ارزیابی پیامدهای تغییراقلیم بر روند و ساختار پارامترهای آب وهوایی مؤثر بر تولید پسته مطالعه ی موردی: سبزوار (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
مطالعه ی اثرات تغییر اقلیم بر محصولات کشاورزی و شاخص های آگروکلیمایی می تواند موجب بهبود و توسعه ی راهبردهای مدیریتی در ارتباط با نیازهای مهم کشاورزی در دهه های آینده باشد و زمینه ساز اتخاذ روش های سازگاری و کاهش اثرات سوء تغییر اقلیم بر بخش کشاورزی گردد. هدف این مطالعه ، بررسی پیامدهای تغییر اقلیم بر ساختار و روند پارامترهای آب و هوایی مؤثر بر تولید پسته (رقم کله قوچی) بر اساس رویکرد جدید در گزارش IPCC-AR5 در شهرستان سبزوار است. جهت انجام این پژوهش ابتدا برمبنای داده های اقلیمی مشاهداتی در دوره ی 2005-1976 نیاز های حرارتی پسته بر اساس شاخص وینکلر محاسبه و سپس 24 شاخص دما و بارش و روند هریک از آن ها با استفاده از آزمون من کندال و شیب سن استخراج گردید. درنهایت، نیاز آبی برای هریک از مراحل فنولوژی محصول برآورد شد. در ادامه با ریزمقیاس گردانی داده های خروجی مدل CanESM2 به کمک نرم افزار SDSM پارامترهای اقلیمی تحت سناریوهای (RCP2.6,RCP4.5,RCP8.5) در دوره ی 2040-2011 شبیه سازی شد. نتایج بررسی شاخص های دمایی و بارشی برای دوره ی مشاهداتی بیانگر این بود که میانگین دمای فصل رشد 0/6 درجه ی سانتی گراد در دهه ، دارای روند افزایشی است. خروجی شاخص های بارشی نشان از کاهش قابل ملاحظه ی این پارامترها در طول مراحل سوم، چهارم و پنجم (مراحل رسیدن میوه) دارد. یافته ها برای دوره ی آتی نشان داد که متوسط دما برای سناریوهایRCP2.6 ،RCP4.5 و RCP8.5 در فصل رشد در محدوده ی 0/6 تا 0/8 درجه ی سانتی گراد دارای روند افزایشی خواهد بود که این امر سبب تسریع در گلدهی و رسیدگی زودتر محصول نسبت به دوره ی مشاهداتی می گردد. بارش در همه ی سناریوها در طول مرحله ی سوم، چهارم و پنجم فنولوژی نسبت به دوره ی پایه کاهش یافته است. با توجه به افزایش دما و کاهش بارش در طول مراحل رشد، نیاز آبی محصول (ETC) باید از طریق آبیاری بیش تر جبران گردد.Evaluating the Consequences of Climate Change on the Process and Structure of Climate Parameters Affecting Pistachio Production (Case study: Sabzevar)
Introduction
In the future decades, climate change will influence the food and water security,and there are substantive evidences indicating that the developing countries will confront extensive pressure from the disastrous consequences of this climate change. The agricultural section is the most vulnerable section to the climate changes due to its dependence on the condition of water resources and changes of temperature. The aim of the present study is to assess the influence of the climate changes on the influential climate indicators for the production of the pastiches in Sabzervar. In this regard, SDSM software has been used for the down scaling of the data of the second generation of canESM2 that has been modeled by the Canadian center of climate change under the new climate change scenarios.
Materials and Methods
In this study, the daily data of meteorological stationincluding the maximum, minimum and average of temperature and the level of rain on the daily basis from 1976-2005 from the Meteorological Organization are obtained. This study has used the effective climate-agricultural parameters on the growth of pastiches which are divided into two indexes of temperature and rain in a general classification. The temperature indicators are both seasonal and annual which the seasonal indexes include the average, maximum and the minimum of the temperature of the growth season, DTR or daily temperature range (maximum and minimum temperature difference) during a month.Additionally, the annual indexes include the number of annual days with a minimumor maximum temperature less than 10thpercent and more than 90percent of the number of the frozen days and the length of the period withoutice. The index of rain include total annual precipitation, total rainfall of growth season, rainfall in different stages of the growth season, the number of the days with more than 95percent(very humid days), the percent of the registered rainfall in very humid days as well as the maximum dry season or DPL. Due to the semi-arid climate of the region and the summer with low level of rainfall, the level of evaporation is calculated by the formula of evaporation and perspiration of the plants. To assess the stages of the climate indexes in different phonological stages, the tests of Man-Kendall (Z) and Steady-axis tiltare used. Also to study the consequences of climate changes on the structure of the effective climate parameters on the production of pastiches the outputs of the model CanESM2 under the scenarios of (RCP2.6, RCP4.5, and RCP8.5) for the period of 2011-2040 are used.
Discussion and Results
The time of the beginning of flowering for pastiches from the period 1976-2005 is from March 20 to the October 27 for six months. The obtained outputs from the used indexes in the research show that the average parameter and the maximum and minimum of the temperature of the growth season have a significant trend. Analysis of the averagerange of daily temperature during the month of cultivation or DTR does not show any significant process. Assessment of the indexes of cold nights and days shows a significantdecrease.This process is incremental for the two indexes of warm nights and days. The results from of annual temperature indexes show that the climate is moving towards warming. Analysis of the parameters of total annual precipitation (250mm), the percentage of the annual precipitation on very humid days (82 percent) and the length of dry period (122days) indicates the dry and low rainfall condition of the region. The result obtained from the sub- scaling data of model Canesm2 under the scenarios of RCP2.6,RCP4.5,RCP8.5 for the period of 2011-2040 showed that the flowering stages ofpastiches in the coming years will start sooner than the base climate. The average indexes of the growth season, the minimum and maximum temperature has increased for all three scenariosthan the base time.The daily range has not changed much due to the increase in both parameters (maximum and minimum). Despite the increase of the temperatureduring the simulation process the number of the warm nights and days does not changedmuch compared to the basic climate. Assessment of the annual indexes of the number of nights and cold days indicates an increase in this index in comparison with the observed period. The frozen days also indicate a slightdecrease of one day for the upcoming period. The ice-free period has increased over the coming years. The average length of the dry period in the decade was increased by 14 days.The results gained from the rate of evaporation shows that in the future the demand for water in all scenarios has risen like the basic course.
Conclusions
The climate elements play a crucial role in the growth of the plants and are considered uncontrollable parameters for agriculture. In this research the effects of climate change on the effective temperature and rainfall indexes on the pistachio production was studied in Sabzevar station by using the output model of Canesm2 under the new scenarios of climate change from 2011-2040. The output from the study of the average temperature of the growth season for the base period showed that this parameter has an increasing trend of about 0.6 ° C per decade. The assessment of the effects of climate change on the indices used in the study for the study area showed that the average temperature for RCP2.6, RCP4.5 and RCP8.5 scenarios in the growing season in the range of 0.6 to 0.8 ° C in decades has increased trend This has led to an accelerated flowering and a quicker examination of the product than the observation period.The acceleration of phonology stages is the most important consequence of climate change in agriculture. Studying the consequences of climate change on the applied indexes of this case study showed that the average temperature forRCP2.6, RCP4.5, RCP8.5 during the growth season has increased 6 percent per year. This increase has made the flowering and ripping stage faster than before.The acceleration of phonological processes is the most important consequence of climate change in agriculture. The results obtained from precipitation in all scenarios indicate a decrease in the base time. The water requirement of the product has increased in the coming decades due to rising temperatures and lower rainfall. Therefore, according to the stated content, the water needed for the product should be provided by modifying the cultivation pattern, proper management of water resources and new irrigation methods.
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