Changes in groundwater oscillations, soil water content and evapotranspiration as the water table declined in an area with deep rooted phreatophytes

Ecohydrology ◽  
2015 ◽  
Vol 9 (6) ◽  
pp. 1082-1093 ◽  
Author(s):  
D.A. Devitt ◽  
B. Bird
2013 ◽  
Vol 864-867 ◽  
pp. 2298-2301
Author(s):  
Jiang Bo Han ◽  
Zhi Fang Zhou

To obtain a better understanding of the role of non-isothermal flow in the unsaturated zone in the presence of the water table, the isothermal and non-isothermal models driven by the observed atmospheric data were used to reproduce soil moisture dynamics observed in the lysimeter with a 100-cm water table level over one year period. Results from the simulations indicated that although the isothermal and non-isothermal models both captured the general trend of soil water content dynamics during one year period, simulated values by the isothermal model presented less dynamic variations, which overestimated the soil water content during the rainy season and underestimated it during other periods. On the other hand, the non-isothermal model not only reproduced well the seasonal variations of soil temperatures but also reproduced more reasonably soil water dynamics in the whole profile and during the whole simulation period.


1996 ◽  
Vol 26 (1) ◽  
pp. 53-62 ◽  
Author(s):  
R.L. Rothwell ◽  
U. Silins ◽  
G.R. Hillman

Hydrologic drainage criteria that describe the position of the water table between adjacent ditches are commonly used to assess the initial effectiveness of peatland drainage projects for tree growth improvement. However, these criteria do not reflect the soil conditions that regulate tree growth and performance after drainage. The effect of three drainage ditch spacings (30, 40, and 50 m) on the spatial variability of soil water conditions at three drained boreal Alberta peatlands was studied. Soil water content (0–30 cm depth) was found to be insensitive (p = 0.686) to drainage ditch spacing several years after drainage. Greater variation was observed between different sampling locations (p = 0.024) relative to the position of the ditch edge within similar ditch spacings. Spatial distribution of soil water in the unsaturated zone was found to be inversely related to the degree of water table lowering. Spatial patterns of soil water content were strongly associated with changes to substrate bulk density resulting from post-drainage peatland subsidence.


Soil Research ◽  
2016 ◽  
Vol 54 (3) ◽  
pp. 311 ◽  
Author(s):  
I. Goodrick ◽  
S. Connor ◽  
M. I. Bird ◽  
P. N. Nelson

Tropical forests play a key role in the global carbon cycle. However, little is known about carbon cycling in the substantial portion of tropical forests that are low-lying, with shallow and fluctuating water tables. This study aimed to determine what factors control emissions of CO2 from soil in a riparian rainforest in Queensland, Australia. Emissions were measured over the course of 1 year, using static chambers. Emission rates were significantly related to soil temperature (0–0.1 m depth), soil water content (0–0.12 m depth) and depth to water table. The most efficient linear model of emissions as a function of measured parameters, which also included soil pH (0–0.1 m depth), had r2 = 0.355. CO2 emissions were highest (5.2–7.5 μmol m–2 s–1) at moderate soil temperature (24−28°C), water table depth (0.2–1.5 m) and soil water-filled porosity (0.25–0.79). They were lowest (<0.5 μmol m–2 s–1) at low soil temperature (<22°C) or when the water table was within 0.15 m of the surface. An additional interaction between temperature and soil water was determined in the laboratory. Incubation of soil cores showed that temperature sensitivity of the heterotrophic component of respiration increased as the soil dried. It is clear that models of soil respiration in lowland tropical forests should take into account depth to water table, which is a key, but hitherto unreported, controller of CO2 emissions in tropical forests.


Author(s):  
M.C.H.Mouat Pieter Nes

Reduction in water content of a soil increased the concentration of ammonium and nitrate in solution, but had no effect on the concentration of phosphate. The corresponding reduction in the quantity of phosphate in solution caused an equivalent reduction in the response of ryegrass to applied phosphate. Keywords: soil solution, soil water content, phosphate, ryegrass, nutrition.


2010 ◽  
Vol 59 (1) ◽  
pp. 157-164 ◽  
Author(s):  
E. Tóth ◽  
Cs. Farkas

Soil biological properties and CO2emission were compared in undisturbed grass and regularly disked rows of a peach plantation. Higher nutrient content and biological activity were found in the undisturbed, grass-covered rows. Significantly higher CO2fluxes were measured in this treatment at almost all the measurement times, in all the soil water content ranges, except the one in which the volumetric soil water content was higher than 45%. The obtained results indicated that in addition to the favourable effect of soil tillage on soil aeration, regular soil disturbance reduces soil microbial activity and soil CO2emission.


Author(s):  
Justyna Szerement ◽  
Aleksandra Woszczyk ◽  
Agnieszka Szyplowska ◽  
Marcin Kafarski ◽  
Arkadiusz Lewandowski ◽  
...  

2014 ◽  
Vol 22 (3) ◽  
pp. 300-307
Author(s):  
Meijun ZHANG ◽  
Wude YANG ◽  
Meichen FENG ◽  
Yun DUAN ◽  
Mingming TANG ◽  
...  

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