Evaluation of microwave soil pasteurization for controlling germination of perennial ryegrass (Lolium perenne) seeds

Graham BrodieA, Lindie PasmaA, Holly BennettA, Gerry HarrisA and Jon WoodworthB

A Faculty of Land and Food Resources, University of Melbourne, Victoria 3010, Australia.

B Environmental Consultant, 22 Edmonds Street, Bucasia, Queensland 4750, Australia.


Lolium species are used as a major feed-source for stock around the world. Unfortunately there are a number of ryegrass species that have inherited the ability to survive a normally lethal dose of herbicide, which has prompted renewed interest in alternative control methods. Interest in microwave soil pasteurization for weed control began in the 1970s.

Two experiments were conducted. The first considered the efficacy of microwave soil pasteurization for controlling Lolium perenne (perennial ryegrass) seed germination, while the second determined the influence of soil type and microwave power setting on soil heating rates. Microwave soil pasteurization killed perennial ryegrass seeds buried in fine sandy soil to a depth of 10 cm. The half lethal temperature (T50) was 54°C in wet soil and 77°C in dry soil. Microwave heating was much more effective in moist soil and soils with higher clay content.


Plant Protection Quarterly (2007) 22 (4) 150-154.