TABLE CONTENTS

Changes in Soil Nematode Assemblages under Low Tillage, Mulched
Vegetable Production Systems in Queensland
Cobon, J. (1), W. O’Neill (1), P. Jones (2) & A. Pattison (2)
Queensland Department of Primary Industries and Fisheries
(1) 80 Meiers Rd, Indooroopilly, Queensland 4068; (2) Centre for Wet Tropics, South Johnstone, Queensland
4859.
Vegetable production requires high use of inputs and frequent soil disturbance to maximise
production. There are concerns that this type of production system is having a negative
impact on the physical, chemical and biological status of the soils. An alternative system,
that reduces tillage operations and grows a green manure crop for use as weed suppressive
mulch, is being investigated commercially. However, growers are unsure if the low tillagemulch
system is having the desired affect on soil properties. Nematodes are integrators of soil
conditions that respond quickly to changes in the food supply or environmental condition and
can be used as indicators of the biological condition of the soil.
Vegetable farms at three locations, Gympie, Bowen and Burdekin, were used in a study
where a low tillage-mulch system was compared to nearby conventional vegetable
production. Nematodes were extracted from composite soil samples by placing 200 g of soil
on a basket supporting a single ply tissue in water for 48 hours. Nematodes were identified
using morphological characters and nematode community assemblage identified and indices
calculated.
A greater proportion of plant-parasitic nematodes and a lower proportion of bacteriavores and
fungivores were found in the low-till mulch system compared to conventional production
systems. However, nematode community analyses showed that the low-till-mulch system had
greater structure index, a measure of the number of trophic layers in the soil food web and the
potential for regulation by predators than the conventional soil.
The results demonstrated that low tillage-mulch production systems resulted in different soil
nematode assemblage compared to conventional vegetable production systems. Further work
is required to determine if the changes in soil nematode assemblages are indicative of long
term sustainability of the low till-mulch production system.
Acknowledgement: Horticulture Australia Limited provided funding for this work under
project VG06100.
5 th International Congress of Nematology, 2008 175