شبيه سازي توزيع رطوبت اطراف ريشه گياه ذرت در خاكي با بافت سنگين تحت آبياري قطرهاي نواري با استفاده از مدل HYDRUS

Simulation of soil moisture distribution around of corn plant root in heavy soil texture under drip-tape-irrigation system using HYDRUS-2D model

آﺑﯿﺎري ﻗﻄﺮهاي ﯾﮑﯽ از ﺑﻬﺘﺮﯾﻦ روشﻫﺎي آﺑﯿﺎري اﺳﺖ ﮐﻪ از ﮐﻢﺗﺮﯾﻦ ﻣﻘﺪار آب در ﻫﺮ واﺣﺪ ﻣﺤﺼﻮل اﺳﺘﻔﺎده ﻣﯽﮐﻨﺪ و ﺗﻠﻔﺎت آب را از ﻃﺮﯾﻖ ﺗﺒﺨﯿﺮ و ﻧﻔﻮذ ﻋﻤﻘﯽ ﺣﺬف ﻣﯽﮐﻨﺪ. ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ اﻓﺰاﯾﺶ ﺗﻤﺎﯾﻞ ﮐﺸﺎورزان ﺑﻪ اﺳﺘﻔﺎده از ﺳﯿﺴﺘﻢ ﻫﺎي آﺑﯿﺎري ﻗﻄﺮهاي ﺑﻪ دﻟﯿﻞ داﺷﺘﻦ راﻧﺪﻣﺎن ﺑﺎﻻﺗﺮ، ﻟﺰوم ﺷﻨﺎﺧﺖ ﻋﻮاﻣﻞ و ﭘﺎراﻣﺘﺮﻫﺎي ﺗﺎﺛﯿﺮﮔﺬار ﺑﺮ اﯾﻦ ﺳﯿﺴﺘﻢﻫﺎ ﺑﻪ ﻣﻨﻈﻮر ﺑﺎﻻﺑﺮدن راﻧﺪﻣﺎن آنﻫﺎ اﻫﻤﯿﺖ ﻣﯽﯾﺎﺑﺪ. ﯾﮑﯽ از اﯾﻦ ﻋﻮاﻣﻞ، اﻟﮕﻮي ﻣﺮﻃﻮب ﺷﺪن ﻗﻄﺮه ﭼﮑﺎنﻫﺎﺳﺖ ﮐﻪ ﻧﺸﺎن ﻣﯽدﻫﺪ ﭼﮕﻮﻧﻪ آب ﺗﻮزﯾﻊ ﻣﯽﺷﻮد و آﯾﺎ ﺑﺮاي رﯾﺸﻪﻫﺎ ﮐﺎﻓﯽ اﺳﺖ ﯾﺎ ﺧﯿﺮ. ﻣﺪل ﻫﺎﯾﺪروس ﺗﻮزﯾﻊ رﻃﻮﺑﺘﯽ ﺧﺎك را ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﺷﺮاﯾﻂ ﻃﺮاﺣﯽ آن )ﺑﺎﻓﺖﺧﺎك و وﯾﮋﮔﯽﻫﺎي ﻫﯿﺪروﻟﯿﮑﯽ، ﺗﺨﻠﯿﻪ ﻗﻄﺮهﭼﮑﺎنﻫﺎ، ﻣﮑﺎن و ﻓﺎﺻﻠﻪ( ﺷﺒﯿﻪﺳﺎزي ﻣﯽﮐﻨﺪ. ﺗﺤﻘﯿﻖ ﺣﺎﺿﺮ ﺑﺮاي ﺑﺮرﺳﯽ ﮐﺎراﯾﯽ ﻣﺪل HYDRUS در ﺷﺒﯿﻪﺳﺎزي ﺣﺮﮐﺖ آب در ﺧﺎك و ﺗﻮزﯾﻊ ﻣﺠﺪد رﻃﻮﺑﺖ اﻃﺮاف رﯾﺸﻪ ﮔﯿﺎه ذرت در ﺧﺎكﻫﺎي ﻫﻤﮕﻦ و ﺳﻨﮕﯿﻦ اﻧﺠﺎم ﮔﺮﻓﺖ. اﯾﻦ ﺗﺤﻘﯿﻖ در ﻣﺮﮐﺰ ﺗﺤﻘﯿﻘﺎت ﮐﺸﺎورزي اﺳﺘﺎن ﺧﻮزﺳﺘﺎن ﺗﺤﺖ آﺑﯿﺎري ﻗﻄﺮهاي ﻧﻮاري ﺗﯿﭗ ﺑﺎ ﺳﻪ رژﯾﻢ آﺑﯿﺎري2 ،3 و4 روزه ﺑﺎ ﺳﻪ ﺗﮑﺮار در ﻃﯽ دو ﺳﺎل زراﻋﯽ اﻋﻤﺎل ﺷﺪ. ﺑﻪ ﻣﻨﻈﻮر ﭘﺎﯾﺶ رﻃﻮﺑﺖ اﻃﺮاف رﯾﺸﻪ، ﻧﯿﻢرخ ﺧﺎك ﺗﺎ ﻋﻤﻖ 75 ﺳﺎﻧﺘﯽﻣﺘﺮي ﻋﻤﻮد ﺑﺮ ﻧﻮار آﺑﯿﺎري ﻗﻄﺮهاي ﺣﻔﺮ ﺷﺪ. ﻣﻘﺎدﯾﺮ رﻃﻮﺑﺖ ﻣﺸﺎﻫﺪهاي و ﺷﺒﯿﻪﺳﺎزي، ﺗﻮﺳﻂ آﻣﺎرهﻫﺎي,R2EF,ME و RMSE ﻣﻘﺎﯾﺴﻪ ﺷﺪﻧﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﻣﯿﺎﻧﮕﯿﻦ ﺗﻮزﯾﻊ رﻃﻮﺑﺖ در رژﯾﻢآﺑﯿﺎري در ﻣﺤﺪوده ﻇﺮﻓﯿﺖزراﻋﯽ اﺳﺖ. ﻣﻘﺎدﯾﺮ RMSE ﺑﺮاي رژﯾﻢﻫﺎي ﻣﺨﺘﻠﻒ از 1/29ﺗﺎ 2/40 درﺻﺪ و ﻣﻘﺎدﯾﺮ ME ﺑﺮاي رژﯾﻢﻫﺎي ﻣﺨﺘﻠﻒ از 1ﺗﺎ 2 درﺻﺪ ﻣﺘﻐﯿﺮ ﺑﻮد. ﺑﺮاﺳﺎس ﻣﻘﺎدﯾﺮ ME و RMSE، ﺷﺒﯿﻪﺳﺎزي رﻃﻮﺑﺖ در رده ﻋﺎﻟﯽ ﻃﺒﻘﻪ ﺑﻨﺪي ﺷﺪ. ﻫﻤﭽﻨﯿﻦ ﻧﺘﺎاﯾﺞ ﺿﺮﯾﺐ ﺗﺒﯿﯿﻦ ﺑﯿﻦ 60 ﺗﺎ 90 درﺻﺪ و ﻣﯿﺰان ﮐﺎراﯾﯽ ﻣﺪل ﺑﯿﻦ 40 ﺗﺎ 90 درﺻﺪ ﻣﯿﺒﺎﺷﺪ ﺑﺮ اﺳﺎس ﻧﺘﺎﯾﺞ ﮐﻤﺘﺮﯾﻦ ﮐﺎراﯾﯽ ﻣﺪل در ﺷﺒﯿﻪ ﺳﺎزي 24 ﺳﺎﻋﺖ ﺑﻌﺪ از آﺑﯿﺎري و ﺑﻬﺘﺮﯾﻦ ﺷﺒﯿﻪ ﺳﺎزي 72 ﺳﺎﻋﺖ ﺑﻌﺪ از آﺑﯿﺎري ﺑﻮده اﺳﺖ. ﻧﺘﺎﯾﺞ ﻧﺸﺎندﻫﻨﺪه ﺗﻮاﻧﻤﻨﺪي ﺑﺎﻻي ﻣﺪل در ﺷﺒﯿﻪﺳﺎزي رﻃﻮﺑﺖ ﺣﺠﻤﯽ ﺧﺎك ﻣﯽﺑﺎﺷﺪ.

The present study was conducted to evaluate the efficiency of the HYDRUS model in simulating soil water movement and redistribution of moisture around the roots of maize in homogeneous and heavy soils. This study was carried out in the Agricultural Research Center of Khuzestan Province under drip strip irrigation with three irrigation regimes of 2, 3 and 4 days with three replications during two cropping years. In order to monitor the moisture around the roots, dig a soil profile to a depth of 75 cm perpendicular to the drip irrigation strip. Observed and simulated moisture values were compared byR2,EF, MAE and RMSE statistics. The results showed that the average moisture distribution in each irrigation regime is in the range of crop capacity. RMSE values for different diets ranged from 1.29 to 2.40% and MAE values for different diets ranged from 1 to 2%. Moisture simulations were classified as excellent based on MAE and RMSE values.Also, the results of the coefficient of explanation are between 60 to 90% and the efficiency of the model is between 40 to 90%. Based on the results, the lowest efficiency of the model was in the simulation 24 hours after irrigation and the best simulation was 72 hours after irrigation. The results show the high capability of the model in simulating soil volumetric moisture.