The Alpert–Stein Factor Separation Methodology (FS) method has been utilized in the study of the biophysical response to changes in the environment to assess the relative contribution of different atmospheric factors to the biological system. In this chapter we will discuss crop simulation and land surface model-based assessments of the sensitivity to past and future changes in climatic conditions: increasing CO2, soil moisture, temperature and radiative conditions, and crop management procedures (irrigation). FS is applied to discern specific contributions to plant responses by single variables or combinations of environmental conditions. Our FS analysis has shown that it is important to understand that biological responses are inherently dependent on multiple variables in the natural world and should not be limited to assessments of single specific parameters.

Introduction

In this chapter we demonstrate how the FS analysis technique is a useful tool for crop–climate change (crop-clim) studies. Important interactions between the atmosphere and biophysical processes occur under land surface and atmospheric carbon dioxide (CO2) level changes. We employ the Alpert–Stein FS Methodology (Stein and Alpert, 1993; Alpert, 1997) to investigate the direct as well as the interactive effects of soil moisture, temperature, and radiative changes on the direct effects of CO2 doubling for different land-use/vegetation types, including agricultural production.