Data from the Arizona FACE (Free-Air CO2 Enrichment) Experiments on Sorghum at Ample and Limiting Levels of Water Supply

Abstract

Two free-air CO₂ enrichment (FACE) experiments were conducted on sorghum (Sorghum bicolor (L.) Möench, a C₄ grain crop) at Maricopa, Arizona, U.S.A. during the 1998 and 1999 summer growing seasons. They were conducted at ample and limited (50% of ample) supplies of water. A large and varied set of data on plant, soil, and microclimatic responses to the elevated CO₂ and its interactions with the water supply was collected. The dataset assembled herein consists of many of these data, including those generally used for model validation, such as management, soils, daily and 15-minute weather, physiology (net photosynthesis, plant water potential, relative water content), phenology, biomass growth, leaf area, yield, canopy temperatures, energy balance, evapotranspiration, soil moisture, reflectance and vegetation indices, and absorption of photosynthetically active radiation. Partitioning of nitrogen between nitrate and cyanide, which affects toxicity of the sorghum forage to livestock, was measured. In addition, isotopic methods were used to trace carbon flows in both FACE and Control plots from atmosphere to plant material to soil carbon pools. The dataset is useful for validation of sorghum growth models, which get used to predict likely future sorghum productivity given projected global climate change.