Dormancy and Nondormancy Alfalfa Yield and Evapotranspiration

Although living alfalfa plants show no elongation during dormancy, evapotranspiration $\left(\mathrm{ET}\right)$ can occur. The yield of the first harvest and dormancy $\mathrm{ET}$ 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 $\mathrm{ET}$ and of water use efficiency (WUE) and $\mathrm{ET}$ 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 $\mathrm{ET}$ was known were added to evaluate the statistical fit. Correlations between yield and $\mathrm{ET}$ for various harvests had one common slope but different intercepts; the same was true for the correlation between WUE and $\mathrm{ET}$, except the latter correlation was weak in terms of $R^2$. Average values of $\mathrm{ET}$ 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 $\mathrm{ET}$ correlation. The remaining amount appeared to be an extra water loss during dormancy.