Article

Recuperation of nitrogen cycling in Amazonian forests following agricultural abandonment. Nature

The Woods Hole Research Center, 149 Woods Hole Road, Falmouth, Massachusetts 02540-1644, USA.
Nature (Impact Factor: 41.46). 07/2007; 447(7147):995-8. DOI: 10.1038/nature05900
Source: PubMed

ABSTRACT

Phosphorus (P) is generally considered the most common limiting nutrient for productivity of mature tropical lowland forests growing on highly weathered soils. It is often assumed that P limitation also applies to young tropical forests, but nitrogen (N) losses during land-use change may alter the stoichiometric balance of nutrient cycling processes. In the Amazon basin, about 16% of the original forest area has been cleared, and about 30-50% of cleared land is estimated now to be in some stage of secondary forest succession following agricultural abandonment. Here we use forest age chronosequences to demonstrate that young successional forests growing after agricultural abandonment on highly weathered lowland tropical soils exhibit conservative N-cycling properties much like those of N-limited forests on younger soils in temperate latitudes. As secondary succession progresses, N-cycling properties recover and the dominance of a conservative P cycle typical of mature lowland tropical forests re-emerges. These successional shifts in N:P cycling ratios with forest age provide a mechanistic explanation for initially lower and then gradually increasing soil emissions of the greenhouse gas nitrous oxide (N(2)O). The patterns of N and P cycling during secondary forest succession, demonstrated here over decadal timescales, are similar to N- and P-cycling patterns during primary succession as soils age over thousands and millions of years, thus revealing that N availability in terrestrial ecosystems is ephemeral and can be disrupted by either natural or anthropogenic disturbances at several timescales.

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Available from: Cláudio José Reis de Carvalho, Apr 02, 2014
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    • "Additionally, unfavorable frame conditions like low return yields, poor technical support, inadequate development policies, and unsecure property rights make the production systems unsustainable. In the end, high fence restoration costs and forage scarcity on the plots force farmers to simply abandon their pastures because further restoration investment is economically not justifiable, anymore (Buschbacher et al., 1988; Müller et al., 2004; Davidson et al., 2007; Dias-Filho, 2011). Besides frequent weeding, the traditional way to increase forage quantity and quality on tropical pastures is to apply Pfertilizer for forage grasses or to plant multi-purpose forage legumes (Gutteridge and Shelton, 1994; Skerman et al., 1988; Cook et al., 2005; Hohnwald et al., 2005). "
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    • "esse elemento na serapilheira . Ao estudar o acúmulo e decomposição da serapilheira em quatro formações florestais , Cunha Neto et al . ( 2013 ) , também constataram maiores teores e conteúdos de N na formação florestal da Leguminosae Acacia mangium , e relacionaram os maiores valores nessa formação à capacidade da espécie em fixar nitrogênio . Já Davidson et al . ( 2007 ) , relatam que as florestas tropicais são limitadas por N nas etapas iniciais da sucessão , com maior ciclagem interna e perda reduzida desse nutriente . Assim , essas evidências acima podem explicar os maiores valores de N na FSEA e os menores na FSEM . Diferindo da expressividade do elemento N na FSEA , na FSEM o Ca se configurou com"

    Full-text · Article · Sep 2015
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    • "Both denitrification and leaching depends on our simulated soil nitrate content and soil moisture. (3) Removal of nitrogen from soils and vegetation from LULUC disturbance including slash burning and decay from product pools (Fig. 7l) as also documented in earlier studies [Davidson et al., 2007; Herbert et al., 2003; Mathers et al., 2006; Schipper et al., 2007]. In summary, our model simulations suggest that large areas of secondary forests will not respond to CO 2 fertilization as strongly as they would when adequate nitrogen was available to meet the plant demands. "
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