It is presented two study cases about the approach in root analysis at field and laboratory conditions based on digit-~lilJ\}"3cge analysis. Grapevine (Vitis vinifera L.) and date palm (Phoenix dactylifera L.) root systems were analyzed by both the monolith and trench wall method aided by digital image analysis. Correlation between root parameters and their fractional distribution over the soil profile were obtained, as well as the root diameter estimation. Results have shown the feasibility of digital image analysis for evaluation of root distribution

ALENCAR, C. M. de

BASSOI, L. H.

HOPMANS, J. W.

JORGE, L. A. de C.

SILVA, J. A. M. e

English

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f/\.-Paper No. 002032An ASAE Meeting PresentationDIGITAL IMAGE ANALYSIS OF ROOT DISTRIBUTION TOWARDS IMPROVEDIRRIGATION WATER AND SOIL MANAGEMENT:GRAPEVINE AND DATE PALM STUDY CASESby/ Luís Henrique Bassoi , José Antonio Moura e Silva ~Embrapa Semi-ÁridoPetrolina, PE, BrazilCristina Miranda de Alencar v-FCAlUNESP - Depto Eng. RuralBotucatu, SP, BrazilLúcio André de Castro Jorge i->Embrapa Instrumentação AgropecuáriaSão Carlos, SP, BrazilJan W. Hopmans c>:University ofCalifornia - Dept, ofL.A.W.R.Davis, CA, USAWritten for Presentation at the2000 ASAE Annuallnternational MeetingSponsored by ASAEMidwest Express CenterMilwaukee, WiscosinJuly 9-12, 2000Abstracts:It is presented two study cases about the approach in root analysis at field and laboratory conditions based on digital imageanalysis. Grapevine (Vitis vinifera L.) and date palm (Phoenix dactylifera L.) root systems were analyzed by both themonolith and trench wall method aided by digital image analysis. Correlation between root parameters and their fractionaldistribution over lhe soil profile were obtained, as well as the root diameter estimation. Results have shown the feasibilityof digital image analysis for evaluation of root distribution.Keywords:image analysis, root distribution, Vitis vinifera L., Phoenix dactylifera L.The author(s) is solely responsible for the content of this technical presentation. The technical presentation does notnecessarily reflect the official position of ASAE, and its printing and distribution does not constitute an endorsement ofviews which may be expressed.Technical presentations are not subject to the formal peer review process by ASAE editorial committees; therefore, they arenot to be presented as refereed publications.Quotation from this work should state that it is from a presentation made by (name of author) at the (Iisted) ASAE meeting.EXAMPLE - From Author's Last Name, Initials. "Title of Presentation." Presented at the Date and Title of meeting, PaperNo. X. ASAE, 2950 Niles Road, St. Joseph, M[ 49085-9650 USA.For information about security permission to reprint or reproduce a technical presentation, please address inquires toASAE.ASAE, 2950 Niles Rd., St. Joseph, M[ 49085-9659 USAVoice: 6[6.429.0300 FAX: 616.429.3852 E.Mai[: <hq@asae.org>r IY\', (.\5 A E Ibv N v ,q L [N TE R N/I 'I Cu IV /1 L rn eE. T f IV b I 2.a o U I !VJwa.A."( k...f!.e I rJ~ ~'Ylíe c),') "lA'c".J r'MU'1'" S r·r \~:As rl é / :20o o ' C j) - e o fV\1. IntroductionDigital image processing techniques can offer advanced analysis of root measurement. Thefeasibility, accuracy and procedures to estimate root area, root length and root diameter by digitalimage analysis have been discussed intensively (Ruark & Bockeim, 1988; Commins et ai., 1991;Tagliavini e. ai., 1993; Murphy & Smucker, 1995; Kaspar & Ewing, 1997; Dowdy et ai., 1998;Bauhus & messier, 1999; Kimura et ai. 1999).Images of roots exposed on a trench waIl or in the laboratory are acquired and the root area andlength are estimated. Root density values are obtained to yield complete root system characterizationin a soil profile. Results with grapevine (Vitis vinifera L.) and date palm (Phoenix dactylifera L.) arepresented in this work. Measurements were performed by both the monolith method (Bohm, 1979) andthe trench wall method using digital image analysis (Crestana et ai. 1994). The objective of this studywas to compare both inethods with different root systems frorn those previously presented by Bassoi etai. (1999).2. Material and MethodsSampling area - grapevineTnan experimental area ofBrazilian Agricultural Research Coorporation (Embrapa), in Petrolina,northeastern Brazil, two trials were carried out to evaluate the root distribution of grapevines cv. ltaliaon rootstock TAC-313 planted in a 4 x 2 m grid spacing in September 1991, in a red yelIow latosol,coarse texture. Grapevines were irrigated by microsprinkler spaced every 4 m along the plant row andcentered between two plants, and by drip emitters spaced 1 m apart along a double drip line. In bothirrigation systems, a 1 m deep and 2 m wide trench was dug between plant rows to expose one halfroot system of four grapevines in October 1995 and two grapevines in April 1996. The distancebetween the trench wall and the plant row was I m, A thin layer of soil (1-2 em) was removed from thesoil profile along the whole trench, and visible roots (greater than I mm) were painted with white inkto enhance color contrast between the roots and the soi\. A 1 x 1 m wire-wood frame with a grid ofO.2x 0.2 m was pressed on the trench walI and video images were collected for each 0.04 m2 area alongthe whole trench. The image collection procedure was repeated for distances 1.0, 0.8, 0.6, 0.4, and 0.2111 from the plant rows.After the image coIlection at every trench waIl, monoliths (0.2 x 0.2 x 0.2 m) corresponding tothe Iilmed area were sampling from two plants in 1995 and another two plants in 1996, whereas eachvine in opposite side of the trench. So, monoliths were collected at distances of 0.2-0.4, 0.4-0.6, 0.6-0.8, and 0.8-1.0 m from the plant rows.Tna commercial growing area in 1997, the root distribution of cv. Piratininga on rootstock lAC-313 was determined using only the trench walI method combined with the digital image analysis, todemonstrate its application in a farmer's field. Grapevines were planted in 1990 using a 3.5 x 2 m gridspacing, in a clayey soi\. The vines were irrigated using furrows on either side of the vine row. Twotrenches (1 m deep and 2 m long) were excavated to expose the rooting system of one vine trunk in thecenter of each trench. Images were captured as described earlier at distances of 1.0, 0.8, 0.6, 0.4, and0.2 m from the plant row.2Sampling area - date palmIn the Embrapa's experimental area, an experiment with date palm cv. Zahidi was carried out inMarch 1997, in a germoplasm bank. Crop was planted in April 1982 in a 5 x 4 m grid spacing and ithas been irrigated by furrows (one in each side of the rows). A 1 m depth trench was excavated in alongitudinal direction to rows to expose half root system from one plant, at 1m distance form the trunk.The procedure in this experiment was similar to that described for the grapevine's trials in theexperimental area, except that roots were shot and the corresponding monolith were sampled in a 1 x 1m area, at one side ofthe trunk.Field imageThe images collected in the field with a video camera were digitized by a board (resolution of640 x 480 pixels). The image analysis was performed by SIARCS 3.0 (Integrated System for Root andSoil Coverage Analysis). For grapevine, root area (Ap , em") was measured in both trial's sites, whilethe root length (L, , em) was measured only in the commercial growing area. For date palm, both rootparameters were measured.Laboratory dataRoots from grapevine and date palm crops were separated from soil by 4 mm smash sieving. lnthe laboratory, roots were washed and classified in four diameter intervals (d): d ~ 2 mm, 2 < d ~ 5mm, 5 < d ~ 10 mm, d> 10 mm. Roots were dried in a 65°C oven to dry weight measurement (Dc , g).For grapevine roots, the length inside the monolith (Lm , em) was estimated based on the numberofroot intersection with the lines of a grid (1 x 1 em for roots with d ::; 10 mm, and a 2 x 2 em for rootswith d > 10 mm), multiplied by a factor (Tennant, 1975).For date palm crop, roots from different diameter intervals presented in each monolith weredivided in so many parts as necessary and put on a color contrast background with delimited area, tobe shot by a digital camera (resolution 480 x 240 pixels) and transferred to a microcomputer. Root area(Am, em') and the root length (Lm , em) inside the monolith were measured by SIARCS 3.0. Valuesfrom each diameter interval were summed to obtain the total value for each parameter.Data analysisFor grapevines in the experimental area (1995 and 1996 trials), Dc and Lm from monolith werecorrelated with the averaged Ap, obtained from the front and back walls ofthe corresponding monolith.In addition, the vertical distribution for both the monolith and trench wall method was compared, usingfractional weight, length or area values, averaged for each horizontal 0.2 m layer along the trench. Forgrapevines in the commercial growing area (1997 trial), correlation was made between Ap and Lp. TheAp/ L, ratio was used to derive the root diameter in each trench wall (d- , mm), and the averaged valuewas obtained from two subsequent soil profiles.For date palm crop, De; Am and Lm from monolith were correlated with the averaged Ap and Lpobtained from the front and back walls ofthe corresponding monolith. The Ap / L, ratio was also usedto estimated d., and the averaged value obtained from the front and back walls of the correspondingmonolith was compared with the root diameter measured directly from the monolith.The root length density (Lc) was calculated using the data obtained in the monolith method:3L,=L; / 20 * 20 * 20Aceording to Bassoi et ai. (1999), and using treneh wall data, it was assumed that the areal rootfraetion (ARF, area of root/area of soil) is approximately equal to the volumetrie root fraction (VRF,volume ofroot/volume ofsoil). So, the root length density (treneh Lc) ean be estimated frorn:AFR = VFR = [(Apt+Ap2) / 2] /20 * 20L,= VFR / 7t [(drt+dr2)/2]2(crrr.cm")(em .cm")where Apt and Ap2are the front and the baek wall in relation to eaeh monolith, and d., and dr2arethe root diameter in the front and in the baek wall, as estimated frorn A, / Lp.The L, ealculated by monolith data were obtained for both erops in the experimental area, whileL, estimated using treneh wall data was obtained for grapevine trial in 1997 and for date palm erop.3. ResultsGrapevineCorrelation obtained between De; Lm and averaged Ap from 1996 trial were slightly better than1995 ones, but in both years the r2-values were not so high, even those between parameters measuredinside the monolith (D; and Lm). Otherwise, correlation performed between the averaged fractionaldistribution of the root parameters for each 0.2 m soil layer along the trench wall, considering eaehplant and eaeh soil profile, were higher (Table 1). L, ealculated by monolith data ranged from 0.001 to0.273 em.em-3. ln the 1997 trial, a similar trend in the eorrelation between parameters and fraetionaldistribution was showed (Table 2). Values of d, were 2.7 ± 1.1,2.7 ± 1.3,2.5 ± 1.2, and 2.3 ± 0.9 mmfor 0.2-0.4, 0.4-0.6, 0.6-0.8, and 0.8-1.0 m soil profiles, respeetively, and estimated L, using trenehwall data varied from 0.0001 to 0.093 em.em".Table 1: Correlation (p < 0.05) of grapevine root parameters and distributions measured by monolithand treneh wall methods in the experimental area in 1995 and 1996.1995 1996parameter0.5990.567distributionmicrosprinkler 0.855 0.698 0.744 0.869 0.913 0.946drip 0.916 0.870 0.873 0.866 0.741 0.893microsprinklerdrip0.5620.6140.4170.6460.5920.7240.6020.6630.6870.783D; - root dry weight inside the monolith; Lm- root length inside the monolith; Ap· average root area in the soil profileTable 2: Correlation (p < 0.05) of grapevine root parameters and distributions measured by treneh wallmethod aided by digital image analysis in a eommereial growing area in 1997.parameter distribution0.858 0.535 0.585 0.968 0.745 0.771Ap· average root area in the soil profile; L, - average root length in the soil profile; Lv . root length density estimated bytrench wall data4Date palmThe eorrelation values from parameters have varied from medium to high, but they were betterfor fraetional distribution (Table 3). L, values obtained from monolith (range frorn 0.020 to 0.169em.em") were higher than those obtained by treneh wall data (range from 0.001 to 0.004 em.em"),and eorrelation between them was 0.567 (p < 0.05). The root diameter estimation by (Ap / Lp) ratio was2.4 ± 0.4, 2.4 ± 0.6, 2.5 ± 0.6, and 2.5 ± 0.4 mm, for 0.2-0.4, 0.4-0.6, 0.6-0.8, and 0.8-1.0 m soilprofiles, respeetively.Table 3: Correlation (p < 0.05) of date palm root parameters and distributions measured by monolithand treneh wall methods in the experimental area in 1997.Dw x A", Dw x Lm Dw x Ap Dw x Lp Am x Lm Am x Ap A", x Lp L", x Ap Lm x Lp Ap x Lpparameters0.962 0.771 0.719 0.686 0.872 0.742 0.721 0.616 0.640 0.959distribution0.986 0.873 0.870 0.840 0.925 0.850 0.846 0.676 0.753 0.962D;- root dry weight inside the monolith; Am - root area inside the monolith; Lm - root length inside the monolith;Ap' average root area in the soil profile; L, - average root length in the soil profile4. DiscussionFor both erops, results related to root parameters ean be eonsidered reasonable, but fraetionaldistribution of root parameters over the entire 0.2 m soil layer were mueh better. For the d ~ 2 mminterval, grapevines showed up a range from 32.8 to 73.0 % of D«, but it eorresponded from 84.7 to96.4 % of Lm. For date palm, 8.8, 30.0, 56.2, and 5.0 % of D; were within d ~ 2 , 2 < d ~ 5, 5 < d ~10, and d > 10 mm, while for the same intervals, 28.1, 23.3, 24.1, and 24.6% of Lm were found,respeetivel y.The estimated root diameter (dr) in the grapevine eommereial area ean be eonsidered asreasonable aeeurate in eomparison with root diameter measured by monolith method in theexperimental area. Greater pereentage of grapevine roots was found within d < 0.5 mm (van Zyl,1998), d < 1 mm (Morlat & Jaequet, 1993) and d < 2 mm (Morano & Kliewer, 1994; Padgett-Johnson,1999). L, estimated by monolith was mueh higher than L, estimated by treneh wall data. For datepalm, it seems that (Ap / Lp) ratio underestimated the root diameter, and L, ealculated by data frornmonolith was also mueh higher, and poorly eorrelated with L, estimated by treneh wall data.Bassoi et ai. (1999) presented higher eorrelation for peaeh palm (parameter and distribution r2higher than 0.9) and asparagus (parameter and distribution r2 higher than 0.8), as well as more aeeurateroot diameter estimation. As 87.8 % of peach palm roots were within d ~ 5 mm, and 87.8 % ofasparagus roots were within 2 < d ~ 5 mm, it leads to believe that finer root systems ean providedbetter correlation between the monolith method and the treneh wall method aided by digital imageanalysis.5. ConclusionsFor grapevine and date palm erops, the eorrelation between root parameters estimated by b.otPmonolith and treneh wall method aided by digital image analysis was reasonable. But correlation wasmueh better for fractional distribution ofthe same parameters over the soilprofile. The higher presenceof grapevine roots within the lower diameter interval probably has contributed for a better correlation5between parameters, distribution and root diameter estimation than date palm crops. Results haveshown the feasibility of digital image for root distribution evaluation.6. ReferencesBassoi, L. H.; Silva, J. A M.e; Alencar, C. M. de; Ramos, C. M. c., Jorge, L. A C.; Hopmans, 1.Digital image analysis of root distribution towards improved irrigation water and soil management.In: ASAE/CSAE Annual International Meeting. Toronto, 1999. 6p. (ASAE paper 992225 - CDRom).Bauhus, J,; Messier, C. Evaluation of fine root length and diameter measurements obtained usingRHIZO image analysis. Agron. J., 91:142-147,1999.Bohm, W. Methods of studying root systems. Spring1er-Verlag, New York, 1979.Commins, P. 1.; McBratney, AB.; Koppi, A J. Development of a tecnique for the measurement ofroot geometry in the soil using resin-impregnated blocks and image analysis. J. Soil Science, 42:237-250, 1991.Crestana, S.; Guimarães, M. F.; Jorge, L. A c., Ralisch, R.; Tozzi, C. L.; Torre, A; Vaz, C. M. P.Avaliação da distribuição de raízes no solo auxiliada por processamento de imagens digitais.Revista Brasileira de Ciência do Solo, 18:365-371, 1994.Dowdy, R. H.; Smucker, A J. M.; Dolan, M. S.; Ferguson, J. C. Automated image analysis forseparating plant roots from soil debris elutrated from soil cores. Plant SoU, 200: 91-94, 1998.Kaspar, T. C.; Ewing, R. P. ROOTEDGE: Software for measuring root length from desktop scannerimages. Agron. J., 89: 932-940, 1997.Kimura, K.; Kikuchi, S.; Yamasaki, S. Accurate root length measurement by image analysis. PlantSoU, 216: 117-127, 1999.Morano, L.; Kliewer, W. M. Root distribution of three grapevine rootstocks grafted to Cabernetsauvignon grown on a very gravely clay loam soil in Oakville, California. Am. J Enol. Vitic.,45:345-348, 1994.MorIat, R.; Jacquet, A The soil effects on the grapevine root system in several vineyards of the Loirevalley (France). Vitis, 32:35-42, 1993.Murphy, S. L.; Smucker, A J. M. Evaluation of video image analysis and line-intercept methods formeasuring root systems of alfafa and ryegrass. Agron. J., 87:.865-868, 1995.Padgett-Johson, M. Vine water relations, gas exchange, growth and root distribution of several Vitisspecies under irrigated and non-irrigated conditions. Thesis, University ofCalifornia, Davis, 1999.Ruark, G. A; Bockheim, J. G. Digital image analysis applied to soil profiles for estimating tree rootbiomass. Soil Science, 146: 119-123, 1988.Tagliavini, M.; Veto, L. J.; Looney, N. E. Measuring root surface area and mean root diameter ofpeach seedlings by digital image analysis. HortSci., 28:.1129-1130, 1993.van Zyl, J. L. Response of grapevine to soil water regimes and irrigation systems. ln: The grapevineroot and its environment. Technical Communication 215. J. L. van Zy\ (Ed.) pp. 30-43. Departmentof Agriculture and Water Supply, Pretoria, 1988.7. A.cknowledgementsThe authors :,\are grateful for financial support provided by Conselho Nacional deDesenvolvimento CIentífico e Tecnológico (CNPq) and Banco do Nordeste, from Brazil, and byInternational Foundà\lon for ScI~hce (IFS), from Sweden.\

Digital image analysis of root distribution towars improved irrigation water and soil management: grapevine and date palm study cases.

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Digital image analysis of root distribution towars improved irrigation water and soil management: grapevine and date palm study cases.

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