Organic farmers often claim positive effects of non-inverting and reduced tillage systems. There is a need of quantifying tilth characteristics in the former plough layer of soil converted to such tillage systems. A non-inverting tillage system (NINV) was tested in a field experiment conducted on a Danish sandy loam soil. It included deep loosening and shallow intensive cultivation and was compared to a conventional ploughing-harrowing tillage system (CONV).
A hierarchical analytical procedure was applied in studies of soil fragmentation and soil strength characteristics for the 7-14 cm soil layer. A visual description was carried out and ease of fragmentation was evaluated in the field using a soil drop test. Soil strength was measured in the field with a cone penetrometer and a torsional shear box method, and in the laboratory using an annulus shear strength method. Tensile strength was determined in the laboratory on field-sampled aggregates.
The CONV treated soil displayed a higher ease of fragmentation in the field in May as well as in September. In general, aggregates from the NINV treated soil were stronger than aggregates from the CONV treatment. The soils had similar friability indices in May. In September, however, a higher friability index was found for the CONV treated soil (k=0.22 and 0.16, respectively for CONV and NINV). The NINV treated soil also displayed the highest soil strength.
The soil tilth was evaluated to be best in the CONV treated soil. Supposed meliorating actions during the growing season did not eliminate the differences between the treatments
