Engenharia Agrícola
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11733
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Item Atmospheric susceptibility to wildfire occurrence during the Last Glacial Maximum and mid-Holocene(Palaeogeography, Palaeoclimatology, Palaeoecology, 2010-09-01) Justino, F.; Barbosa, H. A.; Peltier, W. R.Based on coupled climate model simulations the impact of anomalous climate forcing on the environmental vulnerability to wildfire occurrence is analyzed. The investigation applies the Haines Index (HI), which indicates the potential for wildfire growth by measuring the stability and dryness of the air. Three simulations have been analyzed: for Last Glacial Maximum (LGM), the mid-Holocene (MH) and present day (MOD) conditions. The results indicate that for present day conditions, the HI is a useful tool to identify areas with high susceptibility for fire occurrence, such as the west coast of the United States and the central part of South America. Analyses for the glacial epoch demonstrated that in respect to MOD conditions, the HI is intensified in Africa and south Asia. It is reduced, however, in Australia, the west coast of North America, Europe and in northern Asia. During the mid-Holocene, the atmospheric conditions were likely more favorable for fire occurrence over North America, sub-Saharan Africa and a large part of Eurasia and South America. In the contrary, Australia, northern Africa and the northern part of South America seem to have been less susceptible to intense fire as compared to current conditions. These findings very closely match paleofire inferences based upon charcoal analyses.Item Effects of large-scale changes in land cover on the discharge of the Tocantins River, Southeastern Amazonia(Journal of Hydrology, 2003-12-10) Costa, Marcos Heil; Botta, Aurélie; Cardille, Jeffrey A.Studies that relate changes in land cover with changes in river discharge at the small scale (<1 km2) are abundant. These studies generally indicate that deforestation causes an increase in the annual mean discharge. However, previous studies that evaluated the effects of changes in land cover in larger river basins (>100 km2) usually have not found similar relationships. Here we analyse a 50-year long time series of discharge of a tropical river, the Tocantins River at Porto Nacional (175,360 km2), as well as precipitation over this drainage area, during a period where substantial changes in land cover occurred in the basin (1949–1998). Based on agricultural census data, we estimate that, in 1960, about 30% of the basin was used for agriculture. Previous work indicates that by 1995, agriculture had increased substantially, with about 49% of the basin land used as cropland and pastures. Initially, we compare one period with little changes in land cover (period 1-1949–1968) with another with more intense changes in land cover (period 2-1979–1998). Our analysis indicates that, while precipitation over the basin is not statistically different between period 1 and period 2 (α=0.05), annual mean discharge in period 2 is 24% greater than in period 1 (P<0.02), and the high-flow season discharge is greater by 28% (P<0.01). Further analyses present additional evidence that the change in vegetation cover altered the hydrological response of this region. As the pressure for changes in land cover in that region continue to increase, one can expect important further changes in the hydrological regime of the Tocantins River.Item Evaluation of the effects of drainage and different rest periods as techniques for unclogging the porous medium in horizontal subsurface flow constructed wetlands(Ecological Engineering, 2018-09) Teixeira, Denis Leocádio; Leocádio, Denis; Matos, Mateus Pimentel de; Miranda, Suymara Toledo; Vieira, Delilah PiresThe development of easy-to-perform techniques for unclogging of horizontal subsurface flow constructed wetlands (HSSF-CW) is essential to make them operationally simpler and increase their useful life. The objective of this work was to evaluate the drainable porosity, the extension of the bed presenting surface runoff and the characterization and quantification of the constituent solids clogging the porous medium of the HSSF-CW, after they were drained and submitted to different rest periods. Three systems were evaluated measuring 1.0 m wide and 4.0 m long, with 0.25 m working depth; one was cultivated with Vetiver grass (Chrysopogon zizanioides), the other with Tifton 85 (Cynodon spp.) and a control, in which no plant species were cultivated, where all were used for the treatment of municipal wastewater and presented conditions of partially clogged porous medium. After drainage of the system, the drainable porosity of the porous medium increased exponentially with the rest time during which they remained unsaturated, where the control and the HSSF-CW cultivated with Tifton 85 grass tended to stabilize. There was an increase in porosity of 18, 19 and 39% in relative to the initial porosity for the control HSSF-CW and those cultivated with the Tifton 85 and Vetiver grasses, respectively. Surface runoff in the HSSF-CW bed stopped completely between the 7th and 13th days after draining. However, no change was observed in the volatile solids content in the clogging material of the porous medium due to drainage of the HSSF-CWs.Item Intercropping of coffee with the palm tree, macauba, can mitigate climate change effects(Agricultural and Forest Meteorology, 2018-06-15) Moreira, Sandro L. S.; Pires, Cleverson V.; Marcatti, Gustavo E.; Santos, Ricardo H. S.; Imbuzeiro, Hewlley M. A.; Fernandes, Raphael B. A.Global climate changes can affect coffee production in Brazil, and in other coffee producing countries. We examined the potential for an agroforestry system with the native species, macauba (Acrocomia aculeata), to mitigate impacts on coffee production by reducing maximal air temperature and photosynthetic active radiation. The objective of this study was to investigate the influence of an agroforestry system with macauba on productivity, microclimatic characteristics and soil physical quality on a coffee plantation in the Atlantic Rainforest biome, in Southern Brazil. We measured soil attributes (moisture, temperature, and physical properties), microclimate conditions (air temperature, photosynthetic active radiation) and coffee production parameters (productivity and yield). Macauba palm trees were planted at different planting densities on the rows and distances from the coffee rows. Planting density of macauba and their distance from the coffee rows affected soil thermal-water regime. Compared with the traditional unshaded sole coffee planting, the intercropped cultivation provided more coffee yield on both macauba density planting and distance evaluated. On the other hand, coffee productivity was increased by agroforestry systems just for 4.2 m distance between palm trees and coffee rows. Planting density of macaubas did not affect coffee yield and productivity. Best coffee harvest in agroforestry systems with macauba was related to higher soil moisture at the depth of 20–40 cm, higher photosynthetic active radiation, and maximum air temperatures lower than 30 °C. Agroforestry with coffee and macauba trees can be an adaptation strategy under future climatic variability and change related to high temperatures and low rainfall.Item Modeling the impact of global warming on the sorghum sowing window in distinct climates in Brazil(European Journal of Agronomy, 2013-11) Grossi, Marine Cirino; Justino, Flavio; Santos, Eduardo Alvarez; Rodrigues, Rafael Avila; Costa, Luiz C.; Andrade, Camilo de Lelis TeixeiraCrop models have been used as an important tool to evaluate the agricultural response to climate conditions. This study aims to calibrate, and validate the CSM-CERES-Sorghum model and to investigate the vulnerability of sorghum yield for current (1982–1999) and future (2047–2064) epochs, by applying weather observations and climate outputs based on ECHAM, CCCma and GFDL models. Field experiments have been conducted in the experimental area of Janaúba and Sete Lagoas located in Minas Gerais State, Brazil. It has been found that the CSM-CERES-Sorghum model reasonably simulates crop phenology, crop biomass production, leaf area and yield components that are crucial to ensure the model reliability to reproduce in situ conditions. Comparison between the CSM-CERES-Sorghum results driven by the climate models and baseline observations shows that the ECHAM better reproduces the current observations. However, inaccurate results are found by utilizing the GFDL climate primarily due to lower precipitation values. This is found for both cities. Turning to future conditions, the simulations indicated that in Janaúba the average yields for current and future climate conditions were not statistically different, but in Sete Lagoas, there was a statistically significant increase in the sorghum productivity in the latter scenario. Moreover, it has been found that the simulations using the 52 sowing dates indicated that climate change modifies the grain yield projecting a delay in the most favorable planting date. According to the results the seeding of sorghum will very likely be held later in both cities.Item Overview of the large-scale biosphere–atmosphere experiment in Amazonia data model intercomparison project (LBA-DMIP)(Agricultural and Forest Meteorology, 2013-12-15) Costa, Marcos Heil; Borak, Jordan S.; Gonçalves, Luis Gustavo Gonçalves de; Saleska, Scott R.; Baker, Ian; Restrepo-Coupe, Natalia; Muza, Michel Nobre; Poulter, Benjamin; Verbeeck, Hans; Fisher, Joshua B.; Arain, M. Altaf; Arkin, Phillip; Cestaro, Bruno P.; Christoffersen, Bradley; Galbraith, David; Guan, Xiaodan; Hurk, Bart J. J. M. van den; et al.A fundamental question connecting terrestrial ecology and global climate change is the sensitivity of key terrestrial biomes to climatic variability and change. The Amazon region is such a key biome: it contains unparalleled biological diversity, a globally significant store of organic carbon, and it is a potent engine driving global cycles of water and energy. The importance of understanding how land surface dynamics of the Amazon region respond to climatic variability and change is widely appreciated, but despite significant recent advances, large gaps in our understanding remain. Understanding of energy and carbon exchange between terrestrial ecosystems and the atmosphere can be improved through direct observations and experiments, as well as through modeling activities. Land surface/ecosystem models have become important tools for extrapolating local observations and understanding to much larger terrestrial regions. They are also valuable tools to test hypothesis on ecosystem functioning. Funded by NASA under the auspices of the LBA (the Large-Scale Biosphere–Atmosphere Experiment in Amazonia), the LBA Data Model Intercomparison Project (LBA-DMIP) uses a comprehensive data set from an observational network of flux towers across the Amazon, and an ecosystem modeling community engaged in ongoing studies using a suite of different land surface and terrestrial ecosystem models to understand Amazon forest function. Here an overview of this project is presented accompanied by a description of the measurement sites, data, models and protocol.Item Performance of constructed wetlands in the treatment of aerated coffee processing wastewater: Removal of nutrients and phenolic compounds(Ecological Engineering, 2012-12) Rossmann, Maike; Matos, Antonio Teixeira de; Abreu, Edgar Carneiro; Silva, Fabyano Fonseca e; Borges, Alisson CarraroGiven the scarcity of studies on the behavior of constructed wetlands (CWs) when operating with previously aerated wastewater, the objective of the present study was to evaluate the influence of artificial aeration and vegetation on removal of nutrients and phenolic compounds from coffee processing wastewater (CPW) treated in CWs cultivated with ryegrass (Lolium multiflorum Lam.) For this reason, CWs were constructed measuring 0.6 m × 0.5 m × 2.0 m (H × L × W) and filled with pea gravel to a height of 0.55 m. The experiment was carried out considering a completely randomized design (CRD). Each variant of the experiment was replicated 10 times for each one of two replicates, implying in a total of 20 replicates, and 4 CWs characterized as follows: (i) ryegrass cultivated systems operating with an aerated influent (aiCWc), (ii) non-cultivated systems operating with an aerated influent (aiCW*), (iii) ryegrass cultivated system operating with a non-aerated influent (CWc), and (iv) non-cultivated systems operating with a non-aerated influent (CW*). For oxygenation of the CPW which would be supplied as aerated CPW in two treatments, an aeration system was implanted in the storage tank, consisting of a submerged Sarlobetter S520 pump with a flow of 0.52 m^3 h^−1, a gravel filter and tulle. The CPW was applied at an average flow rate of 0.020 m^3 d^−1, corresponding to a hydraulic retention time of 12 days. Efficiencies of 69, 72, 30 and 72% were obtained for the removal of total nitrogen (NT), total phosphorus (PT), total potassium (KT) and total phenolic compounds (FT), respectively, in the aiCWc. Aeration resulted in improved efficiency of pollutant removal such as N, P and phenolic compounds. The cultivated plant species (L. multiflorum) influenced the removal efficiencies of total-N, total-P and total-K in the systems, however, the best results were obtained by means of combination of vegetation with artificial aeration. Artificial aeration does not totally compensate the absence of plants, suggesting that the role of plants goes beyond the addition of oxygen to the medium, permitting the development of a more active and diverse microbial community near the root zone.