Sonaira Souza da Silva

Evaluation of Landsat-Based METRIC Modeling to Provide High-Spatial Resolution Evapotranspiration Estimates for Amazonian Forests

While forest evapotranspiration (ET) dynamics in the Amazon have been studied both as point estimates using flux towers, as well as spatially coarse surfaces using satellite data, higher resolution (e.g., 30 m resolution) ET estimates are necessary to address finer spatial variability associated with forest biophysical characteristics and their changes by natural and human impacts. The objective of this study is to evaluate the potential of the Landsat-based METRIC (Mapping Evapotranspiration at high Resolution with Internalized Calibration) model to estimate high-resolution (30 m) forest ET by comparing to flux tower ET (FT ET) data collected over seasonally dry tropical forests in Rondonia, the southwestern region of the Amazon. Analyses were conducted at daily, monthly and seasonal scales for the dry seasons (June–September for Rondonia) of 2000–2002. Overall daily ET comparison between FT ET and METRIC ET across the study site showed r2 = 0.67 with RMSE = 0.81 mm. For seasonal ET comparison, METRIC-derived ET estimates showed an agreement with FT ET measurements during the dry season of r2 >0.70 and %MAE <15%. We also discuss some challenges and potential applications of METRIC for Amazonian forests.

Uso de coprólitos de minhoca na produção de mudas de mamoeiro

The purpose of this investigation was to evaluate the effect of substrates prepared with different proportion of soil and earthworm casting in the seedlings production of papaya. Two experiments were carried out in nursery of seedlings production of Federal University of the Acre - UFAC, both complying with completely randomized design with eleven treatments and ten replications. The treatments represent the mixture of different concentrations (0, 10, 20, 30, 40, 50, 60, 70, 80, 90 e 100%) of earthworm (Chibui bari) casting and soil, being dystrophic (V = 29%) in the experiment 1 and eutrophic (V = 80%) in the experiment 2. After 60 days of the planting the seeds was evaluated height of the plant and dry weight matter masses of shoot, root and total. It was verified that the addition of increasing doses of earthworm casting in the composition of the substrate resulted in increase of the growth of the plants in experiment 1 and reduction in experiment 2. The results of the experiments indicate that the use of earthworm casting in substrate prepared with soil only contributes for the increase of the growth seedlings of formosa papaya if the chemical condition of this organic material more will be appropriate than of the soil in taking care of the nutrition necessities of the plants. The results of the experiment with dystrophic soil indicate the possibility of use of the earthworm casting in the traditional production of papaya, especially in situations where the soil presents restrictions how much to the chemical condition.