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Reduced tillage in tobacco

L.M. Pregno, J.M. von Nordheim, B.R. Weeden and J.K. Klein

Queensland Department of Primary Industries, PO Box 1054, Mareeba QLD 4880

Since the late 1970s and early 1980s, planting times for tobacco have become earlier. Paddocks are now clean cultivated in March/April and planted from April to August. The reason for the change in planting dates is twofold. Firstly, early planting considerably reduces the risk of crop damage to hail, and secondly, it enables farmers to split the planting times thus making better use of manpower and farm equipment such as curing barns. While these are advantages to the farmer, the earlier planting time greatly increases the erosion risk. Reducing tillage practices during land preparation has been shown to minimise soil losses in other crops. Consequently, an investigation was begun into reduced tillage affects on tobacco yield and quality.


Three tillage practices were implemented on a fallow grass stand utilising existing equipment for tobacco:

  • Conventional Tillage - Normal farmer practices, that is, cultivation twice per month from December to March.
  • Delayed Tillage - Slashing existing grass stand, spraying regrowth with glyphosate and beginning first mechanical tillage in mid March.
  • Strip Tillage - Initially similar to delayed tillage, however, the central 60 cm strip for plant establishment was cultivated only (mid March), leaving wheel tracks uncultivated.
  • Yield and tobacco quality were measured.

Results and discussion

Good seasonal conditions in 1988 and 1989, at the time of glyphosate spraying (end February), ensured excellent fallow weed control. A dry wet season in 1990 resulted in moderate fallow grass control, however, it did not affect treatment layout. Zero root knot nematode populations were low in all years before planting and at harvest. Organic matter in reduced tillage plots did not interfere with the application of Ethylene Di-Bromide. Transplanting was not hindered by tillage treatment nor were any other crop management practices throughout the life of the crop. Strip tillage plots required wider spacing of tines to prevent bulldozing during fertiliser application and cultivation. Tobacco yield and quality were not significantly different for any of the tillage treatments (Table 1). That is, conventional tillage was equal to delayed and strip tillage treatments.

Table 1. Crop performance (mean over three years).

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