مطالعه مناسب‌ترين روش برآورد بارش مؤثر جهت تعيين نياز آبي گندم ديم در اصفهان

Study of the most appropriate method for estimating effective rainfall to determine the water requirement of rainfed wheat in Isfahan

محاسبهﻣﻘﺪار ﺑﺎرش ﻣﺆﺛﺮ ﺑﻪﻋﻨﻮان ﯾ ﮑﯽ از ﻣﻨﺎﺑﻊ ﺗﺄﻣﯿﻦ آب ﻣﻮرد ﻧﯿﺎز ﺑﺮاي ﮐﺸﺖ ﮔﻨﺪم از اﻗﺪاﻣﺎت ﻣﻄﺎﻟﻌﺎﺗﯽ زﯾﺮﺑﻨﺎﯾﯽ ﺑﻪ ﺷﻤﺎر ﻣﯽ رود ﮐﻪ ﻣﯽﺗﻮاﻧﺪ در ﺑﺮﻧﺎﻣﻪرﯾﺰيﻫﺎي ﻣﺮﺑﻮﻃﻪ ﻣﻮرد اﺳﺘﻔﺎده ﻗﺮار ﮔ ﯿﺮد. ﻟﺬا ﺷﻨﺎﺳﺎﯾﯽ و ﺑﻪ ﮐﺎرﮔﯿﺮي روﺷﯽ ﻣﻨﺎﺳﺐ ﺑﺮاي ﺑﺮآورد ﺑﺎرش ﻣﺆﺛﺮ ﺑﻪ ﺧﺼﻮص در ﮐﺸﺖ دﯾﻢ اﻫﻤﯿﺖ دوﭼﻨﺪان ﭘﯿﺪا ﻣﯽﮐﻨﺪ. در اﯾﻦ ﭘﮋوﻫﺶ ﺑﻪ ارزﯾﺎﺑﯽ روشﻫﺎي ﻣﺨﺘﻠﻒ ﺗﻌﯿﯿﻦ ﺑﺎرش ﻣﺆﺛﺮ ازﺟﻤﻠﻪ: روشﻫﺎي ﺳﺮوﯾﺲ ﺣﻔﺎﻇﺖ ﺧﺎك اداره ﮐﺸﺎورزي اﯾﺎﻻت ﻣﺘﺤﺪه )SCS(، ﺑﺎرش ﻗﺎﺑﻞ اﻃﻤﯿﻨﺎن، ﺗﺠﺮﺑﯽ، روش وزارت ﮐﺸﺎورزي اﯾﺎﻻت ﻣﺘﺤﺪه )USDA(، درﺻﺪي و رﻧﻔﺮو، ﺑﻪ ﮐﻤﮏ ﻧﺮماﻓﺰار SPSSو ﺑﺎ آزﻣﻮن آﻣﺎري داﻧﮑﻦ در ﺷﻬﺮﺳﺘﺎن اﺻﻔﻬﺎن و ﺑﺮاي ﮐﺸﺖ ﮔﻨﺪم دﯾﻢ، ﭘﺮداﺧﺘﻪ ﺷﺪه اﺳﺖ. ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از اﯾﻦ ارزﯾﺎﺑﯽ ﻧﺸﺎن داد ﮐﻪ روش رﻧﻔﺮو ﺑﻪدﻟﯿﻞ آﻧﮑﻪ ﻣﻘﺎدﯾﺮ ﺑﺎرش ﻣﺆﺛﺮ را ﺑﯿﺶﺗﺮ از ﺧﻮد ﺑﺎرش ﻧﺸﺎن ﻣﯽدﻫﺪ ﻣﻮرد ﭘﺬﯾﺮش واﻗﻊ ﻧﺸﺪه اﺳﺖ. روشﻫﺎي SCSو ﺑﺎرش ﻗﺎﺑﻞ اﻃﻤﯿﻨﺎن و ﺗﺠﺮﺑﯽ، ﺑﻪ دﻟﯿﻞ ﺑﺪﺳﺖ آﻣﺪن ﻣﻘﺎدﯾﺮ زﯾﺎد ﻣﻨﻔﯽ )ﺻﻔﺮ(، ﺑﯿﺶﺗﺮ ﻣﻨﺎﺳﺐ ﻣﻨﺎﻃﻖ ﻣﺮﻃﻮب ﻣﯽﺑﺎﺷﻨﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ روش درﺻﺪي و USDAﺗﻄﺎﺑﻖ ﺑﯿﺶﺗﺮي ﺑﺎ ﻣﯿﺰان ﺑﺎر ش ﻧﺴﺒﺖ ﺑﻪ ﺳﺎﯾﺮ روشﻫﺎ دارﻧﺪ. ﺑﺎﺗﻮﺟﻪ ﺑﻪ ﺗﻄﺎﺑﻖ ﺑﯿﺶﺗﺮ ﺑﺎ ﻣﻘﺪار ﺑﺎرش ﻣﺘﻮﺳﻂ ﻣﺎﻫﺎﻧﻪ ﺑﻬﺘﺮﯾﻦ روش ﺑﺮاي ﻣﺤﺎﺳﺒﻪ ﺑﺎرش ﻣﻮﺛﺮ در اﺻﻔﻬﺎن و ﺑﺮاي ﮔﻨﺪم روشUSDA ﭘﯿﺸﻨﻬﺎد ﮔﺮدﯾﺪ.

Calculating the amount of effective rainfall as one of the water supply sources required for wheat cultivation is one of the basic study measures that can be used in the relevant planning. Therefore, identifying and applying a suitable method for estimating effective rainfall, especially in rainfed cultivation, is doubly important. In this study, various methods of determining effective rainfall were evaluated, including: US Department of Agriculture (SCS) Soil Conservation Service Methods, Reliable, Experimental, USDA) Percentage and Renfro Method, using SPSS software and by testing. Duncan's statistics are given in the city of Isfahan for the cultivation of rainfed wheat. The results of this evaluation show that the Renfro method has not been accepted because it shows the effective rainfall values ​​more than the rainfall itself. Reliable and experimental SCS methods and precipitation are more suitable for wet areas due to high negative values ​​(zero). The results show that the percentage method and USDA are more consistent with the amount of precipitation than other methods. Due to greater compliance with the average monthly rainfall, the best method for calculating effective rainfall in Isfahan and USDA for wheat was proposed.