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Nitrogen in shifting cultivation systems of Latin America

El nitrógeno en sistemas de agricultura migratoria en America Latina

Abstract

Relatively little is known about the dynamics of N in shifting cultivation and related cropping systems in the humid tropics of Latin America. The soils that predominate in 82% of the region, namely Oxisols and Ultisols, have a fairly high total N content. Contrary to conventional wisdom, the bulk of the N in tropical rainforests is present in the soil, and not in the biomass. Losses of N through clearing and burning are about 20–25% of the N existing in the ecosystem. Mechanized land clearing causes larger N losses than the traditional slash and burn method. Ashes can contribute substantial amounts (67–127 kg N ha−1) to the soil, which prevents N deficiency for the first crop sown, but N deficiency is observed from the second crop onwards. The rate of total-N decomposition in the arable layer is high during the first two years after burning, but subsequently reaches a new equilibrium with continuous cultivation.

Continuous production of food crops is feasible in Ultisols and Oxisols of the Amazon with correct agronomic practices. Crops such as maize and rice require N fertilization rates of 80–120 kg N ha−1. The efficiency of applied-N utilization is comparable to that in the temperate zone and varies with planting season and cropping system. Pastures following burning do not cause significant losses of N in the soil, particularly if they consist of properly managed mixtures of grasses and legumes. These observations are based on data collected from only a small number of sites, making generalization difficult. Nitrogen dynamics should be viewed in conjunction with other soil factors such as acidity and the availability of other nutrients.

Resumen

Se conoce bastante poco acera de la dinámica del N en sistemas de agricultura migratoria y otras prácticas de cultivo en el trópico húmedo latinoamericano. Los suelos Oxisoles y Ultisoles que predominan en el 82% de la región están bastante bien dotados de N. Contrariamente a lo que comunmente se cree la mayoría del nitrógeno en ecosistemas naturales se encentra en el suelo y no en la biomasa. Por lo tanto las pérdidas de nitrógeno por la quema son del 20–25% del N existente en el ecosistema. El desmonte mecanizado causa mayores pérdidas de N que el desmonte por tumba y quema tradicional. La ceniza contribuye con cantidades considerables de nitrógeno (67–127 kg N ha−1) al suelo lo cual evita las deficiencias de nitrógeno para el primer cultivo que se siembra. En un Ultisol de la Amazonía la deficiencia de nitrógeno es aguda a partir del segundo cultivo. La tasa de descomposición total para el nitrógeno en la capa arable es alta durante los dos primeros años después de la quema pero se alcanza un nuevo valor de equlibrio posteriormente. La producción contínua de cultivos de ciclo corto es factible en estos suelos mediante prácticas agronómicas correctas. Los cultivos como el maiz y el arroz responden positivamente a dósis de 80–120 kg ha−1 de fertilización con N. La eficiencia de utilización del nitrógeno aplicado es comparable a la de zonas templadas y varía con la época de siembra y sistemas de cultivos. El establecimiento de pastizales después de la quema no causa pérdidas apreciable de nitrógeno en el suelo, especialmente si se siembran mezclas de gramineas con leguminosas y se manejan bien. Debido a que estas observaciones están basadas en datos recolectados en pocos sitios es por lo tanto dificil generalizar. La fertilización con nitrógeno debe considerarse conjuntamente con el manejo adecuado de otras limitaciones de los suelos tales como la acidez y el estado del suelo con respecto a otros elementos nutritivos.

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References

  1. 1

    Benites J R 1981 Nitrogen response and cultural practices for corn-based cropping systems in the Peruvian Amazon. PhD Thesis. Raleigh: North Carolina State University. 148 p.

  2. 2

    Bruce R C 1965 Effect ofCentrosema pubescens on soil fertility in the humid tropics. Queensl. J. Agric. Anim. Sci. 22, 221–226.

  3. 3

    Ewel J, Berish C, Brown B, Price N and Raich J 1981 Slash and burn impacts on a Costa Rican wet forest site. Ecology 62, 816–829.

  4. 4

    Falesi I C 1976 Ecossistema de Pastagem Cultivada na Amazônia Brasilera (Cultivated pasture ecosystem in the Brazilian Amazon). Belém, Brazil: EMBRAPA, Centro de Pesquisa Agropecuária do Trópico Umido, CPATU, Bol. Tec. 1.

  5. 5

    Fassbender H W 1977 Ciclos de elementos nutritivos en ecosistemas forestales tropicales y su transformación con la agricultura rotativa (Nutrient cycles in tropical forest ecosystems and their transformation with shifting agriculture).In FAO-SIDA Workshop-Meeting on Soil Management and Conservation in Latin America, Lima, Peru. Rome: FAO.

  6. 6

    Fittkau E J and Klinge H 1973 On biomass and trophic structure of the Central Amazonian forest ecosystems. Biotropica 5, 2–14.

  7. 7

    Greenland D J and Kowal J M L 1960 Nutrient content of a moist tropical forest in Ghana. Plant and Soil 12, 154–174.

  8. 8

    North Carolina State University. 1974, 1980, 1982. Research on Tropical Soils Annual Reports. Raleigh: Soil Science Department, North Carolina State University.

  9. 9

    Salas G de las 1978 El sistema forestal Carare-Opón (The Carare-Opón forest system). CONIF. Ser. Tec. 8, Bogotá, Colombia: Corporación Nacional de Investigación y Fomento Forestal.

  10. 10

    Salas G de las and Folster H 1976 Bio-element loss on clearing a tropical rainforest. Turrialba 26, 179–186.

  11. 11

    Sánchez P A 1979 Soil fertility and conservation considerations for agroforestry systems in the humid tropics of Latin America.In Soils Research in Agroforestry. Eds., H O Mongi and P A Huxley. pp 79–124. ICRAF Bulletin 001 e. Nairobi, Kenya: Int. Council Research Agroforestry.

  12. 12

    Sánchez P A and Cochrane T T 1980 Soil constraints in relation to major farming systems in tropical America.In Priorities for Alleviating Soil-related Constraints to Food Production in the Tropics, pp 107–139. Los Baños, Philippines: IRRI.

  13. 13

    Sánchez P A, Gichuru M P and Katz L B 1982 Organic matter in major soils of tropical and temperate regions. XII International Soil Science Congress (New Delhi). 1, 99–114.

  14. 14

    Sánchez P A, Bandy D E, Villachica J H and Nicholaides J J 1982 Amazon soils: management for continuous crop production. Science. 216, 821–827.

  15. 15

    Serrão E A S, Falesi I C, Viega J B and Texeira J F 1979 Productivity of cultivated pastures in low fertility soils of the Amazon of Brazil.In Pasture Production in Acid Soils of the Tropics. Eds. P A Sanchez and L E Tergas. pp 195–226. Cali, Colombia: Centro Internacional de Agricultura Tropical.

  16. 16

    Seubert C E, Sánchez P A and Valverde C 1977 Effects of land clearing methods on soil properties and crop performance in an Ultisol of the Amazon Jungle of Peru. Trop. Agric. Trinidad 54, 307–321.

  17. 17

    Silva L F da 1979 Influencia do manejo de una ecossistema nas propiedades edáficas dos Oxissolos de ‘Tabuleiro’ (Influence of the management of an ecosystem on the edaphic properties of ‘Tabuleiro’ Oxisols). Itabuna, Bahia, Brazil: Centro de Pesquisas do Cacau, CEPLAC.

  18. 18

    Watters R F 1971 Shifting Cultivation in Latin America. FAO Forestry Dev Paper 16. Rome: FAO.

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Sánchez, P.A. Nitrogen in shifting cultivation systems of Latin America. Plant Soil 67, 91–103 (1982). https://doi.org/10.1007/BF02182758

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Key words

  • Agriculture
  • Forests
  • Land clearing
  • N-cycling
  • N-fertilization
  • Shifting-cultivation
  • Tropics