Agricultural Meteorology
F. Bayatani; Gh. Fallah-Ghalhari
Abstract
Introduction
Increasing food security is at the heart of United Nations policies for sustainable development. On the other hand, the growth of the global population, the reduction of vital natural resources used in agriculture and environmental stress and continuous climate change undermine the achievement ...
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Introduction
Increasing food security is at the heart of United Nations policies for sustainable development. On the other hand, the growth of the global population, the reduction of vital natural resources used in agriculture and environmental stress and continuous climate change undermine the achievement of this goal. In addition, plant diseases and pests cause the loss of 40% of agricultural production of some major crops on a global scale, which puts food security at serious risk. The intensity and frequency of extreme climatic events—such as heatwaves, droughts, and increased climate variability—are projected to rise due to climate change. As a result, pressure on agricultural production is expected to intensify, given the sensitivity of crop growth to shifting weather conditions. This study aims to assess the impacts of climate change on the phenological development of potatoes in Iran's major potato-growing regions.
Methodology
In order to prepare field data for calibration and determining the validity of the WOFOST model in potential conditions (conditions without water and food restrictions, disease and weed control), data from research projects of agricultural research centers in Hamedan, Isfahan regions Ardabil, Shiraz, Tabriz, Shahrekord, Jiroft, Kohnouj, Manojan and Sanandaj, which are the main centers of potato production in the country, were collected during 2012-2016 and used as a base or monitoring period. This information includes planting dates, phenological stages from planting to greening, greening to flowering and greening to physiological maturity of potato plants in each of the study areas. In order to calibrate the WOFOST model using field data, phenological and performance data in 2012, 2013 and 2015 and phenological and performance data in 2014 and 2016 were used to determine the validity of the model.
Results and Discussion
The WOFOST growth simulation model showed that the length of different phenological stages and potato tuber yield under potential conditions will be reduced in the study areas. The stage of germination to the physiological maturation of the tubers, due to its longer duration, the greatest reduction in the length of the period occurred in this stage. The simulation results indicated a decline in potato tuber yield across the studied regions. According to the results, the highest reduction in performance was observed in the third period (2071-2100). The percentage of glandular function reduction was observed on average between 2 and 4.3%. In general, the results showed an increase in the average minimum and maximum temperatures of 0.37 to 0.9 degrees Celsius over the next three periods. The length of the phenological stages of the potato plant from emergence to physiological maturity has decreased in parallel with the increase in the mean minimum and maximum temperatures. The reduction in the length of the germination stage is between 0.2 to 1.9 days, the flowering stage is between 0.5 to 1.7 days, and the maturation stage to maturity is between 1.4 to 3.5 days. The greatest reduction during the phenological stages is related to the emergence stage to maturity of 3.5 days.
In general, the results of this study indicate an increase in the negative effects of climate change on the potato plants in three stations of Jiroft, Kahnooj, and Manojan. As temperatures rise and rainfall decreases, the growing season shortens and potato yields decline, leading to greater potential damage under future climate scenarios. Generally, for a one degree Celsius increase in average annual temperature, tuber yield will decrease by 4.99%.
The results of calibration and validation of the WOFOST model indicated the high accuracy of the model in simulating the phenological stages of the potato plant (planting to greening, greening to flowering and greening to physiological ripening), so that the average value of the Root Mean Square error (RMSE) for all three stages Potato growth in the studied areas was less than 10%. The results of this study showed that the length of the growth period in the studied areas will decrease under future climate conditions. The length of the growth period is reduced by 4.36 days on average in the studied areas. This reduction was also observed at different stages of growth, so that the stage of planting to greening had the least amount of reduction with an average decrease of one day, and the stage of greening to physiological ripening had the largest amount of reduction in the length of the growth period.
