Non-labile plant C contributes to long-lasting macroaggregation of an Oxisol

Decomposition of plant material influences soil aggregation dynamics in ways that are still poorly understood, especially for Oxisols, in which oxides are believed to play a dominant role. In an incubation experiment, we investigated (i) the effect of plant material addition from selected monocot and dicot species on soil organic C (SOC), carbohydrate composition, fungal and total microbial biomass, and aggregation of an Oxisol; and (ii) the relationship among these properties and C mineralization patterns. The experiment was carried out at 25 °C for 180 d after addition of 11 plant materials (4 g C kg-1 soil) and a control (no plant material added). Mineralization of C during the incubation was described considering two pools of C (labile and non-labile) using a first-order plus linear fitting. Compared to the control, corn materials showed larger pentose input, greater mineralization rates for the non-labile C pool (k), greater soil pentose content (xylose + arabinose) and larger mean weight diameter of soil water-stable aggregates at 180 d of incubation. These effects were independent of changes in SOC content, suggesting that total C accrual and macroaggregation may be decoupled processes in this Oxisol. Our results support the hypothesis that the non-labile plant C pool contributes to the long-lasting stability of macroaggregates of this Oxisol and that this effect is mediated by plant and soil pentoses. We propose that plant pentose content and the decomposition rate of the slow pool (k) are useful parameters for the prediction of plant effects on aggregation dynamics of Oxisols and the selection of soil conservation practices. © 2012.

Simulação de perdas de solo em função de cenários de adequação ambiental em microbacias agrícolas

In São Paulo state, deforestation and agriculture activities are increasing soil losses processes, especially in areas of susceptible soils where soil conservation practices are not adopted. Environmental adequacy at property level regarding Permanent Protection Areas and Legal Reserves is considered a potential factor for reducing soil losses and it was based on this fact that we assessed soil losses of different scenarios of environmental adequacy. Simulations of erosive processes were carried out in 15 catchments of the Corumbataí river basin, with different forest restoration scenarios, as well as the current situation of land use/ land cover. The scenarios include reforestation of Permanent Preservation Areas (PPA); the reforestation hydrological sensitive areas; and two scenarios, the Legal Reserve installation in 20% of each catchment, being one of them for most critical areas in terms of erosion and the other at random. It was observed that the establishment of PPA and the reforestation of hydrological sensitive areas (HSA), offered a small contribution to the control of the erosive process, resulting in a reduction of 10% and 7.4%, respectively, while the legal reserve in critical areas has the significant reduction of 69.8%. The random scenario, in turn, resulted in a reduction of 21.4% of erosion. Results show that reforestation can reduce soil losses, but previous studies of land prioritization and planning could significantly increase its efficiency.

Geotechnology applied to land use and sealing in urban areas

Through the geotechnology's use, the aim of this study was to characterize the urban occupation interference and occurrence of floods in the upstream area of watershed from the stream Wenzel (Rio Claro-SP/Brazil). Urbanized watersheds are composed of a variety of features and the development of cartographic material allowed the analysis of the evolution of land used for 1958 and 2006 scenarios. The thematic maps were generated using software Spring 4.3.3, wherein it got the separation of matters from vegetation cover and other intra urban features. Procedures of digital processes and classification of surface cover allowed quantifying the occupied area by each coverage type: woody vegetation, grass, grass with bare soil, bare soil, building, asphaltic sheets and exposed soil. Quantification of the different covers' occupied areas allowed relating the parameter Curve Number (Soil Conservation Service) as efficient methodology for runoff values estimative. The results indicate vegetation cover's reduction, intensive surface's sealing and suppression of water bodies. These factors imply changes of hydrological dynamics of the source, increasing flow and transfer of larger volumes of water and flood peaks to downstream sectors. The use of geotechnology allowed analyzing the evolution of urbanization and it permits also to infer about trends for future or inadequate occupancy to hydrological and environmental point of view. © 2013 IEEE.

Desempenho agronômico de cultivares de soja (Glycine max (L.) Merril) em sistemas de preparo do solo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Atributos físicos e mecânicos do solo avaliados por processamento digital de imagem e ensaios de rotina

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento inicial de duas espécies arbóreas nativas e pioneiras sob tratamentos convencional, orgânico e biodinâmico

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Análise da dinâmica do uso da terra e sua interferência em inundações na cidade de Rio Claro (SP)

Pós-graduação em Geologia Regional - IGCE

Qualidade da água ao longo do Rio Capivara no município de Botucatu - SP

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Modelagem numérica da superfície como instrumento de avaliação de curvas de nível na preservação de manacial de água

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da fragilidade à erosão das margens do reservatório de Ilha Solteira - SP, utilizando as geotecnologias como ferramentas de análise ambiental

Pós-graduação em Engenharia Civil - FEIS

Avaliação e monitoramento da qualidade da água na microbacia do córrego Caçula no Município de Ilha Solteira-SP

Pós-graduação em Engenharia Civil - FEIS

An assessment of the economic impact of climate change on the agriculture sector in Trinidad And Tobago

The economic impact of climate change on root crop, fisheries and vegetable production for Trinidad and Tobago under the A2 and B2 scenarios were modeled, relative to a baseline ―no climate change‖ case, where the mean temperature and rainfall for a base period of 1980 – 2000 was assumed for the years up to 2050. Production functions were used, using ARMA specifications to correct for serial autocorrelation. For the A2 scenarios, rainfall is expected to fall by approximately 10% relative to the baseline case in the 2020s, but is expected to rise thereafter, until by the 2040s rainfall rises slightly above the mean for the baseline case. For the B2 scenario, rainfall rose slightly above the mean for the baseline case in the current decade, but falls steadily thereafter to approximately 15% by the 2040s. Over the same period, temperature is expected to increase by 1.34C and 1.37C under A2 and B2 respectively. It is expected that any further increase in rainfall should have a deleterious effect on root crop production as a whole, since the above mentioned crops represent the majority of the root crops included in the study. Further expected increases in temperature will result in the ambient temperature being very close to the optimal end of the range for most of these crops. By 2050, the value of yield cumulative losses (2008$) for root crops is expected to be approximately 248.8 million USD under the A2 scenario and approximately 239.4 million USD under the B2 scenario. Relative to the 2005 catch for fish, there will be a decrease in catch potential of 10 - 20% by 2050 relative to 2005 catch potentials, other things remaining constant. By 2050 under the A2 and B2 scenarios, losses in real terms were estimated to be 160.2 million USD and 80.1 million USD respectively, at a 1% discount rate. For vegetables, the mean rainfall exceeds the optimal rainfall range for sweet peppers, hot peppers and melongene. However, while the optimal rainfall level for tomatoes is 3000mm/yr, other vegetables such as sweet peppers, hot peppers and ochroes have very low rainfall requirements (as low as 300 mm/yr). Therefore it is expected that any further decrease in rainfall should have a mixed effect on individual vegetable production. It is expected that any further increase in temperature should have a mixed effect on individual vegetable production, though model results indicated that as a group, an increase in temperature should have a positive impact on vegetable production. By 2050, the value of yield cumulative gains (2008$) for vegetables is expected to be approximately 54.9 million USD under the A2 scenario and approximately 49.1 million USD under the B2 scenario, given a 1% discount rate. For root crops, fisheries and vegetables combined, the cumulative loss under A2 is calculated as approximately 352.8 million USD and approximately 270.8 million USD under B2 by 2050. This is equivalent to 1.37% and 1.05% of the 2008 GDP under the A2 and B2 scenarios respectively by 2050. Sea Level Rise (SLR) by 2050 is estimated to be 0.255 m under A2 and 0.215 m under B2. GIS estimation indicated that for a 0.255 m sea level rise, combined with a 0.5 m high tide, there would be no permanent inundation of agricultural land in Trinidad. The total inundation area is 1.18 km2. This occurs only in the Caroni Watershed, on the western coast of Trinidad, and the areas are outside the Caroni Swamp. Even with an additional rise of 0.5 m to simulate a high rainfall event, the estimated inundated area is 4.67 km2, but with no permanent inundation, though likely to be subject to flooding. Based on eleven (11) evaluation criteria, the top potential adaptation options were identified: 1. Use of water saving irrigation systems and water management systems e.g. drip irrigation; 2. Mainstream climate change issues into agricultural management; 3. Repair/maintain existing dams; 4. Alter crop calendar for short-term crops; 5. Adopt improved technologies for soil conservation; 6. Establish systems of food storage; 7. Promote water conservation – install on-farm water harvesting off roof tops; 8. Design and implement holistic water management plans for all competing uses; 9. Build on- farm water storage (ponds and tanks); 10. Agricultural drainage; and 11. Installation of greenhouses. The most attractive adaptation options, based on the Benefit-Cost Ratio are: (1) Build on- farm water storage such as ponds and tanks (2) Mainstreaming climate change issues into agricultural management and (3) Water Harvesting. However, the options with the highest net benefits are, (in order of priority): (1) Build on- farm water storage such as ponds and tanks, (2) Mainstreaming climate change issues into agricultural management and (3) Use of drip irrigation. Based on the area burnt in Trinidad and Tobago between 2005 and 2009, the average annual loss due to fires is 1717.3 ha. At US$17.41 per carbon credit, this implies that for the total land lost to forest fires on average each year, the opportunity cost of carbon credit revenue is 74.3 million USD. If a teak reforestation programme is undertaken in Trinidad and Tobago, the net benefit of reforestation under a carbon credit programme would be 69 million USD cumulatively to 2050.

Uso e ocupação do solo e monitoramento dos recursos hídricos na microbacia do Córrego do Ipê, Ilha Solteira, SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aspectos produtivos e sanitários de sementes de feijoeiro em função do uso de diferentes coberturas de solo no sistema de plantio direto

Pós-graduação em Agronomia - FEIS

Sistema plantio direto: população de plantas de milho e velocidade de semeadura em consórcio com braquiárias

Pós-graduação em Agronomia (Ciência do Solo) - FCAV