A PORTABLE TILLAGE PROFILER FOR MEASURING SUBSOILING DISRUPTION

A PORTABLE TILLAGE PROFILER FOR MEASURING SUBSOILING DISRUPTION R. L. Rper, T. E. Grift, M. Z. Tekeste ABSTRACT. A portle tillge profiler (PTP) ws onstruted using lser distne sensor, liner tutor, portle PC, nd lightweight luminum frme tht n quikly nd urtely mesure oveground nd elowground soil disruption used y tillge. A lortory experiment ws onduted tht determined tht soil olor did not detrimentlly ffet the PTP, with expeted vertil errors of 2.3 mm nd horizontl errors of.6 mm eing found. However, when pure white nd lk ojets were exmined, the errors inresed to 4.2 mm vertilly nd 11 mm horizontlly. This mximum error ws estlished when ttempting to mesure the height nd width of wedge, whih hd shrpened edge pointing vertilly upwrd. The PTP ws used in the Ntionl Soil Dynmis Lortory soil ins to mesure oth oveground nd elowground soil disruption used y two susoiler shnks. The PTP gve results tht enled differenes etween the oveground disruptions used y eh susoiler to e sttistilly estlished. Keywords. Profile, Soil disruption, Susoiling, Tillge. Asignifint mount of reserh hs een onduted to determine reltive differenes in drft etween vrious shnks used for susoiling (Nihols nd Reves, 1958; Gill nd Vnden Berg, 1966; Collins nd Llor, 1973; Updhyy et l., 1984; Grner et l., 1984; Owen, 1989). Most of these studies exmined shnks tht were minly onstruted to disrupt the entire soil profile nd differed in their pproh ngle nd shnk design. Produers were mostly interested in the numer of shnks tht ould e pulled with their trtors nd hd little regrd for how muh surfe disruption ws used y susoilers euse seondry tillge would e used to even the soil surfe prior to plnting. However, griulture in the U.S. hs hnged sustntilly (Towery, 2), nd produers re now interested in muh more thn tillge energy. Mny produers re now dopting onservtion tillge systems tht inorporte fewer psses of seondry tillge. Primry tillge s done with n in-row susoiler my e followed diretly with plnter. Residue should only e minimlly distured so s to provide the soil dequte protetion from wter erosion. Mny dvertisements for susoilers now ontin not only drft fore Artile ws sumitted for review in August 22; pproved for pulition y the Power & Mhinery Division of ASAE in Novemer 23. Presented t the 22 ASAE Annul Meeting s Pper No. 2-1138. Use of ompny nmes or trde nmes does not imply endorsement y USDA-ARS, the University of Illinois, or the University of Georgi. The uthors re Rndy L. Rper, ASAE Memer Engineer, Agriulturl Engineer, USDA-ARS Ntionl Soil Dynmis Lortory, Auurn, Alm; Tony E. Grift, ASAE Memer Engineer, Assistnt Professor, Deprtment of Agriulturl Engineering, University of Illinois t Urn-Chmpign, Urn, Illinois; nd Mehri Z. Tekeste, ASAE Student Memer, Grdute Reserh Assistnt, Deprtment of Biologil nd Agriulturl Engineering, University of Georgi, Athens, Georgi. Corresponding uthor: Rndy L. Rper, USDA-ARS Ntionl Soil Dynmis Lortory, 411 S. Donhue Drive, Auurn, AL 36832; phone: 334-844-4654; fx: 334-887-8597; e-mil: rlrper@rs.usd.gov. informtion, ut lso inlude the mount of residue remining on the soil surfe fter tillge hs een onduted. Determining the mount of soil disruption or soil movement used y tillge implements ould e just s importnt s determining the drft energy. Pin-style profile meters hve een the most ommon method of determining soil movement y tillge implements (Hirshi et l., 1987). These onsist of series of eqully sped pins tht re lowered onto the soil surfe until ontt is mde. However, mnul reording of this informtion is time-onsuming unless photogrphi system is used to digitize this informtion (Wgner nd Yu, 1991). Severl other methods hve een developed tht relied on moving proe tht ontted the soil surfe nd sensed the presene of soil (Henry et l., 198; Hrrison, 199; Shfer nd Lovely, 1967; Mithell nd Jones, Jr., 1973; Currene nd Lovely, 1971). These devies were sed on single proe tht ws moved horizontlly ross the soil ed. To strt, the proe ws moved vertilly downwrd until it ontted the soil surfe. The proe mintined miniml ontt with the soil nd ws moved horizontlly until it sensed sustntil horizontl fore. The proe ws then lifted until the lterl fore deresed nd it ontinued its horizontl pth long the soil surfe. These methods, lthough n improvement over the pin-style profile meters, were mehnilly omplited, ould tke signifint mount of time for mesurements, nd ould distur the soil profile. To llevite the prolems previously mentioned, severl non-ontt methods hve een developed sed either on ultrsoni (Roihud nd Molnu, 199) or optil sensors (Romkens et l., 1988; Hung nd Brdford, 199; Flngn et l., 1995). The ultrsoni mesurement systems hve rther lrge horizontl errors (up to 3 mm), whih ould msk differenes in susoiler shnks. Aording to previous reserh, optil sensors should hve ury dequte for mesurement of tillge profiles (Romkens et l., 1988; Hung nd Brdford, 199; Flngn Trnstions of the ASAE Vol. 47(1): 23-27 24 Amerin Soiety of Agriulturl Engineers ISSN 1-2351 23

et l., 1995). However, previous reserh only exmined reltively smll differenes in elevtion, nd the systems were not evluted sed on their ility to mesure oth the soil surfe nd the ottom of susoiled zone in one pss. Mesuring the distne to the soil surfe with lser requires the projetion of lser em onto the soil, detetion of the em, nd then lultion of distne through tringultion. Improvements in lser nd instrumenttion tehnology now enle reserhers to use single unit, whih ontins oth the lser nd the em detetion unit. It ws expeted tht the lose proximity etween the lser nd the detetion unit would enle the ottom of the soil trenh to e viewed y oth devies t the sme time. Furthermore, the lser mesurement system should e portle nd e ple of eing used in field experiments. The ojetives of this study re therefore: S To develop lser mesurement system for reording soil surfe elevtions. S To evlute this system in lortory setting using vrious stndrd shpes. S To determine if this devie ould e used to detet differenes in soil disruption, oth oveground nd elowground, used y susoiler shnks. METHODS AND MATERIALS The portle tillge profiler (PTP) ws onstruted nd ssemled t the USDA-ARS Ntionl Soil Dynmis Lortory (NSDL) nd onsists of four omponents: (1) lser distne sensor, (2) liner positioning tutor, (3) portle PC, nd (4) lightweight luminum frme. The lser distne sensor used in this study ws Nov Rnger NR-4 (Nov Rnger, In., Sn Diego, Cl.), whih uses lss III lser with n output of less thn 5 mw operting t wvelength of 67 nm. This lser distne sensor hs distne rnge of.3 to.9 m (12 to 36 in.), over whih it hs mximum reported error of.17%. The lser distne sensor requires 12 VDC. Dt quisition is provided y portle PC, whih is onneted y n RS-232 le. A omputer progrm reted in BASIC ws used to quire the dt. Output is updted s fst s every 5 mse (2 Hz). An NSK Positioning Atutor (NSK Ltd., Tokyo, Jpn) ws used to move the lser devie ross the soil surfe. This unit requires 24 VDC nd hs mximum distne rnge of 1 m. The unit hs progrmmle feed rtes of 5 to 4 mm/se. For ll of our tests, stndrd rte of 5 mm/se ws used. An luminum frme ws onstruted t our lortory tht ws oth lightweight nd portle. Figure 1 shows the frme with the positioning tutor nd lser distne sensor tthed. Overll length of the unit is 1.25 m (49 in.), height is.71 m (28 in.), nd width is.61 m (24 in.). Totl weight of the unit is 23 kg (5 l). The lser distne sensor ws mounted so tht it would e positioned.425 m (16.8 in.) from the soil surfe. This positioning llows the sensor to relily mesure displed soil ove the soil surfe up to.13 m (5 in.) nd elow the soil surfe down to.48 m (19 in.). Two fixed ts re tthed to the lower horizontl memers of the frme so tht the eginning nd end of the dt strem n e esily estlished. During initil testing, the unit ws expeted to respond etter to lighter olors, so n experiment ws onduted to Figure 1. Portle tillge profiler onsisting of lser distne mesurement system, horizontl positioning tutor, portle PC, nd lightweight luminum frme. 24 TRANSACTIONS OF THE ASAE

determine if the PTP ws sensitive to soil olor nd to determine its vertil nd horizontl ury. Severl ojets, squre lok (5.14 m high 5.4 m wide), ylinder (15.3 m dimeter), nd wedge (3.66 m high 7.11 m wide), were pinted four different olors. Munsell soil olor hrts were used to selet olors for two soils. These soils re Norfolk sndy lom soil (fine lomy, koliniti, thermi Kndiudults) nd Detur ly lom soil (fine, koliniti, thermi Rhodi Pleudults) loted in the indoor ins of the NSDL. Aording to Munsell nottion (Soil Survey Division Stff, 1993), these soils hve wet olors of gryish rown (1YR 5/2) for the Norfolk soil nd drk reddish rown (5YR 3/2) for the Detur soil. Two other olors were seleted: white (1 8/1) nd lk (1YR 2/1). These two olors were hosen to provide upper nd lower olor extremes. Aording to these four desriptions, pint ws purhsed nd used to pint the stndrd ojets. Eh ojet ws nlyzed with n experiment s rndomized omplete lok design with 2 replitions. To otin true height nd width, the ojets were mnully mesured prior to the test with dil liper. Eh ojet ws mesured due to slight differenes rising from mnufturing proesses nd potentil vrition in pint thikness. Eh ojet ws then lid on stright ord elow the PTP, nd the PTP ws operted t onstnt speed of 5 mm/s. The lser distne sensor gve diret reding of height, while the mesurement of width ws more omplited. First, the totl distne trversed y the PTP ws determined, nd this vlue ws divided y the numer of quired dt points for eh test run. This proedure llowed n verge vlue of distne per reding to e otined. This vlue ws found to e reltively onstnt for eh test performed. The lser distne sensor s output ws then nlyzed nd the distne determined etween the first nd lst mesurement where the ojet ws sensed. A lultion of perent error ws otined for eh run, nd these vlues were tested for sttistil signifine. Fisher s proteted lest signifint differene (LSD) ws used for men omprison. A proility level of.5 ws ssumed to test the null hypothesis tht no differenes existed etween the different olors. The PTP ws lso used in n indoor soil in experiment using the Norfolk sndy lom soil to determine differenes in oveground nd elowground soil disturne used y two shnks operting in soil wetted to severl different moisture ontents (Rper nd Shrm, 22). The shnks used for the experiment were mnuftured y Deere & Co. (Ankeny, Iow). The stright shnk is 1.25 in. (31.8 mm) thik with 5 in. (127 mm) LASERRIP Ripper Point nd is urrently used on the John Deere 955 Row Crop Ripper. The minimum -tillge shnk is.75 in. (19 mm) thik with 7 in. (178 mm) Min-till point nd is used on the John Deere 21 Minimum Till Ripper. The oveground soil disruption ws mesured in severl lotions long the pth of the susoiler shnk immeditely fter tillge hd een onduted. The loosened soil ws then removed, the PTP repositioned, nd mesurements of the trenhed zone quired. Five mesurements were tken in eh lotion with the mhine eing repositioned ross the susoiled trenh eh time. RESULTS AND DISCUSSION An exmple of the output reeived from the PTP is given in figure 2 for eh of the three stndrd ojets. Note the high vlues mesured ner the eginning nd ending of eh run. These points re purposely inluded to determine when the lser leves the ts on the edge of the PTP nd egins mesuring the distne to the ground. Results from the experiment using the ue showed tht the PTP otined very urte mesurements for this ojet. Mesurements of height were ll within 4% (2 mm), with the white olor hving n error of 2.2% nd the other olors hving errors of -3.4%, -3.5%, nd -3.7% for the lk olor, Norfolk soil olor, nd Detur soil olor, respetively (fig. 3). Mesurements of width for this ojet lso showed little error, with the minimum vlue ttriuted to the Norfolk soil olor (.4% error) nd the mximum error found for the lk olor (-3.3% error). Height, m Height, m Height, m.15.1.5 WEDGE.2.4.6.8 1.15.1.5 CUBE.2.4.6.8 1.15.1.5.2.4.6.8 1 Horizontl Distne, m CYLINDER Figure 2. Exmple profiles of the stndrd ojets pinted drk reddish rown to simulte olor of Detur ly lom soil. Perent Error, % 2 1-1 -2 Height Width White Blk Detur Norfolk Figure 3. Perent error for mesurements of height nd width of the ue. LSD.5 (height) ws 1.32%, nd LSD.5 (width) ws 2.46%. Vol. 47(1): 23-27 25

Mesurements of perent error for the height of the ylinder were lso miniml (fig. 4), even though this ojet ws three times lrger thn the ue. For the ylinder, the minimum vlue of error ws found for the lk olor (.3% error;.4 mm error) nd the mximum vlue of error ws found for the white olor (-1.6% error; 2.4 mm error). However, width mesurements of the ylinder were not s lose for the lk olor. This olor showed n error of -14.7% (22 mm error), while ll other olors hd errors muh loser to zero (fig. 4). The wedge proved to e the most hllenging ojet to mesure in oth height nd width (fig. 5). For the height mesurement, the lk olor gin gve the lrgest error of -11.4% (4.2 mm error) with the white olor hving the minimum vlue (-2.9% error; 1.1 mm error). Mesurements of width proved to e diffiult for the white nd lk olors, with rther lrge mesurements of error of 14.9% (11 mm error) nd 8.2% (5.8 mm error), respetively. Miniml vlues of error were oth otined for the Detur soil olor (.5% error) nd the Norfolk soil olor (.2% error). From these experiments, it seems ler tht the PTP is very ple of mesuring urte heights nd widths of ojets olored similr to the tested soils. The mximum perent errors of height found for these olors were for the wedge nd were -6.1% for the Detur soil olor nd -6.3% for the Norfolk soil olor. These errors for soil-olored ojets Perent Error, % 2 1-1 -2 Height Width White Blk Detur Norfolk Figure 4. Perent error for mesurements of height nd width of the ylinder. LSD.5 (height) ws.24%, nd LSD.5 (width) ws 1.3%. Perent Error, % 2 1-1 -2 Height Width White Blk Detur Norfolk Figure 5. Perent error for mesurements of height nd width of the wedge. LSD.5 (height) ws 1.63%, nd LSD.5 (width) ws 5.52%. indite tht our height mesurements should e within 2.3 mm of the tul mesurement. All perent errors of width for soil olored ojets were extremely smll, with the mximum eing otined for the ue (Detur, 1.2%). This mesurement indites tht for soil-olored ojets, our width mesurements should e within.6 mm of the tul mesurement. However, pure lk or white ojets offered some limittions, with lrger errors typilly eing found for these ojets. The mximum height error ws found for the lk olor for the wedge (11.4%), while the mximum width error ws found for the white olor for the wedge (14.9%). If these pure olors re enountered in soil, then lrger errors should e expeted. The previous results showing the vlidity of the PTP for use in soils enled us to pursue other reserh using the PTP to mesure oveground nd elowground soil disruption. Figure 6 shows profile onstruted for eh of the two tillge shnks used in this experiment. The stright shnk hs slightly wider elowground profile with more rounded ottom of the trenh. The minimum-tillge shnk is nrrower nd leves more pointed trenh. However, there ws no sttistil differene in the mount of elowground disruption used y these susoilers, with the stright shnk hving n verge ross-setionl re of 796 m 2 nd the minimum -tillge shnk hving n verge ross-setionl re of 76 m 2. The oveground disruption of eh susoiler is similr, ut the minimum-tillge shnk does not disrupt the soil to the sme height s the stright susoiler, nor does it hve the quntity of soil disrupted ove the soil surfe. A sttistil differene (P <.6) ws found etween the two shnks, with the stright shnk hving n oveground disruption ross-setionl re of 361 m 2 nd the minimum-tillge shnk hving n oveground disruption ross-setionl re of 314 m 2. CONCLUSIONS A portle tillge profiler ws onstruted using four omponents ( lser distne sensor, liner tutor, portle PC, nd n luminum frme) tht quikly nd urtely mesured oveground nd elowground soil disruption. A lortory experiment demonstrted tht the PTP ws urte when used with two soil olors ommonly found in the southestern U.S. When using the PTP to mesure Depth (m).2.1 -.1 -.2 -.3 STRAIGHT MINIMUM-TILLAGE -.4.2.4.6.8 1 Horizontl (m) Figure 6. Averge shnk omprison profiles mesured with the PTP showing differenes etween stright shnk nd minimum-tillge shnk for oth oveground nd elowground soil disruption. 26 TRANSACTIONS OF THE ASAE

height nd width of ojets olored to mth these soils, mximum errors should not e greter thn 2.3 mm vertilly nd.6 mm horizontlly. However, when using the PTP to mesure ojets pinted lk nd white, the ury ws not s good, with mximum errors eing 4.2 mm vertilly nd 11 mm horizontlly. The PTP ws used in the NSDL soil ins to detet differenes in oth oveground nd elowground soil disruption hieved etween susoiler shnks operting t severl moisture ontents. The results showed tht the elowground disruptions were not different etween the shnks, ut tht the minimum-tillge shnk disrupted the soil surfe to lesser degree thn the stright shnk. REFERENCES Collins, E. R., nd W. F. Llor. 1973. Soil-in investigtion of deep-working tillge tool. Trns. ASAE 16(1): 29-33. Currene, H. D., nd W. G. Lovely. 1971. An utomti soil surfe profilometer. Trns. ASAE 14(1): 69-71. Flngn, D. C., C. Hung, L. D. Norton, nd S. C. Prker. 1995. Lser snner for erosion plot mesurements. Trns. ASAE 38(3): 73-71. Grner, T. H., W. R. Reynolds, H. L. Musen, G. E. Miles, J. W. Dvis, D. Wolf, nd U. M. Peiper. 1984. Energy requirement for susoiling ostl plin soils. ASAE Pper No. 84125. St. Joseph, Mih.: ASAE. Gill, W. R., nd G. E. Vnden Berg. 1967. Design of tillge tools. In Soil Dynmis in Tillge nd Trtion, 23-232. Agriulture Hndook 316. Wshington, D.C.: U.S. Government Printing Offie. Hrrison, H. P. 199. Soil surfe profile meter for simple tillge tools. Trns. ASAE 33(1): 21-24. Henry, J. E., M. J. Sirini, nd D. M. Vn Doren, Jr. 198. A devie for mesuring soil surfe profiles. Trns. ASAE 23(6): 1457-1459. Hirshi, M. C., B. J. Brfield, I. D. Moore, nd D. G. Colliver. 1987. Profile meters for detiled mesurement of soil surfe heights. Applied Eng. in Agri. 31(1): 47-51. Hung, C., nd J. M. Brdford. 199. Portle lser snner for mesuring soil surfe roughness. SSSA J. 54(5): 142-146. Mithell, J. K., nd B. A. Jones, Jr. 1973. Profile mesuring devie. Trns. ASAE 16(3): 546-547. Nihols, M. L., nd C. A. Reves. 1958. Soil retion to susoiling equipment. Agri. Eng. 39(6): 34-343. Owen, G. T. 1989. Fore-depth reltionships in pedogenetilly ompted ly lom soil. Applied Eng. in Agri. 5(2): 185-191. Rper, R. L., nd A. J. Shrm. 22. Using soil moisture to determine when to susoil. In Pro. 25th Annul Southern Conservtion Tillge Conferene for Sustinle Agriulture, 44-49. E. vn Snten, ed. Auurn, Al.: Alm Agriulturl Experiment Sttion. Roihud, P. R., nd M. Molnu. 199. Mesuring soil roughness hnges with n ultrsoni profiler. Trns. ASAE 33(6): 1851-1858. Romkens, M. J. M., J. Y. Wng, nd R. W. Drden. 1988. A lser miroreliefmeter. Trns. ASAE 31(2): 48-413. Shfer, R. L., nd W. G. Lovely. 1967. A reording soil surfe profile meter. Agri. Eng. 48(5): 28-282. Soil Survey Division Stff. 1993. Soil Survey Mnul. Wshington, D.C.: USDA-NRCS. Towery, D. 2. No-till on the upswing. CTIC News Relese. Aville t: www.ti.purdue.edu. Updhyy, S. K., T. H. Willims, L. J. Kemle, nd N. E. Collins. 1984. Energy requirements for hiseling in ostl plin soils. Trns. ASAE 27(6): 1643-1649. Wgner, L. E., nd Y. Yu. 1991. Digitiztion of profile meter photogrphs. Trns. ASAE 34(2): 412-416. Vol. 47(1): 23-27 27

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