Nitrate in soil water in three Norway spruce stands in southwest Sweden as related to N-deposition and soil, stand, and foliage properties

1996 ◽  
Vol 26 (5) ◽  
pp. 836-848 ◽  
Author(s):  
Hans-Örjan Nohrstedt ◽  
Ulf Sikström ◽  
Eva Ring ◽  
Torgny Näsholm ◽  
Peter Högberg ◽  
...  

N-cycling was studied at three Norway spruce (Piceaabies (L.) Karst.) sites located within a distance of 30 km in southwest Sweden. Nitrate concentrations in soil water at 50-cm depth differed substantially between the three sites, annual site means being 0, 1, and 9 mg N•L−1. Using simulated runoff, the leaching of inorganic N from the two sites with the highest concentrations was estimated at, respectively, 7–8 and 19–30 kg•ha−1 during the hydrological year 1991–1992. The N-deposition measured as throughfall was 31 kg•ha−1 on the second site, suggesting that it was close to being N-saturated. The differences in nitrate concentration and estimated leaching across sites were not related to differences in forest growth or suggested symptoms of forest decline, such as canopy defoliation and nutrient deficiency. Nitrate concentrations were unrelated to N-deposition in an open field, but positively related to N-deposition in throughfall. However, the difference in N-leaching between the two main sites was much larger than the difference in N-deposition in throughfall. The difference in leaching seemed related to soil conditions. The soil with the highest leaching had the largest potential nitrification and a low C/N ratio (17–20) in the upper part of the profile. Nitrate concentrations in the soil water were positively related to the concentrations of arginine and 15N in foliage, which supports the use of these two variables as indicators of forests approaching N-saturation.

2001 ◽  
Vol 1 ◽  
pp. 572-580 ◽  
Author(s):  
Hideaki Shibata ◽  
Koichiro Kuraji ◽  
Hiroto Toda ◽  
Kaichiro Sasa

Nitrogen (N) emissions in Asian countries are predicted to increase over the next several decades. An understanding of the mechanisms that control temporal and spatial fluctuation of N export to forest streams is important not only to quantify critical loads of N, N saturation status, and soil acidification N dynamics and budgets in Japanese forested watersheds is not clear due to the lack of regional comparative studies on stream N chemistry. To address the lack of comparative studies, we measured inorganic N (nitrate and ammonium) concentrations from June 2000 to May 2001 in streams in 18 experimental forests located throughout the Japanese archipelago and belonging to the Japanese Union of University Forests. N concentrations in stream water during base flow and high flow periods were monitored, and N mineralization potential in soil was measured using batch incubation experiments. Higher nitrate concentrations in stream water were present in central Japan, an area that receives high rates of atmospheric N deposition. In northern Japan, snowmelt resulted in increased nitrate concentrations in stream water. The potential net N mineralization rate was higher in surface soil than in subsurface soil, and the high potential for N mineralization in the surface soil partly contributed to the increase in nitrate concentration in stream water during a storm event. Regional differences in the atmospheric N deposition and seasonality of precipitation and high discharge are principal controls on the concentrations and variations of nitrates in stream water in forested watersheds of Japan.


2017 ◽  
Vol 8 (4) ◽  
pp. 1121-1139 ◽  
Author(s):  
Maarten C. Braakhekke ◽  
Karin T. Rebel ◽  
Stefan C. Dekker ◽  
Benjamin Smith ◽  
Arthur H. W. Beusen ◽  
...  

Abstract. To study global nitrogen (N) leaching from natural ecosystems under changing N deposition, climate, and atmospheric CO2, we performed a factorial model experiment for the period 1901–2006 with the N-enabled global terrestrial ecosystem model LPJ-GUESS (Lund–Potsdam–Jena General Ecosystem Simulator). In eight global simulations, we used either the true transient time series of N deposition, climate, and atmospheric CO2 as input or kept combinations of these drivers constant at initial values. The results show that N deposition is globally the strongest driver of simulated N leaching, individually causing an increase of 88 % by 1997–2006 relative to pre-industrial conditions. Climate change led globally to a 31 % increase in N leaching, but the size and direction of change varied among global regions: leaching generally increased in regions with high soil organic carbon storage and high initial N status, and decreased in regions with a positive trend in vegetation productivity or decreasing precipitation. Rising atmospheric CO2 generally caused decreased N leaching (33 % globally), with strongest effects in regions with high productivity and N availability. All drivers combined resulted in a rise of N leaching by 73 % with strongest increases in Europe, eastern North America and South-East Asia, where N deposition rates are highest. Decreases in N leaching were predicted for the Amazon and northern India. We further found that N loss by fire regionally is a large term in the N budget, associated with lower N leaching, particularly in semi-arid biomes. Predicted global N leaching from natural lands rose from 13.6 Tg N yr−1 in 1901–1911 to 18.5 Tg N yr−1 in 1997–2006, accounting for reductions of natural land cover. Ecosystem N status (quantified as the reduction of vegetation productivity due to N limitation) shows a similar positive temporal trend but large spatial variability. Interestingly, this variability is more strongly related to vegetation type than N input. Similarly, the relationship between N status and (relative) N leaching is highly variable due to confounding factors such as soil water fluxes, fire occurrence, and growing season length. Nevertheless, our results suggest that regions with very high N deposition rates are approaching a state of N saturation.


Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1798
Author(s):  
Piaopiao Ke ◽  
Gaoyue Si ◽  
Yao Luo ◽  
Zhenglin Cheng ◽  
Qian Yu ◽  
...  

Anthropogenic emissions of nitrogen- (N) and sulfur (S)-containing pollutants have declined across China in recent years. However, the responses of N and S depositions and dynamics in soil remain unclear in subtropical forests. In this study, the wet and throughfall depositions of dissolved inorganic N (DIN) and SO42− were continuously monitored in a mildly polluted subtropical forest in Southeast China in 2017 and 2018. Moreover, these solutes in soil water along the soil profile were monitored in 2018. Throughfall deposition of DIN and S decreased by 59% and 53% in recent 3 years, respectively, which can be majorly attributed to the decreases in wet depositions of NO3− and SO42−. Meanwhile, NH4+ deposition remained relatively stable at this site. Even though N deposition in 2018 was below the N saturation threshold for subtropical forests, significant N leaching still occurred. Excess export of N occurred in the upper soil layer (0–15 cm), reaching 6.86 ± 1.54 kg N/ha/yr, while the deeper soil (15–30 cm) was net sink of N as 8.29 ± 1.71 kg N/ha/yr. Similarly, S was excessively exported from the upper soil with net flux of 14.7 ± 3.15 kg S/ha/yr, while up to 6.37 ± 3.18 kg S/ha/yr of S was retained in the deeper soil. The significant N and S leaching under declined depositions suggested that this site possibly underwent a transition state, recovering from historically high acid deposition. Furthermore, the rainfall intensity remarkably regulated leaching and retention of SO42− and DIN at this site. The impacts of climate changes on N and S dynamics require further long-term monitoring in subtropical forests.


2017 ◽  
Author(s):  
Maarten C. Braakhekke ◽  
Karin T. Rebel ◽  
Stefan C. Dekker ◽  
Benjamin Smith ◽  
Arthur H. W. Beusen ◽  
...  

Abstract. In order to study global nitrogen (N) leaching from natural ecosystems under changing N deposition, climate, and atmospheric CO2, we performed a factorial model experiment for the period 1901–2006 with the N-enabled global terrestrial ecosystem model LPJ-GUESS. In eight global simulations we used either the true transient time series of N deposition, climate, and atmospheric CO2 as input, or kept combinations of these drivers constant at initial values. The results show that N deposition is globally the strongest driver of simulated N leaching, individually causing an increase of 88 % by 1997–2006, relative to pre-industrial conditions. Climate change led globally to a 31 % increase in N leaching, but the size and direction of change varied among global regions: leaching generally increased in regions with high soil organic carbon storage or high initial N status, and decreased in regions with a positive trend in vegetation productivity or decreasing precipitation. Rising atmospheric CO2 generally caused decreased N leaching (33 % globally), with strongest effects in regions with high productivity and N availability. All drivers combined resulted in a rise of N leaching by 73 % with strongest increases in Europe, eastern North America and South-East Asia, where N deposition rates are highest. Decreases in N leaching were predicted for the Amazon and Northern India. We further found that N loss by fire regionally is a large term in the N budget, associated lower N leaching, particularly in semi-arid biomes. Predicted global N leaching from natural lands rose from 13.6 Tg N yr−1 in 1901–1911 to 18.5 Tg N yr−1 in 1997–2006, accounting for land-use changes. Ecosystem N status (quantified as the reduction of vegetation productivity due to N limitation) shows a similar positive temporal trend but large spatial variability. Interestingly this variability is more strongly related to vegetation type than N input. Similarly, the relationship between N status and (relative) N leaching is highly variable due to confounding factors such as soil water fluxes, fire occurrence, and growing season length. Nevertheless, our results suggest that regions with very high N deposition rates are approaching a state of N saturation.


2019 ◽  
Author(s):  
Sabine Braun

AbstractThe chemistry of the soil solution is influenced by atmospheric deposition of air pollutants, by exchange processes between the soil matrix and the soil solution and by processes between the rhizosphere and the soil. At sites of the Intercantonal Long-term Forest Observation Programme in Switzerland the soil solution has been monitored since 1998 in a number of forest plots growing from 9 to 47 sites in a wide range of soil conditions and air pollution impacts. The results show various site-specific developments of soil acidification. At sites with already advanced acidification (pH < 4.2), the acidification indicators remained rather stable at high levels, possibly due to the high buffering capacity of the aluminum buffer (pH 4.2 – 3.8). In contrast, in less acidified sites the acidification still progressed further which is reflected by e.g. the ongoing decrease of the base cation to aluminum ratio. Main driver of the acidification is the high N deposition which provokes cation loss and impedes sustainable nutrient balances for tree nutrition in the majority of plots examined. On an average for the years 2005-2017, N leaching rates were 9.4 kg N ha-1 yr-1, ranging from 0.04 to 53 kg N ha-1 yr-1. Three plots with high N input show very low N leaching, suggesting that N leaching may not always be a good eutrophication indicator. Both N deposition and N leaching have decreased since the year 2000 but the latter trend is partly also due to increased drought.


2001 ◽  
Vol 5 (3) ◽  
pp. 299-310 ◽  
Author(s):  
R. F. Wright ◽  
C. Alewell ◽  
J. M. Cullen ◽  
C. D. Evans ◽  
A. Marchetto ◽  
...  

Abstract. Long-term records of nitrogen in deposition and streamwater were analysed at 30 sites covering major acid sensitive regions in Europe. Large regions of Europe have received high inputs of inorganic nitrogen for the past 20 - 30 years, with an approximate 20% decline in central and northern Europe during the late 1990s. Nitrate concentrations in streamwaters are related to the amount of N deposition. All sites with less than 10 kgN ha-1 yr-1 deposition have low concentrations of nitrate in streamwater, whereas all sites receiving > 25 kgN ha-1 yr-1 have elevated concentrations. Very few of the sites exhibit significant trends in nitrate concentrations; similar analyses on other datasets also show few significant trends. Nitrogen saturation is thus a process requiring many decades, at least at levels of N deposition typical for Europe. Declines in nitrate concentrations at a few sites may reflect recent declines in N deposition. The overall lack of significant trends in nitrate concentrations in streams in Europe may be the result of two opposing factors. Continued high deposition of nitrogen (above the 10 kgN ha-1 yr-1 threshold) should tend to increase N saturation and give increased nitrate concentrations in run-off, whereas the decline in N deposition over the past 5 – 10 years in large parts of Europe should give decreased nitrate concentrations in run-off. Short and long-term variations in climate affect nitrate concentrations in streamwater and, thus, contribute "noise" which masks long-term trends. Empirical data for geographic pattern and long-term trends in response of surface waters to changes in N deposition set the premises for predicting future contributions of nitrate to acidification of soils and surface waters. Quantification of processes governing nitrogen retention and loss in semi-natural terrestrial ecosystems is a scientific challenge of increasing importance. Keywords: Europe, acid deposition, nitrogen, saturation, recovery, water


2004 ◽  
Vol 8 (4) ◽  
pp. 764-777 ◽  
Author(s):  
A. Bastrup-Birk ◽  
P. Gundersen

Abstract. Intensive agricultural land use across Europe has altered nitrogen (N) budget of catchments substantially, causing widespread N pollution of freshwater. Although the N cycle in forests has changed due to increased N deposition, most forest soil waters in Europe have low nitrate concentrations. The protective function of forests on water quality has led to increasing interest in the planting of new forests on arable land as a measure to protect valuable or sensitive freshwater resources. The paper illustrates the effects of afforestation on water and N cycling using the Integrated Nitrogen Catchment (INCA) model. The model was calibrated on the Horndrup catchment in the eastern part of Jutland, Denmark, which is dominated by agricultural land use but also covered by 18% of forest land. The dynamics of nitrate concentrations in the stream water were simulated successfully by INCA over a three-year period. The simulation of the dynamics of nitrate concentrations in the soil water is closely linked to the simulation of the hydrological dynamics and especially to the rainfall. The best fit was achieved for both arable and forest land during the wettest year of the study period. The model was then used to simulate the effect of afforestation of a catchment dominated by agriculture on N fluxes with seepage and runoff. Scenarios of whole catchment conversion to forest were run, based on observations of evapotranspiration and N deposition from other Danish sites. The simulated conversion to mature forest reduced runoff by 30–45% and reduced the nitrate concentrations in the soil water by 50–70%. The simulated effect of afforestation on N leaching was an almost direct reflection of the change in the N input: substantial changes in the plant demand and soil N dynamics over the afforestation period were not simulated. To simulate the N dynamics over longer time-scales, appropriate for the study of afforestation, it is suggested that the INCA model be run with transient scenarios and linked to more detailed plant and soil models. Keywords: afforestation, arable land, forest hydrology, INCA, modelling, nitrogen, nitrate leaching


2003 ◽  
Vol 33 (2) ◽  
pp. 375-384 ◽  
Author(s):  
Eva Ring ◽  
Johan Bergholm ◽  
Bengt A Olsson ◽  
Gunnar Jansson

Effects of previous fertilization with N (in total, 600 kg urea-N·ha–1 applied in 1976, 1980, and 1985) were studied after final felling in 1992 of a Norway spruce (Picea abies (L.) Karst.) stand in southern Sweden. The logging residues were removed from the site. In the clearcut, soil water at 50 cm depth was sampled 16 times with ceramic suction samplers (P80) in experimental plots during 1992–1995. The biomass and N content of the field layer was measured on seven occasions. The N storage of the field layer was significantly (p < 0.05) higher in the urea treatment than in the control. Significant interactions between treatment and time were found in soil water for nitrate-N and total N but not for ammonium-N, organic N, and pH. During the first year after final felling, nitrate-N tended to increase faster in the urea treatment than in the control. After a period with similar concentrations in both treatments, nitrate-N in the urea treatment declined while at the same time, a peak was observed in the control showing four to seven times higher concentrations than in the urea treatment. At the end of the study, the concentrations still appeared to be highest in the control. Thus, the study demonstrated the importance of using a sufficiently long study period when investigating environmental effects. Total leaching of nitrate-N from the urea treatment was roughly 40% ([Formula: see text]20 kg·ha–1) less than that from the control. The difference in leaching may be partly explained by the greater accumulation of N in the field-layer vegetation in the urea treatment.


2018 ◽  
Vol 422 ◽  
pp. 338-344 ◽  
Author(s):  
Per Erik Karlsson ◽  
Cecilia Akselsson ◽  
Sofie Hellsten ◽  
Gunilla Pihl Karlsson

CATENA ◽  
2008 ◽  
Vol 76 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Zhao Zhang ◽  
Takehiko Fukushima ◽  
Peijun Shi ◽  
Fulu Tao ◽  
Yuichi Onda ◽  
...  

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