Interntionl Journl of Food, Agriculture nd Veterinry Sciences ISSN: 77-9X (Online) 1 Vol. () Septemer-Decemer, pp. 9-18/Ahuj et l. EFFECT OF IRRIGATION SCHEDULING ON TUBER YIELD OF POTATO UNDER DIFFERENT CROP ESTABLISHMENT METHODS * Snjeev Ahuj 1, Khurn D.S. nd Kulir Singh 1 Krishi Vigyn Kendr, Ropr (Punj) 11, Indi Deprtment of Vegetle Science, Punj Agriculturl University, Ludhin 11, Indi *Author for Correspondence ABSTRACT A field investigtion ws conducted to find out the optiml irrigtion schedule under different crop estlishment methods in sndy lom soil in North-Western plins of Indi during 1- nd -1. The experiment comprised of climtic nd soil mtric potentil sed irrigtion tretments: I 1 : IW/CPE: 1., I : IW/CPE: 1., I : IW/CPE: 1., I : S D nd I : control (frmers prctice). These tretments were compred under furrow-ridge (M 1 ) nd furrow-ed plnting (M ) system. The experiment ws conducted in split plot design nd it ws replicted thrice. The ridge-furrow plnting method proved etter thn ed-furrow system in terms of mrketle tuer yield, lrge nd medium sized tuer yield nd verge tuer weight. Tretment I recorded more thn twice increse in irrigtion wter use efficiency s compred to control s well s enhnced the grded nd mrketle tuer yield s compred to ll other tretments under ridge-furrow plnting system. The results suggest tht scheduling irrigtion sed on soil mtric potentil t - kp mesured t soil depth of cm under ridge-furrow irrigtion system is etter option under the North-Western plins of Indi. Keywords: Potto, Irrigtion Scheduling INTRODUCTION Potto is mjor food crop in the world with n estimted production of 68.1 million tonnes (Anonymous, ). Indi is the second lrgest producer of pottoes fter Chin with production of. million tonnes from n re of 1.99 million h (CPRI, ). In the Indin stte of Punj (North-Western Indi) the re nd production under potto hs witnessed five nd eight times increse, respectively in the lst fifty yers with present production of out million tonnes (CPRI, ). The ridge-furrow plnting system which use furrow irrigtion method is mostly dopted for potto plnting in the North Indin plins. In the previling method of furrow irrigtion, most of the irrigtion wter infiltrte down the root zone re without its proper sorption y the roots. Bed plnting hs een found eneficil for improving yield nd wter use efficiency in potto (Fisher, 199; Sidhu et l., ; Hrms nd Konschuh 1; Singh et l., 1; Qsim et l., ). Vrying geometries of ridge plnting hs een studied y vrious scientists for improving the tuer yield nd qulity (Singh et l., 1; Bomik et l., ; Singh nd Sood, ; Vitos, ). Keeping in view the incresing demnd of wter nd re under potto crop especilly in the Indo- Gngetic plins of Indi, there is need for evluting ccurte irrigtion schedule to improve irrigtion wter use nd energy use efficiency (Gulti nd Singh, 11). Scheduling of irrigtion in ny crop depends upon soil type, crop vriety, methods of plnting s well s loction. In Indi, pn evportion sed irrigtion schedule hs een recommended for potto cultivtion y Directorte of All Indi coordinted project for reserch on wter mngement. But more recently, Medici et l., (1) hs suggested tht soil wter tension is good technique for scheduling irrigtion to the different crops which needs further studies. This technique requires simple instrument like tensiometer for irrigtion scheduling. A preliminry study conducted y the uthors (unpulished) hs estlished scheduling of irrigtion t SWT of kp for higher yield nd etter tuer qulity under furrow-ridge irrigtion system for sndylom soils in the North-Western Indin plins. Further study ws plnned to compre the SMP sed irrigtion schedule with the pn evportion sed irrigtion scheduling under the two crop estlishment methods of ridge-furrow nd ed-furrow plnting system. Copyright 1 Centre for Info Bio Technology (CIBTech) 9
Interntionl Journl of Food, Agriculture nd Veterinry Sciences ISSN: 77-9X (Online) 1 Vol. () Septemer-Decemer, pp. 9-18/Ahuj et l. Considering ll these fctors, this study ws undertken with the ojective to find out the est irrigtion schedule for mximizing tuer yield, nd qulity under different crop estlishment methods in the North- Western plins of Indi. MATERIALS AND METHODS Site, Climte nd Soil The investigtion ws undertken on typic Ustipsmment soil t Vegetle Reserch Frm, Deprtment of Vegetle Science, Punj Agriculturl University, Ludhin (Punj) Indi for two potto growing sesons (Octoer to Jnury) in 1- nd -1. The climte of Ludhin is sutropicl; semi-rid with n nnul rinfll of 7 mm. Mjor prt of the nnul rinfll is received during June to Septemer known s monsoon. Soil type ws sndy lom with composition of 71 % snd, 19% silt nd 1% cly. The experimentl site in 1 hs: ph 7.9, electricl conductivity:. ds m 1, orgnic C. g kg 1,. M NHCO extrctle P (Olsen et l., 19) 8. mg kg 1 nd K (Prtt, 196) 17. mg kg 1, nd in the yer these vlues were ph: 7.8, EC:.1 ds m 1, OC:. g kg 1, extrctle P: 7.7 mg kg 1 nd K: 171. mg kg 1. The detils of other physicl chrcteristics oserved efore plnting the crop t experimentl sites re shown in tle 1. Tle 1: Physicl chrcteristics of soil during the yer 1 nd Soil depth Bulk density (cm) (g cm - ) Sturted conductivity (cm hr -1 ) Unsturted conductivity (cm hr - 1 ) Suction I Suction II (cm) (cm) Infiltrtion rte (cm hr -1 ) Yer 1 1 1 1 1-1.6 1. 1. 1. 1. 16... 7. 6.8-1. 1.8 1.. 8.. 1. 1. - 1.6 1.6 1. 1. 1.... -6 1.69 1.7 1. 1..... Field Experiment Design The experiments were conducted in split plot design with four replictions. There were two min plots comprising ridge-furrow (M 1 ) nd ed-furrow (M ) plnting systems. The tretments under su-plots consisted of five irrigtion levels: I 1 ; IWCPE (Irrigtion wter to cumultive pn evportion) rtio 1., I ; IWCPE rtio 1., I ; IWCPE rtio 1., I ; S D (Mintining suction S of kp y instlling tensiometer t soil depth D of cm) nd I ; control (frmers prctice in the region). Ech ridge ws spced t 6 cm from nother ridge nd it ws followed y furrow in ridge-furrow plnting system. Beds with 8 cm top nd 1 cm ottom width were prepred ech followed y furrow under edfurrow plnting method. Ridge-furrow nd ed-furrow plots were prepred using semi-utomtic potto plnter nd ed plnter respectively, nd plnting ws done mnully. Plots mesuring 1. m. m (gross plot size) comprising eight ridges nd four eds under ed-furrow ech followed y furrow under ed plnting method of plnting were prepred. Two rows of pottoes were plnted on ech ed. Two metre wide order ws kept etween two djcent plots s well from irrigtion chnnel to prevent unwnted wter seepge. Disese free tuers of Kufri Pukhrj were plnted cm prt on top of the ridges. A perform ws prepred nd filled fter polling nd personl interviews with the frmers for collecting informtion regrding crop nd irrigtion mngement prctices followed y them efore finlizing irrigtion scheduling for control tretment. Crop Mngement Pre-sprouted seed tuers weighing pproximtely g ech were plnted t the spcing of 6 cm under ridge-furrow nd 7 cm on the ed (equivlent to mintining equl plnt density of 8. plnts m - ) on 18 th Octoer 1 nd th Octoer. Plnting ws done in the dry soil for control plot nd in pre-irrigted soil for ll other tretments during oth the yers. All plnts emerged 19 nd 1 dys Copyright 1 Centre for Info Bio Technology (CIBTech) 1
Interntionl Journl of Food, Agriculture nd Veterinry Sciences ISSN: 77-9X (Online) 1 Vol. () Septemer-Decemer, pp. 9-18/Ahuj et l. fter plnting during the first nd second yers respectively. Stndrd crop mngement prctices s per the recommendtions of PAU, Ludhin were followed for rising successful crop. Potto vines were dehulmed 9 dys fter plnting nd tuers were lifted dys fter dehulming for hrdening of tuers. The tuers were hrvested on 1 Jnury nd 8 Jnury 1. The yield prmeters were recorded t the time of hrvest. Irrigtion Tretments Good qulity irrigtion wter (EC:. ds m -1 ) ws given to fcilitte the rooting nd estlishment of the crop for its complete emergence nd for this purpose ll plots received cm of pre-plnt irrigtion wter except control plots. The control plots received 11 nd 9 cm nd other plots received nd cm postplnt irrigtion wter under ridge-furrow nd ed-furrow plnting system, respectively for proper estlishment of the crop (Tle ). After these common irrigtions, rest irrigtions were pplied s per the tretment schedule. However, the control tretment received first irrigtion 1 dys fter complete emergence nd remining irrigtions t n intervl of 1 dys. Additionl irrigtion ws given to control plots during the dys when there were chnces of frost occurrence. Only rinfll exceeding mm within hr ws considered effective nd included in the clcultions for totl wter use. Dil vcuum guge tensiometers were instlled t cm depth on the ridge (from the top surfce of the ridge) etween two plnts in the middle potto row of ech I plot. Monitoring of tensiometers ws strted regulrly for SMP reding fter the complete emergence of the crop. The redings were oserved dily etween 8..m. nd 9..m. nd irrigtion ws pplied therefter s per requirement of the tretment. The irrigtion schedule under I 1 to I tretment plots ws followed s per the trgeted IW: CPE rtios. Dt Collection At tuer hrvest, plnts from ech plot were hrvested y rndomly selecting middle three rows of pottoes; the tuers were picked mnully, counted, grded sed on the tuer weight nd weighed to determine verge tuer weight, grded nd mrketle tuer yield. The four grdes were selected sed on tuer weight i.e. lrge (>1 g), medium ( 7g), smll ( g) nd smller ( g). The irrigtion wter use efficiency (WUEi) ws computed sed on the mrketle tuer yield y using the following formul WUEi = to vrious tretments through irrigtion. Meteorologicl Dt Mrketle tuer yield (Kg/h) Totl irrigtion wter (mm ) where, Totl irrigtion wter = wter given Meteorologicl dt were recorded t meteorologicl sttion situted nery the experimentl site. Weekly verge temperture, reltive humidity, sunshine nd totl rinfll nd evportion during the potto growing period from Octoer, to Jnury, 1 in 1- nd -1 sesons, respectively were recorded (Figure 1 & Figure ). Dt Anlysis Two yers dt were sujected to nlysis of vrince (ANOVA) (Gomez nd Gomez, 1) sed on PROC GLM (SAS softwre 9.1). Duncn s multiple rnge tests t p=. ws pplied to compre the mens of different tretments. Copyright 1 Centre for Info Bio Technology (CIBTech) 11
Sunshine (Hrs) Evportion (mm) Reltive humidity (%) Totl rinfll (mm) Interntionl Journl of Food, Agriculture nd Veterinry Sciences ISSN: 77-9X (Online) 1 Vol. () Septemer-Decemer, pp. 9-18/Ahuj et l. 1 Temperture ( C) Mx temp Norml mx rnge Norml Min rnge Min. temp 9 8 7 6 1 Avg. RH % Norml Avg. RH % Norml Totl Rinfll Totl rinfll 18 16 1 1 1 8 6 1 Sunshine Norml rnge (sunshine) Norml rnge (evportion) Evportion 1 Figure 1: Mximum nd Minimum temperture ( C) (), verge humidity percent nd totl rinfll (mm) (), sunshine (Hrs) nd Evportion (mm) (c) during 1-. Copyright 1 Centre for Info Bio Technology (CIBTech) 1
Sunshine (Hrs) Evportion (mm) Reltive Humidity (%) Rinfll (mm) Temperture ( C) Interntionl Journl of Food, Agriculture nd Veterinry Sciences ISSN: 77-9X (Online) 1 Vol. () Septemer-Decemer, pp. 9-18/Ahuj et l. Mx temp Min. temp Norml Min rnge Norml mx rnge 1 1 Avg. RH % Norml vg. RH % 8 6-1 Avg. Sunshine Norml rnge (evportion) Norml rnge (sunshine) Evportion 1 Figure : Mximum nd Minimum temperture ( C) (), verge humidity percent nd totl rinfll (mm) (), sunshine (Hrs) nd Evportion (mm) (c) during -1. Copyright 1 Centre for Info Bio Technology (CIBTech) 1
Interntionl Journl of Food, Agriculture nd Veterinry Sciences ISSN: 77-9X (Online) 1 Vol. () Septemer-Decemer, pp. 9-18/Ahuj et l. Totl Rinfll Totl rinfll ws not uniformly distriuted nd ws lower thn the norml rnge during 1- potto growing seson [Figure 1 ( to c)]. There were two events of rinfll ove mm mesuring.6 mm of wter in the IIIrd week of Decemer (17. mm) nd IIIrd week of Jnury (8. mm). But the rinfll tht occurred in IIIrd week of Jnury ws not considered for further clcultions s this event occurred when the crop hd pproched mturity. During the -1 potto growing period, there were three effective events of rinfll ove mm mesuring in totl 8. mm wter [Figure ( to c)]. One event of rinfll (1 mm) occurred in the Ist week of Novemer nd second event (1. mm) occurred in lst week of Decemer. The rinfll tht occurred in the IInd nd IIIrd week of Jnury (6.1 mm) were not of much use s crop ws pproching ner mturity nd the sme ws not considered for doing further clcultions. RESULTS AND DISCUSSION Irrigtion Wter nd Irrigtion Wter Use Efficiency It ws oserved tht pproximtely 1 % lower wter volume ws utilized under ed plnting thn tht of ridge plnting during oth the yers (Tle ). Highest irrigtion wter ws used under the control during oth the yers nd methods. Totl wter volume utilized vried from to 1 m h -1 during first yer nd to m h -1 during the second yer under ridge-furrow plnting method. The corresponding vlues under ed-furrow method of plnting were 7 to nd to 7 m h -1 during first nd second yer, respectively. Irrigtion wter use efficiency (WUEi) did not vry with the methods of plnting. Tretment I recorded significntly higher WUEi mong ll the irrigtion tretments during oth the yers s well s under oth the plnting methods. Tretment, I recorded 8% higher WUEi thn tht of control s % wter volume ws sved during the first yer nd the corresponding vlues during the second yer were 167% nd 6% under ridgefurrow method of plnting (M 1 ). The corresponding vlues for the sme tretment in the second yer under ed-furrow method of plnting (M ) were 1% & 8% nd 19% & %. Sidhu et l., () lso recorded higher wter use efficiency y mintining soil mtric suction of ± kp under different plnting methods. The control tretment recorded lowest wter use efficiency during oth the yers of plnting ecuse mximum irrigtion wter ws received y these tretments. Copyright 1 Centre for Info Bio Technology (CIBTech) 1
Interntionl Journl of Food, Agriculture nd Veterinry Sciences ISSN: 77-9X (Online) 1 Vol. () Septemer-Decemer, pp. 9-18/Ahuj et l. Tle : Irrigtion wter ppliction nd wter use efficiency during the yer 1 nd Metho d of plntin g M 1 (Ridge-furrow method) M (Bed-furrow method) Irrigt ion tretm ents I 1 I I I I Men I 1 I I I I Men Yer 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Irrigt ion pplic tion (mm) 19 8 8 8 6 6 9 9 9 6 9 1 1 1 1 6 7 7 Totl wter pplic tion (m h - 1 ) 1 6 9 7 8 89 1 1 1 1 7 6 7 76 67 76 7 7 8 9 9 WUEi (kg h - 1 mm - 1 ) 6. 8 78. 1 68. 7 7c 68. 6. c 9. 87. 8. 8c. 6d 6. c 6. 8. 1c 6. 67. 7 6. 9. 8.. d 7. c 61. Column mens followed y the sme letter re not significntly different t p<. Copyright 1 Centre for Info Bio Technology (CIBTech)
Interntionl Journl of Food, Agriculture nd Veterinry Sciences ISSN: 77-9X (Online) 1 Vol. () Septemer-Decemer, pp. 9-18/Ahuj et l. Tle : Tuer yield nd qulity chrcters s ffected y methods of plnting nd irrigtion during the yer 1 nd Meth od of plnti M 1 (Ridge-furrow method) M (Bed-furrow method) ng Irrig tion tret ments I 1 I I I I Men I 1 I I I I Men Yer Avg. Tr wt (g) Mkt. Tr yield (q/h) Lrge Tr yield (q/h) Med. Tr yield (q/h) Smll Tr yield (q/h) Smll er Tr yield (q/h) 1. 9 1.c. 1. 7d 8. 6c 6. 1. 9.7 d 1. c 7. c 1. 1d 68. 1 7. 16 1. c 18.. c. 7c 9 6. 6. cd 17. 1c 9. 9c. 8cd 1 7. 19. 8... 6. 1 7. 177.8 c. 8. 6 9. c 61. 1. 9 1 7. 1.. 6. 68. 1. 6 6.8 1.. 9. 6. 1 8. 9 19. 8.. 8 6. 1 6. 8. 6 18.6... 6. 1. 18.. 9. 9 1. 66.. 17.1. 8. 6 9. 6. 7 Column mens followed y the sme letter re not significntly different t p<. * Avg. Tr wt= Averge tuer weight, Mkt. Tr yield= Mrketle tuer yield, Med. Tr yield= Medium sized tuer yield 1. c. c 11. 18. c. c 1. 6c 6.8 9. c 16. 1. 1c 7. 1. c.c 1. 7. 8c. c 67. 1. 1c 1.9 11. c 19.. 7c 1. 169. 17.. 1 6. 1.9 8.. c 9.7 8. 1 1 9. 198.. 9. 6. 6 7. 6. 18 1.8.. 8. 69. 1 6. 17 1.8 17. 6. 6. 1. 167. 17. 9. 9. 1 1. 16. 16. 7 8. 1. 8. 8 7. 1. 6. 8 9. 67. Copyright 1 Centre for Info Bio Technology (CIBTech) 16
Interntionl Journl of Food, Agriculture nd Veterinry Sciences ISSN: 77-9X (Online) 1 Vol. () Septemer-Decemer, pp. 9-18/Ahuj et l. Averge Tuer Weight nd Mrketle Tuer Yield The nlysis of dt reveled tht verge tuer weight ws significntly higher under ridge-furrow (M 1 ) in comprison to the ed-furrow plnting method during the second yer. It ws significntly higher for I, I nd I under M 1 nd I tretment under M method of plnting during oth the yers nd for I tretment under M during the second yer. The tretments I, I nd I under M 1 method of plnting hve received higher mount of irrigtion wter which my proly hve resulted in etter moisture content in the root zone for etter growth nd development of tuers. Similrly, the tretment I under ed-furrow method of plnting my hve received optimum soil moisture for the etter tuer development. Singh nd Sood () lso otined higher verge tuer weight in the trditionl ridge-furrow plnting s compred to the rised ed plnting. The method of plnting significntly ffected the mrketle tuer yield which ws significntly higher under M 1 i.e. ridge-furrow plnting method s compred to M, method of plnting. The lower mrketle tuer yield under ed plnted crop my e due to moisture stress in the vicinity of the root zone re s the plnttion ws ner the centre of eds. Sidhu et l., () lso reported lower tuer yield under 9 cm wide eds s compred to the 6 cm wide eds. In our study lso ed width on the top ws 8 cm. However, our finding is in contrry to the results of Qsim et l., (), who hd reported higher tuer yield under wide eds s compred to the ridge plnted crop. Among the vrious irrigtion tretments, mrketle tuer yield ws significntly higher for I tretment under oth the plnting methods nd yers nd this tretment were sttisticlly t pr with I tretment during the second yer. Tretment I recorded.1% nd 1.6% higher tuer yield thn tht of control under ridge-furrow plnting system during first nd second yers, respectively nd the corresponding vlues under ed-furrow plnting method were.% nd 8.%. The tretment I under M method of plnting lso recorded significntly higher mrketle tuer yield which ws sttisticlly t pr with I tretment during the second yer. The recording of higher mrketle tuer yield under ridge-furrow plnting method evidenced the dvntge of this method over the ed-furrow plnting. The irrigtion tretments which registered higher mrketle tuer yield my proly hve received the proper mount of irrigtion wter for keeping optimum soil moisture in the root zone for higher production of helthy tuers. Grded Tuer Yield Grded tuer yield ws significntly ffected y method of plnting except for smll size tuers during oth the yers nd smller size tuers for first yer. Among the two methods, ridge-furrow plnting method (M 1 ) recorded significntly higher tuer yield for lrge nd medium sized tuers during oth the yers. However, M showed significntly higher tuer yield for smller sized tuers during the second yer. Among different irrigtion tretments, I tretment during oth the yers nd I nd I during the first yer under M 1 method of plnting recorded significntly higher lrge sized tuer yield. Under M method of plnting, I recorded significntly higher lrge sized tuer yield nd tretments, I nd I for second yer were sttisticlly t pr with I. Tretment, I recorded significntly higher medium nd smll sized tuer yield oth under M 1 nd M methods during two yers. Under M method of plnting, I tretment recorded significntly higher medium nd smll sized tuer yield during the second yer. Medium sized tuers yield for I tretment during second yer under M ws lso significntly higher. It is evident tht the I, I nd I tretments recorded higher lrge nd medium sized tuer yield which indictes tht under these tretment, tuers gthered higher iomss. It my proly ecuse of proper moisture in the root zone which my hve resulted in etter growth nd development of tuers. Similrly, Singh nd Sood () nd Singh et l., (1) lso recorded higher tuer yield of lrge sized (>7g) tuers under conventionl ridge-furrow system s compred to rised ed plnting. In our study, medium size tuers were >7g, thus our results were similr to erlier findings. All the irrigtion tretments under M 1 recorded sttisticlly t pr vlues of smller sized tuer yield during oth the yers. Similrly smller sized tuer yield ws sttisticlly t pr for ll the irrigtion tretments under M method of plnting during the first yer. The dvntge of ridge-furrow plnting method over ed-furrow plnting method in terms of mrketle tuer yield, lrge nd medium sized tuer yield nd wter use efficiency supported the relevnce of ridge- Copyright 1 Centre for Info Bio Technology (CIBTech) 17
Interntionl Journl of Food, Agriculture nd Veterinry Sciences ISSN: 77-9X (Online) 1 Vol. () Septemer-Decemer, pp. 9-18/Ahuj et l. furrow plnting system over tht of ed-furrow plnting method. Singh nd Sood () lso reported tht rised ed plnting of doule nd triple row plnting of potto is non dvntgeous s compred to conventionl ridge plnting under furrow irrigtion method. In conclusion, higher grded nd mrketle tuer yield nd verge tuer weight under ridge-furrow plnting method ws recorded s compred to ed-furrow plnting method. Aout three time s higher irrigtion wter use efficiency ws recorded y I tretment s compred to the control (frmers prctice) long with sving of 8 to 6% irrigtion wter. This suggests tht irrigtion scheduling sed on soil mtric potentil y following ridge-furrow irrigtion system is etter criterion in our conditions thn tht of climtic sed irrigtion scheduling. Thus, irrigtion scheduling y fixing - kp SMP t soil depth of cm form top of the ridge is the est tretment under our conditions. ACKNOWLEDGEMENT This study ws conducted s prt of Ph.D. work of first uthor. The corresponding uthor is thnkful to the Punj Agriculturl University, Ludhin, for providing fcilities for the successful conduct of the reserch. REFERENCES Anonymous (). http://fostt.fo.org [Accessed 1 Octoer 1]. Bomik A, Rymuz K nd Stop D (). Potto yield depending on ridge shpe nd hrvest time Prt I. Totl nd commercil tuer yield Act Scientirum Polonorum seri Agricultur 1() 1-. CPRI (). Centrl Potto Reserch Institute, Shiml, Indi, Aville: http://cpri.ernet.in/ [Accessed Octoer 1]. Fisher A, Biley RJ nd Willims DJ (199). Growing pottoes using ed-plnted techniques. In: Soil Mngement in Sustinle Agriculture, edited y Cook HE nd Lee HC (Wye College Press) 61-68. Hrms TE nd Konschuh MN (1). Wter svings in irrigted potto production y vrying hill furrow or ed furrow configurtion. Agriculturl Wter Mngement 97 99 1. Gomez KA nd Gomez AA (1). Sttisticl Procedures for Agriculturl Reserch (John wiley & Sons; Inc) UK 1-67. Gulti S nd Singh M (11). Energy requirement nd mngement in potto production system. Potto Journl 8 61-66. Medici LO, Reinert F, Crvlho DF, Kozk M nd Azevedo RA (1). Wht out keeping plnts well wtered? Environmentl nd Experimentl Botny 99 8-. Olsen S, Cole C, Wtne F nd Den L (19). Estimtion of ville phosphorus in soils y extrction with sodium icronte. USDA Circulr No. 99, US Gov. Print. Office, Wshington, DC. Prtt PF (196). Potssium. In: Methods of Soil Anlysis: Prt, edited y Blck CA, Agronomy, Americn Society of Agronomy, Mdison, WI 9 1 11. Qsim M, Khlid S, Nz A, Khn MZ nd Khn SA (). Effects of different plnting systems on yield of potto crop in Kghn Vlley: A mountinous region of Pkistn. Agriculturl Sciences () 17-179. Sidhu AS, Thind SS, Sekhon NK, Singh CB nd Hir GS () Plnting Method, Irrigtion nd Nitrogen Effects in Potto. Journl of the Indin Society of Soil Science () 99-. Singh N nd Sood MC (). Rised Bed Plnting Techniques for Potto Production under Furrow nd Sprinkler Irrigtion Methods. Annls of Horticulture 6(1) -8. Singh N, Sood MC nd Singh SP (1). Yield nd economics of potto (Solnum tuerosum L.) influenced y rised ed plnting ptterns nd drip lyout systems. Progress in Agriculture 1(1) 9-. Vitos IZ, Morr G, Motic R, Mike L nd Moldovn C (). Reserch on the Optimum Shpe nd Size of Potto Ridges. Bulletin UASMV Serie Agriculture 7(1) -. Copyright 1 Centre for Info Bio Technology (CIBTech) 18