Litter removal in a sclerophyll forest: short- and medium-term consequences for soil properties

Abstract

Litter extraction (LE) is a common practice in many forests of the world. This process can cause long-term depletion of C substrates, thereby affecting ecosystem balances. The effects of LE on soil properties such as soil respiration (Rs), soil water content (q), soil temperature (T), microbial activity, and dissolved organic C (DOC) are not well understood in various forests ecosystems. We investigated the short and medium-term effects of LE on these soil properties in a sclerophyll forest of central Chile. A completely randomized block design was set with three blocks and two treatments, i.e., a control (no LE) and LE totaling six 10- by 10-m plots. The Rs, q, and T were determined immediately after LE and then at Days 4, 12, 16, and 20. The same properties were determined in the medium term (between Days 448–853). Soil organic C (SOC), basal respiration (Cmin), microbial biomass C (Cbio), and microbial (qCO2, qMic) and mineralization (qMin) quotients were determined at Day 711 after LE from soil cores obtained at depths intervals of 0 to 3, 3 to 6, and 6 to 9 cm. Soil pore water was extracted from suction lysimeters during the rainfall season of 2011 and analyzed for DOC, specific ultraviolet absorbance, the ratio between the absorbance at 465 and 665 nm in water extracts, and electric conductivity. Litter extraction caused large reductions in Rs in the short term (33%) and smaller reductions in the medium term (21.2%). In addition to the effect of LE, Rs was governed by q. The SOC, Cmin, qCO2, qMic, and qMin were unaffected by LE, but DOC significantly decreased with LE by 59.6% (10-cm depth) and 48.8% (30-cm depth). The DOC was comprised of aromatic-rich, low- molecular-weight compounds in both treatments.