Soil and litter respiration in rainforests of contrasting nutrient status and physiognomic structure near Lake Eacham, north‐east Queensland

Abstract

Soil and litter respiration atid nutrient coticetitratiotis(N. P, Ca. Mgand K) were tneasured in two adjacent rainforests near Lalce Eaehatn on the Atherton Tableland in north-east Queensland. One forest had soil fortued on basalt and. in physiognotnic-stritctitral classification of Webb (1968Webb ( . 1978. was structurctlly cotnplex. The other had soil formed on tnetatnorphie rock and was structurally sitnple. Respiration was measured by the alkali trap tnethod on 16 tnonthly occasions in 1986 and 1987. Soil and litter nutrient concentratiotis were higher in the cotnplex forest (with the exeept ion of soil N). The relative differettces were greater for soil than litter and more pronounced for P andCa (and also soil Mg) than other nutrients. Litter polyphenol eoneentrations were lower in the complex forest.Rates of litter respiration in the cotnplex forest were, on average, nearly twiee those of the simple forest. Soil respiration rates were occasionally slightly lower in the complex forest during the wet season but did not differ between the forests during the dry season. Highest rates oj respiration were measured dtiring the wet season although high rates for titter occasionally occurred dtiring the dry season. Cutnulative CO 2 release from the soil and overly i tig litter did not differ between forests and averaged 5134 ± 96 gCOjtn^-per year (mean ± s.e.m.) (1400g C m~-per vear). Litter respiration accounted for 14% of the annual release in the complex forest and 11% in the simple forest.

The impact of deforestation and pasture abandonment on soil properties in the wet tropics of Australia

“…The changes that occurred elsewhere after deforestation and subsequent cropping are decreases in plant available nutrients (Lu et al, 2002;Keenan et al, 1998;Webb et al, 1997;Sparling et al, 1994;Hewett, 1990, 1993), decreases in microbial activity (Kiese et al, 2002;Sahani and Behera, 2001;Sparling et al, 1994;Maggs and Hewett, 1990), increases in bulk density, soil erosion, and runoff (Rasiah and Kay, 1995;Jusoff, 1989), and decreases in porosity, infiltration and water-holding capacity (Lu et al, 2002;Sahani and Behera, 2001;Reiners et al, 1994;Sparling et al, 1994). The aforementioned studies indicate that deforestation and the subsequent land use for crop production, including pasture, in general led to the deterioration in soil chemical, physical, and biological properties.…”