Improving Water and Nutrient Use Efficiency of Potato by Partial Root-Zone Drying Irrigation in a Semi-Arid Area in China: A Field Experimental Study

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1 YAN SHI et l: IMPROVING WATER AND NUTRIENT USE EFFICIENCY OF POTATO BY PARTIAL ROOT-... Improving Wter n Nutrient Use Effiieny of Potto y Prtil Root-Zone Drying Irrigtion in Semi-Ari Are in Chin: A Fiel Experimentl Stuy Yn Shi 1,, Xuein Qi,3,*, Ping Li,3,, Dongmei Qio,3,, Zhongong Hung,3, 1 North Chin University of Wter Resoures n Eletri Power Zhengzhou, Henn, Chin Frmln Irrigtion Reserh Institute of the Chinese Aemy of Agriulturl Sienes (CAAS) Xinxing, Henn, Chin 3 Agriulture Wter n Soil Environmentl Fiel Siene Reserh Sttion of Xinxing City Henn provine of CAAS; Xinxing, Henn, Chin Key lortory of High-Effiient n Sfe Utiliztion of Agriulture Wter Resoures of CAAS Xinxing, Henn, Chin Astrt Prtil root-zone rying irrigtion (PRD) hs een estlishe s n effiient tehnology to sve wter without srifiing rop yiel, ut its effetiveness in sving nutrients n reuing the impt on soil n wter environment is less well unerstoo. In this pper, we present the results of fiel experimentl stuy with pottoes to emonstrte tht PRD n sve not only wter ut lso nitrogen. It keeps soil wter t 9% of the fiel pity, lterntely keeping hlf of the roots ry in oth susurfe-rip n furrow PRD. The mesurements of soil nitrogen fter hrvest revele tht the resiul minerl nitrogen in the soil from to 3m eep reue y 9.7% n 17.5% respetively uner rip PRD n furrow PRD ompre to the orresponing full irrigtion. Similrly, for soil in epth from 3 to m, these inreses to 13.5% n 33.17% respetively uner rip full irrigtion n furrow full irrigtion ompre to the orresponing PRD irrigtion. It inites signifint erese in nitrogen lehing when irrigte using rip PRD. Keywors - potto; nitrogen uptke; resiul nitrogen; prtil root-zone rying; susurfe rip irrigtion; furrow irrigtion I. INTRODUCTION Chin is the iggest potto prouing ountry in growing re n yiel in the worl, with the output of pottoes pproximtely kilogrm per yer, lose to one fourth of totl tuer yiel of the worl [1]. Due to its sprse n shllow root system, soil wter efiit oviously influenes tuer yiel []. Thus, supplementry irrigtion is lwys neee to proue high yieling plnts in semi-ri re. Until now, however, knowlege is unville on how to improve irrigtion wter-use effiieny (IWUE) n nitrogen effiieny of potto y PRD. PRD hs een reporte to enhne WUE while mintining the yiel in severl rops [3]. The PRD metho is to irrigte the plnts lterntely on ifferent zones of the root system n lterntely prt of the plnt root expose to rying soil. []. As stte ove, mny stuies hve een onute to ssess the influene of fertilizer, irrigtion strtegies, plnt speies n other ftors on the nitrogen uptke n WUE y potto [5], ut the response of soil nitrogen resiul s well s uptke to ifferent irrigtion mngement strtegies uner semi-ri environmentl onitions is still not fully unerstoo. The ojetive of this stuy ws tht how to ffet the nitrogen yle n wter use effiieny in the soil-plnt system uring the whole growth yle of potto with the pproh of PRD, efiit irrigtion (DI) n full irrigtion (FI). The stuy results might e useful in the res where efiit irrigtion n soil qulity mintenne re neee in rop proution. II. MATERIALS AND METHODS A. Experimentl Site n Mterils Fiel experiments were rrie out uring 7 n 8 t the Agriulture Wter n Soil Environmentl Fiel Siene Reserh Sttion of the CAAS in Xinxing ity, Henn provine, Chin (ltitue 113.9, longitue 35.3, ltitue 73.m). The limte is temperte with nnul verge rin-fll of out mm. the sesonl vrition of temperture, glol rition, vpor pressure efiit (VPD) n potentil evpotrnspirtion (ETp) uring the experimentl perios in 7 n 8 is showe in Figure 1. Referene evpotrnspirtion (ETo) ws lulte oring to the formul of Penmn-Monteith []. The soil is sny silt lom. The topsoil (.35m epth) ontins 57.75% sn (.. mm), 3.7% silt (..), 11.53% ly (<. mm) n 1.15% orgni mtter. The mile lyer (.35.m epth) ontins 5.% sn, 5.% silt, 18% ly, n.% orgni mtter. The susoil (. 1.m epth) ontins 9.9% sn, 3.31% silt, 15.77% ly n.7% orgni mtter. The soil is lssifie s n lluvil soil with fiel pity (FC) of out 87mm own to the rooting epth of out m, for most rops in this soil, whih efines the mximum rooting epth. Soil ulk ensity for topsoil n susoil is 1. n 1. g/m3, respetively[7]. The retention urve of the topsoil ws otine y pressure plte tehnique; the urve is erive using the Vn Genuhten moel on mesure oservtions. Sturte n resiul soil wter DOI 1.513/IJSSST ISSN: 173-8x online, print

2 YAN SHI et l: IMPROVING WATER AND NUTRIENT USE EFFICIENCY OF POTATO BY PARTIAL ROOT-... ontent (Θ) in the root zone ws.39 n.89m3/m3, respetively. Temperture/ VPD/kp Glol rition/mj.m - Etp Mr 1-Mr 1-Apr 3-Apr -My 9-Jun 9-Jun Dte Figure 1. Dily mens of temperture (), vpor pressure efiit (), rition () n potentil evpotrnspirtion () uring the experimentl perio in 7 n 8 (DAP) n lste until mturity, 97 DAP. Up to 3 DAP, PRD ws irrigte s FI. For more etils, see Li Ping et l. In 8, the fiel tril ws fully rnomize esign with three replites of three susurfe rip irrigtion tretments [full irrigtion (FI1), prtil root-zone rying (PRD1), efiit irrigtion (DI1, 7% irrigtion mount of FI1)] n two furrow irrigtion tretments [fully irrigtion (FI), prtil root-zone rying (PRD)]. The FI tretment ws irrigte ily to mintin the soil wter ontent t 5 1mm elow fiel pity uring the whole growing seson. The PRD tretment reeive 7% of the irrigtion wter volume of FI t eh irrigtion event in whih hlf of the root zone ws irrigte while the other hlf ws rie out. PRD ws strte fter plnting (3 DAP) n lste until mturity (97 DAP). DI n PRD tretments reeive 7% of the irrigtion wter mount of FI in eh irrigtion event uring the whole growing seson. In PRD tretments the irrigtion ws lternte etween the two sies of the rows t 5 1 ys intervl in 7 n weekly in 8. Susurfe rip lines for irrigtion were instlle in the mile of the rige 1 m elow the soil surfe. For the PRD tretments two rip lines were ple in prllel, positione t the sme epths s in the FI n DI tretments(figure ). Other mngement prties uring the whole growth seson were ompletely uniform. () Vertil Level of soil () Horizontl Drip m TDR- m. 3 m B. Experimentl Design n Irrigtion Tretment In 7, the fiel tril ws rnomize omplete lok esign with two susurfe rip irrigtion tretments (full irrigtion (FI1), prtil root-zone rying (PRD1)n two furrow irrigtion tretments (full irrigtion (FI), prtil rootzone rying (PRD)). Irrigtion sheuling ws se on soil wter mesure with Time Domin Refletometer (TDR). Three TDR proes groups were instlle in line with the rip lines lose to plnt n to oth sies hlfwy to the neighoring plnts (Figure n ). The full irrigtion tretment ws irrigte ily to mintin the soil wter ontent t 5 1mm elow fiel pity uring the whole growing seson. The PRD tretment reeive 7% of the irrigtion wter volume of FI t eh irrigtion event in whih hlf of the root zone ws irrigte while the other hlf ws rie out. PRD ws strte fter tuer initition, 3 ys fter plnting ()PRD-irrigtion t 3 m DOI 1.513/IJSSST ISSN: 173-8x online, print

3 YAN SHI et l: IMPROVING WATER AND NUTRIENT USE EFFICIENCY OF POTATO BY PARTIAL ROOT-... Figure. Lyout of TDR proes plement in the plots vertil () n horizontl () setion n PRD irrigtion system () C. Fertiliztion In 7, fertilizers were pplie y ploughing (trtor, YTO-) t rtes of 18.8N, 58P, 58 K (kg/hm) s the se fertilizer. Initil N ontent of the in the top soil (- m) ws 3.18 kg/hm.in 8, fertilizers were pplie y ploughing t rtes of N,.5P,.5K (kg/hm) s the se fertilizer. At the perio of tuer initition, fertilizers were pplie y irrigtion t rtes of 37.5N, 3P, 17.5K (kg/hm). At the perio of the eginning of flowering, fertilizers were pplie y irrigtion t rtes of 37.5N, 3P, 17.5K (kg/hm). Initil N ontent of the root zone ws.3 kg/hm. Initil N on-tent ws mesure y the Key Lortory of High-Effiient n Sfe Utiliztion of Agriulture wter Resoures of the CAAS. D. Crop Mngement Seee preprtion ws onute uring the erly spring. See tuers of the Jinyn were pre-onitione t 1-1 C for out weeks uner im light until they h 5 mm long shoots. They were plnte s soon s possile with temperture of t lest 8 C t 1 m epth in the mile of the y (usully erly Mrh). They were then ple t istne of 3 m prt, 17 m elow rige level. Susequently, the rip lines were ple 1 m elow the top of the riges. Beuse of ely in the instlltion of the irrigtion system (li own lte April n opertionl in My), tuers t the Xinxing site were plnte in erly April n some mesurements were misse. E. Plnt Smpling n Mesurements Plnt smples were tken fter hrvest (3 smples per plot), store t room temperture n nlyze for NO3-N, NH-N, Totl Nitrogen (TN), Aville P (AP), n potssium (AK) in stem n lef. Tuers were store t room temperture n nlyze for NO3-N, NH-N, Totl Nitrogen (TN), Aville P (AP), potssium (AK), strh, eoxiize sugr n totl iity in the tuer. The mesurements were one oring to stnr methos of plnt nlysis. F. Soil Smpling n Mesurements Soil smples(5 smples per plot) were tken y the soil uger with stnr 3.5 m in the it imeter from soil lyers fter key growth stge of potto, store t room temperture n nlyze for NO3-N, NH-N, Totl Nitrogen (TN), Totl Orgni Cron (TOC), Aville P (AP), n potssium (AK), ph, Bulk Density (BD), n CCO3(Figure 3). The mesurements were one oring to the stnr methos esrie in the methos of soil nlysis. G. Sttistil nlysis Anlysis of vrine (ANOVA) ws performe using the generl liner moel univrite proeure from DPS7.5 softwre. ANOVAs were one with irrigtion metho n fertiliztion level s the min effets n their intertion. All the tretment mens were ompre for ny signifint ifferenes using the Dunn s multiple rnge tests t signifint level of P.5 with the DPS7.5 for Winows softwre pkge. 3m Figure 3. Smpling rius for soil smples roun the rip emitters III. RESULTS A. Irrigtion n Wter Use Effiieny Tle 1 shows the irrigtion mount n irrigtion wter use effiieny of ifferent tretments in 7 n 8.In 7, uring the PRD tretment perio, the full susurfe rip irrigtion tretment n full furrow irrigtion tretment were irrigte with 58.91mm. For the whole growing seson the FI n PRD tretments reeive 85.3 n mm, respetively. The tuer yiel of PRD1, FI1, PRD, FI ws 9., 9., 7.8,.31 tons per hetre, respetively. The PRD tretments were not signifintly ifferent from full irrigtion (p <.5). The irrigtion wter use effiieny of PRD1, FI1, PRD, FI ws 11.8, 9.87, 87.75,.85 kg /hm mm, respetively. The WUE or the PRD tretments ws signifintly higher thn tht of FI (p <.5). In 8, the PRD1, FI1, DI1, PRD n FI tretments reeive 131.9, 17.5, 131.9, 1.1 n 19.3 mm uring the growing seson, respetively. The tuer yiel of PRD1, FI1, DI1, PRD, FI ws 18.5±1.9,.88±.95, 18.37±3.3, 1.±.19, 18.57±1.87 tons per hetre, respetively. The tuer yiel of the PRD tretments ws not signifintly ifferent from tht otine uner full irrigtion (p<.5). The irrigtion wter use effiieny (IWUE) ( IWUE = totl fresh tuer/ irrigtion wter mount) of PRD1, FI1, DI1, PRD, FI ws 11.±1.81, 119.5±1.9, 139.9±5.9, 97.8±13.18, 8.7±8.5kg (hm mm) -1, respetively. The PRD1 n DI1 tretments h signifintly higher IWUE thn FI1 y 18.19% n 1.1%, respetively. The PRD tretments h signifintly higher IWUEs thn FI y 1.97% (p <.5). DOI 1.513/IJSSST ISSN: 173-8x online, print

4 YAN SHI et l: IMPROVING WATER AND NUTRIENT USE EFFICIENCY OF POTATO BY PARTIAL ROOT-... Tle I Irrigtion mount n irrigtion wter use effiieny of ifferent tretments in 7 n 8 Yer Tretments Preirrigtion First event Seon event Thir event Totl mount The yiel /t hm- IWUE /kg (hm mm)-1 7 5mm mm PRD FI PRD FI PRD FI DI PRD Full Rinfll uring growth stge of potto in 7. Rinfll uring growth stge of potto in 8. B. Totl Minerl Nitrogen (Nmin) Content in Potto Totl Nmin ontent in tuer, stem n lef of ll of irrigtion tretments re shown in Figure. In 8, totl resiul Nmin for PRD1, FI1, DI1, PRD n FI were 8.85±7.91, 93.7±13.3, 8.33±15.8, 88.8±1.7 n 97.1±9.51 kg/hm, respetively. The resiul Nmin for PRD1, DI1 n PRD tretments ws not signifintly ifferent when om-pre with FI1 n FI (p <.5). It n e onlue tht roots of potto enhne soil N sorne fter wter sup-ply uner wter efiit press. Resiul N(kg.hm - ) PRD1 FI1 DI1 PRD FI 7 8 Tretments Figure. The resiul Nmin ontent in plnts fter hrvest for iffer-ent tretments in 7 n 8 C. Resiul N in Soil The NO3-N, NH-N n minernl N ontent in 7, 8 of ifferent tretments mesure re shown in Figure 5 n Figure. The resiul NO3-N n NH-N in the soil lyers were mesure for ll tretments t the en of the seson. The resiul NO3-N in ifferent soil lyers in 7 is shown in Figure 5. In the top lyer (-3m) soil resiul NO3-N ontent for PRD1, FI1, PRD n FI ws 31.31, 33.9, 9.19 n 9.7 kg/hm, respetively. The upper soil resiul NO3-N ontent for PRD1 n PRD ws lower thn for FI1 n FI, 3.73% n 15.%, respetively. In the eeper lyer(3-m), resiul NO3-N ontent for PRD1, FI1, PRD n FI ws 8.5, 99.1,.1 n 88. kg/hm, respetively. The resiul NO3-N ontent of the eeper soil lyer for PRD1 n PRD ws lower thn FI1 n FI, 1.73%, 7.%, respetively. The resiul NO3-N in ifferent soil lyers in 8 is shown in Figure. In the top lyer (-1m), the mximum n minimum resiul NO3-N on-tent ws n kg/hm, whih ws foun in FI1 n FI. Resiul NO3-N ontent in PRD1 n PRD ws signifintly lower in the top lyer ompre with the FI1, DI1 n FI tretments (p <.5). Resiul NO3-N ontent in PRD1, DI1 n PRD ws signifintly lower in the seon, thir n fourth lyer(1-, -3, 3-m) om-pre with the FI1 n FI (p <.5). It n e onlue tht the soil resiul NO3-N in FI tretments is higher thn tht in PRD n DI tretments. The resiul NH-N in ifferent soil lyers uring 7 is shown in Figure 5. In the top lyer (-3m) soil resiul NH-N ontent for PRD1, FI1, PRD n FI ws 7.5±.93,.5±.8, 9.59±1.17 n 9.78±1.19 kg/hm, respetively. The rtio of NH-N with NO3-N rnge in the upper lyer(-3m) ws.1% to 3.17%, the rtio of NH- N n NO3-N rnge in the eeper lyer ws 7.33% to 1.7%. The resiul NH-N in ifferent soil lyers uring 8 is shown in Figure. In the top lyer (-1m) soil resiul NH-N ontent for PRD1, FI1, DI1, PRD n FI ws.19±.7,.9±.7,.9±.8,.17±.5 n.1±.1 kg.hm-, respetively. The rtio of NH-N with NO3-N rnge in the soil lyer ws.5% to 1.5%. For ll soil lyers, resiul NH-N ontent for PRD1, DI1 n PRD ws not signifintly ifferent ompre with the FI1, DI1 n FI tretments (p <.5). DOI 1.513/IJSSST ISSN: 173-8x online, print

5 YAN SHI et l: IMPROVING WATER AND NUTRIENT USE EFFICIENCY OF POTATO BY PARTIAL ROOT-... Resiul nitrte/1 kg.hm () PRD1 FI1 PRD FI The N lne vriles etermine in 7 n 8 for ifferent tretments re shown in Tle. The resiul Nmin fter hrvest in 7 for PRD1, FI1, PRD n FI ws ±.3, 15.98±1.33, ±1.75 n 338.5±19.97 kg/hm, respetively. The resiul Nmin fter hrvest in 8 for PRD1, FI1, DI1, PRD n FI were 8.3±1.85, 3.51±5.35, 88.9±.31, 97.55±.83 n ±9.5 kg/hm, respetively. The resiul Nmin fter hrvest in 7 n 8 with efiit irrigtion ws signifintly lower thn tht with full irrigtion. The physiologil N use effiieny (PNUE) n gronomi N use effiieny (ANUE) for PRD1 were not signifintly ifferent ompre with FI1. However, the physiologil N use effiieny (PNUE) for PRD ws signifintly higher tht for FI. 1 Resiul mmonium/kg.hm - Resiul Nmin/1 kg.hm () () Soil lyer/m Figure 5. Resiul NO3-N(), NH-N() n minerl N[Nmin]() ontent in ifferent soil lyers in 7 with PRD1, FI1, PRD n FI The resiul Nmin of 7 n 8 in ifferent soil lyers is shown in Figure 5 n Figure respetively. Bse on the ove results the totl resiul Nmin ontent e-rese from the topsoil to the eeper lyers in susurfe rip irrigtion. However, the mximum resiul Nmin ontent for PRD n FI ppere in the thir lyer (-3m), 7.9±8., 8.88±.18 kg/hm, respetively. The minimum resiul Nmin ontent for PRD n FI ppere in the top lyer,.3±1.15 n 39.93±. kg/hm, respetively. The resiul Nmin in upper lyers (-1, 1-, -3, 3- m) for PRD1 n PRD hs signifintly lower thn tht for the FI1 n FI tretments. Resiul Nmin/1 kg.hm - Resiul NH -N/kg.hm - Resiul NO 3 -N/1 kg.hm - 3. () PRD1 FI1 DI1 PRD FI () () Figure. Resiul -1 NO3-N(), 1- NH-N() -3 n minernl 3- N[Nmin]() ontent - in ifferent soil lyers in 8 with PRD1, FI1, DI1, PRDnFI Soil lyers/m DOI 1.513/IJSSST ISSN: 173-8x online, print

6 YAN SHI et l: IMPROVING WATER AND NUTRIENT USE EFFICIENCY OF POTATO BY PARTIAL ROOT-... TABLE. NITROGEN BALANCE IN THE PLANT SOIL SYSTEM AND NITROGEN USE EFFICIENCY OF DIFFERENT TREATMENTS IN 7 AND 8 KG HM- Yer Tretments 7 8 N uptke y plnt Resiul Nmin fter hrvest Nmin efore plnting Fertilizer N ontent in wter PNUE ANUE PRD FI PRD FI PRD FI DI PRD FI PNUE equl to rtio of yiel with plnt uptke N. ANUE equl to rtio of yiel with totl N supplie. IV. DISCUSSION Prtil root-zone rying (PRD) n efiit irrigtion (DI) h een proven effetive wter-sving irrigtion strtegies (Kng n Zhng, ). The irrigtion wter use effiieny (IWUE) ws lulte s the rtio of totl fresh tuer (TFT) weight to irrigtion wter mount (IWA) for the whole growth seson, IWUE=IFT/IWA(kg). In this stuy, PRI n DI slightly reue the totl ry mss uner the sme fertiliztion level ompre with the FI tretment. But PRD sve wter onsumption of potto y.1% to 3.3%, n thus inrese IWUE y %. Our results re in greement with some previous reports. Kng et l. inite tht PRD reue wter onsumption of mize y 35% with slight reution in totl iomss ompre with onventionl wtering. The mehnism of PRD lterntes wetting n rying of the soil profile in the root-zone, y whih it llows the plnt to explore root-soure ABA signling to regulte plnt physiology, stimultes root growth fter wter supplie, n les to similr yiel omprle with FI tretment. The tuer n lef TN ontent of pottoes with PRD is higher thn tht with FI. PRD enhne N umultion in the plnt y %. Our result is in orne with previous reports. The resiul NO3-N n minerl N fter hrvest with PRD were signifint lower thn tht with FI whether it onerne susurfe rip or furrow irrigtion. This might e ue to PRD whih n stimulte minerliztion of orgni nitrogen, thus enhne nitrogen vilility in the root-zone soil. Optiml lternte wetting n rying of prt of the root-zone mintins the soil wter potentil in suitle rnge whih in-reses miroil tivity. In other wors, PRD might hve voie the ehyrtion n hypoxi whih result from the exessive wter in the FI tretment, therey the miroil tivity uner PRD ws inrese s result of suh wetting n rying yle. Li et l. inite tht PRD inreses soil enzymti tivities uner optimum rtios of inorgni to orgni nitrogen fertilizers. In this stuy the IWUE, resiul minerl N, PNUE n ANUE with DI ws slightly lower thn tht with PRD y 1.51%, 1.97%, 3.19% n 1.51%, respetively. Therefore, DI sve wter onsumption n signifintly inrese IWUE ompre with FI. The IWUE, resiul minerl N, PNUE n ANUE with DI ws not signifintly ifferent from tht with PRD. This might e ue to DI with susurfe rip irrigtion whih mintins mil wter efiit n more irrigtion frequeny. But for wie-spe potto in semi-ri region, PRD might e etter irrigtion strtegy. In this stuy, the resiul NO3-N n minerl N with susurfe rip irrigtion erese from top lyer to lower lyers. However, the mximum vlue of resiul NO3-N n minerl N with furrow irrigtion ppere in the thir lyer (-3m), 7.9 n 8.88 kg/hm, respetively. The resiul N with furrow irrigtion first inrese n then erese from top lyer to lower lyers. This might e ue to furrow irrigtion whih enhne the nitrogen trnsfer to lower lyers uner lrger irrigtion mounts ompre with susurfe irrigtion. V. CONCLUSION Potto is very sensitive to wter efiit n tuer yiel woul e reue y soil wter stress. But in Henn provine, potto is grown with supplementry irrigtion uner low rinfll onitions. Bse on yers fiel experiments on sny lom soil uner semi-ri environment we onlue tht: (1) PRD tretment n improve IWUE n soil minerl N vilility, n mintin tuer yiel if suitle irrigtion sheule n lternte yle re pplie. () Furrow irrigtion strtegies, whether PRD or FI, n trnsfer more soil resiul nitrogen to lower lyers ompre with su-surfe rip irrigtion. This might involve the risk of soil nitrogen lehing n shllow grounwter pollution. ACKNOWLEDGMENT This reserh is fune y the EU ommission for its finnil support (SAFIR, ontrt No. FOOD-CT-5-318), the Ntionl 83 Plns Projet of Chin ( 83 Progrm, AA15, the Importnt Ntionl Siene & Tehnology Speifi Projets (8ZX75-), the Ntionl Siene & Tehnology Pillr Progrm of Chin (BAD17) n the Interntionl Coopertion Progrm of Chin (DFA719). DOI 1.513/IJSSST ISSN: 173-8x online, print

7 YAN SHI et l: IMPROVING WATER AND NUTRIENT USE EFFICIENCY OF POTATO BY PARTIAL ROOT-... REFERENCES [1] D. R. Lynh, N. Forou, G. C. Kozu. The effet of moisture stress t three growth stges on the yiel omponents of yiel n proessing qulity of eight potto ultivrs, Am. Potto J., vol. 7, No. 11, pp , [] S. Oner, M. E. Cliskn, D. Oner. Different irrigtion methos n wter stress effets on potto yiel n yiel omponents.agri, Wter Mnge,vol.73, No., pp.73 8, 5. [3] Ali Shhnzri, Fuli Liu, R. Jensen. Effets of prtil root-zone rying on yiel, tuer size n wter use effiieny in potto uner fiel onitions, Fiel Crops Reserh, vol.1, No., pp.117 1, 7. [] Tisheng Du, Shozhong Kng, Jinhu Zhng,. Wter use effiieny n fruit qulity of tle grpe uner lter-nte prtil rootzone rip irrigtion, Agri. Wter Mnge, vol. 95, No., pp.59-8, 8. [5] S. Kng, Z. Ling. Wter use effiieny of ontrolle lternte irrigtion on root-ivie mize plnts, Agri. Wter Mnge, vol. 38, No., pp. 9-7, [] J. Vos, Vn Der Putten, A. M. Leffelr. Fiel oservtions on nitrogen th rops. II. Root length n root length istriution in reltion to speies n nitrogen supply, Plnt Soil, vol.1, No. 11, pp , [7] G.Mk, J. K. Shjoerring. Effet of NO3 supply on N metolism of potto plnts (Solnum tuerosum L.) with speil fous on the tuers, Plnt Cell Environ,vol. 5, No. 13, pp ,. DOI 1.513/IJSSST ISSN: 173-8x online, print

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2014 Southeast Hay Convention 214 Southest Hy Convention Effet of Polymer-Cote Ure on Bermugrss Forge Proution Effet of Polymer-Cote Ure on Bermugrss Forge Proution Introution Without A, users of fe risky lterntives. - H 3 voltiliztion