Growing wheat in Biosphere 2 under elevated CO2: observations and modeling.

Area of Science:

• Agricultural Science
• Plant Physiology
• Environmental Science

Background:

• The Intensive Agricultural Biome (IAB) of Biosphere 2 provides a unique environment for studying crop growth under controlled conditions.
• Understanding plant responses to environmental factors is crucial for developing sustainable agriculture and life support systems.

Purpose of the Study:

• To assess the growth and development of spring wheat (Triticum aestivum L., cv. Yecora Rojo) within the IAB.
• To validate the CERES-Wheat crop growth model's performance in a novel, enclosed environment.
• To analyze factors influencing wheat photosynthetic efficiency in the IAB.

Main Methods:

• Spring wheat was cultivated in the IAB during the 1995-1996 winter/spring season.
• Environmental parameters including temperature, relative humidity, CO2 concentration, and light intensity were monitored.
• Above-ground biomass and phenological stages were recorded weekly.
• The CERES-Wheat model was employed to simulate and analyze crop growth data.

Main Results:

• CERES-Wheat accurately simulated Biosphere 2 wheat growth, predicting phenological stages and dry matter production within 10% of observed values.
• Normalized dry matter production rates indicated photosynthetic efficiencies intermediate between field conditions and NASA's Controlled Ecological Life-Support Systems (CELSS).
• Low light levels within the IAB were identified as the primary factor affecting photosynthetic efficiency, with contributions from elevated CO2 and diffuse light.

Conclusions:

• Wheat growth in the IAB is comparable to that in other documented environments, validating the suitability of the IAB for agricultural research.
• The CERES-Wheat model is a reliable tool for simulating crop growth in controlled environments like Biosphere 2.
• Optimizing light conditions is essential for enhancing photosynthetic efficiency and crop yield in enclosed agricultural systems.