نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Introduction
This temperature varies for each species, but there is a linear relationship between growing degree-days and plant growth rate. Growing degree-days (GDD) are used to classify plants by their flowering date, to estimate harvest maturity, and to predict the length of time between two growth stages. In a study in Ardabil, the findings indicated that the temperature of the region is correlated with the temperature of corn growth, and based on the zoning, about 16% of the total area of the province was identified as very suitable, 22% as suitable, 27% as moderate, and about 35% as unsuitable for corn cultivation. The aim of this study is to zone GDD and identify ranges of cumulative growth degree days, which can be used to more accurately determine the amount of crop cultivation and their production management in different counties of Isfahan province.
Materials and Methods
In this study, 30-year daily temperature statistics (minimum, maximum, and average) from 33 meteorological stations were used to calculate GDD and growing season length (1984 to 2021). To calculate thermal units, the first growing season length for temperature thresholds of 5°C and 10°C was extracted using the Jillosy coding method (March 3rd with code 1 and March 2nd with code 365), and then the growing season thermal units were calculated by subtracting the average daily temperature from the base temperature. Finally, zoning maps were drawn for each indicator in Arc GIS. Despite different definitions of the growing season, temperature and humidity play a special role in all of these definitions. According to the definition of the World Meteorological Organization's Commission on Climatology/Climate Variability, the length of the growing season is the time interval between the first period after July 10th in which the average daily temperature is above 5°C for at least 6 consecutive days (as the starting point) and the first 6-day period with an average daily temperature below 5°C (as the ending point).
Results and Discussion
The cities of Isfahan province were divided into 4 groups based on a base temperature of 5°C, which received a range of 2500 to 5000-degree days of temperature growth. This number changed from 1500 to 4500 degrees Celsius for a base temperature of 10°C. Based on a base temperature of 5°C, the shortest growing season length of 114-200 days was observed in the western and southern regions of the province, and the longest growing season length of 365-331 days was observed in the northern and eastern regions of Isfahan province. For a base temperature of 10°C, a similar geographical trend was observed, with the difference that the range of the shortest and longest growing season lengths was (72-140) and (306-261) days, respectively. The correlation coefficient between GDD at base temperatures of 5 and 10°C and longitude was significant at the 95% level. The relationship between the temperature units received during the growing season and the longitude at the base temperature of 5 and 10 °C was increasing from west to east of Isfahan province.
Conclusion
The results showed that in Isfahan province, the length of the growing season and the absorbed GDD increase as one move from west to east. Moving from north to south of the province was an inverse relationship. Based on the base temperature of 5°C, the shortest growing season length is 114-200 days in the western and southern regions of the province and the longest growing season length is 331-365 days in the northern and eastern regions of Isfahan province. For the base temperature of 10°C, a similar geographical trend is observed, with the difference that the range of the shortest and longest growing season lengths is (72-140) and (306-261) days, respectively. Considering the base temperatures of 5°C and 10°C, the cities of Isfahan province are classified in the range of 1500 to more than 5000 GDD. The help of this classification, it is possible to predict the time of occurrence of weeds and pests in different regions. Certainly, by combining temperature zoning with other elements required by each plant (soil, topography and precipitation), more comprehensive information will be obtained.
کلیدواژهها English
Authors retain the copyright. This is an open access article distributed under Creative Commons Attribution 4.0 International License (CC BY 4.0)
