Conservation Practices in Western Oregon Perennial Grass Seed Systems: III. Impacts on Gray-Tailed Vole Activity

Decreased use of field burning to dispose of straw after harvest of temperate grass seed crops and the implementation of alternative conservation practices including direct seeding (DS) and maximal residue (HR) management have raised questions whether certain pests such as the gray-tailed vole (Microtus canicaudus) are worse than before these changes. The number of vole burrow holes was determined 15 Jan. 1999 at two research locations in western Oregon. Comparisons were made for the effects of DS and conventional tillage (CT) establishment, maximal and minimal residue (LR) management, present perennial seed crops, and immediate-prior crop in the rotation sequence and two-crops-prior in the rotation sequence. The treatments that most greatly influenced vole activity were crop establishment method and the previous crop in the rotation sequence. Vole activity was greatest in DS tillage establishment and when perennial grass seed was the prior crop in the rotation sequence. A possible production strategy to reduce vole activity could be to include meadowfoam (Limnanthes alba Benth.) or cereals in the rotation sequences when DS perennial grass seed crops are grown. This research demonstrates how vole activity can be reduced in perennial grass seed crops, without the need for tillage before establishment of new stands.