Leaf Area Development in Field‐Grown Soybeans1

Author:
  • TST. R. Sinclair
    T. R. Sinclair
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Abstract
Leaf area is critical for crop light interception, and thereby has a substantial influence on crop yield. In this research an attempt was made to characterize the development of soybean [Glycine max(L.) Merr.] leaf area by examining the process in two phases. First, the rate of increase of plastochron index as a function of temperature was evaluated under field conditions. A total of seven cultivars was studied during three cropping seasons on Arredondo fine sand (loamy siliceous hyperthermic Grossarenic Paleudalf). A linear response was confirmed in the rate of increase in plastochron index to temperature with a base temperature of 9 to 11°C for most cultivars. Second, an allometric model for predicting plant leaf area from plastochron index was developed. The same medel with differing coefficients was found to work well for all cultivars. A simplified procedure for estimating the coefficients of the model was developed and found to result in good predictions of leaf area from plastochron index.