Surprisingly rapid nitrogen cycling in tropical forest plantations on volcanically derived soils Raich, James Raich, James Russell, Ann Russell, Ann
dc.contributor.department Natural Resource Ecology and Management 2018-02-15T21:37:09.000 2020-06-30T06:11:19Z 2020-06-30T06:11:19Z Fri Jan 01 00:00:00 UTC 2010 2015-03-03 2010-11-01
dc.description.abstract <p>Secondary forests and young forest plantations frequently have high rates of tree growth and NPP – higher even than mature forests in similar situations. The nutrients required to sustain this rapid growth are derived from the soil and by external inputs such as rainfall or, in the case of nitrogen, by biological N fixation. In our study of the effects of tree species within replicated experimental plantations in a moist, lowland tropical environment in Costa Rica, high rates of biomass accumulation and productivity were coupled with high rates of N accumulation and cycling. We applied extensive sampling through time within a mass-balance approach to address the question “Where does all the nitrogen come from?”<br />Rates of N uptake by the vegetation in these plantations were extraordinarily high, even by tropical forest standards, reaching 412 kg N ha<sup>-1</sup> yr<sup>-1</sup>. Rapid decay coupled to tight nitrogen cycling may have provided large amounts of available N for plant uptake, but do not explain the large quantities of N that accrued in the vegetation, up to 1075 kg N/ha over 16 years. Surface soil organic matter stocks in the plantations increased by as much as 320 kgC/ha in surface soils, but soil nitrogen varied differently. Soil N stocks to 1 m depth were depleted by an average of 2119 kg/ha relative to the mature forest. Thus, mineralization of soil organic nitrogen could have supplied the N that accrued in biomass over the 16-yr period, but this apparently occurred without concomitant net loss of soil C. The C:N ratios of soil organic matter (SOM)in the plantations indicated either replacement of SOM with more C-rich detritus or selective removal of N from existing SOM. Regardless, high productivity in these plantations apparently was supported in part by mining of soil nitrogen. Species varied, however. Depletion of soil N stocks was only 219 kg/ha under <em>Vochysia guatemalensis</em>, in which 1075 kgN/ha had accrued. Asymbiotic N fixation is the next most plausible mechanism for supplying plant-available N, and may be enhanced in stands with high availability of recently produced photosynthates.</p>
dc.description.comments <p>This presentation is from <em><a href="">2010 Annual Meeting of the Ecological Society of America</a></em> (2010): doi:10.1038/npre.2010.5346.1. Posted with permission.</p>
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dc.identifier.articleid 1013
dc.identifier.citation Raich, James and Russell, Ann. Surprisingly rapid nitrogen cycling in tropical forest plantations on volcanically derived soils. Available from Nature Precedings (2010)
dc.identifier.contextkey 6765677
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath nrem_conf/14
dc.language.iso en
dc.source.bitstream archive/|||Fri Jan 14 20:07:24 UTC 2022
dc.source.uri 10.1038/npre.2010.5346.1
dc.subject.disciplines Biogeochemistry
dc.subject.disciplines Forest Biology
dc.subject.disciplines Natural Resources and Conservation
dc.subject.disciplines Natural Resources Management and Policy
dc.subject.keywords fertility
dc.subject.keywords NPP
dc.subject.keywords productivity
dc.subject.keywords soil organic matter
dc.subject.keywords succession
dc.title Surprisingly rapid nitrogen cycling in tropical forest plantations on volcanically derived soils
dc.type article
dc.type.genre presentation
dspace.entity.type Publication
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