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SOYWEED: A Simulation Model of Soybean and Common Cocklebur Growth and Competition
Author(s) -
Wilkerson G. G.,
Jones J. W.,
Coble H. D.,
Gunsolus J. L.
Publication year - 1990
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1990.00021962008200050033x
Subject(s) - weed , competition (biology) , agronomy , crop , canopy , weed control , leaf area index , biology , ecology
The yield reduction caused by a particular weed species depends not only on weed density, but also on many other factors which affect both crop and weed growth through time. The objective of this study was to develop a simulation model of crop/weed competition which could be used to investigate the effects of environmental conditions on weed and crop growth. A previously developed soybean crop growth model was used to simulate the growth of soybean [ Glycine max (L.) Merr.]. A weed growth model was developed and coupled with the soybean model to describe growth of weed and soybean growing together and competing for resources. Published data from a field experiment were used to determine model parameters for common cocklebur ( Xanthium strumarium L.). In the combined soybean‐weed model, only competition for light and water are considered. Competition for light occurs within an “area of influence” around each weed. The size of this area depends on weed canopy diameter, which increases as a function of weed leaf area. Competition for water has been modeled by using a field average total leaf area (weeds and soybean) in the calculation of potential transpiration. The model developed from 1 yr of data fit data from another year reasonably well. The approach developed in this research is a practical way for modeling crop/weed competition which incorporates both the effect of environment on growth processes and the nonuniform effect of a weed on crop plants at different distances from the weed.