Litter Dynamics in Eucalyptus and Native Forest in the Brazilian Cerrado

Abstract

The aim of this study was to evaluate the litter dynamics in the seasons of the year in three areas: Forest formation Cerradão (CE), and in two hybrids stands of Eucalyptus urophylla × E. grandis with different ages: E1 (34-58 months) and E2 (58-82 months). The produced litter, stored litter and the remaining mass was collected over 720 days. The evaluation of the remaining litter mass in each area was performed from the random distribution of 648 litter bags on the soil. Chemical analyzes (N, P, C) and the structural components of the cell wall (lignin, cellulose and hemicellulose) of the remaining litter were performed. The C of the litter stock was also determined. For both years of evaluation were observed higher biomass and C content in litter at E2. In contrast, the highest decomposition rate was for the CE, especially in the second year of evaluation (mass remaining at 720 days of 35%, 37% and 23% for E1, E2 and CE, respectively), attributed to the higher apparent liberation of N, soil moisture and biodiversity in the native area. Lignin contents increased, cellulose decreased, and hemicellulose remained stable throughout the 720 days. It was also observed an increase in the N and P concentration of the remaining mass and positive correlations among the remaining mass and the C:N and C:P ratios. The C:N ratio of litter was ≥ 76:1 at time 0 and ≥ 30:1 at 720 days for the three areas.

Linking soil biodiversity and ecosystem function in a Neotropical savanna

“…We observed that litter decomposition presented a strong seasonal trend, occurring more intensively in the rainy season. This pattern corroborates studies reporting that litter decay can be three to seven times faster in rainy than in dry seasons (Peña-Peña and Irmler, 2016;Ribeiro et al, 2018).…”

Savanas podem se Transformar Funcionalmente em Florestas na Transição Amazônia/Cerrado

“…The k values were higher compared to a study conducted by Souza et al (2016) in a Dense Cerrado, in which the authors reported a coefficient of 0.0007. On the other hand, the k values were lower compared to Ribeiro et al (2018), in Cerradão with a coefficient of 0.0021. In the present study, the results showed that CD and DC are efficient in assimilating and decomposing the carbon material deposited on the soil.…”

“…Comparing the biomass decay in percentage Ribeiro et al (2018) found a loss of 54% litter in a Cerradão, in the Distrito Federal, Brazil, and Souza et al (2016) found a loss of 30% in a Dense Cerrado, also in the Distrito Federal. Both studies reported the trend of decay verified in the present study, where CD had more biomass loss than DC.…”

“…According to Olson (1963), the k coefficient measures the efficiency of decomposing organisms, such as fungi, bacteria and certain decomposing animals. Thus, the higher the k, the greater the amounts of mineralized carbon, organic matter available in the soil, and the greater the biogeochemical dynamics (Ribeiro et al, 2018).…”

C and N stocks in Brazilian woodland savanna (Cerradão) under different land uses, and their dynamicas in the soil

“…Similarly to us, also found higher litter biomass for Eucalyptus plantations (11.71 Mg.ha -1 ) compared to native cerradão (9.18 Mg.ha -1 ). Ribeiro et al (2018) explain the higher litter biomass and litter C stocks in Eucalyptus plantations compared to native Cerrado (cerradão physiognomy) due to greater deposition and low decomposition rates of the plant material, as litter decomposition showed to be faster in the native Cerrado than in areas converted to Eucalyptus plantations. In our research, litter increase did not result on labile C gains; MBCS was substantially reduced, as the PMN, and the lowest NH4-N stocks were found in Eucalyptus plantations, what indicates poor litter quality.…”