اشتقاق و ارزيابي توابع انتقالي ضرايب معادلات نفوذ آب به خاك در مناطق مختلف

Derivation and validation of parametric pedotransfer functions of soil water infiltration in different regions

ﻧﻔﻮذ آب ﺑﻪ ﺧﺎك ﻧﻘﺶ ﻣﻬﻤﯽ در ﭼﺮﺧﻪ ي آﺑﯽ ﻃﺒﯿﻌﺖ دارد و از آﻧﺠﺎ ﮐﻪ اﻧﺪازهﮔﯿﺮي ﻣﺴﺘﻘﯿﻢ اﯾﻦ ﭘﺎراﻣﺘﺮ در ﻫﺮ ﺟﺎﯾﯽ اﻣﮑـﺎن ﭘـﺬ ﯾﺮ ﻧﯿﺴـﺖ، ﻟـﺬا اﯾـﻦ ﭘﮋوﻫﺶ ﺑﻪ ﻣﻨﻈﻮر ﺑﺮرﺳﯽ اﻣﮑﺎن ﺑﺮآورد ﺗﻮاﺑﻊ اﻧﺘﻘﺎﻟﯽ ﺗﺨﻤﯿﻦ ﺿﺮاﯾﺐ ﻣﻌﺎدﻻت ﻧﻔﻮذ آب ﺑﻪ ﺧﺎك ﮐﺎﺳﺘﯿﺎﮐﻒ، ﮐﺎﺳﺘﯿﺎﮐﻒ-ﻟﻮﯾﯿﺲ، ﻫﻮرﺗﻦ و ﺳﺎزﻣﺎن ﺣﻔﺎﻇﺖ ﺧﺎك آﻣﺮﯾﮑﺎ ﺑﺎ اﺳﺘﻔﺎده از وﯾﮋﮔﯽﻫﺎي زودﯾﺎﻓﺖ ﻓﯿﺰﯾﮑﯽ ﺧﺎك و ارزﯾﺎﺑﯽ اﯾﻦ ﺗﻮاﺑﻊ در ﺧﺎرج از ﻣﻨﻄﻘﻪ اﺷﺘﻘﺎق آنﻫـﺎ اﻧﺠـﺎم ﮔ ﺮﻓـﺖ. ﺑﻨـﺎﺑﺮاﯾﻦ وﯾﮋﮔـﯽ ﻫـﺎي ﻓﯿﺰﯾﮑﯽ ﺧﺎك و ﻧﻔﻮذ ﺗﺠﻤﻌﯽ در دو ﻣﻨﻄﻘﻪ ﻣﺘﻔﺎوت )T1 و T2( اﻧﺪازهﮔﯿﺮي ﺷﺪ. ﺑﺎ اﺳﺘﻔﺎده از اﻧﺪازه ﮔﯿﺮي ﻫﺎي ﻣﺤﻞ T1 و رﮔﺮﺳﯿﻮن ﺧﻄﯽ ﭼﻨﺪﮔﺎﻧﻪ، ﺗﻮاﺑﻊ اﻧﺘﻘﺎﻟﯽ ﺷﮑﻞ ﮔﺮﻓﺖ و ﺑﺎ اﺳﺘﻔﺎده از اﻧﺪازه ﮔﯿﺮي ﻫﺎي ﻣﺴﺘﻘﻞ T2 ﮐﺎراﯾﯽ ﺑﺮونﯾﺎﺑﯽ اﯾﻦ ﺗﻮاﺑﻊ ﺑﺮرﺳﯽ ﺷﺪ. ﻧﻔﻮذ ﺗﺠﻤﻌﯽ در 78 ﻧﻘﻄﻪ ﺑﻪ وﺳﯿﻠﻪ اﺳﺘﻮاﻧﻪ دوﮔﺎﻧﻪ 2 ﺑﺎ ﺳﻪ ﺗﮑﺮار اﻧﺪازه ﮔﯿﺮي ﺷﺪ. ﺑﯿﺸﺘﺮﯾﻦ دﻗﺖ ﺗﻮاﺑﻊ اﻧﺘﻘﺎﻟﯽ در ﻣﺮﺣﻠﻪ اﺷﺘﻘﺎق، ﻣﺮﺑﻮط ﺑﻪ ﺿﺮاﯾﺐ ﻣﻌﺎدﻟﻪ SCS ﺑـﺎ ﻣﻘـﺪار ﺿـﺮﯾﺐ ﺗﺒﯿـﯿﻦ )R ( ﺑﺮاﺑـﺮ 0/66 و 2 ﮐﻤﺘﺮﯾﻦ دﻗﺖ ﺑﺎ ﻣﻘﺪار Rﺑﺮاﺑﺮ 0/04 ﻣﺮﺑﻮط ﺑﻪ ﺗﻮان ﻣﻌﺎدﻟﻪ ﻫﻮرﺗﻦ ﺑﻮد. در ﻣﺮﺣﻠﻪ اﻋﺘﺒﺎرﺳﻨﺠﯽ در ﺧﺎرج از ﻣﺤﻞ اﺷـﺘﻘﺎق، دﻗـﺖ ﺗﻮاﺑـﻊ اﻧﺘﻘـﺎﻟﯽ ﮐـﺎﻫﺶ 2 زﯾﺎدي ﻧﺸﺎن داد ﺑﻪ ﻃﻮري ﮐﻪ ﺑﺎزه ﺗﻐﯿﯿﺮات R از 0/00 ﺗﺎ 0/26، ﺑﺎزه ﺗﻐﯿﯿﺮات رﯾﺸﻪ ﻣﯿﺎﻧﮕﯿﻦ ﻣﺮﺑﻌﺎت ﺧﻄﺎي ﻧﺮﻣﺎل ﺷﺪه )nRMSE( از 1/76 ﺗﺎ 80/93 و ﻣﻌﺎدﻻت ﻧﻔﻮذ ﻓﻘﻂ در ﻣﺤﻞ اﺷﺘﻘﺎﻗﺸﺎن ﮐﺎرآﻣﺪ اﺳﺖ و اﻣﮑﺎن اﺳﺘﻔﺎده از اﯾﻦ ﺗﻮاﺑﻊ در ﺧﺎرج از ﻣﺤﻞ اﺷﺘﻘﺎق آنﻫﺎ ﺑﺪون واﺳﻨﺠﯽ اﻣﮑﺎن ﭘﺬﯾﺮ ﻧﯿﺴﺖ.

Soil water Infiltration plays an important role in the water cycle of nature. However, since the direct measurement of soil water infiltration is laborious, time-consuming and expensive. Therefore, in this study was conducted to investigate the possibility of estimating the coefficients of water infiltration equations such as Kastiakov, Kastiakov-Lewis, Horton and USA Soil Conservation Service (SCS) using readily available soil properties and to evaluate the validity of these functions outside of their derivation regions. Therefore, soil physical properties and cumulative infiltration were measured in two different regions (T1 and T2). Parametric functions were derived using T1 location measurements and validation was performed using independent T2 measurements. Cumulative infiltration was measured using double rings with three replications at 78 points. Parametric functions were created using multiple linear regression. The highest accuracy of parametric functions in the derivation stage was related to SCS equations with the coefficient of explanation (R2) equal to 0.66 and the lowest accuracy with the value of R2 equal to 0.04 was related to the power of Horton equation. In the validation stage, the accuracy of the functions showed a large decrease. R2 changes range from 0.00 to 0.26, normalized root mean square error (nRMSE) range from 1.76 to 80.93 and geometric mean error ratio (GMER) range from 0.94 to 1.73 Was obtained. Therefore, in this study, the use of parametric functions to estimate the coefficients of infiltration equations outside of their derivation regions was not efficient.