Growth-Stage-Specific K c of Greenhouse Tomato Plants Grown in Semi-Arid Mediterranean Region

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1 Journl of Agriculturl Science; Vol. 6, No. ; 24 ISSN E-ISSN Pulished y Cndin Center of Science nd Eduction Growth-Stge-Specific K c of Greenhouse Tomto Plnts Grown in Semi-Arid Mediterrnen Region Dnny Hrel, Myron Sofer, Moshe Broner, Dovi Zohr & Shelly Gntz 2 Negev R&D Center, Negev, Isrel 2 Vegetle Deprtment, Extension Services-Ministry of Agriculture, Bet-Dgn, Isrel Correspondence: Dnny Hrel, Negev R&D Center, M.P.O. Negev 4, Isrel. Tel: E-mil: dnih@mopdrom.org.il Received: June 22, 24 Accepted: August 3, 24 Online Pulished: Octoer, 24 doi:.39/js.v6np32 URL: Astrct Growth stge specific crop coefficient for greenhouse tomtoes grown in the semi rid Mediterrnen ws evluted. The evlution consisted of two simultneous field trils: ) Dt ccumultion of the wter consumption of round nd cherry tomto plnts with the use of dringe lysimeters. 2) Irrigtion of tomtoes plnted in locl sndy soil with either reduced or excess irrigtion wter doses using the lysimeter wter consumption dt s the reference criteri. Crop coefficients of etween.3- for the time period from seedling estlishment until first fruit hrvest nd.8 for the fruit hrvest period were recorded for the winter seson round tomto crop. During the summer seson, coefficients of etween.2-.9 for the time period from seedling estlishment until first fruit hrvest nd.8 for the fruit hrvest period were mesured for the round tomto crop. The cherry cluster cultivr showed slightly different pttern of wter consumption with pek in crop coefficient t the middle of the fruit hrvest stge nd continuous reduction in wter consumption until the end of the growth period. Excess irrigtion rtes dmged the post hrvest qulity of the fruit of one of the tested cultivrs. Reduced irrigtion rtes cused reduction in the men weight of the fruit. Keywords: irrigtion, tomto, crop coefficient, growth stge, greenhouse, semi-rid Mediterrnen, dringe lysimeters. Introduction Highly efficient irrigtion of tomto (Solnum lycopersicum L.) grown in greenhouses nd nethouses is n importnt gol, especilly when considering the fct tht wter is n essentil ut incresingly limited nd expensive resource. In ddition to lowering production costs nd reducing negtive environmentl effects, ccurte estimtion of the crop wter requirement in protected cultivtion cn decrese het lod during the hot seson y mximizing the trnspirtion fluxes from the plnt cnopy (Bille, 999). Although severl methods were considered in order to evlute the irrigtion needs of crops, the concept of crop coefficient (Jensen, 968), is widely used y irrigtion prctitioners. The crop coefficient (K c ) is the rtio of the ctul crop evpotrnspirtion (ET c ) to reference crop evpotrnspirtion (ET ) (Lzzr & Rn, 2). Using the crop coefficient provides simple nd inexpensive tool tht enles us to implement prcticl knowledge regrding the wter requirements of vriety of crops. The crop coefficient is ffected y severl fctors such s, irrigtion methods, climtic conditions, soil chrcteristics nd gronomic techniques (Lzzr & Rn, 2). Crop coefficient vlues cn e derived from soil wter lnce trils, using lysimeters nd well wtered crops. These trils should e conducted loclly in order to integrte the climtic, soil nd gronomic techniques of specific growth region where the K c vlues re to e implemented. The second component tht is needed when using the crop coefficient is the reference evpotrnspirtion (ET ) tht in mny cses is clculted using the Penmn-Monteith eqution which is sed on meteorologicl dt nd hypotheticl reference crop (Allen et l. 998). In the semi rid northern prt of the Negev desert, close to the costl plne of Isrel, pproximtely, squre meters ( H) of net houses nd greenhouses re cultivted for tomto crops ll yer round. As in other production regions round the Mediterrnen sin, the structures used for tomto cultivtion in this region cn e descried s Mediterrnen greenhouses (Wittwer & Cstill, 99). These re low cost structures covered with mesh insect proof netting during the summer nd plstic sheets during the winter. They hve no 32

2 Journl of Agriculturl Science Vol. 6, No. ; 24 ctive climte control mesures. The tomto plnts in these net houses nd green houses re plnted in the locl sndy soils, irrigted with drip irrigtion nd compound minerl fertilizers. The tomto vrieties grown re indeterminte vrieties verticlly supported y the high wire support system. The first im of this work ws to evlute K c vlues of greenhouse tomto plnts grown in the semi rid Mediterrnen region. The K c vlues derived from the experiment were ssigned to ech plnt phenologicl stge, s descried y Ko et l. (29) nd Piccinni et l. (29), Thus the use of K c dt is more ccessile to frmers nd extension workers. The second im ws to evlute the influence of deficit or excess irrigtion rtes on the yield, oth mount nd qulity of tomtoes, grown in the semi rid Mediterrnen region under covered cultivtion conditions. For this second im, the lysimeter wter consumption dt were used s reference criteri i.e. the wter requirements of the plnts in the lysimeter were considered to e % of the potentil wter requirements in the given growth conditions. 2. Method 3. Growth environment nd Plnt Cultivtion The experiment ws conducted t the Negev R&D Center locted in the northern prt of the Negev desert nd the southern prt of the Isreli costl plin (34 23 N, 3 6 E, 4 m ove se level). The climte in the region is semi-rid Mediterrnen with riny winters (Octoer-April, 26 mm men nnul precipittion) nd prolonged dry hot summers. The irrigtion wter used ws drinking wter from supply system sourced from mixture of deslinted nd well wter. Wter qulity is shown in Tle. Tle. Anlysis results of the wter used for irrigtion Mg CCO 3 C Cl EC PH (mg/l) (ds/m) The tril took plce in nturlly ventilted, north to south oriented green-house with gutter height of 4m, ridge height of 4. m nd doule slope roof. The structure ws covered (roof nd wlls) with mesh insect proof net during the dry summer seson. During the winter the roof ws covered with trnsprent polyethylene sheeting nd the side wlls with polyethylene sheeting from the ground up to one third of the height of the gutter, nd with mesh insect proof netting for the remining two thirds of the height, to the gutter. The tril consisted of two prts: ) The investigtion of tomto plnt wter consumption levels through the use of dringe lysimeters tht were plced in the greenhouse. This prt of the study ws crried out with the use of two types of tomto vrieties: Round tomto (cv. 42 during the winter nd cv. 2 during the summer) nd cherry cluster strin (cv. Shirn-33 during the summer). 2) A quntittive irrigtion experiment using round tomtoes (cv. 2 for the summer tril nd cv. 42 for the winter tril), plnted in the locl soil (locl snd (87%), silt (7%) nd cly (6%)). In this prt, the experimentl design consisted of three irrigtion tretments, in completely rndomized design with three replictions. ) % of the dily wter requirement (s ssessed y the lysimeters); 2) 2% of the dily wter llownce; 3) 7% (8% during 2-2 winter sesons) of the dily wter llownce. The irrigtion ws crried out s is customry in this re with trickle irrigtion system (.6 l/h emmiters), two irrigtion lines per plnted row nd fertigted with compound fertilizer. Plnt density ws 2.2 plnts/m 2 ). 3.2 Lysimeter Construction nd Opertion The lysimeter plot ws constructed from two sets of five polypropylene plnting troughs filled with high dringe cpcity growth edding medium composed of fine texture M -8 tuff (Mrom Goln, Isrel) nd % (v/v) compost (% orgnic mteril, 2% nitrogen,.% phosphorus nd 3% potssium) for ech set of tomto cultivrs (2 nd 42 round tomto or 33 (Shirn) cherry unch). The troughs were. m wide,.3 m high nd.4 m long. The surfce re of ech set of troughs ws 26 m 2 nd the volume ws 7.8 m 3. Plnt density in 33

3 Journl of Agriculturl Science Vol. 6, No. ; 24 the lysimeter ws identicl to tht recommended for tomto plnting in soil; (2.2 plnts per m 2 round tomto nd 2 plnts per m 2 for cherry tomtoes hung with two stems trined sepertely). Irrigtion ws consistent nd done in such wy s to ensure constnt wter sturtion in the edding mixture. (Detiled in Appendix ). The dringe wter from ech vriety ws collected y grvittionl flow into collection vessel which hd t its se sensor which constntly mesured its content y volume. Quntittive clcultion of irrigtion nd dringe wter enled the clcultion of the evpotnspirtion (ET c ) vlues for these prticulr tomto vrieties. 3.3 Wter Consumption Dt Collection nd Anlysis The plnts wter consumption (ET c ) dt from the lysimeters ws collected ccording to the description in section 3.2 nd Appendix. Reference evpotrnspirtion (ET ) ws clculted using the Penmn-Monteith eqution s dopted y FAO-6 (Allen et l., 998). The crop coefficient ws clculted ccording to the eqution y Allen et l. (998): K c = ET c /ET () 3.4. Fruit Qulity nd Post Hrvest Tests Throughout the experiment, dt ws collected with regrd to the fruit yield qulity including lossom end root, crcks nd fruit size. Those prmeters were used to define mrket qulity yield. Post hrvest tests were mde immeditely fter fruit picking using mrket qulity tomtos. Fruit ws refrigerted in ccordnce with simulted commercil storge protocol, dys t 2 C, 96% RH nd then for 3 dys t 2 C. At the end of the storge period the fruit ws exmined for the following prmeters: Crcked, firm, flexile, soft, rotten nd irregulr color. Totl Solule solids (TSS) were determined in fruit extrct using digitl refrectometer (REF-8 MRC, Isrel). 3.4 sttisticl Anlysis The dt ws nlyzed using the one wy ANOVA. The differences in vrince etween the tretments were tested y the Tukey test with significnce of p <.. The nlyses were conducted using the sttisticl pckge JMP 8 (SAS Institute Inc., Cry, USA). 3. Results 4. Climte Dt Amient temperture nd rdition levels dt throughout the period of the experiment from outside the growth structures re shown in figure. The months of April nd My were chrcterized y extremely high tempertures, reching over 4 C. At the eginning of the seson the reltively low nighttime temperture of 2 C ws recorded (). Aprt from pek dy time temperture of 22 C in the third week of Decemer, verge dily tempertures hovered etween 2 C nd 8 C (). The minimum night time tempertures rnged from C to 3 C nd the rdition vlues were typicl of the spring nd summer sesons in the region. 34

4 Journl of Agriculturl Science Vol. 6, No. ; 24 C //23 2//23 6/4/23 9/8/23 4/8/23 8/7/23 2/7/23 7/6/23 2/6/23 Temp. mx. Temp. min. Glol rdition 3/9/23 2/9/ //23 Mj C /6/22 28//22 8//22 8/4/22 29/3/22 9/3/22 8/2/22 29//22 9//22 2/2/2 3//2 //2 2//2 //2 Glol rdition Temp. mx Temp. min Mj Figure. Climte dt collected throughout the study from outside the green houses. ) Dily winter tempertures ( C) nd rdition levels (Megjoules). ) Dily summer tempertures ( C) nd rdition levels (Megjoules) 4.2 Wter Consumption nd the Growth Coefficient - Winter Seson The winter growth coefficient (K c ) of round tomtoes, ET c nd ET re presented in Figure 2. A shrp rise in the growth coefficient K c during first looming (indicted y the letter A) nd fruit mturtion of the first nd second clusters cn e detected in figure 2. This period is chrcterized y the seedling, estlishment, lef nd root development, flowering nd then fruit set. At round 7 dys fter plnting, fruit picking commences (indicted y the letter B). The growth coefficient slowly nd stedily decreses here until 4 dys fter plnting when the lef removl process egins, prepring the plnt for lowering in order to expedite fruit hrvest (mrked y the letter C). A ten dy stge of reduction in wter consumption fter lef pruning is oserved. Fourth order polynomil equtions tht descrie the reltionship etween plnt ge nd K c nd R 2 vlue re represented in the figure (Figure 2). 3

5 Journl of Agriculturl Science Vol. 6, No. ; B C Kc.8.6 A.4.2 y = -8E-9x 4 + 4E-6x 3 -.9x x R 2 = Dys After Trnsplnting ET c ET ET(mm d -) Dys After Trnsplnting Figure 2. () Correltion etween plnt ge nd growth coefficient vlues of round tomto during winter. Developmentl stges mrked long time line: A- looming, B-first fruit pick, C-lef pruning. () Clculted reference ET (ET ) nd wter requirements of plnts grown in lysimeters (ETc) during winter seson Figure 2 represents ET nd ET c vlues expressed s mm per dy t different growth development stges. The ET or evpotrnspirtionl rte t soil sturtion point is mrked y the nrrow line. ET c or the evpotrnspirtionl rte of the crop is mrked y thick line. The first few dys show noticele difference in wter requirements, difference of 6mm per dy or % higher vlue for ET. From then on the reltionship etween the equtions lters nd the wter requirements remin prllel with ech other until dy 2 when they diverge gin with ET rising ove ET c stedily until the gp is t its gretest t 22 dys. This shdowing of the two vlues during most of the growth period shows tht the lysimeter used in this study could give relile indiction of tomto plnt irrigtion requirements for those tht re grown in the sme climtic conditions ut plnted in the soil. 4.3 Wter Consumption nd the Growth Coefficient - Summer Seson Figure 3 presents the growth coefficient (K c ) of the summer growing seson of 2, s function of dys fter plnting for the 2 vriety (round tomto).the grph initilly runs prllel to tht of the winter seson. The fruit hrvest however (s shown y the rrow mrked B) strts erlier thn in the winter nd the plnt exhusts itself erlier with diminishing yield leding to the culmintion of the crop nd the removl of the plnts t dy 2 s opposed to dy 2 in the winter. The stge fter lef pruning when wter consumption decline is highlighted y the letter C nd n ccompnying circle. A third order polynomil eqution tht descries the reltionship etween plnt ge nd K c nd the R 2 vlue is represented in the figure. Figure 3 portrys vlues of ET c for round tomto plnts from the lysimeter nd ET clculted using the Penmn-Monteith eqution the summer 2 seson. The het of summer rises the ET vlues which remin higher thn ET c for the entire seson. Thus we see tht even though the wter requirements of the plnt rise, the monitoring nd control mechnism of the influx nd dringe wter mintin level t which the plnt cn rech its optiml growth potentil. 36

6 Journl of Agriculturl Science Vol. 6, No. ; 24 Kc.4.3 y = 8E-7x 3 -.3x x R 2 = A B..4 C Dys After Trnsplnting 2 ETc ETo ET (mm d - ) Dys After Trnsplnting Figure 3. () Correltion etween plnt ge nd growth coefficient vlues of round tomto during summer seson. Developmentl stges mrked long time line: A- looming, B-first fruit pick, C-lef pruning. () Clculted reference ET (ET ) nd wter requirements of plnts grown in lysimeters (ET c ) during summer seson Kc..4.3 y = -9E-x x R 2 = C.6. A B Dys After Trnsplnting 2 ETc ETo ET (mm d - ) Dys After Trnsplnting Figure 4. () Correltion etween plnt ge nd growth coefficient vlues of cherry tomtoes during summer seson. Developmentl stges mrked long time line: A- looming, B-first fruit pick, C-lef pruning. () Clculted reference ET (ET ) nd wter requirements of plnts grown in lysimeters (ET c ) during summer seson Figures 4 nd 4 represent the growth coefficient (K c ), (ET ) nd (ET c ) t ll the ges of cherry tomto plnt. 37

7 Journl of Agriculturl Science Vol. 6, No. ; 24 For the cherry tomto wter consumption dt ws collected only during the summer seson. Figure 4 illustrtes the growth coefficient of the cherry tomto s function of plnt ge nd developmentl stge. It highlights the differences etween the growth coefficient K c of the cherry strin nd tht of the round one. The crop coefficient vlue t dy for the cherry tomto ws recorded t.9 wheres the vlue for the round tomto ws.6. 4 dys lter different sitution emerged nd the cherry tomtoes K c ws significntly lower wheres tht of the round tomto remined stedy. Second order polynomil eqution nd regression coefficient re presented in the figure. Figure 4 demonstrtes tht ET is higher thn ET c for the first 4 dys during the seedling estlishment, flowering nd fruit set stge. We cn therefore ssume tht the plnts wter requirements hve een more thn dequtely supplied. Both vlues consequently converge throughout the hrvest period remining similr until the end of the growing seson. Tles 2 nd 3 show men K c vlues clculted for ech growth stge ccording to the dt presented in Figure 3 nd 4. Tle 2. Crop coefficient for round tomtoes grown in plstic covered greenhouse during the winter seson. DAT-Dys fter trnsplnting Growth stge Seedlings estlishment Blooming nd initil fruit set Fruit development of st nd 2nd clusters Fruit pick DAT Round Tomto K c Tle 3. Crop coefficient for round nd cherry cluster tomtoes grown in net house covered with mesh insect proof net during the summer seson. DAT-Dys fter trnsplnting Growth stge Seedlings estlishment Blooming nd initil fruit set Fruit development of st nd 2nd clusters Fruit pick Yield extinguishing DAT Round Tomto K c Cherry cluster Summer growth sttistics revel tht the growth coefficient revels differences in the growth ptterns of round nd cherry tomtoes. The vlues for the seedling estlishment nd root development stges re slightly lower for the cherry tomto plnt nd the vlues for the flowering nd fruit set period sustntilly lower. Comprisons of the fruit development stge show tht the cherry tomto hs n initil 2% higher vlue over the round vriety ut this is not mintined s the plnt ges. 4.4 Yield nd Fruit Size No significnt difference ws found in totl yield, mrket qulity yield (Figure ) or men fruit weight (Figure ) when compring the winter seson tril tretments (42 round tomto cultivr). 38

8 Journl of Agriculturl Science Vol. 6, No. ; Totl yield Mrket qulity yield N.S. 3 2 Kg/m 2 2 8% % 2% 2 8 N.S 6 Fruit weight (gr') % % 2% Wter dose Figure. () Totl yield (Kg/m 2 ) nd () Men fruit weight for round tomto in the winter seson of 2-2 During the summer growing seson the yield levels of 2 round tomto cultivr in the 7% tretment ws reduced y out % in comprison to the % nd 2% tretments (Figure 6) however this chnge ws not significnt. The decrese in the men fruit size of the 7% tretment ws sttisticlly significnt (p =.24, f = 6.68) reltive to the men fruit size of the other two tretments (Figure 6) nd my explin the decrese in totl fruit yield weight. 3 2 Totl yield Mrket qulity yield N.S Yield (kg/m2) 2 7% % 2% Tretment Men fruit weight (gr') ** 7% % 2% Tretment Figure 6. () Totl yield (kg/m) nd ()Men fruit weight for round tomto in the 23 summer growing seson 39

9 Journl of Agriculturl Science Vol. 6, No. ; Post Hrvest Tle shows the results of the post hrvest evlution dt fter period of simulted storge for the fruit picked during the summer growth seson. The dditionl wter llownce in the 2% tretment incresed the percentge of soft nd rotten fruit fter storge period. Color pigmenttion nd TSS (totl solule solids) levels were not ffected y the different tretments. However when compring the mrket yield it cn e seen tht the 2% of the wter requirement irrigtion rte cuses rise in the numer of unmrketle fruit. Tht is to sy rotten, soft or normlly pigmented fruit. However contrry to the results from the summer, post hrvest qulity of the winter seson fruit ws not ffected y the irrigtion tretments. A possile explntion for this difference could e due to higher sensitivity of the 2 tomto vriety used in the summer seson, to excess irrigtion rtes which is not the cse with the winter seson vriety (42). This sensitivity might negtively ffect fruit shelf life nd stored fruit qulity. Tle 4. Post hrvest test results, winter growth seson Tretment Firm soft Rotten Irregulr color TSS % 8% % % 2 69 Tle. Post hrvest test results, summer growth seson Tretment Firm Soft Rotten Irregulr color TSS % 7% % % Discussion Low cost dringe lysimeters were used in order to vlute the K c vlues for greenhouse nd net house tomto crops, plnted in sndy soils nd grown in semi-rid Mediterrnen region. The wter consumption dt ws nlyzed ccording to the relevnt plnt growth stges in order to crete n ccessile nd simple crop coefficient dt se. Crop coefficients of etween.3- for the period from seedling estlishment till fruit hrvest stge nd.8 for the fruit hrvest period were mesured for the winter seson round tomto crop. During the summer seson growth, round tomto crop coefficients of etween.2-.9 for the period from seedling estlishment till fruit hrvest stge nd.8 for the fruit hrvest period were mesured. Those vlues re close to previously mesured crop coefficients for field grown tomtoes in regions with Mediterrnen climte (Hmidt et l., 23; Vzquez et l., 2).The cherry cluster cultivr showed slightly different pttern of wter consumption with pek in the crop coefficient in the middle of the fruit picking stge nd continuous reduction in wter consumption throughout the growth period. Fruit weight nd post hrvest qulity were ffected y reduced or excessive mount of irrigtion, ut only during the summer growth seson. Men fruit weight ws reduced y 2% under deficit irrigtion tretment. Similr effect of deficit irrigtion on fruit weight of glsshouse tomto ws oserved y Pulupol et l. (996). Fruit sugr content (expressed s TSS) ws not effected y the reduced wtering tretments in contrst to severl previous findings (Beckles 22) where wter limittion incresed fruit sugr content in tomto. When wter dose exceeded the mximum plnt wter consumption (2% tretment) more fruits were found soft or rotten t the end of the storge period. Fruit softness is known phenomenon tht ws demonstrted regrding severl fruit types grown under high irrigtion regimes (Hofmn, 998). The lysimeters tht were used in these experiments were comprised of continer filled with growth medium suitle for growing plnts with limited root volume.they mintin optiml wter content nd regulted dringe tht cn e used s tool for evluting mximl wter consumption of plnts grown in certin conditions (Dnielson & Feldhke, 98; Del-Cmpo, 27; Prisi et l., 29). Using such pprtus together 4

10 Journl of Agriculturl Science Vol. 6, No. ; 24 with n irrigtion tril s descried ove cn provide n ccurte indiction of wter crop requirements with reltively simple, low cost, commercilly ville equipment. These experiment results emphsized the importnce of ccurte irrigtion of greenhouse tomtoes when high qulity yield together with reduced costs re importnt gols. Acknowledgements We wish to thnks H. Fdid, A. Slepoy, nd L. Gnot from the Negev R & D Center for their help in conducting this experiment. References Allen, R. G., Pereir, L. S., Res, D., & Smith, M. (998). Crop evpotrnspirtion. Guidelines for computing crop wter requirements. Irrigtion nd Dringe (Pper 6, p. 3). Food nd Agric. Orgniztion of the United Ntions, Rome, Itly. Bille, A. (999). Overview of greenhouse climte control in the Mediterrnen regions. Chiers Op Retrieved from Beckles, D. M. (22). Fctors ffecting the posthrvest solule solids nd sugr content of tomto (Solnum lycopersicum L.) fruit. Posthrvest Biology nd Technology, 63(), Dnielson, & Feldhke. (98). Urn lwn irrigtion nd mngement prctices for wter sving with minimum effect on lwn qulity. Completion Report No. 6.Colordo Stte University. Del-Cmpo, M. G. (27). Effect of wter supply on lef re development, stomtl ctivity, trnspirtion, nd dry mtter production nd distriution in young olive trees. Austrlin Journl of Agriculturl Reserch, 8, -7. Hofmn, P. J. (998). Production fctors influence fruit qulity nd response to posthrvest tretments. Acir Proceedings (Vol. 8, pp. 6-8). Austrlin Centre for Interntionl Agriculturl Reserch. Jensen M. E. (968). Wter Consumption y Agriculturl Plnts, Wter Deficits nd Plnt Growth (Vol. II, pp. -22). In T. T. Kozlowsky (Ed.). Acdemic Press, New York. Lzzr, P., & Rn, G. (2). The crop coefficient (k c ) vlues of the mjor crops grown under Mediterrnen climte. Mediterrnen Dilogue on Integrted Wter Mngement, FP6 INCO-MED Funded Project. Ko, J., Piccinni, G., Mrek, T., & Howell, T. (29). Determintion of growth-stge-specific crop coefficients (Kc) of cotton nd whet. Agriculturl Wter Mngement, 96(2), Wittwer, S. H., & Cstill, N. (99). Protected cultivtion of horticulturl crops worldwide. HortTechnology, (), Hmidt, A., Benyoucef, B., & Hrtni, T. (23). Smll-scle irrigtion with photovoltic wter pumping system in Shr regions. Renewle Energy, 28(7), Prisi, S., Mrtni, L., Col., G., & Mggior, T. (29) Mini lysimeters evpotrnspirtion mesurements on suurn environment. Itlin Journl of Agro meteorology, 3, 3-. Piccinni, G., Ko, J., Mrek, T., & Howell, T. (29). Determintion of growth-stge-specific crop coefficients (K c ) of mize nd sorghum. Agriculturl Wter Mngement, 96(2), Pulupol, L. U., Behoudin, M. H., & Fisher, K. J. (996). Growth, yield, nd posthrvest ttriutes of glsshouse tomtoes produced under deficit irrigtion. HortScience, 3(6), Vázquez, N., Prdo, A., Suso, M. L., & Quemd, M. (26). Dringe nd nitrte leching under processing tomto growth with drip irrigtion nd plstic mulching. Agriculture, Ecosystems & Environment, 2(4),

11 Journl of Agriculturl Science Vol. 6, No. ; 24 Appendix Technicl detils nd opertion of the dringe lysimeters The lysimeters contined growth medium of high dringe cpcity (see section 3.2) nd n utomtic irrigtion regime which ensured optiml wter vilility during the growing seson. The lysimeters were irrigted y doule row of dripper irrigtion pipe (.6 l/s) with cm spcing etween the emmiters. Wtering ws consistent nd done in such wy s to ensure constnt sturtion. The dringe wter from ech tretment ws collected y grvittionl flow into collection vessel which hd t its se sensor constntly mesuring its content volume. In ddition pump ws sumerged which emptied the wter nd guge tht mesured the mount eing emptied. The irrigtion schedule ws sed on n lgorithm ssimilted in the irrigtion controller (Irrinet, Motorol, Isrel).The lgorithm ws sed on wter level dt in the dringe collection vessel. The rte of the chnge in the wter level of the vessel following plot irrigtion ws function of the time mesured from the previous irrigtion. This function slope represented the dringe rte. The rte of the wter level rise (nd the function slope) ws reduced when the dringe mount lessened. This dringe stge ended when the clculted derivtive of the slope reched. At this point two ctions were tken y the irrigtion controller:. The mount of dringe wter ws mesured y the height t the level of the cut off point in the collection continer. 2. Determintion of the time intervl efore susequent wtering (sed on the mount of dringe recorded in stge ). A lrge dringe vlue indictes low wter requirement nd thus prescried longer intervl etween irrigtions. When the dringe mount is smller the following irrigtion is scheduled sooner. The lgorithm function is constructed in order to define the wtering time intervls plotted ginst dringe mounts. Susequently the monitoring system initites the evcution of the collection vessel.once this hs finished, the cycle of irrigtion nd wter collection resumes. Quntittive clcultions of irrigtion nd dringe wter enle clcultion of the evpotnspirtionl vlue over certin time periods which in turn llow n evlution of the totl dily mount. Copyrights Copyright for this rticle is retined y the uthor(s), with first puliction rights grnted to the journl. This is n open-ccess rticle distriuted under the terms nd conditions of the Cretive Commons Attriution license ( 42