Modification of the GRAMI Model for Cotton

A new version of the GRAMI crop model capable of being calibrated within season was developed and tested for cotton (Gossypium hirsutum L.) production in semiarid regions. The model was first verified using field data obtained at Halfway, TX, USA in 2002. The model was then validated using data sets obtained at Lamesa, TX in 1999 and 2001 and at Lubbock, TX in 2002 and 2004. Simulated values of cotton growth and lint yield showed reasonable agreement with corresponding measurements under irrigated conditions. The new model not only has simple input requirements but is also easy to use. Thus, it promises to have applicability to be expanded to other semiarid regions for irrigated cotton production and to have applicability to regional cotton growth monitoring and lint yield mapping projects.