scholarly journals Scaling xylem sap flux and soil water balance and calculating variance: a method for partitioning water flux in forests

1998 ◽  
Vol 55 (1-2) ◽  
pp. 191-216 ◽  
Author(s):  
Ram Oren ◽  
Nathan Phillips ◽  
Gabriel Katul ◽  
Brent E. Ewers ◽  
Diane E. Pataki
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Xylem Sap ◽  
Water Flux ◽  
Soil Water Balance ◽  
Sap Flux ◽  
Xylem Sap Flux

Tree-soil-water relations in a mature temperate forest under elevated CO2

2021 ◽  
Author(s):  
Susan Quick ◽  
Giulio Curioni ◽  
Phillip J Blaen ◽  
Stefan Krause ◽  
Angus Robert MacKenzie
Keyword(s):  
Carbon Dioxide ◽  
Soil Water ◽  
Temperate Forest ◽  
Xylem Sap ◽  
Pedunculate Oak ◽  
Plant Water ◽  
Sap Flux ◽  
Water Usage ◽  
Individual Trees ◽  
Xylem Sap Flux

<p>Extreme anthropogenic global change, such as increasing atmospheric carbon dioxide, can challenge long-lived organisms including trees. Carbon uptake by trees, during photosynthesis, is inevitably accompanied by leaf transpiration; elevated atmospheric CO<sub>2</sub> is, therefore, expected to reduce daytime plant water usage. The Free-Air Carbon-dioxide Enhancement (FACE) experiment at the Birmingham Institute of Forest Research (BIFoR) UK manipulates atmospheric CO<sub>2</sub> in a 150 year old mixed deciduous temperate forest. In the sub-project described here, we compare diurnal and seasonal plant-water dynamics from individual trees under treatment (elevated CO<sub>2</sub>) and control conditions<sub>.</sub> Response of Pedunculate oak (Quercus robur), as the dominant tree species, is reported for the initial three years of elevated CO<sub>2</sub>, enabling us to characterise whether the woodland is starting to adapt. Xylem sap flux measurement reflects tree water usage and has been used as a proxy for transpiration at stand scale in forest experiments. This project explores a modified sap flux analysis approach, enabling individual trees to be compared and responses to be scaled up to treatment patch level. It considers: inputs-outputs (e.g. precipitation, transpiration), water flow (e.g. xylem sap flux), temperature and radiation to see how tree-soil-water interfaces behave and change with increased CO<sub>2. </sub>Measurement methods include spot observations (phenology, porometry), and data-logged measures (e.g. of soil moisture and xylem flow). Initially sap flux and stomatal conductance are considered in comparison with previous reported studies of tree water use efficiency and estimations of water storage. By considering these key measurements driven by a tree-centred view the results provide valuable data to improve vegetation, soil and landscape models and increase understanding of trees in mature future- forest environments.</p>

scholarly journals Evaluation of DSSAT soil-water balance module under cropped and bare soil conditions

2003 ◽  
Vol 46 (4) ◽  
pp. 489-498 ◽  
Author(s):  
Rogério Teixeira de Faria ◽  
Walter Truman Bowen
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Soil Water ◽  
Water Flux ◽  
Soil Water Potential ◽  
Bare Soil ◽  
Root Water Uptake ◽  
Soil Water Balance ◽  
Soil Conditions ◽  
Soil Water Flux

The performance of the soil water balance module (SWBM) in the models of DSSAT v3.5 was evaluated against soil moisture data measured in bare soil and dry bean plots, in Paraná, southern Brazil. Under bare soil, the SWBM showed a low performance to simulate soil moisture profiles due to inadequacies of the method used to calculate unsaturated soil water flux. Improved estimates were achieved by modifying the SWBM with the use of Darcy's equation to simulate soil water flux as a function of soil water potential gradient between consecutive soil layers. When used to simulate water balance for the bean crop, the modified SWBM improved soil moisture estimation but underpredicted crop yield. Root water uptake data indicated that assumptions on the original method limited plant water extraction for the soil in the study area. This was corrected by replacing empirical coefficients with measured values of soil hydraulic conductivity at different depths.

Soil water balance dynamics under plastic mulching in dryland rainfed agroecosystem across the Loess Plateau

2021 ◽  
Vol 312 ◽  
pp. 107354 ◽  
Author(s):  
Ai-Tian Ren ◽  
Rui Zhou ◽  
Fei Mo ◽  
Shu-Tong Liu ◽  
Ji-Yuan Li ◽  
...  
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Loess Plateau ◽  
Soil Water Balance ◽  
The Loess Plateau ◽  
Plastic Mulching ◽  
Balance Dynamics
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