| Summary: | Paper copies in Archives, Acc #:2013-0059 It is well known that the rate at which a plant grows is influenced by air temperature. The problem is to define this relationship in a quantitative manner so that the information can be applied to agricultural problems. In places where growth of a particular crop is limited by the length of the growing season, an evaluation of the "heat-units" available is particularly important. Many heat-unit systems have evolved over the years, with certain advantages claimed for each. In crop production, heat unit systems are used to estimate the time required for a crop to go from one stage of development to another, usually from planting to harvest. Each heat-unit system produces a particular set of values, the values being determined by the relationship between temperature and growth that is assumed in the calculations. This paper lists heat-units available in six areas in Alaska, all having agricultural potential. The system used measures temperature in "growing-degree units" and is described in detail. Recent comparative studies of growing season and growing degree days leads to the conclusion that the temperature records taken at Big Delta may have been favorably affected by the nearness of the weather recording station to an extensive coated runway. The "flywheel" effect of this large heat sink appear to have reduced the occurrence of 32°F. night temperatures in both the spring and fall, making the growing degree accumulation unrealistic. Introduction and general comments -- Description of Stations -- Results and discussion -- Summary -- References -- Appendix -- Figures: Fig. 1 Average weekly growing degree units for Matanuska Experiment Station; Big Delta; University Experiment Station, Fairbanks; Homer; Kasilof; and Kodiak. Fig. 2 Seasonal growing degree unites (May 15 to 1st 30°F or lower temperature in fall) which will be equaled or exceeded for varying probability levels at Big Delta, Matanuska Experiment Station and University Experiment Station, Fairbanks. Fig. 3 ...
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