Abstract

Mazandaran and Khuzestan provinces play pivotal roles in Iran’s rice production, ranking first and third nationally. In this research, the agricultural and climate data in Khuzestan during 1378-1399 and Mazandaran during 1379-1399 were used for assessing rice cultivation potential. To do so, climatology indices including GDD, SAT, BEDD was calculated using the average daily temperature, and then using their results, the range of climatology indices was classified in the areas with cultivation potential in minimum and maximum yield. Using Pearson's correlation coefficient, the relationship between climatology indices and rice yield was evaluated. The obtained results show that Amol and Qarakhil in Mazandaran province with the highest yields (5035 and 5130) kg /ha during the studied years in the range of GDD=1566, GDD=1561, SAT=2586, SAT=2772, BEDD=915 and BEDD=1033 has the greatest cultivation potential compared to other regions of Mazandaran province, and in the western parts of this province we encounter relatively weak cultivation areas. Also, the results in Khuzestan province showed that the central regions of this province including Ahvaz and Shushtar with (4161 and 4252) kg/ha in the range of growing days GDD=2903 and GDD=2965, and SAT=3953 and SAT=4015 for potential rice cultivation They have high cultivation, the eastern areas of this province are also in a relatively good condition for rice cultivation.



Extended Abstract

Introduction

Rice and rice cultivation have had a special place in the basket of Iranian households for a long time due to the nutritional importance of this product, so that the average consumption of rice by Iranians is about 30 kg per year. Mazandaran and Khuzestan have a major share in the country's rice supply and are ranked first and third in terms of production. In 1978, in order to optimize the use of land, water and other resources, the World Food Organization presented a model under the title of ecological-agricultural zoning, and after numerous researches and tests in 1983, it was recommended for all countries. In this research, rice cultivation potential has been evaluated based on climatic profiles in two poles of rice production in the country (Mazandaran province and Khuzestan province).

Materials and methods

Meteorology data

Daily minimum, maximum and average air temperature values were used in Mazandaran province during the statistical period (1379-99) and in Khuzestan province (1378-99) (Tables 1 and 2).

Agricultural data

Based on the availability of statistical data on cultivated area, rice production and yield, the statistical common period of agricultural data in each of the studied provinces has been the criterion for choosing the length of the common period of meteorological data.

Result and discussion

The results obtained from the maps and correlations showed that in Khuzestan province, the two indexes of growing degree days and total active temperatures play the greatest role in plant performance, while the BED index had no relationship with the changes in yield values. In Mazandaran province, no significant relationship was observed between the changes in the degree of growth days and total active temperatures, but in Nowshahr station, a significant relationship was observed at the level of 0.05% with yield. In Izeh station of Khuzestan province, Kiasar and Siah Bisheh of Mazandaran province, the height above the sea level has caused a decrease in temperature in these stations, and therefore in Izeh station it has caused a decrease in yield and in Kiasar and Siah Bisheh, it has caused arable lands to be cultivated due to lack of proper yield. Ranges and classes determined in this research for different rice cultivation areas in two provinces are different according to different climatic conditions. According to the obtained results, better results can be achieved in cultivation by shifting the cultivation date and providing other conditions and factors, including the selection of resistant and compatible cultivars in each environment.

Conclusion

The results of this research showed that environmental factors play a significant role in determining cultivation areas and sometimes these factors act as limiting cultivation conditions or as facilitators in cultivation areas. Considering the high potential of rice cultivation in the central and semi-eastern parts of Mazandaran and Khuzestan provinces, the central parts of Khuzestan province should focus on these areas and increase the cultivated area in them. In Mazandaran province, the two stations of Siah Bisheh and Kiasar encountered negative temperatures at the beginning of the rice planting period, and therefore the plant suffers from cold stress. In the selection of rice varieties, it is expected that by allocating the cultivated area to the lands that can be cultivated in these two stations, it will be possible to cultivate rice to be a turning point for the income of the farmers in these areas. According to the selected data, the results of this study seem to be consistent with the research of Jin et all (2005), Ali et al. (2009), Sultana et all (2019), Boonwichai et all (2019), Abhilash (2017), Ayinde et al. (2013) and Kaur & Dhaliwal (2014) are confirmed.