Resumo

CELAYA-MICHEL, Hernán  e  CASTELLANOS-VILLEGAS, Alejandro E.. Nitrogen Mineralization on Arid and Semi-Arid Land Soil. Terra Latinoam [online]. 2011, vol.29, n.3, pp.343-356. ISSN 2395-8030.

Arid and semi-arid lands soils have low soil organic matter content because of small plant cover and limited primary productivity. Scarce nitrogen content in arid and semi-arid soil organic matter is transformed to inorganic forms through mineralization, making it available to plants, is known as a major limitation to plant productivity in these ecosystems. Nitrogen transformation through decomposition and mineralization is carried on by soil microorganisms, although in arid land environments, optimal temperature and soil moisture growing conditions are not always present, only after rainfall pulses. Nitrogen availability has been difficult to measure because different methods can result in soil disturbance, removal of roots, and limit air and water exchange. Nitrogen mineralization in arid and semi-arid ecosystems are highly heterogeneous throughout the landscape and occurs in patches or fertility islands, because of their unique microclimatic, richness and abundance of plants, as well as nitrogen content in their soil. Those conditions increase nitrogen mineralization under the canopy of trees and shrubs, particularly under nitrogen-fixing legumes, compared to open interspaces where plant cover is scarce. Increased tree and shrub plant cover promote the presence of fertile islands, larger nitrogen mineralization, soil fertility and a rainfall pulses’ use, increasing buffer capacity and resilience of arid and semi-arid ecosystems.

Palavras-chave : deserts; decomposition; islands of fertility.

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