DINÂMICA DO POTÁSSIO, CLORO E FÓSFORO EM SOLO DA REGIÃO DO SUBMÉDIO DO VALE DO RIO SÃO FRANCISCO

DINÂMICA DO POTÁSSIO, CLORO E FÓSFORO EM SOLO DA REGIÃO DO SUBMÉDIO DO VALE DO RIO SÃO FRANCISCO PEDRO ROBINSON FERNANDES DE MEDEIROS1; MARAÍSA DA SILVA FERREIRA2; JARBAS HONÓRIO DE MIRANDA3; MIGUEL JÚLIO MACHADO GUIMARÃES4; ALLAN CUNHA BARROS5 E CLÁUDIO AUGUSTO UYEDA6 1 Colegiado de Engenharia Agrícola e Ambiental, Universidade Federal do Vale do São Francisco – Campus Juazeiro, Av. Antônio C. Magalhães, 510 - Country Club, Juazeiro - BA, CEP: 48902-300. Brasil. E-mail: [email protected]. 2 Programa de Pós-Graduação em Engenharia Agrícola, Universidade Federal do Vale do São Francisco – Campus Juazeiro, Av. Antônio C. Magalhães, 510 - Country Club, Juazeiro - BA, CEP: 48902-300. Brasil. E-mail: [email protected]. 3 Departamento de Engenharia de Biossistemas, Universidade de São Paulo, Escola Superior de Agricultura “Luiz de Queiroz”, Av. Pádua Dias, 11, Piracicaba - SP, CEP 13418-900. Brasil. E-mail: [email protected]. 4 Colegiado de Agronomia, Instituto Federal do Maranhão - Campus São Raimundo das Mangabeiras., Rod. Transamazônica, sn, São Raimundo das Mangabeiras - MA, CEP: 65840-000. Brasil. E-mail: [email protected]. 5 Agronomia, Universidade Federal de Alagoas – Campus Arapiraca, Av. Manoel Severino Barbosa - Bom Sucesso, Arapiraca - AL, CEP: 57309-005. Brasil. E-mail: [email protected]. 6 Departamento de Desenvolvimento Educacional, Instituto Federal do Pernambuco - Campus Vitória do Santo Antão, End.: Propriedade Terra Preta, s/n, Zona Rural, Vitória de Santo Antão - PE, CEP: 55602-970. Brasil. E-mail: [email protected]. 1 RESUMO Os modelos matemáticos podem ser usados para entender a dinâmica dos íons no solo, em função principalmente da mobilidade da fração liquida em ralação a fração sólida. O objetivo da pesquisa foi avaliar o deslocamento miscível dos íons potássio, cloro e fósforo, em colunas de PVC preenchidas com Argissolo Amarelo Distrófico típico (PAd) em diferentes densidades, utilizando como ferramenta adicional, o modelo matemático STANMOD (STudio of ANalytical MODels) para o ajuste numérico das Breakthrough Curves (BTC). Os ensaios foram realizados no Laboratório de Irrigação da UNIVASF Campus Juazeiro-BA, utilizando-se colunas de PVC nas profundidades (alturas) de 0,10; 0,20 e 0,30 m e nas densidades de 1,30; 1,50 e 1,70 g cm-3. Utilizou-se solução com concentração de 1000 mg L-1 contendo os fertilizantes Cloreto de Potássio (58% de K2O e 39% de Cl) e Superfosfato Simples (8% de P2O5, 16% de Cálcio (Ca) e 8% de Enxofre (S)). Os resultados permitiram concluir que os íons potássio, cloro e fósforo tiveram uma elevada mobilidade no Argissolo Amarelo Distrófico típico (PAd) apresentando um menor valor do fator de retardamento (R) e um maior número de Peclet (P). O modelo STANMOD apresentou desempenho satisfatório no ajuste numérico das Breakthrough Curves (BTC´s). Palavras-chave: dispersividade, curvas de avanço de íons, dinâmica de solutos, STANMOD MEDEIROS, P. R. F.; FERREIRA, M. S.; MIRANDA, J. H.; GUIMARÃES, M. J. M.; BARROS, A. C.; UYEDA, C. A. IONS DYNAMICS IN POTASSIUM, CHLORINE AND PHOSPHORUS IN SOILS IN THE SÃO FRANCISCO RIVER VALLEY 2 ABSTRACT Mathematical models can be used to understand the dynamics of ions in the soil, mainly due to the mobility of the liquid fraction in relation to the solid fraction. The objective was to measure the miscible displacement of potassium, chlorine and phosphorus ions in PVC columns filled with typical Dystrophic Yellow Argisol (PAd) in different densities, using the mathematical model STANMOD (Analytical Model Studio) as an additional tool Numeric Advance Curves (BTC). The tests were conducted at the Irrigation Laboratory of UNIVASF Campus Juazeiro-BA, using PVC columns at depths (heights) of 0.10; 0.20 and 0.30 m and densities of 1.30; 1.50 and 1.70 g cm-3. A solution with a concentration of 1000 mg L-1 containing the fertilizers Potassium chloride (58% K2O and 39% Cl) and Simple Superphosphate (8% P2O5, 16% Calcium (Ca) and 8% Sulfur) was used. (S)). The results allowed to conclude that the potassium, chlorine and phosphorus ions had high mobility in the typical Yellow Dystrophic Argisol (PAd), reducing a lower value of the delay factor (R) and a greater number of Peclet (P). The STANMOD model presents satisfactory performance without numerical adjustment of Breakthrough Curves (BTC´s). Keywords: dispersive, ion advance curves, solute dynamics, STANMOD

Comparison between pyrrolidinium-based and imidazolium-based dicationic ionic liquids: intermolecular interaction, structural organization, and solute dynamics

This work investigates the difference in the microscopic behaviour of imidazolium and pyrrolidinium based ILs employing combined steady state and time-resolved fluorescence, EPR and NMR spectroscopy.

Climatic Variabilities Control the Solute Dynamics of Monsoon Karstic River: Approaches from C-Q Relationship, Isotopes, and Model Analysis in the Liujiang River

The dynamics of riverine solutes’ contents and sources reflect geological, ecological, and climatic information of the draining basin. This study investigated the influence of climatic variability on solute dynamics by the high-frequency hydrogeochemical monitory in the Liujiang River draining karst terrain of Guangxi Province, SW (Southwestern) China. In the study river, the content-discharge (C-Q) patterns of riverine solutes indicate that the majority of riverine solutes show similar dilution and near chemostatic behaviors responding to increasing discharge, especially geogenic solutes (such as weathering products from carbonate, silicate, and sulfide oxidation), whereas exogenous solutes (such as atmospheric input to riverine sulfate) and biological solutes (such as soil CO2) show higher contents with increasing discharge. Besides, the biological carbon is the main driver of the chemostatic behaviors of total dissolved inorganic carbon (DIC). The forward model results show that carbonate weathering dominates the water chemistry, and the weathering rates are intensified during high flow period due to additional inputs of weathering agents, i.e., the biologic carbonic acid from dissolution of soil CO2, indicated by δ13CDIC. In addition, there exists the strong capacity of CO2 consumption that is heavily dependent on climatic variables such as precipitation and air temperature in this study river. Our study highlights the impact of climatic variability on solutes dynamics and chemical weathering and thus must be better addressed in C models under future climate change scenarios.

Diurnal Patterns in Solute Concentrations Measured with In Situ UV-Vis Sensors: Natural Fluctuations or Artefacts?

In situ spectrophotometers measuring in the UV-visible spectrum are increasingly used to collect high-resolution data on stream water quality. This provides the opportunity to investigate short-term solute dynamics, including diurnal cycling. This study reports unusual changes in diurnal patterns observed when such sensors were deployed in four tropical headwater streams in Kenya. The analysis of a 5-year dataset revealed sensor-specific diurnal patterns in nitrate and dissolved organic carbon concentrations and different patterns measured by different sensors when installed at the same site. To verify these patterns, a second mobile sensor was installed at three sites for more than 3 weeks. Agreement between the measurements performed by these sensors was higher for dissolved organic carbon (r > 0.98) than for nitrate (r = 0.43–0.81) at all sites. Higher concentrations and larger amplitudes generally led to higher agreement between patterns measured by the two sensors. However, changing the position or level of shading of the mobile sensor resulted in inconsistent changes in the patterns. The results of this study show that diurnal patterns measured with UV-Vis spectrophotometers should be interpreted with caution. Further work is required to understand how these measurements are influenced by environmental conditions and sensor-specific properties.

Spatially Resolved STD-NMR Applied to the Study of Solute Transport in Biphasic Systems: Application to Protein-Ligand Interactions

Fluid biphasic systems are one of the most interesting dynamic systems in chemistry and biochemistry. In nuclear magnetic resonance (NMR) spectroscopy, the study of the solute dynamics across fluid biphasic systems requires the introduction of dedicated NMR methods, due to their intrinsic heterogeneity. Diffusion and spatially resolved NMR techniques represent a useful approach for dealing with the study of solutes in biphasic systems and have been applied lately with success. Nevertheless, other potential applications of NMR spectroscopy for biphasic systems remain to be explored. In this proof-of-concept communication, we specifically aimed to investigate whether solute exchange between two immiscible phases can be followed by NMR experiments involving transfer of magnetization. To that aim, we have used spatially resolved saturation transfer difference NMR (SR-STD NMR) experiments to analyze solute exchange by transfer of saturation from one phase to the other in a biphasic system and have explored which are the underlying mechanisms leading to the transfer of magnetization between phases and the limits of the approach. We hereby demonstrate that SR-STD NMR is feasible and that it might be implemented in pharmacological screening for binders of biological receptors or in the study of chemical and biochemical reactions occurring at interfaces.