THE EFFECT OF SOIL ACIDIFICATION ON CASTING BY EARTHWORMS. II. EXTENDED TRIALS ON GOLF COURSE FAIRWAYS WITH VARYING SOIL CONDITIONS

摘要

Casting from earthworms remains a significant problem affecting turf on golf courses, espe-cially since the approval of chlordane was revoked in 1992. One strategy, which has been usedto reduce the intensity of casting on sports areas, is the manipulation of soil pH. This studyassessed the relative effectiveness of sulphur applications to reduce earthworm casting throughfield trials at six golf clubs and also to assess any effects on turf quality. The application of sulphur at rates of 10, 20, 30 and 40 g m~(-2) all reduced the soil pH of the surface 0-25 mm of the plots. This reduced earthworm casting activity slightlyin the first year of the trial and by up to 50% at the greatest application rate in the second year of the trial. However a balance needs to be struck between reducing earthworm casting and turf damage notably through scorch following high rates of sulphur application. When cumulative sulphur application rates exceeded 60 g m~(-2) over two years unacceptable scorch damage to the turf in some experimental plots was noted. Following the final applications of sulphur to the trial areas, the amount of casting over the course of a number of months appeared to normalise, although the response was variable. For sandier soils the application of sulphur appears to be more effective, providing significant casting suppression for up to 24 months after application. However, for sites where the pH of the surface layer is relatively high, acidification of the surface layer using applications of up to 20 g m~(-2) of sulphur once or possibly twice per year would appear to help reduce earthworm casting,without causing unacceptable turf damage.