scholarly journals Effects of different N sources on riverine DIN export and retention in subtropical high-standing island, Taiwan

2015 ◽  
Vol 12 (19) ◽  
pp. 16397-16430
Author(s):  
J.-C. Huang ◽  
T.-Y. Lee ◽  
T.-C. Lin ◽  
T. Hein ◽  
L.-C. Lee ◽  
...  
Keyword(s):  
N Saturation ◽  
Agricultural Lands ◽  
Retention Capacity ◽  
Total N ◽  
Input Quantity ◽  
N Retention ◽  
Export Ratio ◽  
Nitrogen Inputs ◽  
N Input ◽  
Synthetic Fertilizers

Abstract. Increases in nitrogen (N) availability and mobility resulting from anthropogenic activities has substantially altered N cycle both locally and globally. Taiwan characterized by the subtropical montane landscape with abundant rainfall, downwind to the most rapidly industrializing east coast of China can be a demonstration site for extreme high N input and riverine DIN (dissolved inorganic N) export. We used 49 watersheds classified into low-, moderate-, and highly-disturbed categories based on population density to illustrate their differences in nitrogen inputs through atmospheric N deposition, synthetic fertilizers and human emission and DIN export ratios. Our results showed that the island-wide average riverine DIN export is ~ 3800 kg N km−2 yr−1, approximately 18-fold higher than the global average mostly due to the large input of synthetic fertilizers. The average riverine DIN export ratio is 0.30–0.51, which is much higher than the average of 0.20–0.25 of large rivers around the world indicating excessive N input relative to ecosystem demand or retention capacity. The low-disturbed watersheds, despite of high N input, only export 0.06–0.18 of the input so were well buffered to changes in input quantity suggesting high efficiency of nitrogen usage or high N retention capacity of the less disturbed watersheds. The high retention capacity probably is due to the effective uptake by secondary forests in the watersheds. The moderate-disturbed watersheds show a linear increase of output with increases in total N inputs and a mean DIN export ratio of 0.20 to 0.31. The main difference in land use between low and moderately disturbed watershed is the relative proportions of agricultural land and forests, not the built-up lands. Thus, their greater DIN export quantity could be attributed to N fertilizers used in the agricultural lands. The greater export ratios also imply that agricultural lands have lower proportional N retention capacity and that reforestation could be an effective land management practice to reduce riverine DIN export. The export ratio of the highly-disturbed watersheds is 0.42–0.53, which is very high and suggests that much of the N input is transported downstream and the need of improvement in wastewater treatment capacity or sewerage systems. The increases in riverine DIN export ratio along with the gradient of human disturbance indicates a gradient in N saturation in subtropical Taiwan. Our results help to understand factors controlling riverine DIN export and provide a sound basis for N emissions/pollution control.

scholarly journals Effects of different N sources on riverine DIN export and retention in a subtropical high-standing island, Taiwan

2016 ◽  
Vol 13 (6) ◽  
pp. 1787-1800 ◽  
Author(s):  
Jr-Chuan Huang ◽  
Tsung-Yu Lee ◽  
Teng-Chiu Lin ◽  
Thomas Hein ◽  
Li-Chin Lee ◽  
...  
Keyword(s):  
Agricultural Land ◽  
Eastern Coast ◽  
N Availability ◽  
N Saturation ◽  
Agricultural Lands ◽  
Retention Capacity ◽  
Total N ◽  
N Retention ◽  
Nitrogen Inputs ◽  
N Input

Abstract. Increases in nitrogen (N) availability and mobility resulting from anthropogenic activities have substantially altered the N cycle, both locally and globally. Taiwan characterized by the subtropical montane landscape with abundant rainfall, downwind of the most rapidly industrializing eastern coast of China, can be a demonstration site for extremely high N input and riverine DIN (dissolved inorganic N) export. We used 49 watersheds with similar climatic and landscape settings but classified into low, moderate, and highly disturbed categories based on population density to illustrate their differences in nitrogen inputs (through atmospheric N deposition, synthetic fertilizers, and human emission) and DIN export ratios. Our results showed that the island-wide average riverine DIN export is ∼ 3800 kg N km−2 yr−1, approximately 18 times the global average. The average riverine DIN export ratios are 0.30–0.51, which are much higher than the averages of 0.20–0.25 of large rivers around the world, indicating excessive N input relative to ecosystem demand or retention capacity. The low disturbed watersheds have a high N retention capacity and DIN export ratios of 0.06–0.18 in spite of the high N input (∼ 4900 kg N km−2 yr−1). The high retention capacity is likely due to effective uptake by secondary forests in the watersheds. The moderately disturbed watersheds show a linear increase in DIN export with increases in total N inputs and mean DIN export ratios of 0.20 to 0.31. The main difference in land use between low and moderately disturbed watersheds is the greater proportion of agricultural land cover in the moderately disturbed watersheds. Thus, their greater DIN export could be attributed to N fertilizers used in the agricultural lands. The greater export ratios also imply that agricultural lands have a lower proportional N retention capacity and that reforestation could be an effective land management practice to reduce riverine DIN export. The export ratios of the highly disturbed watersheds are very high, 0.42–0.53, suggesting that much of the N input is transported downstream directly, and urges the need to increase the proportion of households connected to a sewage system and improve the effectiveness of wastewater treatment systems. The increases in the riverine DIN export ratio along the gradient of human disturbance also suggest a gradient in N saturation in subtropical Taiwan. Our results help to improve our understanding of factors controlling riverine DIN export and provide empirical evidence that calls for sound N emission/pollution control measures.

Improving Dryland Cropping System Nitrogen Balance with No-Tillage and Nitrogen Fertilization

2018 ◽  
Author(s):  
Upendra Sainju ◽  
Rajan Ghimire ◽  
Gautam Pradhan
Keyword(s):  
Environmental Sustainability ◽  
Cropping System ◽  
N Fertilization ◽  
N Fixation ◽  
No Tillage ◽  
Soil N ◽  
Total N ◽  
N Retention ◽  
N Removal ◽  
N Input

Studies on N balance due to N inputs and outputs and soil N retention to measure cropping system performance and environmental sustainability are limited due to the complexity of measurements of some parameters. We measured N balance based on N inputs and outputs and soil N retention under dryland agroecosystem affected by cropping system and N fertilization from 2007 to 2011 in the northern Great Plains, USA. Cropping systems were conventional tillage barley (Hordeum vulgaris L.)-fallow (CTB-F), no-tillage barley-fallow (NTB-F), no-tillage barley-pea (Pisum sativum L.) (NTB-P), and no-tillage continuous barley (NTCB). Nitrogen rates to barley were 0, 40, 80, and 120 kg N ha-1. Total N input due to N fertilization, pea N fixation, soil N mineralization, atmospheric N deposition, nonsymbiotic N fixation, and crop seed N and total N output due to grain N removal, denitrification, volatilization, N leaching, gaseous N (NOx) emissions, surface runoff, and plant senescence were 28 to 37% greater with NTB-P and NTCB than CTB-F and NTB-F. Total N input and output also increased with increased N rate. Nitrogen sequestration rate at 0 to 10 cm averaged 22 kg N ha-1 yr-1 for all treatments. Nitrogen deficit ranged from 5 to 16 kg N ha-1 yr-1, with greater deficits for CTB-F and NTB-P and higher N rates. Because of increased grain N removal and reduced N loss to the environment and N fertilizer requirement, NTB-P with 40 kg N ha-1 can enhance agronomic performance and environmental sustainability while reducing N inputs compared to other management practices.

scholarly journals Effects of seabird nitrogen input on biomass and carbon accumulation after 50 years of primary succession on a young volcanic island, Surtsey

2014 ◽  
Vol 11 (5) ◽  
pp. 6269-6302 ◽  
Author(s):  
N. I. W. Leblans ◽  
B. D. Sigurdsson ◽  
P. Roefs ◽  
R. Thuys ◽  
B. Magnússon ◽  
...  
Keyword(s):  
Primary Succession ◽  
Soil Depth ◽  
Carbon Accumulation ◽  
Volcanic Island ◽  
N Accumulation ◽  
Total N ◽  
N Retention ◽  
C Storage ◽  
C Stocks ◽  
N Input

Abstract. What happens during primary succession after the first colonizers have occupied a pristine surface largely depends on how they ameliorate living conditions for other species. For vascular plants the onset of soil development and associated increase in nutrient (mainly nitrogen, N) and water availability is especially important. Here, we report the relation between N accumulation and biomass- and ecosystem carbon (C) stocks in a 50 year old volcanic island, Surtsey, in Iceland, where N stocks are still exceptionally low. However, 27 year old seagull colony on the island provided nutrient-enriched areas, which enabled us to assess the relationship between N stock and biomass- and ecosystem C stocks across a much larger range in N stock. Further, we compared areas on shallow and deep tephra sands as we expected that deep-rooted systems would be more efficient in retaining N. The sparsely vegetated area outside the colony was more efficient in N retention than we expected and had accumulated 0.7 kg N ha−1 yr−1, which was ca. 60% of the estimated N input rate from wet deposition. The seagulls have added, on average, 47 kg N ha−1 yr−1, which induced a shift from belowground to aboveground in ecosystem N and C stocks and doubled the ecosystem "N use efficiency", determined as the ratio of biomass and C storage per unit N input. Soil depth did not significantly affect total N stocks, which suggests a high N retention potential. Both total ecosystem biomass and C stocks were strongly correlated with N stock inside the colony, which indicated the important role of N during the first steps of primary succession. Inside the colony, the ecosystem biomass C stocks (17–27 kg C ha−1) had reached normal values for grasslands, while the soil organic carbon stocks (SOC; 4–10 kg C ha−1) were only a fraction of normal grassland values. Thus, it will take a long time until the SOC stock reaches equilibrium with the current primary production; during which conditions for new colonists may change.

scholarly journals Anthropogenic point-source and non-point-source nitrogen inputs into Huai River basin and their impacts on riverine ammonia–nitrogen flux

2015 ◽  
Vol 12 (14) ◽  
pp. 4275-4289 ◽  
Author(s):  
W. S. Zhang ◽  
D. P. Swaney ◽  
X. Y. Li ◽  
B. Hong ◽  
R. W. Howarth ◽  
...  
Keyword(s):  
Point Source ◽  
River Basin ◽  
Fertilizer Application ◽  
Ammonia Nitrogen ◽  
Point Sources ◽  
Total N ◽  
Huai River Basin ◽  
Nitrogen Inputs ◽  
Huai River ◽  
N Input

Abstract. This study provides a new approach to estimate both anthropogenic non-point-source and point-source nitrogen (N) inputs to the landscape, and determines their impacts on riverine ammonia–nitrogen (AN) flux, providing a foundation for further exploration of anthropogenic effects on N pollution. Our study site is Huai River basin of China, a water–shed with one of the highest levels of N input in the world. Multi-year average (2003–2010) inputs of N to the watershed are 27 200 ± 1100 kg N km−2 yr−1. Non-point sources comprised about 98 % of total N input, and only 2 % of inputs are directly added to the aquatic ecosystem as point sources. Fertilizer application was the largest non-point source of new N to the Huai River basin (69 % of net anthropogenic N inputs), followed by atmospheric deposition (20 %), N fixation in croplands (7 %), and N content of imported food and feed (2 %). High N inputs showed impacts on riverine AN flux: fertilizer application, point-source N input, and atmospheric N deposition were proved as more direct sources to riverine AN flux. Modes of N delivery and losses associated with biological denitrification in rivers, water consumption, interception by dams may influence the extent of export of riverine AN flux from N sources. Our findings highlight the importance of anthropogenic N inputs from both point sources and non-point sources in heavily polluted watersheds, and provide some implications for AN prediction and management.

scholarly journals Feasibility of Nitrogen-Enriched Chars as Circular Fertilizers

2021 ◽  
Author(s):  
Riikka Keskinen ◽  
Johanna Nikama ◽  
Janne Kaseva ◽  
Kimmo Rasa
Keyword(s):  
Sewage Sludge ◽  
Water Purification ◽  
Crop Production ◽  
Slow Release ◽  
Retention Capacity ◽  
Total N ◽  
Fertilizer Use ◽  
N Retention ◽  
Ammonium N ◽  
Practical Feasibility

Abstract Purpose Charred materials are low in bioavailable nitrogen (N) due to gaseous losses and the formation of recalcitrant structures during pyrolysis. Enriching chars with N from wastewaters offers a possibility to upgrade the agronomic value of the chars and manage the liquids. For assessing the practical feasibility of the approach, more information on the extent of the retention and release of the loaded N is needed. Methods The ammonium-N (NH4-N) retention capacity of chars derived from sewage sludge (SS_A-C), Salix wood (SA), broiler manure (BR) and coal (LG85) was determined via equilibrations in solutions containing 400, 1500 and 5000 mg NH4-N L−1. Plant availability of the loaded N in SS_C, SA and BR was studied in a pot experiment with ryegrass. Results Differences in the total N retention of moist chars were small. The amount of N retained increased with increase in the solution N and was at the highest 2–4 g NH4-N L−1 char. In four consecutive ryegrass harvests, the apparent N recoveries were 67, 47 and 34% for SA, BR and SS_C treatments. No slow release of N was observed. Conclusion Considering crop production, the amounts of N retained within the studied chars in bioavailable form were small. Chars with a higher N retention capacity would be needed for an efficient cascade from water purification to fertilizer use. Graphical Abstract

scholarly journals Anthropogenic point and non-point nitrogen inputs into Huai River Basin and their impacts on riverine ammonia-nitrogen flux

2015 ◽  
Vol 12 (4) ◽  
pp. 3577-3615 ◽  
Author(s):  
W. S. Zhang ◽  
D. P. Swaney ◽  
X. Y. Li ◽  
B. Hong ◽  
R. W. Howarth ◽  
...  
Keyword(s):  
River Basin ◽  
Fertilizer Application ◽  
Ammonia Nitrogen ◽  
Point Sources ◽  
N Fixation ◽  
Total N ◽  
Huai River Basin ◽  
Nitrogen Inputs ◽  
Huai River ◽  
N Input

Abstract. This study provides a new approach to estimate both anthropogenic non-point and point nitrogen (N) inputs to the landscape, and determines their impacts on riverine ammonia-nitrogen (AN) flux, providing a foundation for further exploration of anthropogenic effects on N pollution. Our study site is Huai River Basin of China, a watershed with one of the highest levels of N input in the world. Multi-year average (2003–2010) inputs of N to the watershed are 27 200 ± 1100 kg N km−2 yr−1. Non-point sources comprised about 98% of total N input and only 2% of inputs are directly added to the aquatic ecosystem as point sources. Fertilizer application was the largest non-point source of new N to the Huai River Basin (69% of net anthropogenic N inputs), followed by atmospheric deposition (20%), N fixation in croplands (7%), and N content of imported food and feed (2%). High N inputs showed impacts on riverine AN flux: fertilizer application, point N input and atmospheric N deposition were proved as more direct sources to riverine AN flux. Modes of N delivery and losses associated with biological denitrification in rivers, water consumption, interception by dams influenced the extent of export of riverine AN flux from N sources. Our findings highlight the importance of anthropogenic N inputs from point and non-point sources in heavily polluted watersheds, and provide some implications for AN prediction and management.

Nitrogen inputs and losses from clover/grass pastures grazed by dairy cows, as affected by nitrogen fertilizer application

1999 ◽  
Vol 132 (2) ◽  
pp. 215-225 ◽  
Author(s):  
S. F. LEDGARD ◽  
J. W. PENNO ◽  
M. S. SPROSEN
Keyword(s):  
Dairy Cows ◽  
Fertilizer Application ◽  
N Fertilizer ◽  
Organic N ◽  
Total N ◽  
Nitrogen Inputs ◽  
N Input ◽  
Maize Grain ◽  
Intensively Managed ◽  
N Pool

Nitrogen (N) inputs and outputs were measured over 3 years in a trial with four farmlets (each with 16 randomly-allocated 0·4 ha paddocks) on permanent white clover/ryegrass pastures which were grazed throughout the year by dairy cows near Hamilton, New Zealand. Three farmlets were stocked at 3·3 cows/ha and received nominal rates of N fertilizer (urea in 8–10 split applications) of 0, 200 or 400 kg N/ha per year. A fourth farmlet with 4·4 cows/ha received 400 kg N/ha per year and was supplemented with maize grain during the first two years.Nitrogen balances were calculated, with [sum ]N inputs[ape ][sum ]N outputs. Annual inputs from N2 fixation were 99–231 kg N/ha in the 0 N farmlet, but declined to 15–44 kg N/ha in the 400 N farmlets. The main N outputs (in kg N/ha per year) were in milk (72–126), nitrate leaching (20–204), and transfer of N via cow excreta from pastures to lanes and milking shed (54–92). Gaseous losses by denitrification (3–34) and volatilization (15–78) were smaller than the other N outputs but increased significantly with N fertilizer application. In the maize-supplemented farmlet, N outputs in milk were 31% higher than in the corresponding non-supplemented 400 N farmlet, whereas leaching losses averaged 17% lower during the 2 years of supplementation.In the N-fertilized farmlets, estimated N balances were influenced by inclusion of the transitional N processes of immobilization of fertilizer N into the soil organic N pool (estimated using 15N at 42–94 kg N/ha per year) and the contribution from mineralization of residual clover-fixed N in soil not accounted for in the current estimates of N2 fixation (estimated at up to 70% of measured N2 fixation or 46 kg N/ha per year). However, these processes were counteracting and together were calculated to have only a small net effect on total N balances.The output of N in products (milk, meat and feed) relative to the total N input averaged 26% in the 400 N farmlets, and is compared to that measured for commercial intensively-managed dairy farms in England and the Netherlands (14–20%). The 0 N farmlet, which was reliant on N2 fixation as the sole N input, was relatively very N-efficient with the milk production being 83% of that in the 400 N farmlet (at 3·3 cows/ha) and the N output in products relative to total N input averaging 52%.

Nitrous oxide production in two forested watersheds exhibiting symptoms of nitrogen saturation

1998 ◽  
Vol 28 (11) ◽  
pp. 1723-1732 ◽  
Author(s):  
William T Peterjohn ◽  
Richard J McGervey ◽  
Alan J Sexstone ◽  
Martin J Christ ◽  
Cassie J Foster ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Nitrogen Saturation ◽  
N Cycling ◽  
Woody Vegetation ◽  
N Saturation ◽  
Relative Importance ◽  
Forested Watersheds ◽  
Total N ◽  
Nitrous Oxide Production ◽  
Poorly Drained Soils

A major concern about N saturation is that it may increase the production of a strong greenhouse gas, nitrous oxide (N2O). We measured N2O production in two forested watersheds, a young, fertilized forest (WS 3) and an older, unfertilized forest (WS 4), to (i) assess the importance of N2O production in forests showing symptoms of N saturation; (ii) estimate the contribution of chemoautrophic nitrification to total N2O production; and (iii) examine the relative importance of factors that may control N2O production. During the study period, mean monthly rates of N2O production (3.41-11.42 µ N ·m-2·h-1) were consistent with measurements from other well-drained forest soils but were much lower than measurements from N-rich sites with poorly drained soils. Chemoautotrophic nitrification was important in both watersheds, accounting for 60% (WS 3) and 40% (WS 4) of total N2O production. In WS 3, N2O production was enhanced by additions of CaCO3 and may be constrained by low soil pH. In WS 4, N2O production on south-facing slopes was exceptionally low, constrained by low NO3 availability, and associated with a distinct assemblage of woody vegetation. From this observation, we hypothesize that differences in vegetation can influence N cycling rates and susceptibility to N saturation.

Wood ash application in a managed Norway spruce plantation did not affect ectomycorrhizal diversity or N retention capacity

2019 ◽  
Vol 39 ◽  
pp. 1-11 ◽  
Author(s):  
Carla Cruz-Paredes ◽  
Tobias Guldberg Frøslev ◽  
Anders Michelsen ◽  
Toke Bang-Andreasen ◽  
Mette Hansen ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Wood Ash ◽  
Retention Capacity ◽  
N Retention ◽  
Ectomycorrhizal Diversity

scholarly journals Effect of carbon and nitrogen addition on nitrous oxide and carbon dioxide fluxes from thawing forest soils

2017 ◽  
Vol 31 (3) ◽  
pp. 339-349 ◽  
Author(s):  
Wu Haohao ◽  
Xu Xingkai ◽  
Duan Cuntao ◽  
Li TuanSheng ◽  
Cheng Weiguo
Keyword(s):  
Carbon Dioxide ◽  
Nitrous Oxide ◽  
Soil Moisture ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Forest Soils ◽  
Mixed Forest ◽  
Soil Core ◽  
Total N ◽  
Nitrogen Inputs

AbstractPacked soil-core incubation experiments were done to study the effects of carbon (glucose, 6.4 g C m−2) and nitrogen (NH4Cl and KNO3, 4.5 g N m−2) addition on nitrous oxide (N2O) and carbon dioxide (CO2) fluxes during thawing of frozen soils under two forest stands (broadleaf and Korean pine mixed forest and white birch forest) with two moisture levels (55 and 80% water-filled pore space). With increasing soil moisture, the magnitude and longevity of the flush N2O flux from forest soils was enhanced during the early period of thawing, which was accompanied by great NO3−-N consumption. Without N addition, the glucose-induced cumulative CO2fluxes ranged from 9.61 to 13.49 g CO2-C m−2, which was larger than the dose of carbon added as glucose. The single addition of glucose increased microbial biomass carbon but slightly affected soil dissolved organic carbon pool. Thus, the extra carbon released upon addition of glucose can result from the decomposition of soil native organic carbon. The glucose-induced N2O and CO2fluxes were both significantly correlated to the glucose-induced total N and dissolved organic carbon pools and influenced singly and interactively by soil moisture and KNO3addition. The interactive effects of glucose and nitrogen inputs on N2O and CO2fluxes from forest soils after frost depended on N sources, soil moisture, and vegetation types.

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