Submitted to: Irrigation Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/8/2004
Publication Date: 2/22/2005
Citation: Mahan, J.R., Burke, J.J., Wanjura, D.F. 2005. Determination of temperature and time thresholds for BIOTIC irrigation of peanuts on the Texas Southern High Plains. Irrigation Science. 23:145-152. Interpretive Summary: The BIOTIC method for irrigation scheduling has been developed over the past decade. Since it developed gradually, the approaches and methods for its implementation have developed and changed. Interest in the application of the BIOTIC method to irrigation of peanuts on the southern high plains of Texas resulted in studies to determine the time and temperature thresholds required for the method. In this paper, the most current method for the implementation of BIOTIC are described for peanuts. Additionally, this paper describes the recommended methodology for BIOTIC implementation in any crop species desired.
Technical Abstract: The Biologically Identified Optimal Temperature Interactive Console (BIOTIC) is an irrigation protocol that provides irrigation scheduling based upon measurements of canopy temperatures and the temperature optimum of the crop species of interest. Two threshold values are required to implement BIOTIC irrigation of a crop in a given region; a species-specific ctemperature threshold and a species/environment-specific time threshold. The temperature threshold, an indication of the thermal optimum for the plant, is derived from the thermal dependence of its metabolism. The time threshold, which represents the daily time that the canopy temperature of the well-watered crop will exceed the temperature threshold, is calculated from environmental data. Interest in the use of BIOTIC for irrigation scheduling for peanuts resulted in this study in which the temperature and time thresholds for peanuts were determined on the southern high plains of Texas. A temperature threshold value of 27 deg C was determined from the thermal dependence of the reappearance of photosystem II variable fluorescence (PSII Fv) following illumination. A time threshold of 405 minutes was calculated from an analysis of environmental data collected over the course of the 1999 growing season. The determination of these threshold values for peanuts provides the basis for the application of the BIOTIC protocol to irrigation scheduling of peanuts on the southern high plains of Texas.