DORMANCY AND NONDORMANCY ALFALFA YIELD AND EVAPOTRANSPIRATION

Although living alfalfa plants show no elongation during dormancy, evapotranspiration (ET) can occur. The yield of the first harvest and dormancy ET could be statistically correlated as it is correlated during the growing season. The objective of this study was to evaluate the statistical correlations of yield and ET and of water use efficiency (WUE) and ET during dormancy and nondormancy. The correlations involving data from several years, with four harvests per growing season, were evaluated based on slopes and intercepts. Six data points for which dormancy ET was known were added to evaluate the statistical fit. Correlations between yield and ET for various harvests had one common slope but different intercepts; the same was true for the correlation between WUE and ET, except the latter correlation was weak in terms of R(2). Average values of ET and the corresponding estimated yield showed that between one-third and half of the observed average water loss during dormancy fit the estimated yield and ET correlation. The remaining amount appeared to be an extra water loss during dormancy.