Field-Scale Crop Modeling to Assist in Separation of Environment and Genetics.

Quantifying small-scale spatial variability in environmental and crop interactions could provide valuable information to support the analysis of field trials. The PALMScot model, developed by combining the PALMS and Cotton2K models, was designed as a grid based model to deterministically calculate mass and energy dynamics at a fine spatial and temporal resolution. The PALMScot model has been used successfully in the Southern High Plains of Texas to quantify water use in cotton in research and production scale fields, e.g., ~ 9 ha and 40 – 70 ha. In this study, PALMScot was used to calculate potential cotton crop water balance dynamics across an experimental field (~ 5.6 ha, 330 × 170 m) near Lubbock, Texas. Water balance variables were calculated using PALMScot on a 3 × 3 m grid across the experimental field for three growing seasons. Development of the input for the model was based on grid soil sampling (30 × 30 m), real-time kinematic global positioning system elevation measurements (3 × 3 m), hourly weather station measurements collected adjacent to the field, and daily irrigation log records. The spatial variability in calculated water balance variables was translated to the spatial layout of research plots across the field. Calculated values were used by collaborators as covariates to assist in the separation of environmental and genetic influences on measured phenological differences.