D. Jorajuria et L. Draghi, THE DISTRIBUTION OF SOIL COMPACTION WITH DEPTH AND THE RESPONSE OF A PERENNIAL FORAGE CROP, Journal of agricultural engineering research, 66(4), 1997, pp. 261-265
As a result of the great intensity of vehicular traffic to which peren
nial forage crops are subjected, the avoidance of long-term induced su
bsoil compaction is difficult. The object of this work was to study th
e alternatives of using either a light tractor with a high number of p
asses or a heavier one with a reduced amount of wheeling on the field.
Field tests were carried out on grassland on a Typic Argiudol with a
soil moisture below but near field capacity. Three different numbers o
f passes, with two tractors with different weights but the same ground
pressure, were used to obtain six different traffic intensities. In t
he soil profile analysed, ranging from 0 to 600 mm, bulk density and p
enetration resistance were measured before and after traffic. Six mont
hs later grassland yield was evaluated, both in and out of the vehicle
track. Decreases in grass yield ranging from 7 to 25%, were measured
in out-of-track areas, and 52 to 76% in intrack areas. If results are
compared for the same number of passes, then the heavier tractor appea
rs to give either the same or a greater reduction in grassland yield t
han the lighter tractor. If the results are compared on a basis of tra
ffic intensity, the picture is less clear but it seems likely that the
lighter tractor, with a larger number of passes, can do as much or ev
en greater damage than the heavier tractor with fewer passes. (C) 1997
Silsoe Research Institute.