scholarly journals Assessing the impact of acid rain and forest harvest intensity with the HD-MINTEQ model – Soil chemistry of three Swedish conifer sites from 1880 to 2080

2018 ◽  
Author(s):  
Eric McGivney ◽  
Salim Belyazid ◽  
Therese Zetterberg ◽  
Stefan Löfgren ◽  
Jon Petter Gustafsson
Keyword(s):  
Acid Rain ◽  
Soil Solution ◽  
Tree Growth ◽  
Soil Chemistry ◽  
Soil Layer ◽  
Base Cations ◽  
Mineral Weathering ◽  
Solution Ph ◽  
Weathering Rates ◽  
The Impact

Abstract. Forest soils are susceptible to anthropogenic acidification. In the past, acid rain was a major contributor to soil acidification, but now that atmospheric levels of S have dramatically declined, concern has shifted towards biomass-induced acidification, i.e., decreasing soil solution pH due to tree growth and harvesting events that permanently remove base cations (BC) from forest stands. We use a novel dynamic model, HD-MINTEQ, to investigate the long-term impacts of two theoretical future harvesting scenarios in the year 2020, a conventional harvest (CH, which removes stems only) and a whole-tree harvest (WTH, which removes 100 % of the above-ground biomass except for stumps), on soil chemistry and weathering rates at three different Swedish forest sites (Aneboda, Gårdsjön, and Kindla). Furthermore, acidification following the harvesting events is compared to the historical acidification that took place during the 20th century due to acid rain. Our results indicate that historical acidification due to acid rain had a larger impact on pore water chemistry and mineral weathering than tree growth and CH or WTH events, at least if nitrification remained at a low level. However, compared to a no-harvest scenario (NH), WTH and CH significantly impacted soil chemistry and weathering rates. Directly after a harvesting event (CH or WTH), the soil solution pH sharply increased for 5 to 10 years before slowly declining over the remainder of the simulation (until year 2080). WTH acidified soils slightly more than CH, with the largest effects being seen for the B1 horizons by the year 2080. Even though the pH values in the WTH and CH scenario decreased with time as compared to NH, they did not drop to the levels observed around the peak of historic acidification (1980–1990), indicating that the pH decrease due to tree growth and harvesting would be less impactful than that of historic atmospheric acidification. Weathering rates differed across locations and soil layers in response to historic acidification, but at several sites and layers, annual weathering rates decreased in tandem with decreasing pH, which is likely due to Al3+ weathering brakes. Weathering rates after the harvesting scenarios in 2020 generally increased although the dynamics were quite different depending on the site and soil layer.

scholarly journals Assessing the impact of acid rain and forest harvest intensity with the HD-MINTEQ model – soil chemistry of three Swedish conifer sites from 1880 to 2080

SOIL ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Eric McGivney ◽  
Jon Petter Gustafsson ◽  
Salim Belyazid ◽  
Therese Zetterberg ◽  
Stefan Löfgren
Keyword(s):  
Acid Rain ◽  
Soil Solution ◽  
Tree Growth ◽  
Soil Chemistry ◽  
Base Cations ◽  
Mineral Weathering ◽  
Solution Ph ◽  
Weathering Rates ◽  
Model Soil ◽  
The Impact

Abstract. Forest soils are susceptible to anthropogenic acidification. In the past, acid rain was a major contributor to soil acidification, but, now that atmospheric levels of S have dramatically declined, concern has shifted towards biomass-induced acidification, i.e. decreasing soil solution pH due to tree growth and harvesting events that permanently remove base cations (BCs) from forest stands. We use a novel dynamic model, HD-MINTEQ (Husby Dynamic MINTEQ), to investigate possible long-term impacts of two theoretical future harvesting scenarios in the year 2020, a conventional harvest (CH, which removes stems only), and a whole-tree harvest (WTH, which removes 100 % of the above-ground biomass except for stumps) on soil chemistry and weathering rates at three different Swedish forest sites (Aneboda, Gårdsjön, and Kindla). Furthermore, acidification following the harvesting events is compared to the historical acidification that took place during the 20th century due to acid rain. Our results show that historical acidification due to acid rain had a larger impact on pore water chemistry and mineral weathering than tree growth and harvesting, at least if nitrification remained at a low level. However, compared to a no-harvest baseline, WTH and CH significantly impacted soil chemistry. Directly after a harvesting event (CH or WTH), the soil solution pH sharply increased for 5 to 10 years before slowly declining over the remainder of the simulation (until year 2080). WTH acidified soils slightly more than CH, but in certain soil horizons there was practically no difference by the year 2080. Even though the pH in the WTH and CH scenario decreased with time as compared to the no-harvest scenario (NH), they did not drop to the levels observed around the peak of historic acidification (1980–1990), indicating that the pH decrease due to tree growth and harvesting would be less impactful than that of historic atmospheric acidification. Weathering rates differed across locations and horizons in response to historic acidification. In general, the predicted changes in weathering rates were very small, which can be explained by the net effect of decreased pH and increased Al3+, which affected the weathering rate in opposite ways. Similarly, weathering rates after the harvesting scenarios in 2020 remained largely unchanged according to the model.

scholarly journals Current, steady-state and historical weathering rates of base cations at two forest sites in northern and southern Sweden: a comparison of three methods

2020 ◽  
Vol 17 (2) ◽  
pp. 281-304 ◽  
Author(s):  
Sophie Casetou-Gustafson ◽  
Harald Grip ◽  
Stephen Hillier ◽  
Sune Linder ◽  
Bengt A. Olsson ◽  
...  
Keyword(s):  
Steady State ◽  
Soil Depth ◽  
Base Cations ◽  
Base Cation ◽  
Mineral Weathering ◽  
Soil Horizon ◽  
Soil Horizons ◽  
Weathering Rate ◽  
Weathering Rates ◽  
Forest Sites

Abstract. Reliable and accurate methods for estimating soil mineral weathering rates are required tools in evaluating the sustainability of increased harvesting of forest biomass and assessments of critical loads of acidity. A variety of methods that differ in concept, temporal and spatial scale, and data requirements are available for measuring weathering rates. In this study, causes of discrepancies in weathering rates between methods were analysed and were classified as being either conceptual (inevitable) or random. The release rates of base cations (BCs; Ca, Mg, K, Na) by weathering were estimated in podzolised glacial tills at two experimental forest sites, Asa and Flakaliden, in southern and northern Sweden, respectively. Three different methods were used: (i) historical weathering since deglaciation estimated by the depletion method, using Zr as the assumed inert reference; (ii) steady-state weathering rate estimated with the PROFILE model, based on quantitative analysis of soil mineralogy; and (iii) BC budget at stand scale, using measured deposition, leaching and changes in base cation stocks in biomass and soil over a period of 12 years. In the 0–50 cm soil horizon historical weathering of BCs was 10.6 and 34.1 mmolc m−2 yr−1, at Asa and Flakaliden, respectively. Corresponding values of PROFILE weathering rates were 37.1 and 42.7 mmolc m−2 yr−1. The PROFILE results indicated that steady-state weathering rate increased with soil depth as a function of exposed mineral surface area, reaching a maximum rate at 80 cm (Asa) and 60 cm (Flakaliden). In contrast, the depletion method indicated that the largest postglacial losses were in upper soil horizons, particularly at Flakaliden. With the exception of Mg and Ca in shallow soil horizons, PROFILE produced higher weathering rates than the depletion method, particularly of K and Na in deeper soil horizons. The lower weathering rates of the depletion method were partly explained by natural and anthropogenic variability in Zr gradients. The base cation budget approach produced significantly higher weathering rates of BCs, 134.6 mmolc m−2 yr−1 at Asa and 73.2 mmolc m−2 yr−1 at Flakaliden, due to high rates estimated for the nutrient elements Ca, Mg and K, whereas weathering rates were lower and similar to those for the depletion method (6.6 and 2.2 mmolc m−2 yr−1 at Asa and Flakaliden). The large discrepancy in weathering rates for Ca, Mg and K between the base cation budget approach and the other methods suggests additional sources for tree uptake in the soil not captured by measurements.

scholarly journals  Development of chemical soil properties in the western Ore Mts. (Czech Republic) 10 years after liming

2012 ◽  
Vol 58 (No. 2) ◽  
pp. 57-66 ◽  
Author(s):  
v. Šrámek ◽  
V. Fadrhonsová ◽  
L. Vortelová ◽  
B. Lomský
Keyword(s):  
Soil Chemistry ◽  
Magnesium Deficiency ◽  
Mineral Soil ◽  
Soil Layer ◽  
Base Cations ◽  
Base Saturation ◽  
Soil Layers ◽  
Humus Layer ◽  
Exchangeable Magnesium ◽  
Mg Content

The article focuses on changes in soil chemistry observed on plots limed in 2000 in the western Ore Mts.(Krušné hory) on the basis of chemical analyses done before liming and repeated in 2002, 2005 and 2010. In the deeper mineral soil (down to 30 cm), only the increase in pH and exchangeable magnesium was significant. The increase in exchangeable calcium in upper soil layers was significant in 2002 and 2005 only; ten years after liming the effect was negligible, although the number of Ca deficient samples was lower than in 2000. The exchangeable Mg content increased above the deficiency limit in all samples of upper soil, and an increase was also found in the deeper mineral soil. These changes were reflected in increasing base saturation and lower base cations/aluminium ratio in the organic and organomineral soil layer. Despite these positive shifts, calcium and magnesium deficiency and very low base saturation (< 10%) still prevail in the deeper mineral soil (2–30 cm) and are common even in the upper mineral soil. The increased total nitrogen level observed two and five years after liming indicated enhanced decomposition of the humus layer. On the other hand, N content in the upper organic (FH) horizon as well as in deeper mineral soil did not change significantly.  

Effect of calcined magnesite on soil and Pinus radiata foliage magnesium in pumice soils of New Zealand

Soil Research ◽  
1999 ◽  
Vol 37 (3) ◽  
pp. 545 ◽  
Author(s):  
A. D. Mitchell ◽  
P. Loganathan ◽  
T. W. Payn ◽  
R. W. Tillman
Keyword(s):  
New Zealand ◽  
Soil Solution ◽  
Soil Layer ◽  
Tree Breeding ◽  
Solution Ph ◽  
Mg Deficiency ◽  
Exchangeable Al ◽  
Forest Regions ◽  
New Type ◽  
Fertiliser Application

Magnesium (Mg) deficiency is common in a number of forest regions in the world. It has been linked to a condition in P. radiata called ‘upper mid crown yellowing’ (UMCY) in New Zealand and ‘new type forest decline’ in Europe. Mg concentrations are low in many of New Zealand"s forest soils. With increases in the number of rotations and increased growth rates through tree breeding, Mg deficiency is expected to increase. This study was conducted to determine the fate of calcined magnesite (calmag) fertiliser applied at 150 kg Mg/ha at 2 sites in the Kaingaroa Forest near Rotorua, New Zealand. It also investigated the effectiveness of calmag in increasing the soil solution and soil exchangeable Mg in pumice soils and Mg concentrations in the pine needles, and in reducing the likelihood of UMCY 2 and 3 years after fertiliser application. In both sites and for both years of sampling the application of calmag fertiliser resulted in a significant increase in soil exchangeable and soil solution Mg in the 0–5 cm soil layer. Soil and soil solution pH had also been increased in the top 5 cm soil layer. Two years after application about 90% of the fertiliser applied had dissolved and about 70–80% of the Mg remained in a plant-available form (ammonium acetate exchangeable Mg) in the top 10 cm of soil. Calculations suggest that 3–10% of applied fertiliser had been lost due to leaching. Magnesium fertiliser application also resulted in significant reduction in the exchangeable K: Mg ratio and reduced exchangeable Al in the 0–5 cm soil layer. After 3 years, foliar Mg concentrations increased at all sites in the fertilised trees compared with the control trees, although differences were not yet significant. UMCY severity in the trees was also not significantly affected by the application of Mg fertiliser.

scholarly journals Soil weathering rates in 21 catchments of the Canadian Shield

2012 ◽  
Vol 16 (3) ◽  
pp. 685-697 ◽  
Author(s):  
D. Houle ◽  
P. Lamoureux ◽  
N. Bélanger ◽  
M. Bouchard ◽  
C. Gagnon ◽  
...  
Keyword(s):  
Base Cations ◽  
Base Cation ◽  
High Reactivity ◽  
Mineral Weathering ◽  
Forest Growth ◽  
Canadian Shield ◽  
Geochemical Model ◽  
Soil Weathering ◽  
Weathering Rates ◽  
Profile Model

Abstract. Soil mineral weathering represents an essential source of nutrient base cation (Ca, Mg and K) for forest growth in addition to provide a buffering power against precipitation acidity for soils and surface waters. Weathering rates of base cations were obtained for 21 catchments located within the temperate and the boreal forest of the Canadian Shield with the geochemical model PROFILE. Weathering rates ranged from 0.58 to 4.46 kmolc ha−1 yr−1 and their spatial variation within the studied area was mostly in agreement with spatial variations in soil mineralogy. Weathering rates of Ca and Mg were significantly correlated (r = 0.80 and 0.64) with their respective lake concentrations. Weathering rates of K and Na did not correlate with lake concentrations of K and Na. The modeled weathering rates for each catchment were also compared with estimations of net catchment exportations. The result show that modeled weathering rates of Ca were not significantly different than the net catchment exportations while modeled weathering rates of Mg were higher by 51%. Larger differences were observed for K and Na weathering rates that were significantly different than net catchment exportations being 6.9 and 2.2 times higher than net exportations, respectively. The results for K were expected given its high reactivity with biotic compartments and suggest that most of the K produced by weathering reactions was retained within soil catchments and/or above ground biomass. This explanation does not apply to Na, however, which is a conservative element in forest ecosystems because of the insignificant needs of Na for soil microorganisms and above ground vegetations. It raises concern about the liability of the PROFILE model to provide reliable values of Na weathering rates. Overall, we concluded that the PROFILE model is powerful enough to reproduce spatial geographical gradients in weathering rates for relatively large areas as well as adequately predict absolute weathering rates values for the sum of base cations, Ca and Mg.

scholarly journals Soil weathering rates in 21 catchments of the Canadian Shield

2011 ◽  
Vol 8 (3) ◽  
pp. 5743-5768 ◽  
Author(s):  
D. Houle ◽  
P. Lamoureux ◽  
N. Bélanger ◽  
M. Bouchard ◽  
C. Gagnon ◽  
...  
Keyword(s):  
Base Cations ◽  
Base Cation ◽  
High Reactivity ◽  
Mineral Weathering ◽  
Forest Growth ◽  
Canadian Shield ◽  
Geochemical Model ◽  
Soil Weathering ◽  
Weathering Rates ◽  
Profile Model

Abstract. Soil mineral weathering represents an essential source of nutrient base cation (Ca, Mg and K) for forest growth in addition to provide a buffering power against precipitation acidity for soils and surface waters. Weathering rates of base cations were obtained for 21 catchments located within the temperate and the boreal forest of the Canadian Shield with the geochemical model PROFILE. Weathering rates ranged from 0.58 to 4.46 kmolc ha−1 yr−1 and their spatial variation within the studied area was mostly in agreement with spatial variations in soil mineralogy. Weathering rates of Ca and Mg were significantly correlated (r = 0.80 and 0.64) with their respective lake concentrations. Weathering rates of K and Na did not correlate with lake concentrations of K and Na. The modeled weathering rates for each catchment were also compared with estimations of net catchment exportations. The result show that modeled weathering rates of Ca were not significantly different than the net catchment exportations while modeled weathering rates of Mg were higher by 51 %. Larger differences were observed for K and Na weathering rates that were significantly different than net catchment exportations being 6.9 and 2.2 times higher than net exportations, respectively. The results for K were expected given its high reactivity with biotic compartments and suggest that most of the K produced by weathering reactions was retained within soil catchments and/or above ground biomass. This explanation does not apply to Na, however, which is a conservative element in forest ecosystems because of the insignificant needs of Na for soil microorganisms and above ground vegetations. It raises concern about the liability of the PROFILE model to provide reliable values of Na weathering rates. Overall, we concluded that the PROFILE model is powerful enough to reproduce spatial geographical gradients in weathering rates for relatively large areas as well as adequately predict absolute weathering rates values for the sum of base cations, Ca and Mg.

scholarly journals Catchment export of base cations: Improved mineral dissolution kinetics influence the role of water transit time

2019 ◽  
Author(s):  
Martin Erlandsson Lampa ◽  
Harald U. Sverdrup ◽  
Kevin H. Bishop ◽  
Salim Belyazid ◽  
Ali Ameli ◽  
...  
Keyword(s):  
Soil Water ◽  
Transit Time ◽  
Base Cations ◽  
Base Cation ◽  
Mineral Weathering ◽  
Mineral Dissolution ◽  
Catchment Scale ◽  
Major Step ◽  
Weathering Rates ◽  
Catchment Runoff

Abstract. Soil mineral weathering is one of the major sources of base cations (BC), which play a dual role for a forest ecosystem; they function both as plant nutrients, and for buffering against acidification of catchment runoff. On a long-term basis, the soil weathering rates will determine the highest sustainable forest productivity without causing acidification. It is believed that the hydrologic residence time plays a key role in determining weathering rates on a landscape scale. The weathering model PROFILE has been used for almost 30 years to calculate weathering rates in the rooting zone of forest soils. However, the mineral dissolution equations in PROFILE are not adapted for the unsaturated zone, and employing these equations on a catchment scale results in a significant over-prediction of base cation release rates to surface waters. In this study we use a revised set of PROFILE equations which, among other features, include retardation from silica concentrations. Relationships between the water transit time (WTT) and soil water concentrations were derived for each base cation, by simulating the soil water chemistry along a one-dimensional flowpath, using the mineralogy from a glacial till soil. We show how the revised PROFILE equations are able to reproduce patterns in BC- and Si-concentrations, as well as BC-ratios (Ca2+ / BC, Mg2++ / BC and Na+ / BC), observed in soil water profiles and catchment runoff. As opposed to the original set of PROFILE equations, the revised set of equations could reproduce how increasing WTT led to decreasing Na+ / BC, as well as increasing Ca2+ / BC and Mg2+ / BC. Furthermore, the total release of base cations from a hillslope was calculated using a mixing model, where water of different WTT was mixed according to an externally modelled WTT-distribution. The revised set of equations gave a 50 % lower base cation release (0.23 eq m−2 yr−1) than the original PROFILE equations, and are in better agreement with mass balance calculations of weathering rates. The results from this study thus demonstrate that the revised mineral dissolution equations for PROFILE are a major step forward in modelling weathering rates on a catchment scale.

scholarly journals Current, steady-state and historical weathering rates of base cations at two forest sites in northern and southern Sweden: A comparison of three methods

2019 ◽  
Author(s):  
Sophie Casetou-Gustafson ◽  
Harald Grip ◽  
Stephen Hillier ◽  
Sune Linder ◽  
Bengt A. Olsson ◽  
...  
Keyword(s):  
Steady State ◽  
Mass Balance ◽  
Soil Depth ◽  
Base Cations ◽  
Base Cation ◽  
Mineral Weathering ◽  
Soil Layers ◽  
Weathering Rate ◽  
Weathering Rates ◽  
Forest Sites

Abstract. Reliable and accurate methods for estimating soil mineral weathering rate are required tools in evaluating the sustainability of increased harvesting of forest biomass. A variety of methods that differ in concept, temporal and spatial scale and data requirements are available for measuring weathering rate. In this study, release rates of base cations through weathering were estimated in podsolised glacial tills at two experimental forest sites, Asa and Flakaliden, in southern and northern Sweden, respectively. Three different methods were used: (i) historical weathering since deglaciation estimated with the depletion method, using Zr as assumed inert reference; (ii) steady-state weathering rate estimated with the PROFILE model, based on quantitative analysis of soil mineralogy; and (iii) base cation mass balance at stand scale, using measured deposition, leaching and changes in base cation stocks in biomass and soil over a period of 12 years. In the 0–50 cm soil layer at Asa, historical weathering of Ca, Mg, K and Na estimated by the depletion method was 4.7, 3.1, 0.8 and 2.0 mmolc m−2 yr−1, respectively. Corresponding values at Flakaliden were 7.3, 9.0, 1.7 and 4.4 mmolc m−2 yr−1, respectively. Steady state weathering rate for Ca, Mg, K and Na estimated with PROFILE was 8.9, 3.8, 5.9 and 18.5 mmolc m−2 yr−1, respectively, at Asa and 11.9, 6.7, 6.6 and 17.5 mmolc m−2 yr−1, respectively, at Flakaliden. Thus at both sites, the PROFILE results indicated that steady-state weathering rate increased with soil depth as a function of exposed mineral surface area, reaching a maximum rate at 80 cm (Asa) and 60 cm (Flakaliden). In contrast, the depletion method indicated that the largest postglacial losses were in upper soil layers, particularly at Flakaliden. With the exception of Mg and Ca in shallow soil layers, PROFILE appeared to produce consistently higher weathering rates, particularly of K and Na in deeper soil layers. In contrast, the depletion method appeared to to produce consistently lower rather than higher weathering rates, due to natural and anthropogenic variability in (reference) Zr gradients. The mass balance approach produced significantly higher weathering rates of Ca, Mg, and K (65, 23, 40 mmolc m−2 yr−1 at Asa and 35, 14 and 22 mmolc m−2 yr−1 at Flakaliden), but lower Na weathering rates similar to the depletion method (6.6 and 2.2 mmolc m−2 yr−1 at Asa and Flakaliden). The large discrepancy in weathering rates for Ca, Mg and K between mass balance and the other methods suggest that there were additional sources for tree uptake in the soil besides weathering and measured depletion in exchangeable base cations.

scholarly journals Effect of simulated acid rain on growth and micronutrient uptake of okra (Abelmoschus esculentus) on coastal plain sands in Abia State, South-eastern, Nigeria

2020 ◽  
pp. 34-41
Keyword(s):  
Acid Rain ◽  
Foliar Spray ◽  
Growth Parameter ◽  
Simulated Acid Rain ◽  
Abelmoschus Esculentus ◽  
Control Treatment ◽  
Solution Ph ◽  
Shoot Height ◽  
Micronutrient Uptake ◽  
The Impact

The study was conducted in April, 2019 at Umudike to examine the impact of simulated acid rain (SAR) and frequency of SAR spray on growth and micronutrients content of okra (Abelmoschus esculentus (L.) Moench) in an ultisol at Umudike. The treatments consisted of three (3) pH levels: Coca-cola solution (pH 2.7) and SAR (pH 3.5 and 5.5) as well as control (water) and; three (3) frequency of foliar spray at 1, 2 and 3 day weekly, arranged according to their respective pH values and spray treatments in a completely randomized design (CRD) replicated three times. Plant leaves were analysis for micronutrients (Cu, Fe, Mn and Zn) content. The result shows that, under the stress of SAR and frequency of SAR application, growth parameters measured; leaf number, shoot height and leaf area were significantly reduced, compared to the control treatment. Nutritional analysis of the leaves also revealed that, the content micronutrients in okra, increased with declining pH value of AR and frequency of application, from pH 5.5 to pH 2.7. Coke solution (pH 2.7) and three (3) days per weekly application of SAR gave the highest reduction in plant growth parameter in Okra but, had higher increased in micronutrients content, respectively. Further result showed that okra (Abelmoschus esculentus (L.) Moench) is resistant to SAR from pH ≥5.5 in terms of growth and nutritional values.

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