A model for the impact of soil solution Ca: Al ratio, soil moisture and temperature on tree base cation uptake

1992 ◽  
Vol 61 (3-4) ◽  
pp. 365-383 ◽  
Author(s):  
H. Sverdrup ◽  
P. Warfvinge ◽  
Kaj Ros�n
Keyword(s):  
Soil Moisture ◽  
Soil Solution ◽  
Base Cation ◽  
Cation Uptake ◽  
The Impact

Effects of grassland afforestation on exchangeable soil and soil solution aluminium

Soil Research ◽  
2001 ◽  
Vol 39 (5) ◽  
pp. 1003 ◽  
Author(s):  
M. L. Adams ◽  
M. R. Davis ◽  
K. J. Powell
Keyword(s):  
Forest Soil ◽  
Soil Solution ◽  
Base Cation ◽  
Pinus Nigra ◽  
Base Saturation ◽  
Conifer Forest ◽  
Forest Sites ◽  
Hill Slope ◽  
Soil Solutions ◽  
The Impact

The impact of land use change from grassland to conifer forest on the aluminium (Al) concentrations in soils and soil solutions was examined. Soils from grassland were compared with those from adjoining 15–19-year old forest stands at 3 contrasting pairs of sites in South Island, New Zealand. The site pairs were on a terrace [Pinus nigra/P. ponderosa, and grassland (CP)], and a hill slope [Pseudotsuga menziesii and grassland (CF)] in the Craigieburn range, Canterbury, and a hill slope in the Lammerlaw Range, Otago [P. radiata and grassland (LP)]. The sites had never been cultivated or fertilised, and for each pair the forest and grassland were similar in terms of soil and topography. The 1 M KCl exchangeable and 0.02 M CaCl 2 extractable Al levels at 0–10 cm were higher in forest than in grassland topsoil at CP and LP (P < 0.01). In soil solutions there was a trend for both ‘reactive Al’ and Al bound in labile organic complexes to be higher in forest soil at all sites, but site-pair differences were only significant at LP, and only for ‘reactive Al’. The increase in ‘reactive Al’ at this site was linked to the low pH and low base saturation. The ratios of exchangeable and soil solution Ca 2+ and Mg 2+ to ‘reactive Al’ were substantially lower in forest than grassland soils at all sites. Aluminium complexation capacity (Al-CC) values at all sites were higher in forest soil solutions than in grassland soil solutions. For the grassland and forest sites at LP, the Al-CC correlated strongly with the amount of soluble fulvic and humic matter present, as estimated from soil solution UV absorbance at 250 nm. In soils with the lowest percentage base saturation and buffering capacity (LP), afforestation of pastoral grassland with Pinus radiata significantly reduced soil pH and base cation levels, while increasing both soil and soil solution Al concentrations. Under such conditions (base saturation <20%), the increase in ‘reactive Al’ concentrations in soil solutions under fast growing conifer tree species may be sufficient to affect Mg uptake.

Base cation availability and leaching after nitrogen fertilisation of a eucalypt plantation

Soil Research ◽  
2008 ◽  
Vol 46 (5) ◽  
pp. 445 ◽  
Author(s):  
A. D. Mitchell ◽  
P. J. Smethurst
Keyword(s):  
Soil Solution ◽  
Surface Soil ◽  
Base Cations ◽  
Base Cation ◽  
Solution Chemistry ◽  
Future Research ◽  
Soil Solution Chemistry ◽  
Cation Uptake ◽  
Eucalypt Plantations ◽  
N Treatment

Increasing use of nitrogen fertiliser in eucalypt plantations is affecting base cation availability via changes in concentrations in soil solution and leaching. While low base cation availability will probably limit future productivity of some eucalypt plantations, the extent and temporal patterns of availability as affected by N fertilisation were unknown. After applying urea in a fertiliser experiment in a 9-year-old Eucalyptus nitens plantation, soil solution chemistry was monitored for 13 months and maximum potential leaching estimated. The cumulative effects of earlier ammonium sulfate, urea, and superphosphate fertiliser applications had enhanced tree growth, base cation uptake, and probably leaching, but led to decreased pH and concentrations of exchangeable pools of Mg and K in surface soil (0–0.1 m). In soil solution before re-fertilisation, in the high N treatment, concentrations of K in soil solution were significantly lower, and of Ca significantly higher than the treatment that received no fertiliser. On many occasions during the 13-month period after this re-fertilisation event, increased concentrations of NH4, NO3, Ca, Mg, and K in soil solution were significant (0–0.6 m depth), and were consistently highest in the high fertiliser treatment at 0.3–0.6 m depth. We conclude that N fertilisation increased base cation availability during the study and probably for several subsequent years, but there was a risk that significant pools of N and base cations were leached off-site. Future research and modelling of base cation availability in plantations should consider these changes induced by N-fertiliser that increase availability for several years but lead to longer term decreases in availability.

scholarly journals Soil Moisture Dynamics in Response to Precipitation and Thinning in a Semi-Dry Forest in Northern Mexico

Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 105
Author(s):  
Argelia E. Rascón-Ramos ◽  
Martín Martínez-Salvador ◽  
Gabriel Sosa-Pérez ◽  
Federico Villarreal-Guerrero ◽  
Alfredo Pinedo-Alvarez ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Forest Management ◽  
Water Availability ◽  
Dry Forest ◽  
Rainfall Events ◽  
Rainfall Characteristics ◽  
Northern Mexico ◽  
The Difference ◽  
The Impact ◽  
Moisture Dynamics

Understanding soil moisture behavior in semi-dry forests is essential for evaluating the impact of forest management on water availability. The objective of the study was to analyze soil moisture based in storm observations in three micro-catchments (0.19, 0.20, and 0.27 ha) with similar tree densities, and subject to different thinning intensities in a semi-dry forest in Chihuahua, Mexico. Vegetation, soil characteristics, precipitation, and volumetric water content were measured before thinning (2018), and after 0%, 40%, and 80% thinning for each micro-catchment (2019). Soil moisture was low and relatively similar among the three micro-catchments in 2018 (mean = 8.5%), and only large rainfall events (>30 mm) increased soil moisture significantly (29–52%). After thinning, soil moisture was higher and significantly different among the micro-catchments only during small rainfall events (<10 mm), while a difference was not noted during large events. The difference before–after during small rainfall events was not significant for the control (0% thinning); whereas 40% and 80% thinning increased soil moisture significantly by 40% and 53%, respectively. Knowledge of the response of soil moisture as a result of thinning and rainfall characteristics has important implications, especially for evaluating the impact of forest management on water availability.

scholarly journals Towards Including Dynamic Vegetation Parameters in the EUMETSAT H SAF ASCAT Soil Moisture Products

2021 ◽  
Vol 13 (8) ◽  
pp. 1463
Author(s):  
Susan C. Steele-Dunne ◽  
Sebastian Hahn ◽  
Wolfgang Wagner ◽  
Mariette Vreugdenhil
Keyword(s):  
Soil Moisture ◽  
Interannual Variability ◽  
Incidence Angle ◽  
Pearson Correlation ◽  
The United States ◽  
Research Network ◽  
Window Width ◽  
High Frequency Variability ◽  
Vegetation Parameters ◽  
The Impact

The TU Wien Soil Moisture Retrieval (TUW SMR) approach is used to produce several operational soil moisture products from the Advanced Scatterometer (ASCAT) on the Metop series of satellites as part of the EUMETSAT Satellite Application Facility on Support to Operational Hydrology and Water Management (H SAF). The incidence angle dependence of backscatter is described by a second-order Taylor polynomial, the coefficients of which are used to normalize ASCAT observations to the reference incidence angle of 40∘ and for correcting vegetation effects. Recently, a kernel smoother was developed to estimate the coefficients dynamically, in order to account for interannual variability. In this study, we used the kernel smoother for estimating these coefficients, where we distinguished for the first time between their two uses, meaning that we used a short and fixed window width for the backscatter normalisation while we tested different window widths for optimizing the vegetation correction. In particular, we investigated the impact of using the dynamic vegetation parameters on soil moisture retrieval. We compared soil moisture retrievals based on the dynamic vegetation parameters to those estimated using the current operational approach by examining their agreement, in terms of the Pearson correlation coefficient, unbiased RMSE and bias with respect to in situ soil moisture. Data from the United States Climate Research Network were used to study the influence of climate class and land cover type on performance. The sensitivity to the kernel smoother half-width was also investigated. Results show that estimating the vegetation parameters with the kernel smoother can yield an improvement when there is interannual variability in vegetation due to a trend or a change in the amplitude or timing of the seasonal cycle. However, using the kernel smoother introduces high-frequency variability in the dynamic vegetation parameters, particularly for shorter kernel half-widths.

scholarly journals A GNSS-IR Method for Retrieving Soil Moisture Content from Integrated Multi-Satellite Data That Accounts for the Impact of Vegetation Moisture Content

2021 ◽  
Vol 13 (13) ◽  
pp. 2442
Author(s):  
Jichao Lv ◽  
Rui Zhang ◽  
Jinsheng Tu ◽  
Mingjie Liao ◽  
Jiatai Pang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Satellite Data ◽  
Vegetation Index ◽  
Soil Moisture Content ◽  
Support Vector ◽  
Observation Data ◽  
Multipath Effect ◽  
Mars Model ◽  
The Impact

There are two problems with using global navigation satellite system-interferometric reflectometry (GNSS-IR) to retrieve the soil moisture content (SMC) from single-satellite data: the difference between the reflection regions, and the difficulty in circumventing the impact of seasonal vegetation growth on reflected microwave signals. This study presents a multivariate adaptive regression spline (MARS) SMC retrieval model based on integrated multi-satellite data on the impact of the vegetation moisture content (VMC). The normalized microwave reflection index (NMRI) calculated with the multipath effect is mapped to the normalized difference vegetation index (NDVI) to estimate and eliminate the impact of VMC. A MARS model for retrieving the SMC from multi-satellite data is established based on the phase shift. To examine its reliability, the MARS model was compared with a multiple linear regression (MLR) model, a backpropagation neural network (BPNN) model, and a support vector regression (SVR) model in terms of the retrieval accuracy with time-series observation data collected at a typical station. The MARS model proposed in this study effectively retrieved the SMC, with a correlation coefficient (R2) of 0.916 and a root-mean-square error (RMSE) of 0.021 cm3/cm3. The elimination of the vegetation impact led to 3.7%, 13.9%, 11.7%, and 16.6% increases in R2 and 31.3%, 79.7%, 49.0%, and 90.5% decreases in the RMSE for the SMC retrieved by the MLR, BPNN, SVR, and MARS model, respectively. The results demonstrated the feasibility of correcting the vegetation changes based on the multipath effect and the reliability of the MARS model in retrieving the SMC.

scholarly journals Influence of Land Cover and Soil Moisture on the Horizontal Distribution of Sensible and Latent Heat Fluxes in Southeast Kansas during IHOP_2002 and CASES-97

2007 ◽  
Vol 8 (1) ◽  
pp. 68-87 ◽  
Author(s):  
Margaret A. LeMone ◽  
Fei Chen ◽  
Joseph G. Alfieri ◽  
Mukul Tewari ◽  
Bart Geerts ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Latent Heat ◽  
Land Surface ◽  
Field Experiments ◽  
Time Of Day ◽  
Horizontal Distribution ◽  
Heat Fluxes ◽  
Surface Model ◽  
Green Vegetation ◽  
The Impact

Abstract Analyses of daytime fair-weather aircraft and surface-flux tower data from the May–June 2002 International H2O Project (IHOP_2002) and the April–May 1997 Cooperative Atmosphere Surface Exchange Study (CASES-97) are used to document the role of vegetation, soil moisture, and terrain in determining the horizontal variability of latent heat LE and sensible heat H along a 46-km flight track in southeast Kansas. Combining the two field experiments clearly reveals the strong influence of vegetation cover, with H maxima over sparse/dormant vegetation, and H minima over green vegetation; and, to a lesser extent, LE maxima over green vegetation, and LE minima over sparse/dormant vegetation. If the small number of cases is producing the correct trend, other effects of vegetation and the impact of soil moisture emerge through examining the slope ΔxyLE/ΔxyH for the best-fit straight line for plots of time-averaged LE as a function of time-averaged H over the area. Based on the surface energy balance, H + LE = Rnet − Gsfc, where Rnet is the net radiation and Gsfc is the flux into the soil; Rnet − Gsfc ∼ constant over the area implies an approximately −1 slope. Right after rainfall, H and LE vary too little horizontally to define a slope. After sufficient drying to produce enough horizontal variation to define a slope, a steep (∼−2) slope emerges. The slope becomes shallower and better defined with time as H and LE horizontal variability increases. Similarly, the slope becomes more negative with moister soils. In addition, the slope can change with time of day due to phase differences in H and LE. These trends are based on land surface model (LSM) runs and observations collected under nearly clear skies; the vegetation is unstressed for the days examined. LSM runs suggest terrain may also play a role, but observational support is weak.

Drought spatiotemporal propagation via land feedbacks

2021 ◽  
Author(s):  
Diego G. Miralles ◽  
Dominik L. Schumacher ◽  
Jessica Keune ◽  
Paul A. Dirmeyer
Keyword(s):  
Soil Moisture ◽  
Water Vapor ◽  
Mitigation Strategies ◽  
Soil Drought ◽  
The Usa ◽  
Forecast Models ◽  
Atmospheric Feedbacks ◽  
Dry Out ◽  
Water And Food Security ◽  
The Impact

&lt;p&gt;The predicted increase in drought occurrence and intensity will pose serious threats to global future water and food security. This was hinted by several historically unprecedented droughts over the last two decades, taking place in Europe, Australia, Amazonia or the USA. It has been hypothesised that the strength of these events responded to self-reinforcement processes related to land&amp;#8211;atmospheric feedbacks: as rainfall deficits dry out soil and vegetation, the evaporation of land water is reduced, then the local air becomes too dry to yield rainfall, which further enhances drought conditions. Despite the 'local' nature of these feedbacks, their consequences can be remote, as downwind regions may rely on evaporated water transported by winds from drought-affected locations. Following this rationale, droughts may not only self-reinforce locally, due to land atmospheric feedbacks, but &lt;em&gt;self-propagate&lt;/em&gt; in the downwind direction, always conditioned on atmospheric circulation. This propagation is not only meteorological but relies on soil moisture drought, and may lead to a downwind cascading of impacts on water resources. However, a global capacity to observe these processes is lacking, and thus our knowledge of how droughts start and evolve, and how this may change as climate changes, remains limited. Furthermore, climate and forecast models are still immature when it comes to representing the influences of land on rainfall.&lt;/p&gt;&lt;p&gt;Here, the largest global drought events are studied to unravel the role of land&amp;#8211;atmosphere feedbacks during the spatiotemporal propagation of these events. We based our study on satellite and reanalysis records of soil moisture, evaporation, air humidity, winds and precipitation, in combination with a Lagrangian framework that can map water vapor trajectories and explore multi-dimensional feedbacks. We estimate the reduction in precipitation in the direction of drought propagation that is caused by the upwind soil moisture drought, and isolate this effect from the influence of potential evaporation and circulation changes. By doing so, the downwind lack of precipitation caused by upwind soil drought via water vapor deficits, and hence the impact of drought self-propagation, is determined. We show that droughts occurring in dryland regions are particularly prone to self-propagate, as evaporation there tends to respond strongly to enhanced soil stress and precipitation is frequently convective. This kind of knowledge may be used to improve climate and forecast models and can be exploited to develop geo-engineering mitigation strategies to help prevent drought events from aggravating during their early stages.&lt;/p&gt;

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