Abstract
Brazilian agriculture is now expanding toward the Amazon region, where large new areas of virgin lands are being brought under cultivation. There is therefore an urgent need to better understand the conditions and characteristics of the soils of that region. In this study a Red Yellow Podzol and a Yellow Latosol were used to examine urea transport and transformation in the laboratory under water-saturated conditions. The soils were collected in an area that was deforested in 1976 and planted to tropical fruits since then.
Soils were subjected to miscible displacement techniques under both continuous feed and pulse applications of urea to mathematically describe urea transport and transformation as functions of depth and time. Transformation mechanisms were considered to be first order kinetics.
Urea was readily leached from both soils. Recovery of urea in the effluent of the 30 cm colums was 91% for the Podzol and 86% for the Latosol. NH4 +−N from urea hydrolysis was also readily leached and its recovery in the effluent was 4.2% for the Podzol and 11.2% for the Latosol. Very little nitrogen-including exchangeable NH4 +−N and biomass nitrogen-was left in the columns of either soil at the end of the experiment.
These results emphasize that extremely careful management of these soils is necessary to prevent nitrogen losses, particularly losses of fertilizer-N.
Resumen
La agricultura brasileña se expande a la región amazónica donde áreas virgenes grandes se ponen actualmente bajo cultivo. Es por lo tanto urgente mejorar el conocimiento de las características y condiciones de los suelos de esa región. En este estudio un podzol amarillo rojizo y un latosol amarillo fueren usados para estudiar el transporte de urea y sus transformaciones bajo saturación en el laboratorio. Los suelos fueron colectados en un área deforestada en 1976 y plantada bajo frutales.
Los suelos se sometieron a técnicas de desplazamiento miscible bajo alimentación contínua y aplicaciones pulsadas con el fin de describir matemáticamente el transporte de úrea en función del tiempo y de la profundidad. Se consideró que los mecanismos de transformación obedecían cinéticas de primer orden.
La úrea es rápidamente lixiviada de ambos suelos. La recuperación de úrea en el efluente de las columnas de 30 cm de diámetro fué de 91% para el podzol y 86% para el latosol. El nitrógeno amoniacal, producto de la hidrólisis de úrea se lixivió rápidamente y su recuperación en el efluente fué 4,2% para el podzol y 11,2% para el latosol. Una proporción muy pequeña del nitrógeno, incluyendo el NH4 + intercambiable y el nitrógeno en la biomasa, permaneció en las columas al final del experimento.
Estos resultados indican el extremo cuidado en el manejo de estos suelos necesario para evitar pérdidas de nitrógeno, particularmente del aplicado en fertilizantes.
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References
Ardakani M S, Volz M G and McLaren A D 1976 Consecutive steady state reactions of urea, ammonium and nitrite-nitrogen in soil. Can. J. Soil Sci. 55, 83–91.
Bremner J M 1965 Inorganic forms of nitrogen.In Black C A (Ed.) Methods of Soil Analysis, pp 1179–1237. Madison, Wisconsin: American Society of Agronomy.
Bremner J M 1965 Total nitrogen.In Black C A (Ed.) Methods of Soil Analysis, pp 1149–1178. Madison, Wisconsin: American Society of Agronomy.
Cassel D K, Krueger T H, Schroes F W and Norum E B 1974 Solute movement through disturbed and undisturbed soil cores. Soil Sci. Soc. Am. Proc. 38, 36–40.
Castro C L and Rolston D E 1977 Organic phosphate transport and hydrolysis in soil: theoretical and experimental evaluation. Soil Sci. Soc. Am. J. 41, 1085–1092.
Cho C M 1971 Convective transport of ammonium with nitrification in soils. Can. J. Soil Sci. 51, 339–350.
Corey J C, Nielsen D R and Kirkham D 1967 Miscible displacement of nitrate through soil columns. Soil Sci. Soc. Am. Proc. 31, 497–503.
Davidson J M, Mansell J M and Baker D R 1972 Herbicide distributions within a soil profile and their dependence upon adsorption. Soil Crop. Sci. Soc. Florida 32, 36–41.
Davidson J M, Ou L T and Rao P S C 1976 Behaviour of high pesticide concentrations in soilwater systems. Tuscon, Proc. of Hazardous Waste Research Sum. Washington, D.C.: EPA. 7 p.
Douglas L A and Bremner J M 1970 Colorimetric determination of microgram quantities of urea. Anal. Lett. 3, 79–87.
Hoffman D L and Rolston D E 1980 Transport of organic phosphate in soil as affected by soil type. Soil Sci. Soc. Am. J. 44, 46–52.
IAEA 1976 Tracer Manual on crops and soils. Vienna. International Atomic Energy Agency. 227 p.
Misra C, Nielsen D R and Biggar J W 1974 Nitrogen transformations in soil during leaching. II. Steady-state nitrification and nitrate reduction. Soil Sci. Soc. Am. Proc. 38, 294–299.
Misra C, Nielsen D R and Biggar J W 1974 Nitrogen transformations during continuous leaching. III. Nitrate reduction in soil columns. Soil Sci. Soc. Am. Proc. 38, 300–304.
Selim H M, Kanchanssut P, Mansell R S, Zelasny L W and Davidson J M 1974 Phosphorus and chloride movement in a spodosol.-Soil Crop Sci. Soc. Florida 34, 18–23.
Selim H M, Mansell R S and Elzeftawy 1976 Distributions of 2.4-D and Water in soil during infiltration and redistribution. Soil Sci. 121, 176–183.
Starr J L, Broadbent F E and Nielsen D R 1974 Nitrogen transformations during continuous leaching. Soil Sci. Soc. Am. Proc. 38, 283–289.
Victória R L 1980 Miscible displacement of urea in some Amazonian soils. Ph. D. Thesis. Escola Superior de Agricultura Luiz de Quieroz (ESALQ), University of São Paulo, Piracicaba-SP, Brazil. 90 p. (In Portuguese.)
Wagenet R J, Biggar J W and Nielsen D R 1977 Tracing the transformations of urea fertilizer during leaching. Soil Sci. Soc. Am. J. 41, 896–902.
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Victoria, R.L., Libardi, P.L., Reichardt, K. et al. 15N-urea transport and transformation in two deforested Amazonian soils under laboratory conditions. Plant Soil 67, 129–137 (1982). https://doi.org/10.1007/BF02182761
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DOI: https://doi.org/10.1007/BF02182761