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Evaluation of trends in wheat yield models
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Ferguson, M. C. |
| Copyright Year | 1982 |
| Description | Trend terms in models for wheat yield in the U.S. Great Plains for the years 1932 to 1976 are evaluated. The subset of meteorological variables yielding the largest adjusted R(2) is selected using the method of leaps and bounds. Latent root regression is used to eliminate multicollinearities, and generalized ridge regression is used to introduce bias to provide stability in the data matrix. The regression model used provides for two trends in each of two models: a dependent model in which the trend line is piece-wise continuous, and an independent model in which the trend line is discontinuous at the year of the slope change. It was found that the trend lines best describing the wheat yields consisted of combinations of increasing, decreasing, and constant trend: four combinations for the dependent model and seven for the independent model. |
| File Size | 21467542 |
| Page Count | 123 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19830019053 |
| Archival Resource Key | ark:/13960/t4mm15657 |
| Language | English |
| Publisher Date | 1982-12-01 |
| Access Restriction | Open |
| Subject Keyword | Earth Resources And Remote Sensing Earth Resources Program Agristars Project Meteorological Parameters Correlation Coefficients Independent Variables Collinearity Yield Mathematical Models Regression Analysis Great Plains Corridor North America Wheat Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
