Gl. Willoughby et al., SEASONAL-VARIATIONS IN INFILTRATION-RATE UNDER NO-TILL AND CONVENTIONAL (DISK) TILLAGE SYSTEMS AS AFFECTED BY LUMBRICUS-TERRESTRIS ACTIVITY, Soil biology & biochemistry, 29(3-4), 1997, pp. 481-484
Lumbricus terrestris activity can improve water how into soils, but th
e effects of L, terrestris (nightcrawlers) on infiltration and runoff
rates throughout the growing season have not been quantified. Our obje
ctive was to quantify and describe the effects of L. terrestris on inf
iltration rates under an established no-till and a disk tillage system
on a silt loam Alfisol (fine-loamy, mixed, mesic Aquollic Hapludalf)
in west central Indiana. Under each tillage practice there were areas
within the field that had L. terrestris activity and other areas that
had no activity as indicated by the presence or absence, respectively,
of middens. Infiltration was measured using a portable sprinkling inf
iltrometer which delivered 7 cm of water h(-1) to a 1.4 m(2) area. Inf
iltration was measured five times during the growing season, for the d
isk tillage treatment: (1) before any spring field work began; (2) imm
ediately after tillage but before planting; (3) immediately after plan
ting; (4) 3 weeks after planting; and (5) after harvest. For no-till t
reatments, the measurement times were the same as times 1, 3, 4, and 5
of the tilled site. Results showed that in early spring before any ti
llage was performed, the tilled treatment without middens had the high
est infiltration rate and the tilled treatment with middens had the lo
west. Immediately after planting and 3 weeks after planting, no-till w
ith middens had the highest infiltration rates, but disk tillage treat
ments had the lowest infiltration rates. Measurements after harvest sh
owed that no-till with middens again had the highest infiltration rate
s. The presence of L. terrestris, as indicated by the presence of midd
ens, appears to have increased infiltration rates in a no-till system
on this soil. In the disk system, however, the activity of L, terrestr
is and the presence of their middens apparently was not persistent eno
ugh to affect infiltration rates, and the amount of surface residue co
ver may be a more important factor in this system. (C) 1997 Elsevier S
cience Ltd.