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| Web URL(s): | https://dl.sciencesocieties.org/publications/cs/pdfs/45/1/0209
Last checked: 03/29/2016
Requires: PDF Reader |
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| Publication Type:
| Refereed |
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| Author(s): | Steppuhn, H.;
van Genuchten, M. Th.;
Grieve, C. M. |
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| Author Affiliation: | Steppuhn: Semiarid Prairie Agricultural Research Centre, Agriculture and Agri-Food Canada, Swift Current, Saskatchewan, Canada; van Genuchten: Soil Physics/Pesticide Unit, George E. Brown, Jr. Salinity Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Riverside, California; and Grieve: Plant Sciences Group, George E. Brown, Jr. Salinity Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Riverside, California |
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| Title: | Root-zone salinity: I. Selecting a product - yield index and response function for crop tolerance |
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| Section: | Crop ecology, management & quality
Other records with the "Crop ecology, management & quality" Section
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| Source: | Crop Science. Vol. 45, No. 1, January/February 2005, p. 209-220. |
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| Publishing Information: | Madison, WI: Crop Science Society of America |
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| # of Pages: | 12 |
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| Keywords: | TIC Keywords: Root zone; Salinity; Soil salinity; Yield response; Measurement; Salt tolerance
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| Abstract/Contents: | "Six empirical functions were compared for describing the product yields of agricultural crops grown while subject to increasing levels of root-zone salinity. The four nonlinear functions fit the test data from a spring wheat (Triticum aestivum L., cv. Biggar) experiment conducted in Canada's Salt Tolerance Testing Facility closer than the two liner functions. Although each of the four nonlinear declining functions could reasonably describe the data, the modified compound-discount equation recorded the lowest root mean square error and the highest R2 value. Additional response data using the nonlinear discount function obtained from 33 separate trials averaged 11% closer in statistical fit and 45% lower in statistical error than the best linear function. The discount function {Yr = 1/(1 + [(C/C50)exp(sC50)]} follows a sigmoidal form and relates relative yield (Yr) to a measure of root-zone salinity (C) such as the solute concentration with an electrical conductivity of an equivalent saturated soil paste extract (ECe). This function features two parameters the salinity level producing 50% of the nonsaline crop yield (C50) and the absolute vale of the general decline in relative yield with salinity at and near C50, the steepness constant (s). These parameters combine to form a single-value, salinity-tolerance index (ST-Index) consisting of the 50% reduction in crop yield (C50) plus the tendency to maintain some product yield as the crop is subjected to increasing salinity levels approaching C50, i.e., ST-Index = C50 + s(C50). The ST-Index for the Biggar wheat registered 6.44. Approximations for C50 and s can be derived from the threshold salinity (Ct) and declining slope (b) parameters of the threshold-slope linear response function [Yr = 1 - b(C - Ct)]. Procedures for converting Ct to C50 and b to s offer linkages between these linear and nonlinear response function parameters, and are further explored in this paper's companion. The resulting ST-Index-values equal 6.56, 9.43, and 5.67 for sample field (corn, Zea mays L.), forage (alfalfa, Medicago sativa L. and falcata L.), and vegetable (radish, Raphanus sativus L.) crops, respectively." |
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| Language: | English |
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| References: | 107 |
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| Note: | Tables
Graphs |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Steppuhn, H., C. M. Grieve, and M. Th. van Genuchten. 2005. Root-zone salinity: I. Selecting a product - yield index and response function for crop tolerance. Crop Sci. 45(1):p. 209-220. |
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https://dl.sciencesocieties.org/publications/cs/pdfs/45/1/0209
Last checked: 03/29/2016
Requires: PDF Reader |
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MSU catalog number: SB 183 .C7 |
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