Zeitschriftenartikel: „Nutrient cycling“

1

van Breemen, Nico. „Nutrient cycling strategies“. Plant and Soil 168-169, Nr. 1 (Januar 1995): 321–26. http://dx.doi.org/10.1007/bf00029344.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

2

MAHENDRAPPA, M. K., N. W. FOSTER, G. F. WEETMAN und H. H. KRAUSE. „NUTRIENT CYCLING AND AVAILABILITY IN FOREST SOILS“. Canadian Journal of Soil Science 66, Nr. 4 (01.11.1986): 547–72. http://dx.doi.org/10.4141/cjss86-056.

Der volle Inhalt der Quelle

Annotation:

Nutrient availability in different forest soils must be known before increased wood production can be sustained either by adding supplemental nutrients or by judicious silvicultural operations to optimize the linkage between the variable nutrient requirements of forest crops. This is complicated by the variable availability of nutrients on forest sites during crop development. Forest crops unlike agricultural crops have long rotation periods which make it difficult to apply agricultural methods of estimating potentially available nutrients directly to forest soils. Presented in this review are (i) various approaches used in forestry to estimate the nutrient supplying potential of different sites, (ii) factors affecting nutrient availability, and (iii) evidence to suggest that nutrient cycling processes in forest ecosystems are important factors affecting tree growth. It is suggested that data from chemical analyses of soil samples collected at specific times and sites should be used with caution for both practical decision making and simulation modelling purposes. Key words: Nitrogen, phosphorus, litterfall, throughfall, stemflow, mineralization

APA, Harvard, Vancouver, ISO und andere Zitierweisen

3

Santos, Perlon Maia dos, Antonio Clementino dos Santos, Durval Nolasco das Neves Neto, Wallace Henrique de Oliveira, Luciano Fernandes Sousa und Leonardo Bernardes Taverny de Oliveira. „Implementation of Silvopastoral Systems under Nutrient Cycling in Secondary Vegetation in the Amazon“. Journal of Agricultural Science 10, Nr. 4 (05.03.2018): 124. http://dx.doi.org/10.5539/jas.v10n4p124.

Der volle Inhalt der Quelle

Annotation:

Silvopastoral systems can be implemented in idle secondary forests; however, they may affect nutrient cycling in these ecosystems. This farming practice using babassu palms (Attalea speciosa Mart.) and Mombasa grass (Panicum maximum Jacq.) has been little studied, and the nutrient cycling occurred during this practice is yet unknown. The goal of this paper was to detect the leaf litter accumulation, decomposition, and nutrient release occurring in silvopastoral systems in a babassu secondary forest, and compared the results with those of a native forest and of a pasture grown under full sunlight. The data relating to deposition, chemical composition, decomposition, and macronutrient release of leaf litter and pasture litter were evaluated by multivariate analyses. The results showed that forest thinning reduced leaf litter deposition and overall nutrient cycling but had no effect on decomposition rates. Conversely, the presence of grass in the understory promoted increased overall nutrient cycling rates. The cycling in integrated systems occurs more similar to that of forests than that of monocultures. The greater the thinning intensity the more similar the cycling will be relative to that occurring in pastures and in monocultures. The nutrients Ca, Mg, and N were the most affected by thinning. Moreover, the presence of grass in integrated systems provided an increased N and Mg cycling, whereas the thinning reduced Ca cycling. K showed the highest release and return ratio to the soil. Lastly, leaf litter from pasture areas showed higher contents of nutrients, decomposition rates, as well as an enhanced nutrient cycling capacity.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

4

Macedo, Priscila Helena da Silva, Emily Mariano da Cruz Lopes, Mariano Vieira dos Santos de Souza Lopes, Fernando César Sala und Claudinei Fonseca Souza. „Macronutrient cycling in hydroponic lettuce cultivation“. Ambiente e Agua - An Interdisciplinary Journal of Applied Science 17, Nr. 5 (04.10.2022): 1–11. http://dx.doi.org/10.4136/ambi-agua.2849.

Der volle Inhalt der Quelle

Annotation:

In order to address issues of limited resources and contamination by fertilizers, nutrient solutions may be reused in hydroponics as an alternative to their disposal in the environment. This work evaluated the feasibility of nutrient replacement for the nutrient solutions reused during lettuce hydroponic cultivation. The experiment was carried out in an agricultural greenhouse in an NFT hydroponic system using the “Milena” lettuce cultivar. The experiment was divided into two stages: 1) monitoring and data collection and proposition of nutrient replacement management; and 2) validation of the proposed replacement management. Monitoring the consumption of the crop's nutritional solution in the first stage served as the basis for the proposed nutritional replacement management. Management was validated in the second stage through the evaluation of fresh and dry mass, crop nutritional status, and the amount of the fertilizer applied in the treatments: T1 - nutrient replacement with nutrient solution reuse; and T2 - nutrient replacement without nutrient solution reuse. The fresh and dry mass data and the amount of nutrients absorbed by the plants were submitted to the t-test at 5% probability, showing no significant difference between the treatments, making it possible to conclude that the nutrient solution reuse provided nutrient replacement during the lettuce crop cultivation. Keywords: hydroponic system, Lactuca sativa L., macronutrient rational use.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

5

Rogers, Howard M. „Litterfall, decomposition and nutrient release in a lowland tropical rain forest, Morobe Province, Papua New Guinea“. Journal of Tropical Ecology 18, Nr. 3 (26.03.2002): 449–56. http://dx.doi.org/10.1017/s0266467402002304.

Der volle Inhalt der Quelle

Annotation:

The analysis of litter quantity, litter decomposition and its pattern of nutrient release is important for understanding nutrient cycling in forest ecosystems. Plant growth and maintenance are partly met through nutrient cycling (O'Connell & Sankaran 1997) which is dominated by litter production and decomposition. Litter fall is a major process for transferring nutrients from above-ground vegetation to soils (Vitousek & Sanford 1986), while decomposition of litter releases nutrients (Maclean & Wein 1978). The rate at which nutrients are recycled influences the net primary productivity of a forest. Knowledge of these processes from tropical rain forests is relatively poor (O'Connell & Sankaran 1997), and in particular there are no known published studies on nutrient cycling from lowland tropical forests in Papua New Guinea. The few studies from Papua New Guinea are confined to the mid-montane forest zone (Edwards 1977, Edwards & Grubb 1982, Enright 1979, Lawong et al. 1993).

APA, Harvard, Vancouver, ISO und andere Zitierweisen

6

Anderson, Wendy B., und William G. Eickmeier. „Nutrient resorption in Claytonia virginica L.: implications for deciduous forest nutrient cycling“. Canadian Journal of Botany 78, Nr. 6 (01.06.2000): 832–39. http://dx.doi.org/10.1139/b00-056.

Der volle Inhalt der Quelle

Annotation:

According to the vernal dam hypothesis, spring ephemeral herbs temporarily sequester large nutrient pools in deciduous forests prior to canopy closure and return the nutrients to the soil following senescence of aboveground tissues. However, many species resorb nutrients from their leaves back to belowground tissues during senescence, and the degree of resorption is often associated with soil nutrient availability. Species that store large proportions of their absorbed nutrients between years are not participating in the temporary sequestering and rapid recycling of nutrients implied by the vernal dam. We investigated the extent to which Claytonia virginica L. sequestered and returned nutrients to the soil in response to nitrogen (N) and phosphorus (P) availability. We tested the effect of nutrient availability on nutrient use efficiency, resorption efficiency, and resorption proficiency (% nutrient in senescent leaves) of Claytonia. Nutrient additions significantly decreased N but not P use efficiency of Claytonia, particularly as the growing season progressed. Nutrient additions also significantly reduced N resorption efficiency from 80 to 47% and decreased P resorption efficiency from 86 to 56%. N and P resorption proficiencies were also significantly lower in senesced leaves of fertilized plants: N concentrations were 2.33% when unfertilized and 4.13% when fertilized, while P concentrations were 0.43% when unfertilized versus 0.57% when fertilized. When unfertilized, Claytonia was more efficient at resorption compared with other spring herbs, but similar to other species when fertilized. However, Claytonia was much less proficient in resorbing nutrients than other reported plants, because senescent tissues maintained substantially higher concentrations of N and P, particularly when fertilized. In conclusion, Claytonia, an important spring ephemeral species, exhibits physiological responses that emphasize its role in the vernal dam by its temporary sequestration and substantial, rapid return of nutrients in deciduous forests. Adding nutrients to the site increases the total mass and the relative proportion of nutrients that Claytonia returns to the soil rather than sequestering between seasons, which ultimately increases nutrient recycling rates within the entire system.Key words: Claytonia virginica, nutrient response, resorption efficiency, nutrient cycling, spring ephemerals, vernal dam.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

7

Saravanan, S., C. Buvaneswaran, P. Manivachagam, K. Rajagopal und M. George. „Nutrient cycling in Casuarina (Casuarina equisetifolia) based agroforestry system“. Indian Journal of Forestry 35, Nr. 2 (01.06.2012): 187–91. http://dx.doi.org/10.54207/bsmps1000-2012-apbnt4.

Der volle Inhalt der Quelle

Annotation:

The present report gives an account of the results of research carried out on litter production, accumulation and nutrient return through rainfall, stem flow, throughfall and interception to soil litter fall, under Casuarina-Black Gram Agroforestry Models (age 4 years, density 650 trees/ha). It was found that of the total rainfall (497.9 mm) 1.2% was recorded as stem flow and 80% as throughfall while the interception accounted for 19 %. It is found that on an average annual basis, of the total uptake of various nutrients was retained in the non-photosynthetic biomass and the rest returned to soil. These results show that among the nutrients, maximum annual retention was accounted for potassium while, the minimum for nitrogen. This paper deals the nutrient accumulation in standing crop, nutrient concentration and return, rainfall interception, nutrient concentration in rain wash, nutrient return through rain wash and Nutrient retained, returned and uptake (kg/ha/yr) in Casuarina under Agroforestry System in detail.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

8

BROWN, DENNIS H., und JEFFREY W. BATES. „Bryophytes and nutrient cycling“. Botanical Journal of the Linnean Society 104, Nr. 1-3 (September 1990): 129–47. http://dx.doi.org/10.1111/j.1095-8339.1990.tb02215.x.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

9

ATTIWILL, PETER M., und MARK A. ADAMS. „Nutrient cycling in forests“. New Phytologist 124, Nr. 4 (August 1993): 561–82. http://dx.doi.org/10.1111/j.1469-8137.1993.tb03847.x.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

10

L�ng, I. „Nutrient cycling and sustainability“. Fertilizer Research 43, Nr. 1-3 (1996): 31–35. http://dx.doi.org/10.1007/bf00747679.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

11

Gomes Júnior, Diêgo, Marcos Vinicius Winckler Caldeira, Dione Richer Momolli, William Macedo Delarmelina, Henrique Machado Dias, Ranieri Ribeiro Paula und Kelly Nery Bighi. „Accumulated litter, nutrient stock and decomposition in an Atlantic Forest fragment“. Ambiente e Agua - An Interdisciplinary Journal of Applied Science 17, Nr. 2 (05.04.2022): 1–16. http://dx.doi.org/10.4136/ambi-agua.2787.

Der volle Inhalt der Quelle

Annotation:

Litter dynamics is one of the fundamental processes for the growth and maintenance of native forest fragments, being considered the main pathway for nutrient cycling in forests. Therefore, studies on accumulated litter and nutrient content provide information for a better understanding of nutrient dynamics. The aim of the study was to evaluate leaf litter and nutrient stock in different seasons and the instantaneous rate of decomposition in an Atlantic Forest Fragment over two years. Litter sampling was carried out in 12 permanent plots with dimensions of 20 m x 50 m. Litter dry mass and nutrient concentration were determined. The average annual accumulation of litter was 5269 kg ha-1. There was no statistically significant difference in the amount of litter between seasons. There was a statistically significant difference in the contents of N, P, K Ca and Mg between the different seasons. Nutrient stocks were 123.3, 92.8, 13.2, 11.8, 9.6, 3.0 kg ha-1 year-1 for Ca, N, Mg, S, K and P respectively. The total of nutrients in the accumulated litter was 253.7 kg ha-1 year-1. The litter renewal time was 281 days. The times required for 50% and 95% litter decomposition were 196 and 850 days. The average litter stocks, nutrients and decomposition are in line with other studies, indicating that the Atlantic Forest fragment seasonal semi-deciduous presents indicators of nutrient cycling. These results show that the ecosystem is sustainable from the point of view of cycling and nutrient release. Keywords: ecosystem functions, nutrient cycling, secondary succession.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

12

Anderson, Wendy B., und William G. Eickmeier. „Physiological and morphological responses to shade and nutrient additions of Claytonia virginica (Portulacaceae): implications for the "vernal dam" hypothesis“. Canadian Journal of Botany 76, Nr. 8 (01.08.1998): 1340–49. http://dx.doi.org/10.1139/b98-134.

Der volle Inhalt der Quelle

Annotation:

Because of their unique phenology and physiology, spring ephemeral herbs are believed to play an important role in intrasystem nutrient cycling in deciduous forest ecosystems. It was hypothesized that they function as a "vernal dam" by temporarily sequestering nutrients and preventing leaching from the system during a period of high nutrient availability. However, spring ephemerals require high-irradiance growing conditions. How do their physiological and morphological responses to ambient light and shade limit their ability to sequester excess nutrients? We performed field experiments using Claytonia virginica L. as a model to test several responses to shade and increasing levels of nutrient additions. We also examined the biomass responses and nutrient storage capacities of other spring ephemeral herbs. In C. virginica, shading reduced ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco) activity, photosynthesis rate, specific leaf weight, leaf width/length (W/L), and biomass; nutrient additions increased W/L and biomass only under unshaded conditions. Other herbs responded similarly but reached maximum biomass at lower nutrient addition levels than C. virginica. Shading reduced and nutrient additions increased nitrogen and phosphorus concentrations in both C. virginica and other herbs. Shaded herbs generally reached nutrient saturation at lower nutrient addition levels than unshaded herbs. Overall, unshaded plants sequestered larger amounts of nutrients than shaded plants. This pattern is best explained by a reduction in biomass under shaded conditions. We concluded that C. virginica and other spring herbs, although important components in forest nutrient cycling in the early spring, are limited in their capacity to store excess nutrients, particularly when shaded.Key words: Claytonia virginica, nutrient cycling, spring ephemerals, vernal dam.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

13

Murbach, Marcos Roberto, Antonio Enedi Boaretto, Takashi Muraoka und Euclides Caxambu Alexandrino de Souza. „Nutrient cycling in a RRIM 600 clone rubber plantation“. Scientia Agricola 60, Nr. 2 (2003): 353–57. http://dx.doi.org/10.1590/s0103-90162003000200021.

Der volle Inhalt der Quelle

Annotation:

Few reports have been presented on nutrient cycling in rubber tree plantations (Hevea brasiliensis Muell. Arg.). This experiment was carried out to evaluate: the effect of K rates on the amount of nutrients transfered to the soil in a 13-year old Hevea brasilensis RRIM 600 clone plantation, nutrient retranslocation from the leaves before falling to the soil, and nutrient loss by dry rubber export. The experiment started in 1998 and potassium was applied at the rates of 0, 40, 80 and 160 kg ha-1 of K2O under the crowns of 40 rubber trees of each plot. Literfall collectors, five per plot, were randomly distributed within the plots under the trees. The accumulated literfall was collected monthly during one year. The coagulated rubber latex from each plot was weighed, and samples were analyzed for nutrient content. Increasing K fertilization rates also increased the K content in leaf literfall. Calcium and N were the most recycled leaf nutrients to the soil via litterfall. Potassium, followed by P were the nutrients with the highest retranslocation rates. Potassium was the most exported nutrient by the harvested rubber, and this amount was higher than that transfered to the soil by the leaf literfall.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

14

Sagi, Nevo, und Dror Hawlena. „Arthropods as the Engine of Nutrient Cycling in Arid Ecosystems“. Insects 12, Nr. 8 (14.08.2021): 726. http://dx.doi.org/10.3390/insects12080726.

Der volle Inhalt der Quelle

Annotation:

Nutrient dynamics in most terrestrial ecosystems are regulated by moisture-dependent processes. In drylands, nutrient dynamics are often weakly associated with annual precipitation, suggesting that other factors are involved. In recent years, the majority of research on this topic focused on abiotic factors. We provide an arthropod-centric framework that aims to refocus research attention back on the fundamental role that macro-arthropods may play in regulating dryland nutrient dynamics. Macro-arthropods are prevalent in drylands and include many detritivores and burrowing taxa that remain active during long dry periods. Macro-arthropods consume and process large quantities of plant detritus and transport these nutrients to the decomposer haven within their climatically buffered and nutritionally enriched burrows. Consequently, arthropods may accelerate mineralization rates and generate a vertical nutrient recycling loop (VRL) that may assist in explaining the dryland decomposition conundrum, and how desert plants receive their nutrients when the shallow soil is dry. The burrowing activity of arthropods and the transportation of subterranean soil to the surface may alter the desert microtopography and promote desalinization, reducing resource leakage and enhancing productivity and species diversity. We conclude that these fundamental roles and the arthropods’ contribution to nutrient transportation and nitrogen fixation makes them key regulators of nutrient dynamics in drylands.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

15

Knops, J. M. H., T. H. Nash Iii, V. L. Boucher und W. H. Schlesinger. „Mineral Cycling and Epiphytic Lichens: Implications at the Ecosystem Level“. Lichenologist 23, Nr. 3 (Juli 1991): 309–21. http://dx.doi.org/10.1017/s0024282991000452.

Der volle Inhalt der Quelle

Annotation:

AbstractThe nutrient contribution of lichens as litterfall in forests is discussed for a number of different ecosystems and it is hypothesized that lichens are important in capturing nutrients from wet deposition, occult precipitation, sedimentation, impaction and gaseous uptake. Most nutrients captured by these processes represent new nutrient inputs that would otherwise not be intercepted by the ecosystem. Part of these nutrients will be incorporated into lichen biomass and only become available upon death and decomposition, but a portion will be leached by precipitation and become deposited on the soil surface. Although quantifying nutrient sources, fluxes and pool sizes is a potentially complex task, we describe a simplified approach for determining whether lichens significantly affect the mineral cycling of a forest. Preliminary results for an oak woodland in California document that epiphytic lichens may reduce throughfall and alter throughfall chemistry.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

16

Cherif, Mehdi, und Michel Loreau. „Plant–herbivore–decomposer stoichiometric mismatches and nutrient cycling in ecosystems“. Proceedings of the Royal Society B: Biological Sciences 280, Nr. 1754 (07.03.2013): 20122453. http://dx.doi.org/10.1098/rspb.2012.2453.

Der volle Inhalt der Quelle

Annotation:

Plant stoichiometry is thought to have a major influence on how herbivores affect nutrient availability in ecosystems. Most conceptual models predict that plants with high nutrient contents increase nutrient excretion by herbivores, in turn raising nutrient availability. To test this hypothesis, we built a stoichiometrically explicit model that includes a simple but thorough description of the processes of herbivory and decomposition. Our results challenge traditional views of herbivore impacts on nutrient availability in many ways. They show that the relationship between plant nutrient content and the impact of herbivores predicted by conceptual models holds only at high plant nutrient contents. At low plant nutrient contents, the impact of herbivores is mediated by the mineralization/immobilization of nutrients by decomposers and by the type of resource limiting the growth of decomposers. Both parameters are functions of the mismatch between plant and decomposer stoichiometries. Our work provides new predictions about the impacts of herbivores on ecosystem fertility that depend on critical interactions between plant, herbivore and decomposer stoichiometries in ecosystems.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

17

Le Mézo, Priscilla, Jérôme Guiet, Kim Scherrer, Daniele Bianchi und Eric Galbraith. „Global nutrient cycling by commercially targeted marine fish“. Biogeosciences 19, Nr. 10 (18.05.2022): 2537–55. http://dx.doi.org/10.5194/bg-19-2537-2022.

Der volle Inhalt der Quelle

Annotation:

Abstract. Throughout the course of their lives fish ingest food containing essential elements, including nitrogen (N), phosphorus (P), and iron (Fe). Some of these elements are retained in the fish body to build new biomass, which acts as a stored reservoir of nutrients, while the rest is excreted or egested, providing a recycling flux to water. Fishing activity has modified the fish biomass distribution worldwide and consequently may have altered fish-mediated nutrient cycling, but this possibility remains largely unassessed, mainly due to the difficulty of estimating global fish biomass and metabolic rates. Here we quantify the role of commercially targeted marine fish between 10 g and 100 kg (CTF10g100kg) in the cycling of N, P, and Fe in the global ocean and its change due to fishing activity, by using a global size-spectrum model of marine fish populations calibrated to observations of fish catches. Our results show that the amount of nutrients potentially stored in the global pristine CTF10g100kg biomass is generally small compared to the ambient surface nutrient concentrations but might be significant in the nutrient-poor regions of the world: the North Atlantic for P, the oligotrophic gyres for N, and the high-nutrient, low-chlorophyll (HNLC) regions for Fe. Similarly, the rate of nutrient removal from the ocean through fishing is globally small compared to the inputs but can be important locally, especially for Fe in the equatorial Pacific and along the western margin of South America and Africa. We also estimate that the cycling rate of elements through CTF10g100kg biomass was on the order of 3 % of the primary productivity demand for N, P, and Fe globally, prior to industrial fishing. The corresponding export of nutrients by egestion of fecal matter by CTF10g100kg was 2.3 % (N), 3.0 % (P), and 1 %–22 % (Fe) of the total particulate export flux and was generally more significant in the low-export oligotrophic tropical gyres. Our study supports a significant, direct role of the CTF10g100kg fraction of the ichthyosphere in global nutrient cycling, most notably for Fe, which has been substantially modified by industrial fishing. Although we were not able to estimate the roles of smaller species such as mesopelagic fish because of the sparsity of observational data, fishing is also likely to have altered their biomass significantly through trophic cascades, with impacts on biogeochemical cycling that could be of comparable magnitude to the changes we assess here.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

18

Cai, Zhi-quan, und Frans Bongers. „Contrasting nitrogen and phosphorus resorption efficiencies in trees and lianas from a tropical montane rain forest in Xishuangbanna, south-west China“. Journal of Tropical Ecology 23, Nr. 1 (Januar 2007): 115–18. http://dx.doi.org/10.1017/s0266467406003750.

Der volle Inhalt der Quelle

Annotation:

Tropical montane rain forest is widely considered to be a highly threatened hotspot of global diversity (Brummitt & Nic Lughadha 2003), and one of the least understood humid tropical forest ecosystems in terms of nutrient cycling (Bruijnzeel & Proctor 1995). There is, therefore, an urgent need to improve our understanding of nutrient cycling processes in this ecosystem, including the absorption of nutrients (mainly N and P) from senescing leaves, which may be a key component of adaptive mechanisms that conserve limiting nutrients (Killingbeck 1996). Nutrients which are not resorbed, however, will be circulated through litterfall in the longer term (Aerts 1996). The degree of nutrient resorption affects litter quality, which consequently affects decomposition rates and soil nutrient availability (Aerts & Chapin 2000). The importance of resorption in nutrient conservation has led to general hypotheses that species adapted to nutrient-poor environments have high resorption efficiencies (Richardson et al. 2005), and that low leaf nutrient concentrations are associated with high resorption efficiencies within species (Aerts 1996, Kobe et al. 2005). Nutrient resorption has also been shown not to differ greatly between growth forms (e.g. shrubs, grasses, forbs and trees) (Aerts 1996). However, its relative importance among plant functional groups is still highly controversial (Richardson et al. 2005).

APA, Harvard, Vancouver, ISO und andere Zitierweisen

19

Pihlblad, Johanna, Louise C. Andresen, Catriona A. Macdonald, David S. Ellsworth und Yolima Carrillo. „The influence of elevated CO₂ and soil depth on rhizosphere activity and nutrient availability in a mature Eucalyptus woodland“. Biogeosciences 20, Nr. 3 (02.02.2023): 505–21. http://dx.doi.org/10.5194/bg-20-505-2023.

Der volle Inhalt der Quelle

Annotation:

Abstract. Elevated carbon dioxide (eCO2) in the atmosphere increases forest biomass productivity but only where soil nutrients, particularly nitrogen (N) and phosphorus (P), are not limiting growth. eCO2, in turn, can impact rhizosphere nutrient availability. Our current understanding of nutrient cycling under eCO2 is mainly derived from surface soil, leaving mechanisms of the impact of eCO2 on rhizosphere nutrient availability at deeper depths unexplored. To investigate the influence of eCO2 on nutrient availability in soil at depth, we studied various C, N, and P pools (extractable, microbial biomass, total soil C and N, and mineral-associated P) and nutrient cycling processes (enzyme activity and gross N mineralisation) associated with C, N, and P cycling in both bulk and rhizosphere soil at different depths at the Free Air CO2 enrichment facility in a native Australian mature Eucalyptus woodland (EucFACE) on a nutrient-poor soil. We found decreasing nutrient availability and gross N mineralisation with depth; however, this depth-associated decrease was reduced under eCO2, which we suggest is due to enhanced root influence. Increases in available PO43-, adsorbed P, and the C : N and C : P ratio of enzyme activity with depth were observed. We conclude that the influences of roots and of eCO2 can affect available nutrient pools and processes well beyond the surface soil of a mature forest ecosystem. Our findings indicate a faster recycling of nutrients in the rhizosphere, rather than additional nutrients becoming available through soil organic matter (SOM) decomposition. If the plant growth response to eCO2 is reduced by the constraints of nutrient limitations, then the current results would call to question the potential for mature tree ecosystems to fix more C as biomass in response to eCO2. Future studies should address how accessible the available nutrients at depth are to deeply rooted plants and if fast recycling of nutrients is a meaningful contribution to biomass production and the accumulation of soil C in response to eCO2.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

20

Gautam, Tilak Prasad, und Tej Narayan Mandal. „Storage and Flux of Nutrients in Disturbed and Undisturbed Tropical Moist Forest of Eastern Nepal“. International Journal of Forestry Research 2018 (18.10.2018): 1–12. http://dx.doi.org/10.1155/2018/8516321.

Der volle Inhalt der Quelle

Annotation:

The disturbance activities in tropical forests shrink the nutrient cycling between the vegetation and soil. To understand the nutrient cycling in undisturbed and disturbed stands of mixed deciduous tropical forest of eastern Nepal, plant biomass was estimated within seventy randomly established sampling plots. The biomass values were multiplied with nutrient concentration of respective parts to estimate the nutrient stocks. The nutrient concentrations varied widely amongst components. In trees, concentrations of all nutrients were highest in leaves followed in decreasing order by fine roots (<5 mm) and twigs and then by branches, bole, and coarse roots. The contribution of different components to total nutrient stocks was in the following order: tree > stand fine root > shrub > herb, in both stands. The relative contribution of different components of trees to total nutrient stocks was in the following order: bole > coarse root > branch > leaf > twig > fine roots. In trees, leaves and fine roots had greater gross uptake of nutrients than other components. The concentrations of different nutrients in the plants are in the following order: nitrogen > potassium > phosphorus. Total nutrient return to the soil through the litterfall is almost 1.5 times greater than that from fine roots in both forests. In conclusion, various types of forest disturbances had adverse effect on the nutrient stocks and nutrient dynamics.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

21

Moore, John C. „Nutrient Cycling and Food Web“. Ecology 74, Nr. 3 (April 1993): 966–67. http://dx.doi.org/10.2307/1940823.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

22

Azcón-Aguilar, C., und J. M. Barea. „Nutrient cycling in the mycorrhizosphere“. Journal of soil science and plant nutrition, ahead (2015): 0. http://dx.doi.org/10.4067/s0718-95162015005000035.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

23

Almeida, Cinara Xavier de, José Luiz Pita Junior, Danilo Eduardo Rozane, Henrique Antunes de Souza, Amanda Hernandes, William Natale und Antonio Sergio Ferraudo. „Nutrient cycling in mango trees“. Semina: Ciências Agrárias 35, Nr. 1 (27.02.2014): 259. http://dx.doi.org/10.5433/1679-0359.2014v35n1p259.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

24

Sigleo, Anne C. „Primary Production and Nutrient Cycling“. Ecology 87, Nr. 1 (Januar 2006): 264–65. http://dx.doi.org/10.1890/0012-9658(2006)87[264:ppanc]2.0.co;2.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

25

Holt, J. A., und R. J. Coventry. „Nutrient Cycling in Australian Savannas“. Journal of Biogeography 17, Nr. 4/5 (Juli 1990): 427. http://dx.doi.org/10.2307/2845373.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

26

Chapman, P. „NUTRIENT CYCLING IN MARINE ECOSYSTEMS“. Journal of the Limnological Society of Southern Africa 12, Nr. 1-2 (Januar 1986): 22–42. http://dx.doi.org/10.1080/03779688.1986.9639397.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

27

Tivy, Joy. „Nutrient cycling in agro-ecosystems“. Applied Geography 7, Nr. 2 (April 1987): 93–113. http://dx.doi.org/10.1016/0143-6228(87)90044-0.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

28

Ndlovu, Siphelele, Terence N. Suinyuy, María A. Pérez-Fernández und Anathi Magadlela. „Encephalartos natalensis, Their Nutrient-Cycling Microbes and Enzymes: A Story of Successful Trade-Offs“. Plants 12, Nr. 5 (24.02.2023): 1034. http://dx.doi.org/10.3390/plants12051034.

Der volle Inhalt der Quelle

Annotation:

Encephalartos spp. establish symbioses with nitrogen (N)-fixing bacteria that contribute to soil nutrition and improve plant growth. Despite the Encephalartos mutualistic symbioses with N-fixing bacteria, the identity of other bacteria and their contribution to soil fertility and ecosystem functioning is not well understood. Due to Encephalartos spp. being threatened in the wild, this limited information presents a challenge in developing comprehensive conservation and management strategies for these cycad species. Therefore, this study identified the nutrient-cycling bacteria in Encephalartos natalensis coralloid roots, rhizosphere, and non-rhizosphere soils. Additionally, the soil characteristics and soil enzyme activities of the rhizosphere and non-rhizosphere soils were assayed. The coralloid roots, rhizosphere, and non-rhizosphere soils of E. natalensis were collected from a population of >500 E. natalensis in a disturbed savanna woodland at Edendale in KwaZulu-Natal (South Africa) for nutrient analysis, bacterial identification, and enzyme activity assays. Nutrient-cycling bacteria such as Lysinibacillus xylanilyticus; Paraburkholderia sabiae, and Novosphingobium barchaimii were identified in the coralloid roots, rhizosphere, and non-rhizosphere soils of E. natalensis. Phosphorus (P) cycling (alkaline and acid phosphatase) and N cycling (β-(D)-Glucosaminidase and nitrate reductase) enzyme activities showed a positive correlation with soil extractable P and total N concentrations in the rhizosphere and non-rhizosphere soils of E. natalensis. The positive correlation between soil enzymes and soil nutrients demonstrates that the identified nutrient-cycling bacteria in E. natalensis coralloid roots, rhizosphere, and non-rhizosphere soils and associated enzymes assayed may contribute to soil nutrient bioavailability of E. natalensis plants growing in acidic and nutrient-poor savanna woodland ecosystems.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

29

Peterson, David L., und R. David Hammer. „Soil Nutrient Flux: A Component of Nutrient Cycling in Temperate Forest Ecosystems“. Forest Science 32, Nr. 2 (01.06.1986): 318–24. http://dx.doi.org/10.1093/forestscience/32.2.318.

Der volle Inhalt der Quelle

Annotation:

Abstract Extractable nutrient levels in a floodplain forest soil varied significantly over the course of a year. Temporal variation in nutrient pools expressed as the ratio range/mean was in the following order: NH4-N > NO3-N » extractable P > exchangeable K > exchangeable Mg > exchangeable Ca. Lowest concentrations occurred during the summer months for all nutrients except NO3-N. The magnitude of this variation exceeded the size of several other nutrient fluxes within the ecosystem, which indicated that the soil system was a dynamic component of the floodplain forest ecosystem. Considerable evidence from diverse soil and vegetation types suggests that temporal variation in soil nutrient levels is a feature common to most temperate forest ecosystems. Forest Sci. 32:318-324.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

30

Gomes Júnior, Diêgo, Marcos Vinicius Winckler Caldeira, Sustanis Horn Kunz, William Macedo Delarmelina, Dione Richer Momolli, Elzimar de Oliveira Gonçalves und Julia Siqueira Moreau. „Seasonal litterfall and nutrients in an Atlantic Forest fragment“. Ambiente e Agua - An Interdisciplinary Journal of Applied Science 17, Nr. 1 (03.02.2022): 1–15. http://dx.doi.org/10.4136/ambi-agua.2775.

Der volle Inhalt der Quelle

Annotation:

Litter dynamics is one of the fundamental processes for the growth and maintenance of native forest fragments, being considered the main pathway for nutrient cycling in forests. Studies on litter production and nutrient content therefore provide insights that provide a better understanding of nutrient dynamics. This study identifies the seasonality and meteorological conditions that influence the quantity and return of nutrients through litter in an Atlantic Forest fragment. Litter sampling was carried out monthly in 12 permanent plots. Each plot contained 5 littertraps distributed systematically. The litter was classified, and the dry mass and nutrients in the leaves and branches and miscellaneous fractions was quantified. Seasonal behavior was observed, with the highest depositions in the winter season. The average annual production was 6.78 Mg ha-1, with 64.9% being composed of leaves. The mean annual nutrient intake was 135.1, 115.7, 39.7, 23.5, 17.6 and 4.6 kg ha-1 for Ca, N, K, Mg, S and P, respectively. The meteorological variable precipitation influenced the deposition pattern. The increase in nutrient-use efficiency in the second year compared to the first indicates that plants strategically may be re-translocating relative amounts of their nutrients under water stress conditions. Keywords: ecosystem functions, nutrient cycling, secondary succession.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

31

Lin, T. C., P. L. Shaner, L. J. Wang, Y. T. Shih, C. P. Wang, G. H. Huang und J. C. Huang. „Effects of mountain agriculture on nutrient cycling at upstream watersheds“. Hydrology and Earth System Sciences Discussions 12, Nr. 5 (04.05.2015): 4785–811. http://dx.doi.org/10.5194/hessd-12-4785-2015.

Der volle Inhalt der Quelle

Annotation:

Abstract. The expansion of agriculture to rugged mountains can exacerbate negative impacts of agriculture activities on ecosystem function. In this study, we monitored streamwater chemistry of four watersheds with varying proportions of agricultural lands (0.4, 3, 17, 22%) and rainfall chemistry of two of the four watersheds at Feitsui Reservoir Watershed in northern Taiwan to examine the effects of agriculture on watershed nutrient cycling. We found that the greater the proportions of agricultural lands, the higher the ion concentrations, which is evident for fertilizer-associated ions (NO3-, K+) but not for ions that are rich in soils (SO42-, Ca2+, Mg2+), suggesting that agriculture enriched fertilizer-associated nutrients in streamwater. The watershed with the highest proportion of agricultural lands had higher concentrations of ions in rainfall and lower nutrient retention capacity (i.e. higher output–input ratio of ions) compared to the relatively pristine watershed, suggesting that agriculture can influence atmospheric deposition of nutrients and a system's ability to retain nutrients. Furthermore, we found that a forested watershed downstream of agricultural activities can dilute the concentrations of fertilizer-associated ions (NO3−, K+) in streamwater by more than 70%, indicating that specific landscape configurations help mitigate nutrient enrichment to aquatic systems. We estimated that agricultural lands at our study site contributed approximately 400 kg ha−1 yr−1 of NO3-N and 260 kg ha−1 yr−1 of PO4-P output via streamwater, an order of magnitude greater than previously reported around the globe and can only be matched by areas under intense fertilizer use. Furthermore, we re-constructed watershed nutrient fluxes to show that excessive leaching of N and P, and additional loss of N to the atmosphere via volatilization and denitrification, can occur under intense fertilizer use. In summary, this study demonstrated the pervasive impacts of agriculture activities, especially excessive fertilization, on ecosystem nutrient cycling at mountain watersheds.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

32

Corbett, D. R. „Resuspension and estuarine nutrient cycling: insights from the Neuse River Estuary“. Biogeosciences Discussions 7, Nr. 2 (16.04.2010): 2767–98. http://dx.doi.org/10.5194/bgd-7-2767-2010.

Der volle Inhalt der Quelle

Annotation:

Abstract. For at least the past several decades, North Carolina's Neuse River Estuary (NRE) has been subject to water quality problems relating to increased eutrophication. Research studies initiated in the past several years have addressed the complex nutrient cycles in this system. Most of this research, however, is concerned with the nutrient processes of the water column and the passive diffusion processes of the benthic sedimentary environment. Resuspension of bottom sediments, by bioturbation, tides, or wind-generated waves, may have a significant effect on the flux of nutrients in an estuarine system These processes can result in the advective transport of sediment porewater, rich with nitrogen, phosphorus and carbon, into the water column. Thus, estimates of nutrient and carbon inputs from the sediments may be too low. This study focused on the potential change in porewater and bottom water nutrient concentrations associated with measured resuspension events. Previous research used short-lived radionuclides and meteorological data to characterize the sediment dynamics of the benthic system of the estuary. These techniques in conjunction with the presented porewater inventories allowed evaluation of the depth to which sediments have been disturbed and the advective flux of nutrients to the water column. The largest removal episode occurred in the lower NRE as the result of a wind event and was estimated that the top 2.2 cm of sediment and corresponding porewater were removed. NH4+ advective flux (resuspended) was 2 to 6 times greater than simply diffusion. Phosphate fluxes were estimated to be 15 times greater than the benthic diffusive flux. Bottom water conditions with elevated NH4+ and PO43− indicate that nutrients stored in the sediments continue to play an important role in overall water quality and this study suggests that the advective flux of nutrients to the water column is critical to understand estuarine nutrient cycling.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

33

Dighton, John. „Nutrient cycling in different terrestrial ecosystems in relation to fungi“. Canadian Journal of Botany 73, S1 (31.12.1995): 1349–60. http://dx.doi.org/10.1139/b95-397.

Der volle Inhalt der Quelle

Annotation:

Comparisons are made between nutrient cycling systems of arctic tundra, temperate forest, tropical forest, grassland, arable, and desert ecosystems. Detailed nutrient budgets are not given, but general differences between ecosystems are discussed primarily in relation to the role of soil fungi. General discussion reviews the impact of anthropogenic factors, including land management, pollution, and climate change on the role of fungi in nutrient cycling. Areas where further research is needed to complete our understanding of the functional aspects of fungi and nutrient cycling are highlighted and some of the techniques that may be employed are discussed. Key words: nutrient cycling, ecosystems, fungi.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

34

Lambert, Marcia, und John Turner. „Nutrient distribution and cycling in a subtropical rainforest in New South Wales“. Australian Journal of Botany 64, Nr. 2 (2016): 100. http://dx.doi.org/10.1071/bt14342.

Der volle Inhalt der Quelle

Annotation:

Subtropical rainforests in New South Wales (NSW) are distributed on the more fertile forest soils and are nutritionally distinct from the Eucalyptus forests in the same areas. The distribution, cycling of organic matter and nutrients and nutrient use efficiency in an Australian subtropical rainforest were studied and aspects were compared with reported Eucalyptus studies. The available nutrients were greatly in excess of the stand uptake or requirement. A single undisturbed plot within a research trial in mature forest was selected for the study. At the beginning of the study, the aboveground forest biomass was ~334 t ha–1 of organic matter and, 22 years later, there was 357 t ha–1, giving a net accumulation rate of 1.03 t ha–1 year–1, and net primary productivity of 13.0–14.6 t ha–1 year–1. Litterfall and forest-floor analyses indicated a very rapid turnover of organic matter, with an estimated half-life of ~0.5 years. The quantity of nutrients in the stand was high relative to other forest types in the area, with 1109.2 kg N ha–1, 62 kg P ha–1, 1999 kg Ca ha–1, 591 kg Mg ha–1 and 901 kg K ha–1. Nutrient requirement estimated as nutrient content of the current tissue was estimated to be 107, 5.3, 99, 26 and 61 kg ha–1 year–1 for N, P, Ca, Mg and K, respectively, and uptake defined as removal from the soil was estimated to be 112, 4.7, 128, 37 and 49 kg ha–1 year–1 for the same nutrients, the difference between these being net nutrient redistribution. Nutrient use efficiency (NUE), defined as net primary productivity (NPP) per requirement (t kg–1), was calculated to be 0.12, 2.43, 0.13, 0.50 and 0.21 for N, P, Ca, Mg and K, respectively; these values were low, for example, compared with mature E. pilularis, for which NPP was 0.20, 6.5, 0.43, 1.04 and 0.52 t kg–1 for N, P, Ca, Mg and K, respectively. Using NUE defined as NPP per uptake provided comparable estimates. The rainforest represents a forest growing with basically no nutrient limitations, and, as such, is a benchmark for forest nutrient distribution, cycling and NUE.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

35

Kurihara, Carlos Hissao, Hamilton Kikuti, Flávio Ferreira da Silva Binotti und Cesar José da Silva. „Nutrient accumulation, export and cycling in Jatropha curcas L .“ Revista Ceres 63, Nr. 3 (Juni 2016): 361–70. http://dx.doi.org/10.1590/0034-737x201663030013.

Der volle Inhalt der Quelle

Annotation:

ABSTRACT The knowledge concerning nutrient accumulation rate allows defining the best amount and most appropriate time for its supply. Estimating nutrient amount in the aerial part of the plants is particularly important to species such as Jatropha curcas L., since there are no consistent calibration studies to indicate the amount of fertilizer to be applied. The objective of this study was to evaluate nutrient accumulation, export and cycling in Jatropha curcas. The experiment was carried out in Cassilândia, state of Mato Grosso do Sul, Brazil, during 52 months in a completely randomized design, with four replications and fifteen treatments, which consisted of different evaluation times. A large variation in the amount of nutrients accumulated in leaves was found due to senescence and leaf abscission in the driest and/or coldest period of the year. Nutrient accumulation in the aerial part is relatively low in the first 22 months. To meet Jatropha curcas requirements, fertilization during the first two years must provide 40; 50; 50; 21; 16; 5; 0.7; 0.3; 4; 8 and 1 kg ha-1 of N, P2O5, K2O, Ca, Mg, S, B, Cu, Fe, Mn and Zn, respectively. From the third year of cultivation, topdressing fertilization should restitute 40, 110, 55 and 3 kg ha-1 of N, P2O5, K2O and S, respectively. To replace the exported amount of nutrients, it should be supplied more 50, 100, 30 and 3 kg ha-1 of N, P2O5, K2O and S, respectively, per ton of grain to be produced.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

36

Lodhiyal, L. S., R. P. Singh und S. P. Singh. „Productivity and nutrient cycling in poplar stands in central Himalaya, India“. Canadian Journal of Forest Research 24, Nr. 6 (01.06.1994): 1199–209. http://dx.doi.org/10.1139/x94-158.

Der volle Inhalt der Quelle

Annotation:

Productivity and nutrient-use efficiency were investigated in plantations of similar age of poplar clone D121 (Populusdeltoides Marsh.) that differed mainly in plant density. The plantations were located in the Tarai belt (low-lying area with high water table) of the Indian Central Himalaya. The total net primary productivity of the high-density plantation (4 years old with 666 trees/ha) was conspicuously higher (32.4 tones•ha−1•year−1) than that of the low-density (20 tonnes•ha−1•year−1) plantation (5 years old with 400 trees/ha), while nutrient-use efficiency was similar in these plantations. The net primary productivity/leaf nutrient ratios and percent nutrient retranslocation from senescing leaves were higher in the high-density than in the low-density plantations. In these young plantations leaf litterfall accounted for most of the litterfall (96–97%). The amount of nutrients that returned through litterfall to the soil was distinctly greater in the high-density plantation than in the low-density plantation. The greater nutrient return was due to first, the greater dry weight of litterfall and the lower proportional nutrient retranslocation from leaves during senescence in the high-density plantation. The high-density plantation also showed greater nutrient extraction efficiency from soil. Compared with a Eucalyptustereticornis Sm. plantation, and with natural forests of the study region, the nutrient use efficiency of poplar, regardless of its density, was lower.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

37

Hu, Zhiyuan, Jiating Li, Kangwei Shi, Guangqian Ren, Zhicong Dai, Jianfan Sun, Xiaojun Zheng et al. „Effects of Canada Goldenrod Invasion on Soil Extracellular Enzyme Activities and Ecoenzymatic Stoichiometry“. Sustainability 13, Nr. 7 (29.03.2021): 3768. http://dx.doi.org/10.3390/su13073768.

Der volle Inhalt der Quelle

Annotation:

The rapid expansion of Canada goldenrod (Solidago canadensis L.) in China has drawn considerable attention as it may not only decrease vegetation diversity but also alter soil nutrient cycling in the affected ecosystems. Soil extracellular enzymes mediate nutrient cycling by catalyzing the organic matter decomposition; however, the mechanisms by which alien plant invasion may affect soil extracellular enzymes remain unclear. The objective of this study was to investigate the responses of soil extracellular enzyme activities and ecoenzymatic stoichiometry to S. canadensis invasion. Several extracellular enzymatic activities related to carbon, nitrogen, and phosphorus cycling were measured using a fluorometric method. Ecoenzymatic stoichiometry was used as a proxy of soil microbial metabolic limitations. S. canadensis invasion appeared to be associated with decreased activities of enzymes and with substantial conversions of microbial metabolic carbon and nitrogen limitations. The changes in the activities of extracellular enzymes and the limitations of microbial metabolism were correlated with the alterations in the nutrient availability and resource stoichiometry in the soil. These findings reveal that the alterations in soil available nutrients associated with S. canadensis invasion may regulate extracellular enzymatic activities and cause microbial metabolic limitations, suggesting that S. canadensis invasion considerably affects biogeochemical cycling processes.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

38

Sims, J. T., N. Goggin und J. McDermott. „Nutrient management for water quality protection: integrating research into environmental policy“. Water Science and Technology 39, Nr. 12 (01.06.1999): 291–98. http://dx.doi.org/10.2166/wst.1999.0558.

Der volle Inhalt der Quelle

Annotation:

Agriculture's impacts on water quality have been the focus of basic and applied research in Delaware for more than 25 years. Research has examined nutrient cycling in soils, nutrient transport from soils to water, and the environmental consequences of ground water contamination and surface water eutrophication by nutrients. Much of the research has specifically been oriented towards the development of agricultural management practices to prevent the degradation of water quality by nutrients. Other research has focused on increasing our understanding of the chemical, physical, and biological processes that control nutrient cycling and transport and improving the monitoring techniques needed to document how changing management practices affects water quality. Agencies responsible for water quality protection have sought to integrate this research into environmental policy, but have often been frustrated by the fragmented and sometimes contradictory nature of the information provided to them. This paper reviews key advances in research on nutrient management and water quality in Delaware and discusses the obstacles faced in translating research into widely accepted management practices and environmental policies.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

39

Tuerena, Robyn E., Claire Mahaffey, Sian F. Henley, Camille de la Vega, Louisa Norman, Tim Brand, Tina Sanders et al. „Nutrient pathways and their susceptibility to past and future change in the Eurasian Arctic Ocean“. Ambio 51, Nr. 2 (16.12.2021): 355–69. http://dx.doi.org/10.1007/s13280-021-01673-0.

Der volle Inhalt der Quelle

Annotation:

AbstractClimate change is altering nutrient cycling within the Arctic Ocean, having knock-on effects to Arctic ecosystems. Primary production in the Arctic is principally nitrogen-limited, particularly in the western Pacific-dominated regions where denitrification exacerbates nitrogen loss. The nutrient status of the eastern Eurasian Arctic remains under debate. In the Barents Sea, primary production has increased by 88% since 1998. To support this rapid increase in productivity, either the standing stock of nutrients has been depleted, or the external nutrient supply has increased. Atlantic water inflow, enhanced mixing, benthic nitrogen cycling, and land–ocean interaction have the potential to alter the nutrient supply through addition, dilution or removal. Here we use new datasets from the Changing Arctic Ocean program alongside historical datasets to assess how nitrate and phosphate concentrations may be changing in response to these processes. We highlight how nutrient dynamics may continue to change, why this is important for regional and international policy-making and suggest relevant research priorities for the future.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

40

Vitousek, Peter M., Grant Gerrish, Douglas R. Turner, Lawrence R. Walker und Dieter Mueller-Dombois. „Litterfall and nutrient cycling in four Hawaiian montane rainforests“. Journal of Tropical Ecology 11, Nr. 2 (Mai 1995): 189–203. http://dx.doi.org/10.1017/s0266467400008634.

Der volle Inhalt der Quelle

Annotation:

ABSTRACTThe mass of fine litterfall and nutrient circulation through litterfall were determined in four Melrosideros polymorpha/Cibotium spp.-dominated rainforests that differed in substrate age, parent material texture and annual precipitation on Kilauea and Mauna Loa volcanoes on the island of Hawaii. Three of the sites had rates of litterfall of 5.2 Mg ha−1 y−1; the fourth, which was on the most fertile soil, produced 7.0 Mg ha−1 y−1 of litterfall with higher concentrations of nitrogen and phosphorus. Tree ferns of the genus Cibotium cycled relatively large amounts of nitrogen, phosphorus and potassium through litterfall; their contribution to nutrient circulation was disproportionate to their mass in the forest, or in litterfall. The forest on the youngest substrate, which also had the lowest concentrations of nitrogen in litterfall, was fertilized with complete factorial combinations of nitrogen, phosphorus and a treatment consisting of all other plant nutrients. Additions of nitrogen increased the quantity and nitrogen concentration in litterfall during the second year following the initiation of fertilization, while no other treatment had a significant effect. Additions of nitrogen had no effect on litterfall mass or nutrient concentrations in the most nutrient-rich site.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

41

Corbett, D. R. „Resuspension and estuarine nutrient cycling: insights from the Neuse River Estuary“. Biogeosciences 7, Nr. 10 (26.10.2010): 3289–300. http://dx.doi.org/10.5194/bg-7-3289-2010.

Der volle Inhalt der Quelle

Annotation:

Abstract. For at least the past several decades, North Carolina's Neuse River Estuary (NRE) has been subject to water quality problems relating to increased eutrophication. Research initiated in the past several years have addressed the nutrient processes of the water column and the passive diffusion processes of the benthic sedimentary environment. Resuspension of bottom sediments, by bioturbation, tides, or winds, may also have a significant effect on the flux of nutrients in an estuarine system These processes can result in the advective transport of sediment porewater, rich with nitrogen, phosphorus and carbon, into the water column. Thus, estimates of nutrient and carbon inputs from the sediments may be too low. This study focused on the potential change in bottom water nutrient concentrations associated with measured resuspension events. Previous research used short-lived radionuclides and meteorological data to characterize the sediment dynamics of the benthic system of the estuary. These techniques in conjunction with the presented porewater inventories allowed evaluation of the depth to which sediments have been disturbed and the advective flux of nutrients to the water column. The largest removal episode occurred in the lower NRE as the result of a wind event and was estimated that the top 2.2 cm of sediment and corresponding porewater were removed. NH4+ advective flux (resuspended) was 2 to 6 times greater than simply diffusion. Phosphate fluxes were estimated to be 15 times greater than the benthic diffusive flux. Bottom water conditions with elevated NH4+ and PO43− indicate that nutrients stored in the sediments continue to play an important role in overall water quality and this study suggests that the advective flux of nutrients to the water column is critical to understand estuarine nutrient cycling.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

42

Proctor, J., und C. F. Jordan. „Nutrient Cycling in Tropical Forest Ecosystems.“ Journal of Applied Ecology 23, Nr. 3 (Dezember 1986): 1070. http://dx.doi.org/10.2307/2403967.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

43

Vendramini, J. M. B., J. C. B. Dubeux Júnior und M. L. Silveira. „Nutrient cycling in tropical pasture ecosystems“. Revista Brasileira de Ciências Agrárias - Brazilian Journal of Agricultural Sciences 9, Nr. 2 (30.06.2014): 308–15. http://dx.doi.org/10.5039/agraria.v9i2a3730.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

44

Edwards, P. J., und C. F. Jordan. „Nutrient Cycling in Tropical Forest Ecosystems.“ Journal of Ecology 75, Nr. 1 (März 1987): 280. http://dx.doi.org/10.2307/2260554.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

45

Johnson, Dale W., Trine Sogn und Sheila Kvindesland. „The nutrient cycling model: lessons learned“. Forest Ecology and Management 138, Nr. 1-3 (November 2000): 91–106. http://dx.doi.org/10.1016/s0378-1127(00)00414-x.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

46

Quested, Helen M. „Parasitic plants—impacts on nutrient cycling“. Plant and Soil 311, Nr. 1-2 (12.06.2008): 269–72. http://dx.doi.org/10.1007/s11104-008-9646-9.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

47

Ericsson, Tom. „Nutrient cycling in energy forest plantations“. Biomass and Bioenergy 6, Nr. 1-2 (Januar 1994): 115–21. http://dx.doi.org/10.1016/0961-9534(94)90090-6.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

48

Vitousek, P. M., und R. L. Sanford. „Nutrient Cycling in Moist Tropical Forest“. Annual Review of Ecology and Systematics 17, Nr. 1 (November 1986): 137–67. http://dx.doi.org/10.1146/annurev.es.17.110186.001033.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

49

Dubeux, J. C. B., L. E. Sollenberger, B. W. Mathews, J. M. Scholberg und H. Q. Santos. „Nutrient Cycling in Warm-Climate Grasslands“. Crop Science 47, Nr. 3 (Mai 2007): 915–28. http://dx.doi.org/10.2135/cropsci2006.09.0581.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

50

Binkley, Dan. „What's new in forest nutrient cycling?“ Forest Ecology and Management 82, Nr. 1-3 (April 1996): 249–50. http://dx.doi.org/10.1016/0378-1127(95)03685-7.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Zeitschriftenartikel zum Thema „Nutrient cycling“

Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an