Estimating earthworm-influenced soil structure by morphometric image analysis

Earthworms have a profound influence on soil processes. However, there is g enerally a lark of adequate means by which to assess the influence of earth worms on soil structure. Not until quantitative methods on undisturbed soil samples are developed will there be any adequate measure of the influence of earthworms on soil structure. This paper describes an extension of an im age-analysis method developed for the quantitative determination of the inf luence of earthworms on soil structural properties, Mammillated vughs are m ost likely developed by the burrowing of soil macrofauna, in particular ear thworms. A learning set of mammillated vughs was compiled with pores taken from a soil developed solely through the channeling and casting of earthwor ms, This learning set was used to classify soil blocks taken from a no-till and conventionally tilled treated soil. The results indicated that the no- till soils had more than twice the number of mammillated vughs >1000 mu m i n diameter. This was attributed to the larger earthworm population in the n o-till soils, coupled with the change in morphology or destruction of some of the mammillated vugh features caused by disturbance in the conventionall y tilled soil. This method should allow for a more effective means to evalu ate the influence of earthworms on soil properties within any given soil pr ofile.