A Macroscopic Water Extraction Model for Nonuniform Transient Salinity and Water Stress

2002 ◽  
Vol 66 (6) ◽  
pp. 1764-1772 ◽  
Author(s):  
M. Homaee ◽  
R. A. Feddes ◽  
C. Dirksen
Keyword(s):  
Water Stress ◽  
Water Extraction ◽  
Extraction Model

scholarly journals Yield, transpiration efficiency, and water-use variations and their interrelationships in the sorghum reference collection

2011 ◽  
Vol 62 (8) ◽  
pp. 645 ◽  
Author(s):  
V. Vadez ◽  
L. Krishnamurthy ◽  
C. T. Hash ◽  
H. D. Upadhyaya ◽  
A. K. Borrell
Keyword(s):  
Water Stress ◽  
Grain Filling ◽  
Water Extraction ◽  
Transpiration Efficiency ◽  
Total Water ◽  
Multilinear Regression ◽  
Extraction Capacity ◽  
Terminal Drought ◽  
Multilinear Regression Analysis ◽  
Treatment Interaction

Sorghum is well adapted to water-limited conditions, but the traits responsible for this enhanced adaptation under drought conditions remain unclear. In this study, yield, transpiration efficiency (TE) and water extraction were assessed in 149 germplasm entries from the sorghum reference set (plus three control cultivars) using a lysimetric system under terminal water stress and fully irrigated conditions outdoors. A 10-fold range for grain yield and harvest index (HI), 2-fold range for TE and a 1.25-fold variation for water extraction were observed under terminal water stress conditions. Transpiration efficiency and water extraction under water stress related poorly to that under fully irrigated conditions, reflecting a large genotype-by-water treatment interaction. Under drought stress, total water extraction varied by ~3 L plant–1 among germplasm. Entries from the Durra race had highest water extraction capacity, whereas Caudatum-Bicolor and Caudatum-Durra intermediate races had poor water extraction. Durra, Caudatum and Caudatum-Guinea races had highest TE, whereas the Guinea race had the lowest. Although yield was closely related to HI, at any level of HI there were substantial yield differences that remained unexplained, and these residual yield variations were closely related to TE (R2 = 0.60). Similarly, substantial yield variations that were still not explained by HI or TE were closely related to the total water extracted under water stress (R2 = 0.35). A multilinear regression analysis confirmed these results and showed the importance of water extraction during grain filling. Therefore, next to HI, the yield differences under terminal drought in sorghum were driven by TE, and then next by water extraction. The large genetic variation for TE and water extraction offer great breeding opportunities and in particular, highlight the Durra race as a critical source of variation.

Response of four grain legumes to water stress in south-eastern Queensland. II.Plant growth and soil water extraction patterns

1982 ◽  
Vol 33 (3) ◽  
pp. 497 ◽  
Author(s):  
RJ Lawn
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Water Use ◽  
Developmental Plasticity ◽  
Water Extraction ◽  
Green Gram ◽  
Black Gram ◽  
Drought Period ◽  
Soil Water Extraction ◽  
Dehydration Avoidance

Growth and water use of soybean (Glycine max), black gram (Vigna mungo), green gram (V. radiata) and cowpea (V. unguiculata) in response to water stress were evaluated in the field at Dalby in southeast Queensland. Differing strategies of growth and water use which reflected the differential expression of dehydration avoidance and developmental plasticity in response to stress were identified among species. The primary difference between strategies related to differences in dehydration avoidance. Soil water extraction during the initial phases of drought was faster, and leaf area development and plant growth were relatively less affected, in soybean than in the Vigna spp. Where adequate soil water existed, these differences were sustained during the drought period but were reversed where soil water was limited. Soil water extraction by soybean occurred to greater depths, and to lower potentials, than in the Vigna spp. Developmental plasticity influenced growth pattern in the Vigna spp. to varying degrees. Drought periods invariably curtailed growth and hastened maturity in green gram and black gram, but rain prior to maturity induced renewed growth in black gram. Moderate stress curtailed growth and hastened maturity in cowpea, which also responded to late rains with renewed growth. Severe stress inhibited growth and delayed development in cowpea indefinitely.

A framework for quantifying water extraction and water stress responses of perennial lucerne

2009 ◽  
Vol 60 (8) ◽  
pp. 785 ◽  
Author(s):  
Hamish E. Brown ◽  
Derrick J. Moot ◽  
Andrew L. Fletcher ◽  
Peter D. Jamieson
Keyword(s):  
Water Stress ◽  
Water Supply ◽  
Soil Water ◽  
Stress Responses ◽  
Soil Profile ◽  
Potential Evapotranspiration ◽  
Soil Layer ◽  
Water Extraction ◽  
Crop Models ◽  
Wide Range

A generic framework was developed and validated for predicting the water extraction and water stress responses of perennial lucerne (Medicago sativa) to improve existing crop models. Perennial forages have roots established throughout a soil profile so require a different approach to quantify water extraction patterns than annual crops. Two years of experimental data from two fields in New Zealand, each containing dryland and irrigated lucerne crops, were analysed to develop the theory of the water extraction framework. This showed that the temporal pattern of water extraction was consistent and each year commenced in the shallowest layer and progressed downward. Water extraction from each soil layer was quantified as the minimum of soil water supply and crop demand for that layer. For each soil layer, water demand was represented by transpiration demand (the product of potential evapotranspiration and crop cover) minus the sum of water extraction in overlying layers. This approach gave accurate descriptions of water extraction patterns over a range of rainfall and irrigation situations. Water supply from each soil layer (l) was quantified as the product of plant-available water and an extraction rate constant (kll). The kll of lucerne could not be calculated using the traditional curve-fitting procedure so kll was calculated by integrating the water extraction framework described above with a soil water balance and fitting kll to minimise residuals for water extraction predictions in each soil layer. This gave kll values that decreased from 0.035/day in the 0–0.2 m layer of soil to 0.01/day in the deepest layer measured (1.8–2.3 m). The water extraction framework was validated against another 3 years of dryland and irrigated lucerne data and gave accurate predictions of water extraction patterns throughout the soil profile. Water stress was quantified from actual transpiration relative to transpiration demand (T/TD). The most sensitive variable was leaf area expansion, which decreased from an optimum at T/TD = 1 to zero at T/TD = 0.2, followed by radiation-use efficiency, which decreased from an optimum at T/TD = 1 to zero at a T/TD of zero. The framework for quantifying water extraction and the techniques determined for identifying appropriate parameters to measure and characterise the framework are expected to be generally applicable to perennial forages in a wide range of environments.

Comparing forms and solutions of the single root soil water extraction model

1982 ◽  
Vol 2 (4) ◽  
pp. 347-357 ◽  
Author(s):  
Reuven Steinhardt ◽  
Rienk R. Van der Ploeg ◽  
Wilfried Ehlers
Keyword(s):  
Soil Water ◽  
Water Extraction ◽  
Single Root ◽  
Soil Water Extraction ◽  
Extraction Model
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