Authors : Kamaljit Kaur , Rajesh K. Jalota , David J. Midmore and Kerry Walsh
Abstract: Forest clearing, a topical issue the world over, historically occurred at a high rate in Queensland to ostensibly increase pasture production. Our research evaluates the impact of clearing on selected soil biological properties (i.e. total soil respiration, root respiration, microbial respiration and microbial biomass (C and N)). Three major woodland communities of central Queensland region i.e. Eucalyptus populnea, E. melanophloia and Acacia harpophylla were selected for paired comparisons between sites that had, or had not, been cleared of trees to develop land for exotic pastures. The cleared sites representing three different time periods since clearing (5, 11-13 and 33 years) were used to determine the temporal impact of clearing on soil biological properties. Cleared and uncleared sites did not differ in annual or seasonal rates of soil respiration. The average annual rate of CO2 emission across all treatments was 0.11 g CO2/m2.h. Microbial respiration and microbial biomass (measured in January 2002) were, however, greater at uncleared than at cleared sites and conversely, root respiration (for roots from herbaceous plants) was greater at cleared than uncleared site. The Q10 value of 1.42 (measured for different seasons over a year) suggested some response of soil respiration to soil temperature, which is less compared to that in temperate climates possibly due to the limited availability of soil moisture or organic matter in the semi-arid climates of central Queensland.
Kamaljit Kaur , Rajesh K. Jalota , David J. Midmore and Kerry Walsh , 2006. Impact of Tree Clearing on Soil Respiration and Soil Microbial Biomass in Pasture Systems of Central Queensland, Australia. Agricultural Journal, 1: 291-302.