scholarly journals The use of pre-dawn leaf water potential and MODIS LAI to explore seasonal trends in the phenology of Australian and southern African woodlands and savannas

2008 ◽  
Vol 56 (7) ◽  
pp. 557 ◽  
Author(s):  
Anthony R. Palmer ◽  
Sigfredo Fuentes ◽  
Daniel Taylor ◽  
Cate Macinnis-Ng ◽  
Melanie Zeppel ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Mean Value ◽  
Dry Season ◽  
Leaf Water ◽  
Wet Season ◽  
Area Index ◽  
Climate Change Research ◽  
Modis Lai

Trends in global soil moisture are needed to inform models of soil–plant–atmosphere interactions. Predawn leaf water potential (Ψpd), a surrogate for soil moisture and an index of plant water stress, has been routinely collected in Australian forests, woodlands and savannas, but the associated leaf area index (LAI) has seldom been available to enable the preparation of a Ψpd on LAI relationship. Following an analysis of Ψpd and MODIS LAI data from Australian forests, woodlands and savannas, we identified patterns in Ψpd which provide an understanding of the role of soil-moisture status in controlling LAI. In the savanna of northern Australia, the MODIS LAI product had a basal value of 0.96 during the dry season as compared with a mean value of 2.5 for the wet season. The dry season value is equivalent to the LAI of the tree component and corresponds with ground-truthed LAI. Ψpd is lowest (more negative) during the height of the dry season (late October) at −2.5 MPa, and highest (−0.1 MPa) during the wet season (early March). We present two models which predict Ψpd from the MODIS LAI product. These may be useful surrogates for studying trends in soil moisture in highly seasonal climates and may contribute to climate change research.

scholarly journals Seasonal leaf gas exchange and water potential in a woody cerrado species community

2004 ◽  
Vol 16 (1) ◽  
pp. 7-16 ◽  
Author(s):  
Carlos Henrique Britto de Assis Prado ◽  
Zhang Wenhui ◽  
Manuel Humberto Cardoza Rojas ◽  
Gustavo Maia Souza
Keyword(s):  
Gas Exchange ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Leaf Gas Exchange ◽  
Water Status ◽  
Dry Season ◽  
Leaf Water ◽  
Wet Season ◽  
Leaf Water Status ◽  
Mean Values

Predawn leaf water potential (psipd) and morning values of leaf gas exchange, as net photosynthesis (A), stomatal conductance (gs), transpiration (E), and morning leaf water potential (psimn) were determined seasonally in 22 woody cerrado species growing under natural conditions. Despite the lower mean values of psipd in the dry season (-0.35 ± 0.23 MPa) compared to the wet season (-0.08 ± 0.03 MPa), the lowest psipd in the dry season (-0.90 ± 0.00 MPa) still showed a good nocturnal leaf water status recovery for all species studied through out the year. Mean gs values dropped 78 % in the dry season, when the vapor pressure of the air was 80% greater than in the wet season. This reduction in gs led to an average reduction of 33% in both A and E, enabling the maintainance of water use efficiency (WUE) during the dry season. Network connectance analysis detected a change in the relationship between leaf gas exchange and psimn in the dry season, mainly between gs-E and E-WUE. A slight global connectance value increase (7.25 %) suggested there was no severe water stress during the dry season. Multivariate analysis showed no link between seasonal response and species deciduousness, suggesting similar behavior in remaining leaves for most of the studied species concerning leaf gas exchange and psimn under natural drought.

Towards a spatial understanding of water use of several land-cover classes: an examination of relationships amongst pre-dawn leaf water potential, vegetation water use, aridity and MODIS LAI

Ecohydrology ◽  
2009 ◽  
pp. n/a-n/a ◽  
Author(s):  
Anthony R. Palmer ◽  
Sigfredo Fuentes ◽  
Daniel Taylor ◽  
Cate Macinnis-Ng ◽  
Melanie Zeppel ◽  
...  
Keyword(s):  
Land Cover ◽  
Water Potential ◽  
Water Use ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Potential Vegetation ◽  
Spatial Understanding ◽  
Vegetation Water ◽  
Modis Lai

Criteria for Scheduling the Irrigation of wheat

1981 ◽  
Vol 17 (2) ◽  
pp. 157-162 ◽  
Author(s):  
R. D. Misra ◽  
P. C. Pant
Keyword(s):  
Soil Moisture ◽  
Field Experiment ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Sandy Loam ◽  
Leaf Water ◽  
Pan Evaporation ◽  
Loam Soil ◽  
Moisture Conditions ◽  
Better Than

SUMMARYA field experiment evaluating criteria for scheduling wheat irrigation was conducted from 1975 to 1977 in a sandy loam soil with treatments scheduled according to physiological stages, soil moisture conditions, pan evaporation and leaf water potential. Grain and straw yields, spikes/m, fertile spikelets/spike and number and weight of grains/spike were significantly influenced by treatments. Irrigation based on leaf water potential was as good as when based on physiological stages or soil moisture, and the use of pan evaporation was no better than other methods of scheduling.

scholarly journals AN EVALUATION OF DIFFERENT MULCHES USED IN SOIL MOISTURE CONSERVATION OF COCONUT LANDS

CORD ◽  
1998 ◽  
Vol 14 (02) ◽  
pp. 34
Author(s):  
Vidhana Arachchi L P
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Bare Soil ◽  
Leaf Water ◽  
Dry Period ◽  
Water Losses ◽  
Different Types ◽  
Ecological Region ◽  
Soil Moisture Status

An investigation on the ability ofdifferent types of mulches to conserve soil moisture and their effect on coconutpalm (Dwarfx Tall; CRIC 65) was carried out in Madampe soil series at Bandirripuwa Estate, Lunuwila located in agro ecological region of IL3 of Sri Lanka. Different types ofmulches compared in this study were dried coconut fronds and leaves, cover crop with Pueraria phasioloides and Brachiaria milliformis versus bare soil (Control). Soil moisture status was monitored using the neutron scattering technique. Leaf water potential of coconut with respect to different treatments was also monitored during dryperiod   Results showed that Brachiaria milliformis and Pueraria phasioloides extracted significantly (p<0.001) more waterfrom soils than diied mulch and the control. The amount of water extracted in the above treatments were 74.4Yo, 62.5Yo, 59.79yo and 61.3% respectively. However, the extraction was not significantly different when the rainfall was greater than 100 mm. About 33 mm of water retained in Brachiaria milliformis introduced soil profiles even by the end of dry period Water losses by Pueraria phasioloides grown plots, specially through evapotranspiration, were 1higher in initial stages of the dry period, but later stage losses were lower than that of Brachiaria due to defoliation of Pueraria leaves during severe dry period Leaf water potential of coconut with respect to stress conditions of different treatments revealed that Pueraria phasioloides and Brachiaria milliformis did not adversely affect coconut palm grown in Madampe series, although those live materials extracted more waterfrom soilprofile compared to the other treatments. In general, dry mulching wasfound to be the most efficient moisture conservative practice that can be adoptedfor coconut lands.

Plant hydraulics accentuates the effects of atmospheric moisture stress on transpiration

2020 ◽  
Author(s):  
Alexandra Konings ◽  
Yanlan Liu ◽  
Mukesh Kumar ◽  
Xue Feng ◽  
Gabriel Katul
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Moisture Stress ◽  
Hydraulic Model ◽  
Leaf Water ◽  
Empirical Approach ◽  
Joint Control ◽  
Atmospheric Moisture ◽  
Plant Hydraulics

&lt;p&gt;Transpiration directly links the water, energy and carbon cycles. It is commonly restricted by soil (through soil moisture) and atmospheric (through vapor pressure deficit, VPD) moisture stresses governed by the movement of water through plants, also known as plant hydraulics. These sources of moisture stress are likely to diverge under climate change, with globally enhanced VPD due to increased air temperatures but more variable and uncertain changes in soil moisture. In most Earth system and land surface models, the ET response to each of the two stresses is evaluated through independent empirical relations, while neglecting plant hydraulics. Comparison of these two models is challenged by the difficulty of ensuring any perceived differences are due to the model structure, not an imperfect parametrization. Here, we use a model-data fusion approach applied to long-term ET records collected at 40 sites across a diverse range of biomes to demonstrate that the widely used empirical approach underestimates ET sensitivity to VPD, but compensates by overestimating the sensitivity to soil moisture stress. The bias originates from the joint control of leaf water potential on plant response to soil moisture and VPD stress. To a lesser degree, it also overestimates from increased sensitivity to VPD under dry (low leaf water potential) conditions in the plant hydraulic model. As a result, a hydraulic model captures ET under high-VPD conditions for wide-ranging soil moisture states better than the empirical approach does. Our findings highlight the central role of plant hydraulics in regulating the increasing importance of atmospheric moisture stress on biosphere-atmosphere interactions under elevated temperatures.&lt;/p&gt;

Effect of snow removal on leaf water potential, soil moisture, leaf and soil nutrient status and leaf peroxidase activity of sugar maple

1994 ◽  
Vol 162 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Christian E. Pilon ◽  
Beno�t C�t� ◽  
James W. Fyles
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Peroxidase Activity ◽  
Sugar Maple ◽  
Soil Nutrient ◽  
Nutrient Status ◽  
Leaf Water ◽  
Soil Nutrient Status ◽  
Snow Removal

scholarly journals Water relations of field-grown grapevines in the São Francisco Valley, Brazil, under different rootstocks and irrigation strategies

2009 ◽  
Vol 66 (4) ◽  
pp. 436-446 ◽  
Author(s):  
Claudia Rita de Souza ◽  
Luís Henrique Bassoi ◽  
José Moacir Pinheiro Lima Filho ◽  
Fabrício Francisco Santos da Silva ◽  
Leandro Hespanhol Viana ◽  
...  
Keyword(s):  
Water Potential ◽  
Root System ◽  
Water Relations ◽  
Leaf Water Potential ◽  
Water Status ◽  
Irrigation Management ◽  
Leaf Water ◽  
Stem Water Potential ◽  
Area Index ◽  
Grape Quality

There is an increased demand for high quality winegrapes in the São Francisco Valley, a new wine producing area in Brazil. As the grape quality is closely linked to the soil water status, understanding the effects of rootstock and irrigation management on grapevine water relations is essential to optimize yield and quality. This study was carried out to investigate the effects of irrigation strategies and rootstocks on water relations and scion vigour of field-grown grapevines in Petrolina, Pernambuco state, Brazil. The cultivars used as scions are Moscato Canelli and Syrah, both grafted onto IAC 572 and 1103 Paulsen rootstocks. The following water treatments were used: deficit irrigation, with holding water after veraison; and partial root-zone drying, supplying (100% of crop evapotranspiration) of the water loss to only one side of the root system after fruit set, alternating the sides periodically (about 24 days). In general, all treatments had values of pre-dawn leaf water potential higher than -0.2 MPa, suggesting absence of water stress. The vine water status was more affected by rootstock type than irrigation strategies. Both cultivars grafted on IAC 572 had the highest values of midday leaf water potential and stem water potential, measured on non-transpiring leaves, which were bagged with both plastic sheet and aluminum foil at least 1 h before measurements. For both cultivars, the stomatal conductance (g s), transpiration (E) and leaf area index (LAI) were also more affected by roostsotck type than by irrigation strategies. The IAC 572 rootstock presented higher g s, E and LAI than the 1103 Paulsen. Differences in vegetative vigor of the scion grafted onto IAC 572 rootstocks were related to its higher leaf specific hydraulic conductance and deeper root system as compared to the 1103 Paulsen, which increased the water-extraction capability, resulting in a better vine water status.

The Water Relations of Allosyncarpia ternata (Myrtaceae) at Contrasting Sites in the Monsoonal Tropics of Northern Australia

1997 ◽  
Vol 45 (2) ◽  
pp. 259 ◽  
Author(s):  
I. R. Fordyce ◽  
G. A. Duff ◽  
D. Eamus
Keyword(s):  
Seasonal Variation ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Water Relations ◽  
Leaf Water Potential ◽  
Dry Season ◽  
Leaf Water ◽  
Northern Australia ◽  
Leaf Water Relations ◽  
Arnhem Land

Allosyncarpia ternata S.T.Blake (Myrtaceae) is an evergreen tree, restricted largely to rocky habitats on the Arnhem Land Plateau in the wet–dry tropics of northern Australia. Allosyncarpia ternata grows in a wide range of habitats, including sites near permanent springs, where it forms a distinctive closed-canopy forest with an understorey of rainforest plants, and sites on exposed cliffs and hilltops, where it occurs in open forest and woodland. Leaf water relations differ markedly between these contrasting sites. During the dry season, trees at open sites show strong diurnal hysteresis in stomatal conductance (gs); afternoon depressions in gs coincide with regular afternoon increases in vapour pressure deficit. Pressure–volume analyses indicate that A. ternata maintains turgor down to leaf water potential values of about –2.8 MPa, close to the minimum experienced by hilltop leaves late in the dry season. By contrast, trees on the ravine floor, with year-round access to water, exhibit much smaller diurnal and seasonal variation in stomatal conductance and little seasonal variation in leaf water potential. It is concluded that this flexible response in leaf water relations to seasonally dry conditions is partly responsible for the ability of A. ternata to occupy and dominate the vegetation in such a wide variety of habitats. The near confinement of the species to the Arnhem Land Plateau is in part due to the water-holding capacity of the bedrock.

LEAF WATER POTENTIAL AND CWSI OF SWEET SORGHUM IN RELATION TO THE AVAILABLE SOIL MOISTURE

1993 ◽  
pp. 219-226
Author(s):  
R. Stricevic ◽  
V. Pocuca ◽  
R. Cvetkovic ◽  
N. Jovanovic
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Sweet Sorghum ◽  
Leaf Water ◽  
Available Soil Moisture

scholarly journals LEAF WATER POTENTIAL OF THE PURPLE ELEPHANT GRASS, PENNISETUM PURPUREUM SCHUMACH. (POACEAE) AND IT�S RELATIONSHIP WITH SOIL MOISTURE

2018 ◽  
Vol 11 (22) ◽  
pp. 1-7
Author(s):  
Euriel Mill�n-Romero ◽  
Andr�s Mass-Cruz ◽  
Yerye Chajin-Salcedo ◽  
Carlos Mill�n-P�ramo ◽  
◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Pennisetum Purpureum ◽  
Elephant Grass
Sign in / Sign up

Export Citation Format

Share Document