Plant and Soil

, Volume 67, Issue 1–3, pp 167–186 | Cite as

Crop utilization and fixation of added ammonium in soils of the West Indies

  • N. Ahmad
  • E. D. Reid
  • M. Nkrumah
  • S. M. Griffith
  • L. Gabriel


NH4+-fixation by inorganic and organic soil components and crop utilization of fertilier nitrogen was studied in a number of Carbbean soils using15N fertilizers.

At moderate rates of nitrogen application, NH4+-fixation by clays during several-week laboratory incubations was rapid and highly vaiable, ranging from less than 10% to over 70% of the NH4+ added. The 2: 1 lattice types were the most reactive, and the process were almost complete by one week after fertilization. Fixation increased with rate of NH4+-N application and was higher at elevated temperatures in soils that were allowed to air-dry during incubation. NH4+-N fixation was more active in the fulvic fractions of the soil organic matter than in the humuc fractions (25–69%vs0–3% of the added NH4+ was fixed in each, respectively). There was little incorporation of fertilizer-N by the N-containing fractions of soil organic matter.

Plant uptake of added NH4+-N in greenhouse pot experiments showed that a greater percentalte of fertilizer-N was taken up by Sudan grass (Sourghum sudanese) at a fertilizer rate of 40 kg NH4+-N ha−1 than at a rate of 200n kg NH4+N ha−1. howver, the recovery was low, ranging from 10 to 25 percent of that applied.

In field experiments with maize (Zea mays), urea-N was rapidly lost when applied to soils in a wet tropical environment. At normal rates of application (100 kg urea-N ha−1) only about half of the fertilizer was utilized by the crop. Mulches did not significantly affect the fate of added nitrogen; however, mulching did result in increased yields for dry-season cropping, due probably to water conservation effects.

There is good indication that for conditions in Trinidad, NH4+-N is better utilzed and less subject to unidentified losses than is urea. Addition of fertilizer-N resulted in crop uptake of important quantities of native soil nitrogen.

The Caribbean Andepts were outstanding in that the showed very little NH4+-fixation under all experimental conditions and very little tendency for apparent nitrification of added NH4+-N.

Key words

Ammonia-fixation Fulvic acids Humic acids Maize N-fertiler Sorghum Tropical soils West Indies 

Utilización y fijación de nitrógeno amoniacal en cultivos de las Indias Occidentales


Cuando se aplicaron tasas moderades de nitrógeno se observó una rápida y muy variable proporción de fijacion de NH4+ en las arcillas durante incubaciones de varias semanas en el laboratorio. Los valores de fijación iban de 10 a 70% del NH4+ añadido. Las arcillas del tipo 2:1 fueron las que mostraron mayor actividad y el proceso se completé en una semana desqués de la fertilización., La fijación aumentó con la tasa de aplicación de N amonical y fué mayor a altas temperaturas en aquellos suelos que se sometieron a secado durante la incubación. La fijación de amonio fué asi mismo mayor en las fracciones fulvicas de la materia orgáncica que en las húmicas (25–29%vs 0–3% del NH4+ añadido, respectivamente). Hubo poca incorporación de nitrógeno proveniente del fertilizante en las fracciones nitrogenadas de la materia orgáanica del suelo.

La absorción del NH4 añadido en experimentos en potes bajo condiciones de invernadero, fueé mayor cuando se aplicaron 40 kg NH4+-N ha−1 que cuando se aplicarion 200 kg NH4+-N ha−1 aSorghum sudanense. Sin embrago la recuperación fue bja, entre 10 y 25% del total aplicado.

En experimentos de campo con maiz el nitrógeno proveniente de la aplicacíon de úrea se perdió rapidamente en sue los tropicales húmedos recuperándose solo cerca de la mitad del total aplicado (100 kg úrea-N ha−1). La adición de material vegetal al suelo no alteró significativamente el comporaminento del nitrógeno aplicado aunque si aumentó los rendimentos en cultivos de secano, probablemente debido a efectos de conservación de agua.

Existe una buena evidencia de que en Trinidad la utilización de nitroógeno amonical es mejor y menos sujeta a pérdidas no identificadas que las aplicaciones de úrea. La ferdtilización nitrogenada produjo importanes incrementos en la absorción del nitrógeno nativo del suelo.

Los Andepts del Carbe mostraron una notable baja capacidad de fijación de NH4+ bajo todas las condiciones experimentales y poca tendencia a la nitrificación del nitrógeno añadido.


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Copyright information

© Martinus Nijhoff/Dr W. Junk Publishers 1982

Authors and Affiliations

  • N. Ahmad
    • 1
  • E. D. Reid
    • 1
  • M. Nkrumah
    • 1
  • S. M. Griffith
    • 1
  • L. Gabriel
    • 1
  1. 1.Departmen of Soil ScienceUniversity of the West IndiesSt. AugustineTrindad, W.I.

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