Influence of Chemical Fertilizer Applications on Water Quality in Paddy Fields in Nong Harn, Sakon Nakhon Province, Thailand

Transcription

1 Ksetsrt J. (Nt. Si.) 49 : (2015) Influene of Chemil Fertilizer Applitions on Wter Qulity in Pddy Fields in Nong Hrn, Skon Nkhon Provine, Thilnd Anurk Khruekhm 1,2, * Bundit Anurugs 2 nd Nth Hungspreug 2 Astrt This study investigted the effet of hemil fertilizer on wter qulity in pddy fields. Six experiments were onduted using hemil fertilizer (formul 16168; NPK) nd ure fertilizer (46 00) using two different fertilizer pplitions t vried onentrtions in Nong Hrn, Skon Nkhon provine, Thilnd: 1) kg.h 1 of t 30 d fter plnting nd kg.h 1 of 4600 t 60 d nd 90 d fter plnting y rodsting (), deep plement t 10 m () nd t 20 m (); nd 2) kg.h 1 of t 30 d fter plnting nd kg.h 1 of 4600 t 60 d nd 90 d fter plnting y rodsting (), deep plement t 10 m () nd t 20 m (). The results showed tht t 90 d, the lowest dissolved oxygen level ws 3.21 mg.l 1 in. The NH 4+ N levels deresed with time. The highest nd lowest levels of NH 4+ N were in (60 d) nd (90 d), respetively, wheres the highest nd lowest levels of NO 3 N were in nd (90 d), respetively. The levels of NO 3 N in, nd were higher thn those in, nd. Additionlly, the level of PO 4 3 P deresed due to the growing seson of rie. The onentrtions of phosphte y rodsting were higher thn those of deep plement t 10 nd 20 m. The rie yield ws higher (P < 0.05) in, nd thn in, nd nd the rie yields using deep plement t 10 m were higher thn those t 20 m nd y rodsting. Nitrogen fertilizer pplition ffeted the utiliztion effiieny, influening the rie yields nd nitrogen loss. However, the reommendtion of n pproprite nitrogen fertilizer pplition ws deep plement t 10 m sed on the rie yield nd the levels of NH 4+ N, nd NO 3 N. Furthermore, wter should e retined in the rie field, leding to redued nutrients esping nd interfering with the environment. Keywords: rodsting, hemil fertilizer, deep plement, pddy field, wter qulity, Nong Hrn, Skon Nkhon Introdution Thilnd is one of the mjor griulture ountries nd reently griulture in Thilnd hs een hnging to onventionl or hemil griulture in order to inrese the yield (Sunntpongsk, 2008). With the inrese in popultion nd eonomi development, frmers re eing enourged to inrese hemil fertilizer inputs in order to inrese yields, espeilly in 1 Reserh Deprtment, Reserh nd Development Institute, Ksetsrt University, Chlermphrkit Skon Nkhon provine mpus, Skon Nkhon 47000, Thilnd. 2 Fulty of Siene nd Tehnology, Thmmst University, Rngsit mpus, Khlong Nueng, Khlong Lung, PthumThni 12120, Thilnd. * Corresponding uthor, emil: snrk@ku..th Reeived dte : 03/11/14 Aepted dte : 10/07/15

2 Ksetsrt J. (Nt. Si.) 49(6) 869 pddy fields. Aording to Offie of Agriulturl Eonomis (2009), In Thilnd, rie frming hs een mjor, longstnding ouption with million h of pddy fields whih onsist of 9.12 million h of wet seson rie nd 1.92 million h of dry seson rie (Deprtment Pollution Control, 2011). Skon Nkhon is one of the northestern provines of Thilnd with 322,768 h of pddy fields (6% of this region). It is loted on the Khort Plteu, not fr from the Mekong River nd inludes mountinous nd forested res s well s the Nong Hrn Lke the iggest nturl lke in Northest Thilnd whih is n importnt wetlnd used for griulture espeilly pddy fields (Skon Nkhon Rie Reserh Center, 2009). However, in 2008, the gross rie yield in Skon Nkhon provine ws 566,649 t nd the verge prodution yield ws 2,025 kg.h 1 (Skon Nkhon Rie Reserh Center, 2009). The nturl soils in this region re of low qulity with rpid wter runoff; therefore, hemil fertilizers re used intensively to inrese prodution yields. Chemil fertilizers n enrih the soil with mronutrients nd mironutrients nd hve een trditionlly pplied in Thilnd to mintin soil fertility (Offie of Agriulturl Eonomis, 2009). Frmers lwys used more nitrogen fertilizer thn required to gin high rop yield nd this inreses the ost of griulturl mngement, deresing the effiieny of fertilizer use nd the qulity of produts (Gong et l., 2011). Additionlly, this n use environmentl pollution, s the movement of N fertilizer from griulturl tivities into the surfe wter nd groundwter ontriutes to wter qulity degrdtion nd eutrophition through runoff nd lehing, (Xing nd Zhu, 2000; Konnerup et l., 2009; Luo et l. 2011). Nitrogen emissions from mmoni voltiliztion following N fertilizer pplition to soils hve een lso investigted (Ds et l., 2009; Co et l., 2013; Xu et l., 2013). The pplition of nitrogen fertilizers to rie ontriutes to the formtion of lrge mounts of mmonium ions whih eventully re onverted into nonionized mmoni tht espes in gs form nd this onstitutes lrge proportion of the nitro fertilizer lost from rie growing soils (Hui et l., 2006). Nitrte produed in the surfe lyer of flooded rie pddies n e lost through denitrifition, s it diffuses into the redued soil zone where it serves s n eletron eptor for miroil neroi respirtion (Ponnmperum, 1972; Reddy nd Ptrik, 1984, 1986). Nitrte in floodwter or eroi soil lyers moves esily y peroltion nd diffusion into the underlying redued lyers, where it is rpidly denitrified (Reddy nd Ptrik, 1986; Dtt, 1987). Ds et l. (2009) reported tht fertilizer pplitions to rie n led to signifint emissions of NH 3 nd NH 4 + nd NO 3 ions. The fertilizer pplitions lso ffet the movement of nutrients. Iql (2011) reported tht nitrte onentrtions in lehte t soil depth of 30 m were higher thn tht t 60 m depth. Xu et l. (2013) found tht the mmoni onentrtion in the surfe wter or in soil solution nd mmonium voltiliztion y the deep plement of fertilizer were lower thn those using fertilizer rodsting. Moreover, the nitrogen levels diretly ffeted the rie yield t different growth stges, espeilly from the trnsplnting to jointing stges (Yu et l., 2013). Therefore, effetive nutrient mngement hs plyed mjor role in omplishing n enormous inrese in rie yield. However, the pplition of imlned nutrients hs led to deresing nutrientuse effiieny mking fertilizer onsumption uneonomil nd produing dverse effets in the environment. This study investigted the effet of hemil fertilizers on wter qulity nd rie yield in pddy fields. The wter qulity nd nutrients (NH 4+ N, NO 3 N nd PO 4 3 P) were determined. The field experiments were onduted using two different fertilizer pplitions (rodsting nd deep plement) t vried onentrtions on dry seson rie in Nong Hrn. This study my help to selet the optiml hemil fertilizer pplition to redue environmentl pollution nd improve

3 870 Ksetsrt J. (Nt. Si.) 49(6) hemil fertilizer pplition nd rie yield. MATERIALS AND METHODS Site preprtion nd experimentl design The field experiment ws onduted in 2013 in Nong Hrn, Skon Nkhon provine (17 15 N, E) s illustrted in Figure 1. The limte is sutropil with n nnul verge ir temperture nd nnul men preipittion of 26.1 C nd 1,694 mm, respetively (Skon Nkhon Rie Reserh Center, 2009). Six tretments (s desried in Tle 1) were estlished to investigte the effet of hemil fertilizer pplitions with vried onentrtions nd time. The six tretments were pplied in 4 4m plots nd were tilled to depth of 30 m. For seedling preprtion, the seeds of stiky rie (Oryz stiv L.) were soked in wter for 12 h nd then overed with gunny sks for 48 h. The seeds tht sprouted were sown into smll plots nd were mintined for d nd then were trnsplnted to the experimentl tretments. Two grnulr ommeril hemil fertilizers Figure 1 Lotion of study re (Nong Hrn, Skon Nkhon provine) Tle 1 Experimentl tretments Code Fertilizer pplition Brodsting 16168: Deep plement t 10 m Deep plement t 20 m Brodsting 16168: Deep plement t 10 m Deep plement t 20 m Applition (dys fter plnting) of fertilizer (NPK) 0d 30d 60d 90d kg.h kg.h kg.h : 4600: kg.h kg.h : 4600: kg.h 1

4 Ksetsrt J. (Nt. Si.) 49(6) 871 (NPK) nd 4600 (ure fertilizer) were purhse lolly nd were pplied t rtes equivlent to nd kg.h 1 nd t nd kg.h 1, respetively. Brodsting nd deep plement methods with different onentrtions nd soil depths of 10 nd 20 m were onduted. The fertilizer pplitions were onduted three times t the seeding stge (30 d fter plnting), the vegettive stge (60 d fter plnting) nd the pnileformtion stge (90 d). Surfe wter ws mintined t depth of 10 m until the mturtion period for ll tretments. The plots were drined efore hrvesting. Smple olletion nd mesurement Wter smples were olleted 2 d fter eh fertilizer pplition (efore trnsplnting (0 d), t seeding (30 d), t the vegettive stge (60 d) nd t pnileformtion (90 d). The wter smples were nlyzed for temperture, ph, ondutivity, dissolved oxygen (DO), iohemil oxygen demnd (BOD) nd nutrients (NH 4+ N, NO 3 N, PO 4 3 P) using the stndrd methods (Amerin Puli Helth Assoition et l., 1998). NH 4+ N onentrtions were mesured sed on the determintion of mmonium in wter using flow injetion nlyzer (FIAstr 5000; U.S. Environmentl Protetion Ageny, 1991). The rie yields were mesured using moisture meter nd reported sed on 14% moisture ontent s presented in Eqution 1: # ^100 h # 10,000 Rie yield t 14% moisture ontent = ^ # h (1) where is the rie weight (mesured in kilogrms) t moisture ontent (mesured s perentge) nd is the hrvested re (mesured in hetres). Sttistil nlysis The sttistil signifine of differenes mong tretments of NH 4+ N, NO 3 N, PO 4 3 P nd rie yield fter fertiliztion ws ssessed using nlysis of vrine nd signifint differenes were determined using Dunn s new multiple rnge test, t P < 0.05 y using different letter RESULTS AND DISCUSSION Effet of hemil fertilizer on wter qulity Eletril ondutivity nd ph The vlues for the wter smples olleted t the four stges during the rie rop rottion re presented in Figure 2. The results showed tht the men (± SD) ph levels of the wter in ll tretments t 0 d fter plnting were in the rnge 5.79±0.03 to 6.61±0.03. After the fertilizer pplitions in the pddy field t 60 d fter plnting, the ph levels inresed (7.85± ±0.06) euse of the ddition of ure fertilizer in the pddy field to promote rie growth. The ure fertilizer dissolved in the wter forming NH 4 + ions. Consequently, lge nd quti plnts in the pddy fields sored CO 2 gs for photosynthesis due to the inrese in the ph. The highest ph level ws 8.71±0.06 in. It should e noted tht the ph level following fertilizer pplition y rodsting ws signifintly higher thn tht of the deep plement pplition, wheres there were no signifint differenes in the ph levels etween the deep plement pplitions t 10 nd 20 m. The optiml ph level in pddy fields is 6 8 (Alexnder, 1977) nd phosphorus is ville in most plnts t ph level etween 6.5 nd 7.0. The rnge in eletril ondutivity t 0 d fter plnting ws ± ±10.3 µs.m 1 nd the eletril ondutivity in (1,638± µs.m 1 ) t 30 d fter plnting ws signifintly higher thn in,, nd fter hemil fertiliztion. At 60 d fter plnting, ions were relesed into the wter pplied s irrigtion, so tht the nutrients were mostly relesed into the wter. The highest eletril ondutivity ws 1,638±101.5 µs.m 1 t 30 d fter plnting in. Otherwise, there were no signifint differenes in ondutivity t 60 nd 90 d fter plnting. The DO levels t 0 d fter plnting were in the rnge 2.5±0.1 to 2.93±0.06 mg.l 1 nd inresed fter hemil fertilizer pplition

5 872 Ksetsrt J. (Nt. Si.) 49(6) (3.21± ±0.82 mg.l 1 ), wheres in ontrst, the DO level deresed fter ure fertiliztion s shown in Figure 3. The DO level t 30 d fter plnting in ws signifintly higher thn in nd. In ontrst, the DO level t 30 d fter plnting in ws signifintly lower thn in, nd. Additionlly, the DO level t 30 d fter plnting ws the highest of ll stges, wheres the lowest DO level ws in t 90 d fter plnting (3.21±1.01 mg.l 1 ). At DO onentrtions of 1.0 mg.l 1 or more, nitrifition ourred only under eroi onditions, wheres it ws miniml t DO onentrtions of less thn 0.5 mg.l 1. However, the DO onentrtions t 0, 60 nd 90 d fter plnting were not signifintly different. The BOD deresed fter hemil fertiliztion s shown in Figure 3. At 30 d fter plnting, the BOD ws lowest (6.83± ±1.2 mg.l 1 ). At 60 d fter plnting, in ll tretments the BOD ws highest t whih ws signifintly higher thn in,,,, nd. In ontrst, the BOD t 90 d fter plnting ws signifintly higher thn in,,, nd. It ws lso oserved tht the BOD t 30 d ws the lowest wheres in ontrst, the DO level ws highest. NH 4+ N The NH 4+ N levels in the six tretments t 30, 60 nd 90 d fter plnting were 67.76±1.23 to ±1.18, 96.24±1.82 to ±6.19 nd 41.45±7.20 to ±3.40 mg.l 1, respetively, s illustrted in Figure 4. ph (EC (µs.m1) d 400 e 0 Figure 2 Eletril ondutivity (EC) nd idity (ph) in wter of pddy fields t different times fter plnting nd levels of fertiliztion: ) ph; nd ) EC. re the experimentl tretments shown in Tle 1. Error rs show ± SD. Different letters ove eh olumn re signifintly different ording to Dunn s new multiple rnge test, t P < 0.05).

6 Ksetsrt J. (Nt. Si.) 49(6) DO (mg.l 1 ) BOD (mg.l 1 ) d 5 0 Figure 3 Dissolved oxygen (DO) nd iohemil oxygen demnd (BOD) onentrtions in wter of pddy fields t different dys fter fertiliztion: ) DO; nd ) BOD. re the experimentl tretments shown in Tle 1. Error rs show ± SD. Different letters ove eh olumn re signifintly different ording to Dunn s new multiple rnge test, t P < 0.05). NH 4 + N (mg.l 1 ) d d e e f d e f f Figure 4 NH 4+ N onentrtions in wter of pddy fields t different dys fter fertiliztion. re the experimentl tretments shown in Tle 1. Error rs show ± SD. Different letters ove eh olumn re signifintly different ording to Dunn s new multiple rnge test, t P < 0.05).

7 874 Ksetsrt J. (Nt. Si.) 49(6) The NH 4+ N onentrtion in the pddy wter ws signifintly higher in thn in,,, nd t 30, 60 nd 90 d fter plnting. The highest NH 4+ N onentrtion ws in euse the onentrtion of fertilizer in ws higher thn in, nd. Ji et l. (2007) reported tht totl nitrogen nd NH 4+ N in wter inresed fter the pplition of ure fertilizer. In ontrst, the onentrtion of NH 4+ N ws low in the tretments pplied in nd due to the deep plement pplition t 10 nd 20 m, respetively. The NH 4+ N onentrtion in the surfe wter fter ure fertiliztion t 90 d fter plnting ws lower thn tht t 60 d fter plnting. Lin et l. (2012) reported tht the NH 4+ N onentrtion fter pnile fertiliztion to t lest the 2lef stge ws lower thn tht t the 4lef stge. Consequently, the onentrtion of NH 4+ N in nd ws signifintly lower thn in nd. NH 4 + is one of two nitrogen forms tht plnts n use nd s NH 4+ N rries positive hrge nd is sored onto soil prtiles, lehing of nitrogen n e ignored (Roertson nd Groffmn, 2007). The results lso found tht the onentrtions of NH 4+ N in tretments of rodsting ( nd ) were higher thn with deep plement. It ws possile tht the pplition of ure fertilizer y rodsting ould e esily dissolved nd NH 4+ N ws relesed into the wter fster thn tht y deep plement. Therefore, NH 4+ N ws found t high onentrtion in the surfe wter. The relese of NH 4+ N from ure fertilizer n our fter hydrolysis s presented in Equtions 2 nd 3 (Mikkelsen, 2009; Azeem et l., 2014): CO(NH 2 ) 2 + 2H 2 O (NH 4 ) 2 CO 3 (2) (NH 4 ) 2 CO 3 + 2H + 2NH CO 2 + H 2 O (3) After fertiliztion, the onentrtions of NH 4+ N deresed with time due to the mmonium voltiliztion nd nitrifition proesses. The relese of NH 4+ N from the hemil fertilizer nd ure proeeded slowly followed y n eventul deline due to mmonium voltiliztion (Ds et l., 2009). The NH 4+ N onentrtions in, nd were signifintly higher thn in, nd due to the relese of fertilizer y hydrolysis euse the ph levels in, nd were higher thn in, nd. The hydrolysis of ure is fster t high ph levels (Chowdry et l., 2004). The ph of wter during the experiment vried in the rnge 7.85 to 8.71 whih ws lmost idel for the relese of NH 4+ N fter hydrolysis. The verge NH 4+ N level from the experimentl rie field ws 0.77±0.39 prts per million (ppm) nd the mximum NH 4+ N level reorded ws 1.67 ppm fter hemil fertiliztion (Ds et l., 2009). NO 3 N The NO 3 N levels in six tretments of pddy fields t 30, 60 nd 90 d fter plnting were 0.80±0.24 to 1.49±0.22, 0.72±0.07 to 2.21±0.22 nd 0.46±0.09 to 2.39±0.53 mg.l 1, respetively, s illustrted in Figure 5. The results showed tht the highest onentrtion of NO 3 N ws 2.39±0.53 mg.l 1 in t 90 d fter plnting nd the lowest onentrtion of NO 3 N (0.46±0.09 mg.l 1 ) ws in t 90 d fter plnting euse the NO 3 N ion rries negtive hrge nd is not sored onto soil prtiles; thus, NO 3 N is esily lehed from the soil. After fertiliztion, the onentrtion of NO 3 N t 30, 60 nd 90 d fter plnting ws higher thn t 0 d fter plnting nd the onentrtion of NO 3 N ws lower thn for NH 4+ N euse of the onversion of NH 4+ N to NO 3 N whih is known s nitrifition under eroi onditions (DO >1.0 mg.l 1 ) s presented in Equtions 4 nd 5: Nitrosomons 2NH O 2 > 2NO 2 + 4H + + 2H 2 O + energy (4) Nitroter 2NO 2 + O 2 > 2NO 3 + energy (5) The retion proeeded to the nitrte form; therefore, the NO 3 N onentrtions t ny given time were usully low. Additionlly the trnsformtion of NH 4+ N to NO 3 N in the surfe wter using rodst fertilizer pplition ws greter thn y deep plement. It ws lso found tht the onentrtions of NO 3 N in, nd

8 Ksetsrt J. (Nt. Si.) 49(6) 875 NO 3 N (mg.l 1 ) d Figure 5 NO 3 N onentrtions in wter of pddy fields t different dys fter fertiliztion. re the experimentl tretments shown in Tle 1. Error rs show ± SD. Different letters ove eh olumn re signifintly different ording to Dunn s new multiple rnge test, t P < 0.05). were signifintly higher thn in, nd t 90 d fter plnting due to the high onentrtion of hemil fertilizer, leding to the nitrifition proess. The onentrtion of NO 3 N in ws signifintly lower thn in,,, nd t 60 nd 90 d fter plnting, proly euse the ph ws lower thn in the other tretments, resulting in the inhiition of nitrifition (Chowdry et l., 2004). The hydrolysis of ure ws fster t high ph level. Otherwise, there were no signifint differenes in the NO 3 N onentrtion in wter t 0 nd 30 d fter plnting. The onstnt rte of nitrifition is lower thn tht of hydrolysis (Chowdry et l., 2004; Ling et l., 2007), resulting in low onentrtion of NO 3 N. Compred to the stndrd of wter qulity set y Amerin Puli Helth Assoition (1988), the level of NO 3 N in the surfe wter should not exeed 5.0 mg.l 1 nd the NO 3 N level otined in this study fter fertiliztion ws lower thn tht requirement. NO 3 N lso n e lost to the tmosphere through denitrifition when soils eome wter sturted s presented in Eqution 6: C 6 H 12 O 6 + NO 3 6CO 2 + 6H 2 O + 2N 2 (6) Wter temperture lso ffets the rte of nitrifition nd the mximum rte of nitrifition ours t temperture etween 30 nd 35 C (Jeynygm, 2005). Therefore, the onentrtions of NO 3 N in this study were not high. Nmdev et l. (2011) found tht the nitrte onentrtion in wter ws 1.16 to 2.69 mg.l 1 fter fertiliztion, whih exeeds the permissile limit euse of the exessive use of hemil fertilizer. PO 4 3 P The PO 4 3 P levels in the six tretments t 30, 60 nd 90 d fter plnting were 6.12±0.06 to 19.61±0.01, 0.89±0.42 to 1.95±1.35 nd 1.68±0.52 to 2.39±0.14 mg.l 1, respetively, s presented in Figure 6. The highest onentrtion of PO 4 3 P ws in euse the hemil fertilizer formul ws pplied t 30 d fter plnting whih provided 16% ville phosphorus (P 2 O 5 ). On the other hnd, ure fertilizer (4600) ws pplied t 60 nd 90 d fter plnting nd ontined no phosphorus. Ure fertilizer ws used to tivte the pnile formtion nd mturtion in the rie. Therefore, the PO 4 3 P onentrtions fter fertiliztion t 30 d fter plnting deresed s illustrted in Figure 6. This result ws similr to AlShmi et l. (2010) who reported tht

9 876 Ksetsrt J. (Nt. Si.) 49(6) PO 4 3 P (mg.l 1 ) d d 4 0 Figure 6 PO 4 3 P onentrtions in wter of pddy fields t different dys fter fertiliztion. ( re the experimentl tretments shown in Tle 1. Error rs show ± SD. Different letters ove eh olumn re signifintly different ording to Dunn s new multiple rnge test, t P < 0.05). phosphte onentrtions were high during the erly growing seson due to the fertiliztion proess. Low onentrtions ppered t the end of the seson when most phosphte hs een utilized y rie plnts. It ws possile tht the wter level in the pddy field deresed. The onentrtions of phosphte following fertilizer rodsting were higher thn from using deep plement ut rodsting phosphte ws not s effetive s plement euse of the likelihood of more rpid onversion to less ville phosphorus ompounds. Consequently, the onentrtion of phosphte y deep plement t 10 m ws higher thn t 20 m euse phosphorus is reltively immoile in the soil. Thus, it will not leh like nitrte or e rried to plnt roots y soil wter. The onentrtion of phosphte inresed with inresing onentrtion of hemil fertilizer. Therefore, irrigtion in pddy fields should e mnged to ontrol the wter in the pddy field t 30 d fter plnting nd wter dringe should e prevented to prevent nutrient removl. The PO 4 3 P onentrtions in, nd were higher thn in, nd due to the higher pplition levels. Effet of hemil fertilizers on rie yield The rie yield ws signifintly higher in, nd thn in, nd s presented in Tle 2. Tle 2 Rie yields fter different fertilizer tretments for 120 d. Tretment Rie yield (kg.h 1 ) 1, e ± d ± , f ± , ± , ± , ± f = Vlues (± SD) with different supersript letters re signifintly different ording to Dunn s new multiple rnge test, t P < re the experimentl tretments shown in Tle 1.

10 Ksetsrt J. (Nt. Si.) 49(6) 877 The rie yield of ws 1.47 fold higher thn tht of fter douling the fertilizer onentrtion s ourred in nd. lso produed signifintly higher yields (2,250±5.05 kg.h 1 ) thn (2,156.25±9.54 kg.h 1 ) nd (1,593.75±16.21 kg.h 1 ), proving tht the rie yield response ws due to ville plnt nitrogen supplied y the fertilizer. In ontrst, the lowest rie yield (1,343.75±20.09 kg.h 1 ) ws in. The rie yields in,, nd signifintly inresed due to the inrese of nitrogen fertilizer rte.. In ontrst, inresing the onentrtion of fertilizer y deep plement t 20 m from kg.h 1 () to kg.h 1 (), resulted in 1.19 fold inrese in the rie yield in ompred to. Additionlly, the rie yields in nd where nitrogen fertilizer ws pplied t soil depth of 20 m were signifintly lower thn tht t the 10 m depth nd with rodsting due to the nutrient ville to roots t 10 m. The rie yields in, nd inresed fter inresing the onentrtion of fertilizer twofold, due to the nutrient requirement from the tillering stge onwrd. Fertilizers promoted rie growth nd ffeted the rie yield euse nitrte nd phosphte re primry nutrients for rie growth in ll stges of rie (Mejo University, 2013). This suggests tht field experiments should e onduted to llow frmers to preisely predit the effet of nitrogen pplition on rie growth. The rie yields t the sme pplition rte of fertilizer with deep plement t 10 m were higher wheres the NH 4+ N nd NO 3 N onentrtions were lower thn y rodsting. Therefore, exessive depth y deep plement nd the greter onveniene of fertilizer pplition y rodsting in the rie field ould not inrese the rie yield ut did result in greter nitrogen loss. CONCLUSION The levels of NH 4+ N, NO 3 N, PO 4 3 P nd rie yields were determined in pddy fields t different hemil fertilizer onentrtions nd pplitions (rodsting nd deep plement) in Nong Hrn, Skon Nkhon provine. The results showed tht rie ultivtion long with fertilizer pplitions led to signifint releses of NH 4+ N, NO 3 N nd PO 4 3 P. The NH 4+ N onentrtion in the wter ws mrkedly (P < 0.05) higher in thn in,,, nd under 30, 60 nd 90 d fter plnting. The highest NH 4+ N nd NO 3 N onentrtions were in t 60 d fter plnting nd t t 90 d fter plnting, respetively euse the onentrtion of hemil fertilizer ws higher thn in. In ontrst, the onentrtions of NH 4+ N nd NO 3 N were low in nd. Ure fertilizer pplied y deep plement ws not esily dissolved nd NH 4+ N ws relesed into the wter more slowly thn with rodsting. The relese of NH 4+ N from the hemil fertilizer nd from the ure proeeded slowly followed y n eventul deline. The NH 4+ N level deresed with time. It ws lso found tht the onentrtions of NO 3 N in, nd were higher thn in, nd. The onentrtion of NO 3 N in ws signifintly lower thn in the other tretments t 60 nd 90 d fter plnting. Additionlly, the highest onentrtion of PO 4 3 P ws lso in t 30 d fter plnting. The onentrtions of phosphte using rodsting were higher thn y using deep plement nd the tretment t 10 m hd higher phosphte levels thn tht t 20 m. Therefore, irrigtion in pddy fields should e ontrolled t 30 d fter plnting with wter dringe from the re not llowed to use nutrient removl from the pddy. The rie yield ws signifintly higher in, nd thn in, nd nd the rie yields were higher for the sme rte of fertilizer pplition t deep plement t 10 m thn t 20 m nd y rodsting. Therefore, nitrogen fertilizer pplition nd the onentrtion n ffet the utiliztion effiieny of the fertilizer, influening rie yields nd nitrogen usge. The optimum pplition of nitrogen fertilizer gined from this study ws deep plement t 10 m sed on the rie yield nd the NH 4+ N, nd NO 3 N ontents of

11 878 Ksetsrt J. (Nt. Si.) 49(6) pddy field wter. Furthermore, the wter should e stored in the rie field to redue nutrient loss into the environment. Aknowledgments This reserh ws finnilly supported y the Thmmst University Reserh Fund under TU Reserh Sholrship. The uthors grtefully thnk the Reserh nd Development Institute, Ksetsrt University (KURDI), Chlermphrkit Skon Nkhon provine mpus for the experimentl res provided. LITERATURE CITED AlShmi, S.A., M.R. CheSlmh, M.N. Siti Azizh nd A. AuHssn The influene of routine griuturl tivities on the qulity of wter in tropil rie field eosystem. Appl. Ed. Environ. Res Alexnder, M Introdution to Soil Miroiology. 2nd ed. Wiley & Sons, In. New York, NY, USA. Amerin Puli Helth Assoition, Amerin Wter Works Assoition nd Wter Pollution Federtion Stndrd Methods for the Exmintion of Wter nd Wstewter. 20th ed. Amerin Puli Helth Assoition, Amerin Wter Works Assoition, Wter Pollution Federtion. Wshington DC, USA. Azeem, B., K. Kushri, Z.B. Mn, A. Bsit, T.H. Thnh Review on mterils & methods to produe ontrolled relese oted ure fertilizer. J. Control. Relese 181: Co, Y., T. Yuhu, Y. Bin nd Z. Zholing Assessment of mmoni voltiliztion from pddy fields under rop mngement prties imed to inrese grin yield nd N effiieny. Field Crop Res. 147: Chowdry, V.M., NH. Ro nd BS. Srm A oupled soil wter nd nitrogen lne model for flooded rie fields in Indi. Agri. Eosyst. Environ. 3: Ds, P., J.H. S, K.H. Kim nd E.C. Jeon Effet of fertilizer pplition on mmoni emission nd onentrtion levels of mmonium, nitrte, nd nitrite ions in rie field. Environ. Monit. Assess. 154: Dtt, S.K.D Nitrogen trnsformtion proesss in reltion to improved ulturl prties for lowlnd rie. Plnt Soil 100: Deprtment Pollution Control The sttus of pddy field pollution nd mngement. Ministry of Nturl Resoure nd Environment. Bngkok, Thilnd. Gong, W., X. Yn, J. Wng, T. Hu nd Y. Gong Longterm pplitions of hemil nd orgni fertilizers on plntville nitrogen pools nd nitrogen mngement index. Biol. Fert. Soils 7: Hui, F.X., S.Y. Sheng, L.D. Xi, Y.L. Zhng nd L.J. F Ammonium voltiliztion loss nd 15 N lne from ure pplied to rie on pddy soil. J. Environ. Si. (Chin) 18: Iql, M.T Nitrogen lehing from pddy field under different fertiliztion rtes. Mlysin J. Soil Si. 15: Jeynygm, S True onfessions of the iologil nutrient removl proess. Florid Wter Resoures Journl Jn: Ji, X.H., S.X. Zheng, Y.H. Lu nd Y.L. Lio Study of dynmis of floodwter nitrogen nd regultion of its runoff loss in pddy fieldsed tworopping rie with ure nd ontrolled relese nitrogen fertilizer pplition. Agr. Si. Chin 2: Konnerup, D., T. Kootttep nd H. Brix Tretment of domesti wstewter in tropil, susurfe flow onstruted wetlnds plnted with Cnn nd Helioni. Eol. Eng. 2: Ling, X.Q., Y.X. Chen, H. Li, G.M. Tin, W.Z. Ni, M.M. He nd Z.J. Zhng Modeling trnsport nd fte of nitrogen from ure

12 Ksetsrt J. (Nt. Si.) 49(6) 879 pplied to nertrenh pddy field. Environ. Pollut. 150: Lin, Z.C., Q.G. Di S.C. Ye, F.G. Wu, Y.S. Ji, J.D. Chen, L.S. Xu, H.C. Zhng, Z.Y. Huo, K. Xu nd H.Y. Wi Effets of nitrogen pplition levels on mmoni voltiliztion nd nitrogen utiliztion during rie growing seson. Rie Siene 19: Luo, L.G., S. Itoh, Q.W. Zhng, S.Q. Yng, Q.Z. Zhng nd Z.L. Yng Lehing ehvior of nitrogen in longterm experiment on rie under different N mngement systems. Environ. Monit. Assess. 2: Mejo University Plnt nutrients nd fertilizer usge. Aville from: oursewres.mju..th:81/elerning47/ setion2/sf313/001leture/html/hpter005. htm]. [Soured: 31 Otoer 2013] Mikkelsen, R Ammoni emission from griulture opertions: Fertilizer. Better Crops 4: Nmdev, G.R., A. Bjpi nd S. Mlik Effet of hemil fertilizers on wter qulity of irrigtion reservoir (Klisote Reservoir) of Bhopl (M.P.). Curr. World Environ. 1: Offie of Agriulturl Eonomis The Demnd of Using Fertilizer for Agriulture in Thilnd. [Aville from: oe.go.th/ewt_news.php?nid=684&filenme= index]. [Soured: 23 Otoer 2013]. Ponnmperum, F.N The hemistry of sumerged soils. Adv. Agron. 24: Reddy, K.R., W.H. Ptrik Nitrogen trnsformtions nd loss in flooded soils nd sediments. Crit. Rev. Env. Contr. 13: Reddy, K.R., W.H. Ptrik Denitrifition losses in rie fields. Fert. Res. 9: Roertson, G.P., P.M. Groffmn Soil Mioiology, Biohemistry nd Eology. Springer. New York, NY, USA. Skon Nkhon Rie Reserh Center Rie Prodution Potentil Zoning of Skon Nkhon Provie. Bureu of Rie Reserh nd Development, Rie Deprtment, Ministry of Agriulture nd Coopertives. Bngkok, Thilnd. Sunntpongsk, W Orgni griulture in Thilnd. [Aville from: udmgt.om/gri01/orggri3thi.html]. [Soured: 22 Septemer 2013]. U.S. Environmentl Protetion Ageny ESS method 220.3: Ammoni nitrogen nd nitrte + nitrite nitrogen, utomted flow injetion nlysis method. [Aville from: methd220.pdf]. [Soured: 31 Otoer 2013] Xing, G.X., Z,L. Zhu An ssessment of N loss from griulturl fields to the environment in Chin. Nutr. Cyl. Agroeosys. 1: Xu. J., L. Lio, J. Tn nd X. Sho Ammoni voltiliztion in gemmiprous nd erly seedling stges from diret seeding rie fields with different nitrogen mngement strtegies: A pots experiment. Soil Till. Res. 126: Yu, Q.G., J. Ye, S.N. Yng, J.R. Fu, J.W. M, W.C. Sun, L.N. Jing nd Q. Wng Effets of Nitrogen Applition Level on Rie Nutrient Uptke nd Ammoni Voltiliztion. Rie Siene 2: