J. Pitkanen et V. Nuutinen, EARTHWORM CONTRIBUTION TO INFILTRATION AND SURFACE RUNOFF AFTER 15 YEARS OF DIFFERENT SOIL-MANAGEMENT, Agriculture, ecosystems & environment. Applied soil ecology, 9(1-3), 1998, pp. 411-415
The contribution of earthworm burrows to infiltration and surface runo
ff was investigated in a 15-year-old tillage experiment. The tillage t
reatments were autumn mouldboard ploughing, autumn stubble cultivation
and spring stubble cultivation, each replicated four times. At the ti
me of the study, all treatments had been left untilled following the h
arvest. Earthworms were sampled by combined formalin extraction and ha
nd-sorting. Undisturbed soil samples taken from formalin-sampled areas
were subjected to simulated rainfall treatments in the laboratory, an
d percolating water and surface runoff were collected. After the rainf
all treatments the saturated hydraulic conductivity (K-SAT) Of each sa
mple was measured, and a dye was applied to study the preferential pat
hways of soil water. The earthworm fauna consisted of the dominant Apo
rrectodea caliginosa and clearly less abundant Lumbricus terrestris an
d L. rubellus. The only discernible difference between the tillage tre
atments was that L. terrestris was present only in unploughed soils, a
lthough in very low numbers. During the rains, there were no significa
nt differences between the treatments in volumes of percolated water,
but there was significantly less runoff from spring stubble-cultivated
soil than from autumn-tilled soils. K-SAT was also significantly high
er in the spring stubble-cultivated soil. K-SAT was positively related
to the volume of percolation, and negatively to the volume of surface
runoff collected during the second rain, Total areas of stained earth
worm burrows at the depths of 20 and 30 cm were correlated positively
with K-SAT. (C) 1998 Elsevier Science B.V.