Strategic tillage and soil-borne pests and diseases

Field trials were undertaken at Tully and Bundaberg to compare strategic tillage land preparation with conventional cultivation land preparation for planting. Strategic tillage is defined as minimum tillage of the row without cultivating the inter-row space. A concern by industry was planting back into the old row due to potential soil diseases and soil insect problems. Two varieties were grown at each site, one resistant and one susceptible to the known disease of Pachymetra chaunorhiza. Results showed that levels of Pachymetra increased under the susceptible variety but remained low under the resistant variety. The known cane pathogen, Pratylenchus, was in similar numbers under all tillage practices, although numbers of Rotylenchus apparently increased under stool sprayout. Earthworm numbers recovered more rapidly after minimal soil disturbance compared with maximum disturbance. This suggests that, in the medium to long-term, soil health will benefit by the adoption of strategic tillage. There is no detrimental effect to planting back into the old crop row if Pachymetra-resistant varieties are used and less soil disturbance has beneficial effects on earthworms. This has ramifications for soil health in the medium to long-term and potential benefits for soil-disease and soil insect suppression.