Nitrogen dynamics in Amazon forest and pasture soils measured by 15N pool dilution

Neill, Christopher; Píccolo, Marisa de Cássia; Melillo, Jerry M.; Steudler, Paul A.; Cerri, Carlos C.

doi:10.1016/s0038-0717(98)00159-x

Cited by 119 publications

(98 citation statements)

References 18 publications

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“…Brachiaria brizantha deposits large quantities of litter and decaying roots of very low N content of 0.5 to 1% (Boddey et al, 1996). Furthermore in pastures, the microbial biomass gradually reworks soil organic matter (SOM) to more recalcitrant forms that cycle N more slowly as compared with SOM in the original forest (Neill et al, 1999). The strong decline of microbial biomass N following deforestation that we observed has also been reported for young pasture sites near Manaus, in the central Amazon (Luizão et al, 1992).…”

Section: Changes Of N Transformation Along the Forest-topasture Chronsupporting

confidence: 79%

“…7), a trend that has also been observed in old pastures in other studies (Castilla and Jackson, 1996;Fernandes et al, 2002). A pattern of increased N limitation with increasing pasture age has also been observed in forest-topasture chronosequence studies in Rondônia (Neill et al, 1995(Neill et al, , 1999 and in Costa Rica (Veldkamp et al, 1999). Progressive N limitation with pasture age is probably caused by a combination of early loss of nitrogen through gaseous emissions and leaching, reduced inputs of nitrogen (e.g.…”

Section: Changes Of N Transformation Along the Forest-topasture Chronsupporting

confidence: 72%

“…Slash burning in Amazonian forests is accompanied by a temporary input of low quality, high C/N debris to soils (Kauffman et al, 1995). The peak of microbial biomass N in the 4 to 6 year old pasture sites (wet season) with a high aboveground biomass production is probably related to the large (-above-) and sub-surface inputs of organic material from shoots, roots, and root residues returning labile C and nutrients to the soil as was found in other studies in Brazil (Boddey et al, 1996;Neill et al, 1999). The aboveground biomass in the intermediate pasture age classes was 12 t ha −1 compared to 8 t ha −1 in both the young and old pasture sites.…”

Section: Changes Of N Transformation Along the Forest-topasture Chronsupporting

confidence: 61%

“…In contrast to the clay-textured Oxisols in central and eastern Amazon, soils in Rondônia are coarser textured Ultisols. This difference in texture may lead to rapid SOM turnover and Nmineralization rates in Rondônia (Desjardins et al, 1994;Moraes et al, 1996;Neill et al, 1999), whereas in the eastern Amazon, the higher clay content may protect SOM against rapid mineralization (Koutika et al, 1997). Furthermore, the variation in soil mineralogy on P availability likely contributed to the differences in pasture productivity and N cycling across the Amazon basin (see Davidson et al, 2004).…”

Section: Factors Controlling N 2 O Fluxes From Forest and Pasture Sitesmentioning

confidence: 99%

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Nitrous oxide fluxes and nitrogen cycling along a pasture chronosequence in Central Amazonia, Brazil

et al. 2005

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Abstract. We studied nitrous oxide (N 2 O) fluxes and soil nitrogen (N) cycling following forest conversion to pasture in the central Amazon near Santarém, Pará, Brazil. Two undisturbed forest sites and 27 pasture sites of 0.5 to 60 years were sampled once each during wet and dry seasons. In addition to soil-atmosphere fluxes of N 2 O we measured 27 soil chemical, soil microbiological and soil physical variables.Soil N 2 O fluxes were higher in the wet season than in the dry season. Fluxes of N 2 O from forest soils always exceeded fluxes from pasture soils and showed no consistent trend with pasture age. At our forest sites, nitrate was the dominant form of inorganic N both during wet and dry season. At our pasture sites nitrate generally dominated the inorganic N pools during the wet season and ammonium dominated during the dry season. Net mineralization and nitrification rates displayed large variations. During the dry season net immobilization of N was observed in some pastures. Compared to forest sites, young pasture sites (≤2 years) had low microbial biomass N and protease activities. Protease activity and microbial biomass N peaked in pastures of intermediate age (4 to 8 years) followed by consistently lower values in older pasture (10 to 60 years). The C/N ratio of litter was low at the forest sites (∼25) and rapidly increased with pasture age reaching values of 60-70 at pastures of 15 years and older.Nitrous oxide emissions at our sites were controlled by C and N availability and soil aeration. Fluxes of N 2 O were negatively correlated to leaf litter C/N ratio, NH

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Section: Changes Of N Transformation Along the Forest-topasture Chronsupporting

confidence: 79%

Section: Changes Of N Transformation Along the Forest-topasture Chronsupporting

confidence: 72%

Section: Changes Of N Transformation Along the Forest-topasture Chronsupporting

confidence: 61%

Section: Factors Controlling N 2 O Fluxes From Forest and Pasture Sitesmentioning

confidence: 99%

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Nitrous oxide fluxes and nitrogen cycling along a pasture chronosequence in Central Amazonia, Brazil

et al. 2005

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“…- (Stark & Hart 1997, Neill et al 1999, Ingwersen et al 1999). These findings highlight the importance of measuring gross nitrification rates to understand N transformation in forest ecosystems.…”

Section: Introductionmentioning

confidence: 99%

Seasonal dynamics of soil respiration and nitrification in three subtropical plantations in southern China

Wang¹,

Cheng²,

Shi³

et al. 2016

iForest

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Numerous studies have documented that soil respiration and nitrogen cycling show a distinct seasonal dependence regulated by environmental factors (e.g., soil temperature and soil water content). The mechanisms controlling the seasonal dependence of these two key ecosystem processes have rarely been linked to both soil microbial community and soil environmental factors. Here, we present results on the seasonal patterns of soil respiration and gross nitrification rates in three subtropical plantations of Pinus massoniana, Castanopsis hystrix and Erythrophleum fordii over a period of 11 months. Turnover rates were measured with the Barometric Process Separation technique (BaPS). We elucidated how soil respiration and gross nitrification are controlled by the soil microbial community and by soil environmental factors. Soil respiration and gross nitrification showed strong seasonal dynamics, although no significant differences were observed among plantations. The turnover rates were the highest during the wet season and the lowest during the dry season. Microbial biomass, total phospholipid fatty acids (PLFAs), fungal PLFAs and bacterial PLFAs peaked during the dry season. Both soil respiration and gross nitrification rates were positively correlated with soil temperature and soil water content. Microbial biomass decreased with increasing turnover rates. Our findings highlight that carbon and nitrogen turnover rates were mostly controlled by soil temperature and soil water content.

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Soil nitrogen dynamics within profiles of a managed moist temperate forest chronosequence consistent with long‐term harvesting‐induced losses

2014

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This study investigates whether clear-cut forest harvesting leads to alterations in the decadal-scale biogeochemical nitrogen (N) cycles of moist temperate forest ecosystems. Using a harvested temperate red spruce (Picea rubens Sarg.) forest chronosequence in Nova Scotia, Canada, representing <1 to >80 year old postharvest conditions, alongside a reference old-growth (125+ year old) site with no documented history of disturbance, we examine harvesting-related changes in soil N pools and fluxes. Specifically, we quantify soil N storage with depth and age across the forest chronosequence, examine changes in physical fractions and δ 15 N of soil N through depth and time, and quantify gross soil N transformation rates through depth and time using a 15 N isotope dilution technique. Our findings point to a large loss of total N in the soil pool, particularly within the deep soil (>20 cm) and organomineral fractions. A pulse of available mineralized N (as ammonium) was observed following harvesting (mean residence time (MRT) > 6 days), but its MRT dropped to <1 day 80 years following harvesting, in contrast to the MRT of 2-3 days observed in the reference old-growth forest site. These mineralization patterns coupled with inferred leaching losses to groundwater are consistent with storage estimates that suggest soil N may not reaccrue for almost a century following this disturbance.

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Nitrogen dynamics in Amazon forest and pasture soils measured by 15N pool dilution

Cited by 119 publications

References 18 publications

Nitrous oxide fluxes and nitrogen cycling along a pasture chronosequence in Central Amazonia, Brazil

Nitrous oxide fluxes and nitrogen cycling along a pasture chronosequence in Central Amazonia, Brazil

Seasonal dynamics of soil respiration and nitrification in three subtropical plantations in southern China

Soil nitrogen dynamics within profiles of a managed moist temperate forest chronosequence consistent with long‐term harvesting‐induced losses

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