Rural Industries Research & Development Corporation

Research Compendium 1993 - 1994

Research Project

USING EARTHWORMS TO IMPROVE THE PRODUCTIVITY OF BRIGALOW LAND

Objective

To find native or naturalised species of earthworm that might improve productivity of brigalow soils, to test the survival of these species and to evaluate their effect on productivity.

Background

In perennial grass pastures that have been established on land previously cleared of brigalow, there is a marked decline in productivity as the pasture ages. Similarly, annual crops such as sorghum, or tree crops such as citrus, can have problems that are associated with poor nutrition and poor structure.

While elsewhere earthworms have been shown to have beneficial effects on pasture and crop production, their numbers in brigalow soils are understood to be very low. It has been proposed that the low productivity of brigalow soils could be alleviated if an active earthworm population was present.

Research

Initially, a survey in southern and central Queensland was done to determine the extent and composition of earthworm populations. Results from twenty locations confirmed patchiness and seasonal variations in distributions as well as the relative sparseness of earthworms in brigalow soils. Nevertheless, seventy-five species were collected, including twenty-seven new species.

Subsequently, glasshouse studies were used to examine survival and effect on productivity to identify the most promising species. From these studies, twelve promising species were selected for field trials.

The field trials were established at two sites in replicated blocks to monitor the survival of introduced earthworms and measure the effect on pasture production. These trials encountered exceptionally dry conditions. Even so there were survivors at both sites and some evidence that the introduced worms increased pasture growth.

Outcome

The study has provided considerable unexpected new information about earthworms. Significantly, the wide diversity of species in the study area was unprecedented for Australian soils. Under experimental conditions the earthworm survival rates and effects on plant yields were found to vary greatly, emphasising the importance of matching species and soils and the need for appropriate methodology.

Implications

Although research in this area will not pay immediate dividends, the results reported here show useful directions for the future. These would include long term testing in the field to cover variations in several conditions and identification of productive combinations of species of earthworm and agricultural systems.

RIRDC Project No: CSC-45A

RESEARCHER: V R Catchpoole

ORGANISATION: CSIRO Division of Tropical Crops & Pastures

PHONE: 07 377 0318

Last updated: 10 October 1996
Copyright © RIRDC
Index of RIRDC Projects URL
http://www.rirdc.gov.au/pub/compendium/93-94/index-b.html