Determination of temperature and time thresholds for BIOTIC irrigation of peanut on the Southern High Plains of Texas

Abstract

The timely application of irrigation water to a crop is essential for optimizing yield and production efficiency. 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. One of the goals of this paper is to document the gradual development of the method and its implementation. Two threshold values are required to implement BIOTIC irrigation of a crop in a given region, a species-specific temperature 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 average amount of time each day that the canopy temperature of the well-watered crop will exceed the temperature threshold, is calculated from weather data. Interest in the use of BIOTIC for irrigation scheduling for peanut ( Arachis hypogaea L.) resulted in this study in which the temperature and time thresholds for peanut were determined on the Texas Southern High Plains. A temperature threshold value of 27°C was determined from the thermal dependence of the reappearance of photosystem II variable fluorescence (PSII Fv) following illumination. A time threshold of 405 min was calculated from an analysis of weather data collected over the course of the 1999 growing season. The determination of these threshold values for peanut provides the basis for the application of the BIOTIC protocol to irrigation scheduling of peanut on the Southern High Plains of Texas.