Spatial Variability Analysis of Hydraulic Conductivity in Tilled and No-Tilled Soil

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Iteratoal Joural of Farmg ad Alled Sceces Avalable ole at www.jfas.

1 Iteratoal Joural of Farmg ad Alled Sceces Avalable ole at 14 IJFAS Joural / / 31 December, 14 ISSN IJFAS Spatal Varablty Aalyss of Hydraulc Coductvty Tlled ad No-Tlled Sol V. Shamsabad 1*, P. afrasab 2, A. Mohamadafar 1, S.Abd 1, Y. Esmael jam 1 ad M. Kazem 1 1.Torbat-e-jam Collage Agrculture ad Amal Scce, Torabat-e-jam, Ira 2.Collage of water ad sol scces, Uversty of Zabol, Zabol, Ira Correspodg author: V. Shamsabad ABSTRACT: Kowledge of spatal varablty of hydraulc s ecessary may processes such as draage projects desg. Ths study were amed to exame the spatal varablty of hydraulc a area of 5000 square meters. Data were collected from tlled ad o-tlled sols ad at two dfferet scales. I large-scale a umber of 47 ad 111 sample were take from tlled ad o-tlled sols respectvely, ad small-scale 66 samples were take both tlled ad tlled sols. Three methods Krgg, log krgg ad verse dstace weghtg () for Estmato. The methods performace s evaluated usg cross-valdato techque wth the comparso crtera of mea absolute error (MAE), mea bas error (MBE) ad the root mea square error (RMSE). The results showed that the spatal structure of hydraulc large-scale o-tlled sol wth ad wthout logarthmc trasformato follows a sphercal model. Spatal correlato s also weak. I large scale ad tlled sol the sem varogram of hydraulc ad ts logarthmc follow a Gaussa model. I ths case the spatal correlato s also weak. The semvarogram of hydraulc small-scale o-tlled sol wth ad wthout logarthmc trasformato ad follows a lear model. I ths case a strog weak correlato s observed. After Plowg the lad the best ftted model semvarogram s the expoeatal ad sphercal model for logarthcs ad raw data, respectvely. The spatal correlato s weak ths case. The results of cross-valdato dcate that the Krgg method estmates hydraulc more accurate. Keywords: Estmato ordary krgg, log ormal krgg,, hydraulc INTRODUCTION Hydraulc of sol s the most mportat physcal ad hydraulc parameter that affect the draage projects from a techcal Pot of vew (Alzadeh, 05). Geerally, the hydraulc s obtaed by laboratory ad feld methods. The results of the feld methods are more accurate tha the laboratory methods due to atural codtos ad a larger sample sze. I areas where the groudwater level s the scope of the root actvty, usually, the methods of determg sol hydraulc below water table are used. I the areas where both the water table ad the mpeetrable layer are lower tha the depth of the root actvty ad there s the possblty of rsg water ad draage the future, the methods above water table are used to measure hydraulc. Oe of the method above the water table s the versed augerhole method(porchmethod) (Joural of Maagemet ad Plag., 05). The sol hydraulc vares from oe pot to aother. Sce farmg operato causes dsturbace ad chages the sol physcal structure, t affects the spatal varablty (Joural of Maagemet ad Plag, 05). Amog methods that ca be used to estmate spatal varablty of sol hydraulc each rego are geostatstcal methods (Mahda., 05). I recet decades a umber of researcher have examed geostatstcal

2 Itl J Farm & All Sc. Vol., 3 (12): , 14 scece, the spatal varablty of some sol propertes usg (Alam al., 190; Sepaskhah al., 05). Delbar al. (05) performed the evaluato of the geostatstcal methods the estmato of sol hydraulc shbab ad poshtab areas below ssta pla were. Ths research was doe o 605 Hydraulc Measured data. Iterpolato methods, Krgg methods, weghted movg average() ad TPSS Had bee used. ths study was performed large-scale ad the spatal structure was ot observed so much. hoshmad al (09) to assessed the Geostatstcal methods for estmato sol hydraulc dosalgh Khuzesta rego GIS evromet ad cocluded that spatal correlato of hydraulc ths rego s Modest. Amog the types of krgg methods, ordary krgg wth sphercal sem-varogram ad to the power of two had the hghest accuracy estmatg hydraulc. The purpose of ths study was spatal varablty aalyss of hydraulc tlled ad o-tlled Sols ad evaluato of the krgg terpolato method, Log krgg ad estmatg Hydraulc. Mohamadzadeh al. (09) used geostatstcs optmzato of the hydraulc assessmet draage desgs (a case study of rrgato etwork ad zeydo draage).i ths surrey, t has bee tred to use geostatstcs for categorzg the agrcultural lads regardg the hydraulc ad the dstct areas were also compared by polygo tse method regardg the hydraulc ( low, medum, hgh). Estmato were doe by usg the ormal krgg, smple ad geeral krgg. The results showed that from amog dfferet methods ad dfferet varagram models area surface, the sphercal model s capable of the hydraulc approxmato the area surface. MATERIALS AND METHODS Study area lthe study was doe a area over 5,000 square meter located at the uversty of Zabol Ssta pla(ira). Ths feld cotaed the logtude 61 degrees 4 mutes east ad lattude 31 degrees 1 mutes North ad at a alttude of 40 meters above sea level. The rafall Zabol cty s mostly the showery precptato ad maly starts December ad cotues utl early sprg. Accordg to the forty-year statstcs the aual rafall average Zabol cty s 60. mm ad accordg to the twety-year statstcs t s 4.4 mm. Mmum temperature recorded zabol stato durg the prevus 40 years s -10 C ad maxmum temperature s 51 C. the aual temperature s mea 22 C at ths stato. Hydraulc Coductvty Measuremets For Hydraulc measuremets ths study, reverse aguerhole method was used. ths method, frst, aguerhole shoud be drlled some pots the usaturated sol, the the sol of the aguerhole body shoud be fully saturated for the test the desred depth the t shoud be measured. for measurg the hydraulc the followg formula ca be used (Maagemet ad Plag Orgazato Publcato, 134): K = {1.15r[log(h. + r/2)- log(h + r/2)]}/(t- t.) (1) K= hydraulc (cetmeters per secod), r=aguerhole radus (cm), t = tme sce the begg of water level Drop the measuremet (s), h. = water colum heght the aguerhole at tme t. or measuremet Start ad h= water colum heght the aguerhole at tme t(cm). To determe the samplg pots coordates GPS was used. two regular etwork wth dfferet scales were determed usg a GPS devce. samplg was started at December 22 th 12 ad cotued utl 1 Jauary 13. frst, the o-tlled sol pots were take large ad small scale, afterwaeds the lad was plowed ad the of tlled sol pots were take. At the tme of samplg, lad was ot cultvated. Sol texture was loamy. Frst, large-scale, o-tlled sol wth tervals of 10 m, 47 pots(fgure 1) ad tlled sol addto to takg the pots take from the o-tlled sol other pots were take for the tlled sol three dfferet rego of lad ad wth 2 meter dstace such that ca be see Fgure 2. I ths case, 111 pots were take. for small scale both types of sol lad was selected the ma lad wth the area 5 10 m ad the lad was etted the tervals of oe meter ad separately 66 pots were take each sol (Fgure 3). 1312

3 Itl J Farm & All Sc. Vol., 3 (12): , 14 Fgure 1. Locato of pots measurg hydraulc large scale o-tlled sol Fgure 2. Locato of pots measurg hydraulc large scale tlled sol Fgure 3. Locato of pots measurg hydraulc small scale o-tlled ad tlled sol The used Iterpolato Methods Accordg to the results of other researches, ths study, ordary krgg terpolato methods, Log krgg ad were used whch had better results mostly. Software used ths study was GS + software (De Souza, 09). Krgg Ordary krgg method s the most commo type of krgg whch the varable values the statstcs mssg pots were estmated based o the Lear weghted movg average of varable values clear pots: Z * x. Z 0 1 x (2) Z * x I whch, 0 the estmated quatty of the Z varable at o-sampled pot 0 x Z, x, the quatty of the Z x varable at the samplg Pot, weght attrbuted to the varable Z pot the eghborhood of the estmate pot (Isaac ad Asryvastava, 199). x, ad s the umber of pots 1313

4 Itl J Farm & All Sc. Vol., 3 (12): , 14 Log krgg Coverso of ormal log s oe of the most commo coversos especally for dstrbutos havg postve skewess that was used ths study. Applcato of krgg method o the trasformed data s commoly kow as the log-ormal krgg method (Hassa Pak, 07). I ths method,the basc premse s that Smlarty ad Correlato betwee eghbors s proportoal wth dstace betwee them. that ca be dcated as a fucto of dstace verse aywhere from the eghborg pots. Ths method s used whe the sample pots are dstrbuted at local scale surfaces wth a adequate suffcetly dstrbuto. The rater orgal formula s as follows: Where Z0 s the estmated quatty of the varable Z at pot 0, Z s the observed quatty of the varable at pot, d dstace betwee the apparet pot up to estmato pot ad s a factor that determes the weght based o the dstace(safar, 06). Method ad Crtero Assessmet I ths study,the cross-valdato method wll beused to evaluate the terpolato methods. ths method, frst, a observed pot wll be elmated ad the estmato wll be made by usg other pots ad by applyg the desred terpolato method for ths pot. the wll be retured to ts place ad the ext pot wll be omtted. ths procedure wll be performed for all the observed pots. crtera used ths study cluds mea absolute error (MAE), the mea bas error (MBE) ad root mea square error(rmse)s: MAE 1 Z Z * MBE 1 * x Zx x Zx ) 3( ) 4( RMSE 1 * Z x Zx 1 2 ) 5( MAE ad RMSE show the amout of the error measuremet ad MBE show the devato of the results of the used methods. Bascally, the best method s a method havg the least amout of MAE ad RMSE ad ts MBE be closer to zero RESULTS AND DISCUSSION Statstcal descrptos of the Data studed Statstcal descrptos of the hydraulc data both, tlled ad o-tlled sol are preseted respectvely Tables (1) ad (2). coeffcet of varato vares for Hydraulc o-tlled sol both large ad small scale ad exsts a terval betwee 11/32 ad 9/22 percet. I tlled sol, the coeffcet of varato s a terval betwee 13/22 ad 52/19. As t s show tables 1 ad 2, the hydraulc follows the log-ormal 1314

5 Itl J Farm & All Sc. Vol., 3 (12): , 14 dstrbuto both scales. Log-ormal of hydraulc dstrbuto Rogers, (1991) ad Mustafa, (00) stydes has also bee obtaed. Table 1. statstcal Summary of the data o o- tlled sol Elogato 1/14 0/46-11/3 2/94 Skewess 1/25 0/42 2/93 0/ Varace 29/52 0/15 26/07 0/091 Coeffcet of Varato (%) 9/22 15/7 75/33 11/31 sd 5/43 0/3 5/1 0/30 m 6/09 1/1 6/77 1/91 mea 12/2 2/47 13/61 26/51 max 2/53 3/36 40/14 3/69 varable Hydraulc Logarthm of hydraulc Hydraulc Logarthm of hydraulc Large scale Small scale Table 2. statstcal Summary of the data o tlled sol Elogato 2/4 0/2 /42 0/96 Skewess 1/69 0/6 2/45 0/41 Varace 101/1 0/ /42 0/19 Coeffcet of Varato (%) 45/9 13/22 52/19 14/67 sd 10/05 0/397 10/3 0/43 m 9/52 2/25 6/77 1/91 mea 21/9 3/002 /75 2/93 max 59/22 4/0 74/41 4/31 varable Hydraulc ) Logarthm of hydraulc Hydraulc Logarthm of hydraulc Large scale Small scale Geostatstcal Descrpto of the Data For vestgatg Isotropc ad asotropc of the hydraulc, frst drectoal sem-varogram was plotted for four drectos, 0, 45, 90, 135 to agular devato of 22/5 Usg GS+ software plotted. results dd ot show a cosderable asotropy. So the sotropc sem-varogram was used for the subsequet stages of the research. No-tlled sol Fgures ad 9 show that the best sem-varogram model of the hydraulc s sphercal model both, logarthmc ad o-logarthmc cases large scale. Spatal correlato s also weak both cases. Delbar al(04) ad Rogers al (1991) also express that the best sem-varogram model for hydraulc s the sphercal model ad ther researches also ether there sot the spatal correlato or t s very weak. Alem al (190) have reports, the spatal correlato the spatal correlato of the hydraulc whch s the best semvarogrammodel of the hydraulc both, logarthmc ad o-logarthmc cases a Lear small scale ad the coeffcet spatal correlato s weak. Fgure. the experetal sem varogram model o-tlled sol large scale 1315

6 Itl J Farm & All Sc. Vol., 3 (12): , 14 Fgure 11. the experetal sem varogram model tlled sol small scale Tlled sol Fgure 10 shows that large scale the best sem-varogram model of the hydraulc s gaussa model both logarthmc ad o-logarthmc cases, tlled sol the logarthmc mode the radus affecto s more tha o- logarthmc mode. Also the spatal correlato coeffcet s weak. I both logarthmc ad o- logarthmc cases small scale tlled sol, the best sem-varogram model of the hydraulc s the sphercal model(fgure 11). The spatal correlato coeffcet both cases s weak. Fgure 9. the model experetal sem varogram model o-tlled sol small scale Fgure 10. the experetal sem varogram model tlled sol large scale Choosg the best method of estmatg the hydraulc data Tables 5 ad 6 show the results of cross-valdato for each of the parameters. Based o the results obtaed from the cross-assessmet ad by comparg MAE, t was foud that the best estmato method tlled sol ad o tlled sol s krgg method large scale, also small scale o-tlled sol the best estmato procedure s to the power of 2 ad the best procedure s the log krgg tlled sol. Hoshmad al ( 09) foud to the power of 2 ad the commo krgg methods as havg the most accuracy hydraulc estmato amog the varous methods Iterpolato. 1316

Itl J Farm & All Sc. Vol., 3 (12): 1311-131, 14 Table 5.

Hydraulc Logarthm of hydraulc Large scale 14/3 131/3 373/3 275/5 242/5 350/5 354/0 352/0 906/0 14 krgg Log krgg Hydraulc Logarthm of hydraulc Small scale Table 6.

7 Itl J Farm & All Sc. Vol., 3 (12): , 14 Table 5. Results of cross-valdato of hydraulc estmato o-tlled sol MAE 930/3 0774/4 009/4 RMSE 251/5 3225/5 302/5 MBE 0/ /0-049/0- the umber of eghborhood Iterpolato Method krgg Log krgg varable Hydraulc Logarthm of hydraulc Large scale 14/3 131/3 373/3 275/5 242/5 350/5 354/0 352/0 906/0 14 krgg Log krgg Hydraulc Logarthm of hydraulc Small scale Table 6. Results of cross-valdato of hydraulc estmato tlled sol MAE 726 /6 325/7 97/6 36/7 746/7 13/7 RMSE 59/9 393/10 65/9 131/11 42/11 917/10 MBE 910/0 75/0 404/1 0025/0-043/0-316/0- the umber of eghborhood 12 Iterpolato Method Krgg Log krgg Krgg Log krgg varable Hydraulc Logarthm of hydraulc Hydraulc Logarthm of hydraulc Large scale Small scale Drawg maps estmate Accordg to tables 5 ad 6, mapsrelated to the best terpolato methods were draw fgures 12 ad 13 fgures. 12 ad 13 dcate that hydraulc tlled sol s more tha o-tlled sol. Large scale Fgure 12. maps of hydraulc estmato tlled ad o- tlled sols large scale 1317

Itl J Farm & All Sc. Vol., 3 (12): 1311-131, 14 Small scale Fgure 13.

varato coeffcet of hydraulc tlled sol has decreased comparso to otlled sol large scale both cases logarthmc ad o-logarthmc ad small scale case, logarthmc case t has also reduced.

8 Itl J Farm & All Sc. Vol., 3 (12): , 14 Small scale Fgure 13. maps of hydraulc estmato tlled ad o- tlled sols small scale CONCLUSION Accordg to the results obtaed ths survey the best method for the estmato of hydraulc s mostly krgg method. varato coeffcet of hydraulc tlled sol has decreased comparso to otlled sol large scale both cases logarthmc ad o-logarthmc ad small scale case, logarthmc case t has also reduced. Accordg to the obtaed results, both tlled sol ad o-tlled sol, ad both large ad small scale, hydraulc cotas postve skewess. data dstrbuto follow the ormal log dstrbuto. I both types sol the affecto radus s more large scale tha small scale. Accordg to the obtaed results, the spatal correlato hydraulc s weak. REFERENCES Alem MH, Azar AS ad Nelse DR Krgg ad uvarate modelg of a spatally correlated data. Sol Techology, 1: Alzade A. 05. Moder lad draage. 2 d edto, Uversty of Imam Reza, Mashad, Ira. Delbar M, khayatkholgh M ad mahda M. 05. Evaluato of the geostatstcs methods estmatg hydraulc coduct vty shbab ad poshtab areas of ssta pla. Iraa Joural of Agrcultural Sceces. 35: Hasapak A. 0. GeoStatstcs, 2 d edto, Uversty of Tehra, Tehra, Ira. Hormoz S. 06. The comparso of two terpolato method as krgg ad. Shahregar magaze, p: Hoshmad A. salar A ad salarjaz M. 09. Assessg the geostatstcs methods hydraulc estmato of sol GIS evromet. 2 d Natoal Coferece o water. Uversty of Behbaha, Behbaha, ra, p: Isaak EH ad Srvastava RM A troducto to appled geostatstcs. Uversty of Oxford. Oxford. Eglad. P: 561. Maagemet ad Plag Orgazato. 05. structos to determe the hydraulc of sol dfferet methods. Maagemet ad Plag Orgazato Publcatos of the coutry, p: 322. Mohamadzadeh P, dahazadeh b, boromadasab S ad hosse S. 09. Use of geostatstcs optmzato of estmatg the hydraulc draage Plas Case Study (zeydo rrgato etwork ad zeydo). 2 d Natoal Coferece o Water. Uversty of Behbaha, Behbaha, ra, p: Mahda MH. 04. Geostatstcs applace draage. 3 d draage techcal workshop, p: Sepaskhah AR, Ahmad SH ad shahbaz N. 05. Geostatstcal aalyss sorptvty for uder tlled ad o-tlled coductos. Sol & tllage Research 3:

Journal of Water and Soil Vol. 26, No. 1, Mar-Apr 2012, p Kriging. (

Journal of Water and Soil Vol. 26, No. 1, Mar-Apr 2012, p Kriging. ( Joural of Water ad Sol Vol. 26, No. 1, Mar-Apr 212, p. 53-64 ( ) 53-64. 1391 1 26 *2 1-89/7/26: 9/8/15:.. (1386-87 1361-62) 26 32.. (GPI) (IDW). (Co-Krgg) (Krgg) (RBF) (LPI) 64/46 6/49 77/2 66/86 IDW RBF.