Incorporation of tracers and dazomet by rotary tillers and a spading machine

J. Juzwik, D. L. Stenlund, R. R. Allmaras, S. M. Copeland, R. E. McRoberts

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Soil fumigant efficacy in forest-tree and ornamental nurseries depends on the tillage tool used for incorporation. Maximum depth and uniformity of incorporation of surface applied materials by three rotary tillers and a spading machine were compared in a loamy sand nursery using ceramic-sphere tracers (1-3 mm diameter) and dazomet (tetrahydro-3,5,dimethyl-2H-1,3,5-thiadiazone-2-thione) micro-granules. Depth of incorporation in the top 30 cm of soil was evaluated by (1) recovery of incorporated spheres in 2 cm increments, (2) biocidal activity in 6 cm increments, and (3) cone resistance by 1.5 cm increments to 45 cm. Uniformity of incorporation was evaluated by sphere recovery and biocidal activity. Depths above which more than 95% of the spheres were recovered for the four implements were: 12.5 cm, Kuhn and Fobro rotary tillers; 17 cm, Northwest rotary tiller; 21 cm, Gramegna spading machine. The spading machine produced a distribution of spheres through the soil profile closest to a uniform distribution compared with that produced by the three rotary tillers. Lettuce seed (Lactuca sativa L.) germination was inhibited in the upper 12 cm in low and high dazomet rate treatments, indicating that all four implements effectively incorporated dazomet into that zone. Maximum depth (24 cm) for total inhibition of germination was observed for the spading machine regardless of chemical rate. Cone index values showed the following maximum penetration: 14 cm, Fobro rotary tiller; 22 cm, Kuhn and Northwest rotary tillers; 27 cm, spading machine. All three measures of depth show a distinct superiority of the spading machine when the chemical fumigant must reach depths greater than 18 cm. Within transects across the width of the implement, variations of sphere counts among 5 cm3 volumes were much larger for the rotary tillers than for the spade machine.

Original languageEnglish (US)
Pages (from-to)237-248
Number of pages12
JournalSoil and Tillage Research
Issue number3-4
StatePublished - Apr 1997

Bibliographical note

Funding Information:
The authors thank J. Borkenhagen, Hayward Nursery, for excellent cooperation and technical assistance; D. Grafstrom, BASF Corp., and D. Hoeft, Hayward Nursery, for field assistance; T. Pickens for field and laboratory assistance.E quipment was kindly provided by: P. Bennett, Bartschi Corp.; C. Lemons, Hendrix and Dail, Inc.; M. Armstrong, West Wisconsin Nursery. Laboratory space was provided by Dr. I. Charvat, University of Minnesota. This work was partially funded by the National Agricultural Pesticide Impact AssessmentP rogram, US Department of Agriculture. Mention of trade names does not constitute endorsement by the US Department of Agriculture and the University of Minnesota.


  • Fumigation
  • Pesticide incorporation
  • Rotary tillers
  • Spading machine


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