J. Shen et al., INCORPORATION OF A SUBSURFACE TILE DRAINAGE COMPONENT INTO A SOYBEAN GROWTH-MODEL, Transactions of the ASAE, 41(5), 1998, pp. 1305-1313
A Simple tile drainage model was incorporated into a recent version of
the CROPGRO-soybean model. The model was calibrated and validated usi
ng four years of data from the Water Quality Research site, located at
the Iowa State University Northeast-Research Center near Nashua, Iowa
having two soil types (Readlyn and Kenyon). The data consisted of mea
surements of soil water contents at different depths and times, cumula
tive monthly tile pow, and final crop yield from 36 different 0.41 ha
plots that were individually tile drained. The model was calibrated to
give the best fit between the predicted and measured tile flow, soil
water content, and crop yield from 1993 and 1994 for each soil type. I
t was validated by using data from 1995 and 1996 for each soil type. P
redicted soil water contents, tile drainage and soybean yield matched
measured values very well over all years for these two soil types. The
results of this study show that the modified CROPGRO model does a ver
y good job in simulating soybean yields and water dynamics for Readlyn
and Kenyon soil in the experiment.