis of 3 Mg wheel load as an upper threshold for not inducing
subsoil compaction was confirmed for the tractor-trailer treatments with repeated wheel passes but not
supported for the single-pass machinery. The results call for further studies of the potential for carrying
high loads using wide, low-pressure tyres by crab steering/dog-walk machinery.
Original languageEnglish
JournalSoil & Tillage Research
Pages (from-to)298-308
Number of pages11
Publication statusPublished - 2016

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