مدل‌سازی میانگین وزنی قطر خاکدانه‌ها با استفاده از شاخص‌های پوشش گیاهی در کاربری‌های مرتع و جنگل

ﺳﺎﺑﻘﻪ و ﻫﺪف: ﯾﮑﯽ از ﻣﻬﻢ ﺗﺮﯾﻦ وﯾﮋﮔﯽ ﻫﺎی ﻓﯿﺰﯾﮑﯽ ﺧﺎک، ﭘﺎﯾﺪاری ﺧﺎﮐﺪاﻧﻪ ﻫﺎ اﺳﺖ ﭼﺮا ﮐﻪ ﺑﻪ ﻋﻨﻮان ﺷﺎﺧﺼﯽ از ﻓﺮﺳﺎﯾﺶ ﭘﺬﯾﺮی ﺧﺎک ﻫﺎ ﻣﺤﺴﻮب ﻣﯽ ﺷﻮد. آﮔﺎﻫﯽ از ﭘﺎﯾﺪاری ﺧﺎﮐﺪاﻧﻪ ﻫﺎ ﻣﯽ ﺗﻮاﻧﺪ اﺑﺰاری ﮐﺎرآﻣﺪ ﺟﻬﺖ ﻣﺪﯾﺮﯾﺖ ﺧﺎک در ﺑﺮاﺑﺮ ﻋﻮاﻣﻞ ﺗﺨﺮﯾﺐ ﺧﺎک ﺑﺎﺷﺪ. ﺑﻨﺎﺑﺮاﯾﻦ، ﻣﺪل ﺳﺎزی ﭘﺎﯾﺪاری ﺧﺎﮐﺪاﻧﻪ ﻫﺎ ﺑﺎ اﺳﺘﻔﺎده از وﯾﮋﮔﯽ ﻫﺎی زودﯾﺎﻓﺖ ﻣﺎﻧﻨﺪ ﺷﺎﺧﺺ ﻫﺎی ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ در ﻣﺪﯾﺮﯾﺖ ﻣﻨﺎﺑﻊ ﺧﺎک ارزش زﯾﺎدی دارد. ﻣﻄﺎﻟﻌﻪ ﺣﺎﺿﺮ ﺑﺎ ﻫﺪف ﺑﺮرﺳﯽ ارﺗﺒﺎط ﺷﺎﺧﺺ ﻫﺎی ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ و ﻣﯿﺎﻧﮕﯿﻦ وزﻧﯽ ﻗﻄﺮ ﺧﺎﮐﺪاﻧﻪ ﻫﺎ (mwd) در دو ﮐﺎرﺑﺮی اراﺿﯽ ﺟﻨﮕﻞ و ﻣﺮﺗﻊ اﻧﺠﺎم ﺷﺪه اﺳﺖ. ﻣﻮاد و روش ﻫﺎ: اﯾﻦ ﭘﮋوﻫﺶ در ﺣﻮﺿﻪ آﺑﺮﯾﺰ دﻫﺪز در ﺷﻤﺎل ﺷﺮق اﺳﺘﺎن ﺧﻮزﺳﺘﺎن اﻧﺠﺎم ﮔﺮدﯾﺪ. ﺑﺮای اﺳﺘﺨﺮاج ﺷﺎﺧﺺ ﻫﺎی ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ، اﺑﺘﺪا ﺗﺼﺎوﯾﺮ ﻟﻨﺪﺳﺖ 8 درﯾﺎﻓﺖ و ﺳﭙﺲ ﺗﺼﺤﯿﺤﺎت رادﯾﻮﻣﺘﺮی ﺑﻪ ﮐﻤﮏ ﻧﺮم اﻓﺰار 5.1 envi ﺑﺮ روی ﺗﺼﻮﯾﺮ اﻋﻤﺎل ﺷﺪﻧﺪ. ﺷﺎﺧﺺ ﻫﺎی ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ ﻣﻮرد ﺑﺮرﺳﯽ ﺷﺎﻣﻞ yvi ،tvi ،vin ،rvi، arvi ،tsavi ،savi ،pvi ،ndvi ،ndi ،ri ،ndgi ،dvi ،sbl و msavi ﻣﯽ ﺑﺎﺷﻨﺪ. ﺧﺼﻮﺻﯿﺎت 50 ﻧﻤﻮﻧﻪ ﺧﺎک ﺟﻤﻊ آوری ﺷﺪه از دو ﮐﺎرﺑﺮی اراﺿﯽ ﺷﺎﻣﻞ درﺻﺪ ﮐﺮﺑﻦ آﻟﯽ، درﺻﺪ ﺷﻦ، ﺳﯿﻠﺖ، رس و ﻣﯿﺎﻧﮕﯿﻦ وزﻧﯽ ﻗﻄﺮ ﺧﺎﮐﺪاﻧﻪ ﻫﺎ (mwd) ﻃﺒﻖ روش ﻫﺎی اﺳﺘﺎﻧﺪارد آزﻣﺎﯾﺸﮕﺎﻫﯽ ﺗﻌﯿﯿﻦ ﺷﺪ. ﺑﺮای ﺑﺮرﺳﯽ ارﺗﺒﺎط ﺷﺎﺧﺺ ﻫﺎی ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ ﺑﺎ ﺷﺎﺧﺺ mwd از آﻧﺎﻟﯿﺰﻫﺎی ﻫﻤﺒﺴﺘﮕﯽ ﭘﯿﺮﺳﻮن و اﺳﭙﻼﯾﻦ رﮔﺮﺳﯿﻮن ﺗﻄﺒﯿﻘﯽ ﭼﻨﺪﻣﺘﻐﯿﺮه (mars) اﺳﺘﻔﺎده ﮔﺮدﯾﺪ. ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﻧﺸﺎن ﻣﯽ دﻫﺪ ﮐﻪ در ﮐﺎرﺑﺮی ﻣﺮﺗﻊ، ﺑﯿﻦ ﺷﺎﺧﺺ ﻫﺎی savi ،rvi ،msavi ،tvi ،vin، ndvi ،tsavi و pvi ﺑﺎ ﺷﺎﺧﺺ mwd ﻫﻤﺒﺴﺘﮕﯽ ﻣﻌﻨﯽ داری در ﺳﻄﺢ ﯾﮏ درﺻﺪ وﺟﻮد دارد. ﺣﺎل آن ﮐﻪ در ﮐﺎرﺑﺮی ﺟﻨﮕﻞ ﺑﯿﻦ ﺷﺎﺧﺺ ﻫﺎی ﻣﻮردﺑﺮرﺳﯽ ﻫﯿﭻ ﮔﻮﻧﻪ ارﺗﺒﺎط ﻣﻌﻨﯽ داری ﺑﺮﻗﺮار ﻧﺒﻮد. ﻫﻢ ﭼﻨﯿﻦ ﻣﺪل ﺳﺎزی mars ﻧﺸﺎن داد ﮐﻪ ﻣﺪل ﺑﺮازش ﯾﺎﻓﺘﻪ ﺑﺮ اﺳﺎس ﺷﺎﺧﺺ ﻫﺎی ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ در ﮐﺎرﺑﺮی ﻣﺮﺗﻊ (0/16=rmse، 0/55=.adjusted r-sq) دارای ﻗﺪرت و دﻗﺖ ﭘﯿﺶ ﺑﯿﻨﯽ ﺑﺴﯿﺎر ﺑﺎﻻﺗﺮی ﻧﺴﺒﺖ ﺑﻪ ﻣﺪل ﺑﺮازش ﯾﺎﻓﺘﻪ ﺑﺮای ﮐﺎرﺑﺮی ﺟﻨﮕﻠﯽ (0/36=adjusted r-sq.=0/35 ،rmse) اﺳﺖ. ﻧﺘﯿﺠﻪ ﮔﯿﺮی: در ﻣﺠﻤﻮع ﯾﺎﻓﺘﻪ ﻫﺎی اﯾﻦ ﭘﮋوﻫﺶ ﻧﺸﺎن ﻣﯽدﻫﺪ ﮐﻪ ﻋﻮاﻣﻞ ﮐﻨﺘﺮل ﮐﻨﻨﺪه ﭘﺎﯾﺪاری ﺧﺎﮐﺪاﻧﻪﻫﺎ در ﮐﺎرﺑﺮی ﻣﺮﺗﻊ و ﺟﻨﮕﻞ ﻣﺘﻔﺎوت ﻣﯽ ﺑﺎﺷﺪ. ﻫﻤﯿﻦ اﻣﺮ ﺳﺒﺐ ﺗﻔﺎوت ﻫﻤﺒﺴﺘﮕﯽ ﺑﯿﻦ ﺷﺎﺧﺺ ﻫﺎی ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ و mwd و ﺑﻪ ﺗﺒﻊ آن ﻧﺘﺎﯾﺞ ﻣﺪل ﺳﺎزی ﺷﺪه اﺳﺖ. ﺳﻨﺠﺶ ازدور، ﻣﯽ ﺗﻮاﻧﺪ زﻣﯿﻨﻪ ای را ﺟﻬﺖ ﺑﻬﺮه ﮔﯿﺮی از ﻓﻨﺎوری ﻫﺎی ﻧﻮﯾﻦ ﺑﻪ ﻣﻨﻈﻮر ﻣﺪﯾﺮﯾﺖ ﭘﺎﯾﺪار ﻣﻨﺎﺑﻊ ﺧﺎک و آب ﻓﺮاﻫﻢ ﺳﺎزد. ﺑﺪﯾﻦ ﺗﺮﺗﯿﺐ اﺳﺘﻔﺎده از ﻓﻨﺎوریﻫﺎی ﻧﻮﯾﻦ ﻣﯽﺗﻮاﻧﺪ ﺑﺴﺘﺮﺳﺎز ﻋﻤﻠﯿﺎﺗﯽ ﺷﺪن ﺳﻨﺎرﯾﻮﻫﺎی ﻣﺪﯾﺮﯾﺘﯽ ﭘﺎﯾﺪار ﻣﺤﻮر ﺑﺎﺷﺪ ﮐﻪ ﻣﺎﺣﺼﻞ آن ﺻﯿﺎﻧﺖ از ﻣﻨﺎﺑﻊ ﻃﺒﯿﻌﯽ اﺳﺖ.

Modeling mean weight-diameter of aggregates based on vegetation indices in rangeland and forest land uses

Extended AbstractIntroductionAggregate stability is one the most important soil physical properties, which is estimated using easily accessible parameters. Remote sensing (RS) is a useful technique that has meaningful capabilities to monitor soil and water resources. Moreover, soil aggregate stability is an index of soil erodibility which can be used as a useful tool to manage and control the soil against destructive factors. Therefore, it is really important to model the effective factors on soil aggregate stability. The present study conducted because of importance of soil physical properties and land use effects on crop cover status and its modeling.Methods and materialIn this research, the relation between vegetation indices and mean weight diameter (MWD) as an index of soil aggregate stability was investigated in forest and rangeland land uses. In order to evaluate the relation between land uses and vegetation indices in Dehdez watershed located in the southeast of Khuzestan Province, Iran country; the images of Landsat 8 with pass number 164 and the row of 38 provided from the Earth Explorer website with GeoTIFF format. The radiometric correction performed using ENVI 5.1 software. The evaluated vegetation indices including, RVI, VIN, TVI, YVI, SBL, DVI, NDGI, RI, NDI, NDVI, PVI, SAVI, TSAVI, ARVI ,and MSAVI. The Pearson correlation between the above vegetation indices and organic carbon, sand, silt, clay ,and mean weight diameter evaluated for 50 soil samples collected from two land uses. In this study, two type of land use, including forest and rangeland assessed. Pearson ´s correlation analysis and multivariate adaptive regression spline (MARS) applied to investigate the relation between vegetation indices and MWD.Results The results illustrated that in the rangeland, MWD had a significant correlation with VIN, TVI, MSAVI, RVI, SAVI, TSAVI, NDVI, and PVI indices at the level of 0.01. However, in the forest, there was no significant relation between the studied indices. Also, MARS modeling showed that the fitted model based on vegetation indices in rangeland (Adjusted RSq. = 0.55, RMSE = 0.16) has much higher predictive power and accuracy than the fitted model for forest (Adjusted RSq. = 0.35, RMSE= 0.36).ConclusionIn general, the results of this study revealed that the controlling factors of soil aggregate stability are different for rangeland and forest land uses. This has led to differences in correlation coefficient between vegetation indices and MWD, and consequently modeling results. Also, remote sensing can provide convenient technology for providing the sustainable management purposes of soil and water resources. To cover the sustainability purposes in the watershed scale, it is necessary to utilize different technologies such as remote sensing. Indeed application of various techniques helps to simplify the processes and finally preserve the soil and water resources against degradable factors.