Herbaceous layer development during spring does not deplete soil nitrogen in th...

• Author(s): Otieno, D.O. ; Mirzaei, H. ; Hussain, M.Z. ; Li, Y.L. ; Schmidt, M.W.T. ; Wartinger, M. ; Jung, E. ; Ribeiro, N. ; Pereira, J.S. ; Tenhunen, J.
• Date: 2010
• Persistent ID: http://hdl.handle.net/10174/10188
• Origin: Repositório Científico da Universidade de Évora
• Subject(s): Biomass development of the herbaceous vegetation; Mediterranean ecosystems; Portuguese montado; Pasture; Plant and soil nitrogen pools; Root distribution and nutrient uptake; Soil moisture
• Document Type: Article
• Language: Portuguese

Description

Nitrogen (N) content in the soil and in the herbaceous biomass were monitored during spring of 2004-2006 to determine how the herbaceous layer development influences soil N availability in the montado ecosystem of southern Portugal. Highest (246.6 ± 52.7 g m-2) and lowest (123.2 ± 89.5 g m-2) peak biomass occurred in 2006 and 2005 respectively. Total soilNwithin the top 20 cmsoil profile ranged between 0.2 0.1% in February and 0.41 0.2% inMay,while available soil N was lowest (5 ± 2 μg g-1soil) in February but increased three-to-five fold in March and was >17.5 μg g-1 soil at senescence in May. Significant (p < 0.001) increase in total N in the aboveground pool occurred between February and May. There was however, no decay in soil N content. Instead, the herbaceous vegetation enhanced soil N input and N retention in the ecosystem. Most of the herbaceous plants were annuals with large reserves of organic N at senescence, which returned to the soil as detritus. The herbaceous vegetation is a critical component of the montado that contributes to N recharge and cycling within the ecosystem.