Nitrogen orgdiv2mineralization in a silandic andosol fertilized with dairy slurry and urea

• J Martínez-Lagos ^[1] ; F Salazar ^[1] ; M Alfaro ^[1] ; M Rosas ^[2] ; F Macías ^[3]
  1. [1] Instituto de Investigaciones Agropecuarias

     Instituto de Investigaciones Agropecuarias

     Santiago, Chile

     
  2. [2] Universidad Santo Tomás

     Universidad Santo Tomás

     Santiago, Chile

     
  3. [3] Universidade de Santiago de Compostela

     Universidade de Santiago de Compostela

     Santiago de Compostela, España

     

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• Localización: Journal of soil science and plant nutrition, ISSN-e 0718-9516, ISSN 0718-9508, Vol. 15, Nº. 1, 2015, págs. 60-75
• Idioma: inglés
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• Resumen

  • Knowledge about the size and cycle of inorganic N pool on grasslands is necessary to develop adequate fertilization strategies and to determine the potential pathways of N losses. The objectives of this study were to: 1) quantify the N mineralization rates in permanent grassland on an Andosol of southern Chile; and 2) determine the effect of high N application rates as urea and dairy slurry on this process. Mineralization was measured over a three years period on grassland fertilized with 400 kg N ha-1 yr-1 by acetylene inhibition method, incubating soil cores under field conditions. Subsequently, a laboratory assay was carried out to determine potential residual N mineralization rate by anaerobic incubation method. Higher N mineralization was measured on the urea treated plots (314 - 420 kg NH4+-N ha-1 yr-1) followed by slurry (320 - 344 kg NH4+-N ha-1 yr-1) (p<0.05). Most of the N was mineralized during spring and summer seasons (p<0.05). Laboratory results indicate that slurry treated soil had greater net potential N mineralization rates than urea (p<0.05). Results suggest that in Andosols of southern Chile, N mineralization can be a major N input into the soil N budget, with implications for grassland fertilizer managements and pathways of N loss