Impacts of earthworms on soil nutrients and plant growth in soybean and maize agroecosystems

N. S. Eriksen-Hamel and J. K. Whalen

Earthworms are commonly referred to as ecosystem engineers for their ability to modify soils and plant communities. We evaluated the effects of earthworms on soil N pools and plant growth in soybean and maize agroecosystems.

The species and number of earthworm communities were manipulated in plot-scale field enclosures by first reducing earthworm populations within enclosures with carbaryl pesticide, and then adding earthworm treatments to the enclosures.

In 2004, when climate conditions were favourable for earthworm survival and growth, there was a significant increase in soil mineral-N and microbial biomass-N concentrations in the 0 – 15 cm depth of enclosures with more earthworms.

Similarly, soybean grain and grain-N yield was significantly greater in enclosures with the largest earthworm populations. In 2005, when climate conditions were less favourable, there was no effect of earthworms on soil N pools or maize plants.

Our research suggests that earthworms contribute positively to plant growth in some agroecosystems only when populations are high (> 300 individuals m-2) and when favourable weather conditions exist.


Source
Agriculture, Ecosystems and Environment (2007) 120: 442-448


Contact
Joann K. Whalen, Department of Natural Resource Sciences, Macdonald Campus of McGill University, 21,111 Lakeshore Rd., Ste-Anne-de-Bellevue, QC, H9X 3V9
Joann.whalen@mcgill.ca


en français


Posted March 2007