Alfalfa Leaf Area as a Function of Dry Matter1

Abstract

This study was undertaken to determine the relationship between leaf area and dry matter of alfalfa (Medicago sativa L.) to obtain leaf area estimates without having to make the time‐consuming area measurements directly. Alfalfa samples were taken from a wellwatered field crop during three growing seasons at the University of Minnesota‐St. Paul campus. Additional data were collected from the literature. A logarithmic transformation of the leaf area (LA), the leaf dry matter (LDM), and the total dry matter (TDM) data indicated that the relationships between LA‐LDM and LA‐TDM were not significantly different between data collected from our field study and those obtained from the literature. The relationships derived from both sources of data are: LA = 28.7 LDM0.993 and LA = 10.7 TDM0.992, where LA is in m2, and LDM and TDM are in kg. The standard error of estimate equalled 0.089 and 0.1 11 for the regression of LA on LDM and LA on TDM, respectively. The LA‐LDM and LATDM correlation coefficients (r) were greater than 0.99 and 0.99, respectively. These results indicate that leaf dry matter and, under some experimental situations, total dry matter determinations, can be used to estimate alfalfa LA in lieu of electronic meters or determining the leaf area‐dry weight ratio.