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ARS Home » Research » Publications at this Location » Publication #63511


item Sinclair, Thomas

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Drought is a chronic problem in all cropping systems which lead to decreased yields. Important in assessing the impact of drought on yield is understanding the relationship between soil water content and physiological traits such as transpiration and leaf area development. For field pea, none of these relationships have been developed, so the objective of this research was to undertake greenhouse and field experiments to obtain these relationships. Initial pot studies showed consistent relationships for two pea cultivars. There was virtually no decrease in transpiration or leaf growth until about 60% of the available soil water had been lost. After this point, both processes declined linearly. These relationships were found to describe results in independent greenhouse and field studies. These relationships can be used in modeling efforts to evaluate field pea development, growth and yield.

Technical Abstract: No quantitative functions existed to describe transpiration rates and leaf expansion rates of drought-stressed pea (Pisum sativum) plants relative to well-watered plants. Such functions are especially important in analyses of the effects of water deficit periods on crop yielding capability under a range of field conditions. This research was undertaken in both pot and field experiments to develop and evaluate drought-stress functions for transpiration and leaf area expansion. The level of water deficit was characterized as the fraction of transpirable soil water (FTSW). In both processes, little or no decrease in activity was observed until FTSW reached about 0.4, and then there was a roughly linear decrease through FTSW equal to 0. Comparison of the functions for transpiration and leaf area expansion for independent pot studies and field studies showed good agreement. These experiments provide functions that can be used to predict the response of pea crops to the development of soil water deficits.