Azmul Huda, Yam Kanta Gaihre, M. R. Islam, Upendra Singh, Md. R. Islam, Joaquin Sanabria, M. Abdus Satter, Hasina Afroz, et al.

Transcription

1 Floowter mmonium, nitrogen use effiieny n rie yiels with fertilizer eep plement n lternte wetting n rying uner triple rie ropping systems Azmul Hu, Ym Knt Gihre, M. R. Islm, Upenr Singh, M. R. Islm, Joquin Snri, M. Aus Stter, Hsin Afroz, et l. Nutrient Cyling in Agroeosystems (formerly Fertilizer Reserh) ISSN Volume 14 Numer 1 Nutr Cyl Agroeosyst (216) 14:53-66 DOI 1.17/s

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3 Author's personl opy Nutr Cyl Agroeosyst (216) 14:53 66 DOI 1.17/s ORIGINAL ARTICLE Floowter mmonium, nitrogen use effiieny n rie yiels with fertilizer eep plement n lternte wetting n rying uner triple rie ropping systems Azmul Hu. Ym Knt Gihre. M. R. Islm. Upenr Singh. M. R. Islm. Joquin Snri. M. Aus Stter. Hsin Afroz. Alee Hler. M. Jhiruin Reeive: 11 August 215 / Aepte: 31 Deemer 215 / Pulishe online: 8 Jnury 216 Springer Siene+Business Mei Dorreht 216 Astrt Fertilizer mngement shoul onsier optimum time, rtes n methos of pplition to inrese use effiieny n rop yiel. We onute fiel experiments t Bnglesh Agriulturl University, Bnglesh, to investigte the effets of eep plement of ure riquettes (UB) n NPK riquettes (NPK) ompre to rost prille ure (PU) t ifferent N rtes on ynmis of floowter NH? 4 -N, mmoni (NH 3 ) voltiliztion, rie yiel n nitrogen use effiieny (NUE) uring four onseutive rie-growing sesons in The floowter NH? 4 -N n NH 3 voltiliztion in rost PU inrese with N rtes, while in eep-ple tretments irrespetive of N rtes it ws similr to the ontrol. Aross sesons n wter regime, UB or NPK signifintly (P \.5) inrese grin yiel n nitrogen reovery ompre to rost PU. During A. Hu M. R. Islm M. R. Islm H. Afroz A. Hler M. Jhiruin Deprtment of Soil Siene, Bnglesh Agriulturl University, Mymensingh, Bnglesh Y. K. Gihre (&) M. A. Stter EurAsi Division, Interntionl Fertilizer Development Center (IFDC), House 4B, Ro 62, Gulshn 2, Dhk, Bnglesh e-mil: ygihre@if.org; gihreym@gmil.om U. Singh J. Snri Interntionl Fertilizer Development Center, Musle Shols, AL, USA the Boro seson (ross wter regime), UB78 n NPK78 inrese grin yiel y 4 n 29 %, respetively, ompre to rost PU78, while N reovery inrese from 35 % of PU to % in eep plement. Deep plement of UB52 or NPK52 uring Aus Amn n UB78 or NPK78 uring Boro n e one of the est N mngement options for inresing NUE n rop yiel. Alternte wetting n rying irrigtion, though, h no signifint effet on grin yiel or on NUE. Its option oul sve irrigtion wter without ny yiel reution uring the Boro seson. However, more stuies ross ifferent soils, limte n mngement prties re neee for further unerstning the intertive effets of fertilizer n wter mngement on yiel, NUE n soil fertility. Keywors Best nitrogen mngement Fertilizer eep plement Nitrogen use effiieny Lowln rie Introution Nitrogen (N) use effiieny (NUE) of rost pplie prille ure (PU) in lowln rie fiel is only 3 45 % ue to the losses from mmoni (NH 3 ) voltiliztion, surfe runoff, nitrifition enitrifition n lehing (Dong et l. 212; Hyshi et l. 28; Svnt n Stngel 199; Singh et l. 1995; Sommer et l. 24; Wtne et l. 29; Zho et l. 29). Brost pplition of PU results in higher

4 Author's personl opy 54 Nutr Cyl Agroeosyst (216) 14:53 66 mounts of mmonium (NH 4? ) N in floowter ompre with eep plement of ure (Kpoor et l. 28) tht inreses NH 3 voltiliztion. Fertilizer-N tht espes NH 3 voltiliztion is lso suseptile to losses through nitrifition n susequent enitrifition euse muh of the N remins ner the soil surfe prtilly eroi zone (Buresh et l. 28; Freney et l. 199; Singh et l. 1995). Nitrifition n enitrifition use tmospheri pollution ue to emissions of nitrous oxie n nitri oxie. Moreover, fter rost pplition of fertilizer, the high perentge of pplie nutrients present in floowter (Singh et l. 1995; Kpoor et l. 28) inreses the hne of runoff losses prtiulrly in the sitution where wter flows from fiel to fiel without ny ringe systems. The nutrient-enrihe runoff wter hs the potentil for environmentl pollution suh s eutrophition (Svnt n Stngel 199) n grounwter nitrte (NO 3 - ) pollution (lehing loss). Therefore, fertilizer rost not only uses sustntil monetry losses to frmers, ut lso uses high environmentl ost to the soiety (Mohnty et l. 1999). In ition to N, rost pplie P n K fertilizer oul e lost vi surfe runoff n use eutrophition in wter oies, prtiulrly in rinfe rie uring perios of high rinfll. There is n urgent nee for lterntive fertilizer mngement strtegies tht inrese rop yiel n mximize nutrient use effiieny. Fertilizer eep plement (FDP) of ure riquettes (UB) n N, P, K riquettes (NPK) is n effetive mngement prtie for inresing grin yiel n nutrient use effiieny in lowln rie fiels (Svnt n Stngel 199; Kpoor et l. 28; Bnogo et l. 214) n for reuing nutrient losses, prtiulrly from NH 3 voltiliztion, surfe runoff of N n P (Rohette et l. 213; Sommer et l. 24) n from nitrifition n enitrifition (Chien et l. 29) leing to reue nitrous oxie n nitri oxie emissions (Gihre et l. 215). Deep-ple fertilizer remins in reue soil lyer for longer time, n its movement to soil surfe/floowter is negligile. Due to reue nutrient onentrtion in floowter, ny wter runoff from rie pies reues nutrient loss n the potentil eutrophition prolem (Chien et l. 29; Kpoor et l. 28; Singh et l. 1995). The eep plement of NPK through lne fertiliztion lso inreses fertilizer use effiieny n rop proution n reues negtive environmentl onsequenes. FDP, in ition to performing well with lowln rie, lso performe etter in eroi rie (Xing et l. 213) n upln rops suh s potto (Azm et l. 212) n ge (Hussin et l. 21), showing the potentil for its option on upln rops. Limite evlution of FDP with NPK hs tken ple in Ini (Dftrr et l. 1997; Kpoor et l. 28), Cmoi (Bhttri et l. 21) n Bnglesh (Islm l. 211). In ition to inresing yiels n improving soil fertility, it reues lor ost euse ll three nutrients n e pplie t the sme time. In Bnglesh, rie is grown two to three sesons per yer in out 11 million hetres (h) of ln, whih overs lmost 8 % of the griulturl ln. Boro,or ry seson, rie is the min rie rop, n it is ompletely epenent upon irrigtion. The nee for wter-sving irrigtion prties suh s lternte wetting n rying (AWD) is inresing in Bnglesh (Prie et l. 213; Lmpyn et l. 215) ue to grounwter epletion. It is reporte tht AWD n reue wter use y up to 38 % while mintining rie yiel (Lmpyn et l. 215) n is expete to e wiely opte y frmers in the ountry. However, the effet of AWD on soil C n N ynmis n nutrient use effiieny is not well quntifie, prtiulrly with FDP. Most of the previous stuies on FDP were onute uner ontinuously stning wter (CSW) onitions. Moreover, stuies on the effets of eep plement of NPK on rie ultivtion re still limite uner oth CSW n AWD onitions. Therefore, fiel experiments were onute to etermine the effets of FDP n wter mngement (AWD vs CSW) on rie yiel n NUE. The speifi ojetives of this stuy were: To etermine the effets of FDP n rost PU t ifferent N rtes on ynmis of floowter NH 4 -N n NH 3 voltiliztion. To ssess the effets of FDP n AWD on rie yiel n NUE in ifferent rie-growing sesons. To etermine seson-speifi optimum N rtes for rost PU n FDP. Mterils n methos Experimentl site n wether onitions The fiel experiments were onute t Bnglesh Agriulturl University (BAU), Mymensingh, Bnglesh (ltitue: , longitue: ),

5 Author's personl opy Nutr Cyl Agroeosyst (216) 14: Air temperture ( C) 4 Rinfll Temp /1 3/1 4/3 6/29 8/28 1/27 12/26 2/24 4/25 Dte (Month/Dy, ) uring four rie-growing sesons in Jnury 212 My 213. There re three rie-growing sesons in yer, i.e., Boro (De/Jn April/My), Aus (My/June Aug/Sep) n Amn (Aug/Sep Nov/De). The limte is humi sutropil monsoon. Averge nnul rinfll is. 15 mm, primrily reeive from June to Otoer. Dily rinfll n men temperture for the experiment perio re shown in Fig. 1. The physiohemil properties of the soil from oth experiments (CSW n AWD) efore strt of the experiment re shown in Tle 1. Experimentl esign n tretments Rinfll (mm -1 ) Fig. 1 Dily verge of rinfll n ir temperture uring experiment perio (Jn 212 April 213) (t soure Deprtment of Irrigtion n Wter Mngement, Bnglesh Agriulturl University) The eight tretments with ifferent soures n rtes of N fertilizer were teste (Tle 2). The soures of N fertilizer were PU, UB n NPK. PU ws pplie s onventionl rost metho, while UB n NPK were eep ple s esrie lter. Tretments were rrnge in rnomize omplete lok esign with three replitions. Eh experimentl plot (6 m 9 4m) ws seprte y 5 m wie un. Experiments were onute uner CSW onition in 212 (ll three rie growing sesons). But in Boro 213, experiment ws onute uner two wter regimes CSW n AWD following the sme tretments. There were slight vritions in soil physiohemil properties, prtiulrly orgni ron etween CSW n AWD experiments (Tle 1). Size n numers of riquette per plement site were etermine se on the N rtes. The N rtes were fixe t 52, 78, 14, n 156 kg h -1 for eep plement of N. The N rtes for rost n eep Tle 1 Physiohemil properties of soil efore strt of the experiments Soil property CSW AWD ph H 2 O Orgni ron (%) Totl N (%) Aville P (mg kg -1 ) Aville K (mol kg -1 ).9.8 Aville S (mg kg -1 ) Prtile size (%) Sn Silt Cly ple tretments inrese from the existing reommene rte. The reommene N rte for UB or NPK is 3 % less thn rost PU, i.e., 52 n 78 kg h -1, respetively for Aus Amn n Boro sesons. This is euse eep plement sves 3 35 % ure ompre with surfe rost n inreses yiel y 15 2 % (FRG 212; Mih et l. 215). On the other hn, higher N rte uring ry (Boro) seson thn uring wet (Aus n Amn) seson ws ue to the higher rie yiel potentil. N rtes for NPK vrie ±3 kgh -1 ompre with N rtes of UB ue to mixing rtio of three fertilizers, i.e., PU, i-mmonium phosphte (DAP) n murite of potsh (MOP). One or two riquettes of either 1.8 or 2.7 g were eep-ple t 4 m y 4 m sping (62,5 plement sites per h) (Tle 2). The ie (riquetting rolls) in riquetting mhine use to proue 1.8 n 2.7 g UB proue NPK of 2.4 n 3.4 g, respetively. While prepring NPK, the reommene rte of P n K were mintine. Crop mngement P (triple super phosphte, TSP) n K (MOP) fertilizers were pplie slly in ll the plots (exept plots reeiving NPK) uring finl ln preprtion t 16 kg n 25 kg P h -1 n 42 kg n 64 kg K h -1 in Aus Amn n Boro sesons, respetively. P n K in NPK tretments were pplie long with riquette. PU ws pplie s rost in three splits t 7 1 ys fter trnsplnting (DAT), t mximum tillering n t pnile initition stges while ure, n NPK riquettes were pplie t one time uring the first rost pplition of PU. The riquettes were eep-ple t epth of 7 1 m etween four hills

6 Author's personl opy 56 Nutr Cyl Agroeosyst (216) 14:53 66 Tle 2 Nitrogen soure n rtes use in the experiments uring ifferent rie-growing sesons (Boro Aus Amn) Fertilizer/nitrogen soure N rte (kg h -1 ) Briq wt. (g) n no/four hills Boro Aus Amn Boro Aus Amn Control Prille ure (PU) Ure riquette (UB) (1) 1.8 (1) (2) 2.7 (1) (2) 1.8 (2) NPK riquette (NPK) (2) 3.4 (1) (3) 2.4 (2) The tretments were sme for oth ontinuously stning wter (CSW) n lternte wetting n rying (AWD) onitions for Boro 213 Vlues in prenthesis inites the numer of riquettes use per pplition site; fertilizer riquettes were eep-ple etween four hills of rie, PU ws roste in two (Aus Amn) to three (Boro) equl splits of rie t the lternte rows. In ition, sulfur (S) n zin (Zn) were pplie to ll plots t the rte of 2 kg S h -1 s gypsum n 3 kg Zn h -1 s zin oxie. Rie seelings (two to three per hill) were trnsplnte t sping of 2 m 9 2 m. Rie vrieties grown in Boro, Aus n Amn sesons were BRRI hn 28, BRRI hn 27 n BR 22, respetively. All the plots uner CSW onitions were ontinuously flooe until 2 weeks efore hrvesting, while plots uner AWD onitions (Boro 213) were irrigte following sfe AWD priniple, i.e., plots were irrigte when wter epth in AWD pipes ws m elow soil surfe. However, plots were mintine ontinuously flooe for week fter topressing of PU for the purpose of floowter mmonium ynmis. Floowter mmonium-n (NH 4? -N) n mmoni voltiliztion mesurement Floowter smples were ollete every y from eh experimentl plot for week fter topressing of PU s esrie y Kpoor et l. (28). After topressing of PU, floowter smpling ws ollete 2 h fter pplition of fertilizers n then one y from 8 to 1H for six onseutive ys. Smples were ollete in i-wshe plsti ottles n rought to the lortory. Ammonium-N ws mesure with Phenol-hypohlorite metho (Solorzno et l. 1969). The onentrtion of floowter NH 4 -N (mg L -1 ) is onverte to kg h -1 fter justing with floowter epth. The moifie mmoni voltiliztion eqution (Freney et l. 1983) ws use to etermine NH 3 loss from floowter using NH 4 -N, floowter ph n win spee. Rie growth, yiel n nitrogen reovery Plnt smples for totl ry iomss were ollete two times from 1.2 m 2 (3 hills 9 1 hills), first t pnile initition (PI) stge n then t heing stge. Grin n strw yiel were reore t finl hrvest of the rop from 5 m 2 in eh plot. In ition to the iomss, plnt N ontent ws etermine t eh growth stge. The totl nitrogen uptke ws etermine t PI, heing n mturity stges to etermine the N reovery y plnts. Agronomi effiieny (AE N ) n reovery effiieny (RE N ) were lulte from totl N uptke t hrvest using following formul (Singh et l. 1999). AE N ¼ kg grin inrese kg 1 N pplie ¼ ðy N Y Þ=F N where Y N is rie grin yiel (kg h -1 ) t ertin level of pplie fertilizer N (F N,kgh -1 ), n Y is the rie grin yiel (kg h -1 ) mesure in ontrol plot with no N pplition. RE N kg N tken up kg 1 N pplie ¼ ðu N U Þ=F N where U N is the totl N in ovegroun plnt iomss (grin plus strw) t physiologil mturity (kg h -1 ) in plot reeiving N t the rte of F N (kg h -1 ), n U is the totl plnt N without N ition.

7 Author's personl opy Nutr Cyl Agroeosyst (216) 14: Dt nlysis ANOVA of ifferent response vriles within seson in 212 ws one using SAS mixe proeure. While ANOVA for the omintion of the two experiments (AWD n CSW) in Boro 213 were onute with split-plot generlize liner mixe moel where the wter regime ws use s the min plot n the tretments s su-plots. After testing errors for normlity n vrine homogeneity, it ws eie to use the norml istriution s the proility istriution for the moel, n non-homogenous vrine ovrine mtrix for lultion of stnr errors. Tretment, wter regime, n wter regime 9 tretment were hnle s fixe effets; n replition together with the resiul were hnle s rnom effets. The effet wter 9 tretment ws teste with the resiul s error term. The resiul enomintor egrees of freeom were use for lultions of the F sttisti. Pirwise men omprisons of intertion (wter 9 tretment) or within wter regime were one using Tukey Krmer metho. Results Dynmis of floowter NH 4? -N n mmoni voltiliztion Floowter NH 4? -N ws mesure in ll rie-growing sesons in 212 n showe similr pttern to Boro 213. Mgnitues of floowter NH 4? -N in eepple tretments were negligile irrespetive of N rtes n growing seson. Therefore, mmonium ynmis uring Boro, Aus n Amn in 212 is omine (Fig. 2), ut it ws not omine with Boro 213 euse it ws mesure uner two wter regimes unlike one wter regime in 212. To synhronize N rte vritions ross sesons in 212, they were tegorize s low, meium n high for prtiulr fertilizer. The ynmis in floowter NH 4? -N uring 212 (verge ross sesons) n Boro 213 uner CSW n AWD onitions re shown in Fig. 2. The results lerly show tht the eep plement of fertilizer N either s UB or NPK resulte in signifintly lower mounts of floowter NH 4? -N. Even though the mount of rost PU ws only one-thir (3 split pplition) the rte of UB n NPK, it resulte in NH 4 -N (kg/h) NH 4 -N (kg/h) NH 4 -N (kg/h) Control-N PU-L PU-H UB-L UB-M UB-H NPK-L NPK-H () 212 (Averge ross sesons) TD-1 TD-2 TD-3 Control-N PU-N78 PU-N156 UB-N78 UB-N14 UB-N156 NPK-N78 NPK-N12 () Boro 213 (CSW) () Boro 213 (AWD) Dys fter fertilizer pplition Fig. 2 Dynmis of floowter NH 4? -N uner ifferent N rtes n pplition methos rost PU versus eep plement of ure n NPK riquettes in ; TD-1, TD-2 n TD- 3 represent first, seon n thir topressing of PU, respetively. Vertil rs inite stnr error of men (n = 3). CSW ontinuous stning wter, AWD lternte wetting n rying. PU, UB n NPK represent rost prille ure, ure riquette eep plement n NPK riquette eep plement, respetively. L, M n H in 212 represent low, meium n high N rtes, respetively. Experiments in 212 were onute only uner CSW onition signifintly higher mounts of NH 4? -N in floowter. Floowter NH 4? -N in rost PU tretments rehe its pek (5 8 kg N h -1 ) t 2 3 ys fter its rost n then showe shrp eline, eoming similr to the level in the N tretment fter 5 6 ys. The mount of floowter NH 4? -N in PU inrese with N rtes. But for UB n NPK tretments, the mount of NH 4? -N in floowter remine negligile n ws similr to the ontrol (N) plot throughout the 7 ys of mesurement perio irrespetive of the N rtes. The mgnitues n pttern of NH 4? -N ws

8 Author's personl opy 58 Nutr Cyl Agroeosyst (216) 14:53 66 Tle 3 Cumultive mmoni losses ross sesons, N tretments n timing of pplition, vlues re totl of seven onseutive ys fter top ressing of PU N soure N rte First TD Seon TD Thir TD Totl NH 3 -N (kg h -1 ) N (%) NH 3 -N (kg h -1 ) N (%) NH 3 -N (kg h -1 ) N (%) NH 3 -N (kg h -1 ) N (%) Boro 212 Control PU UB NPK Aus 212 Control PU UB NPK Amn 212 Control PU UB NPK Boro 213 Control PU UB NPK Within olumn n seson, mens followe y sme letters re not signifintly ifferent t 5 % proility level y Tukeys s honest signifint ifferene (HSD) test PU prille ure, UB ure riquette, NPK fertilizer riquette ontining NPK Fertilizer riquettes were eep-ple t time uring first topressing of PU

9 Author's personl opy Nutr Cyl Agroeosyst (216) 14: similr in ll three split mesurements. Similrly, mgnitues n pttern of the NH 4? -N in floowter were similr etween CSW n AWD onitions uring Boro 213. Ammoni voltiliztion ws lulte using floowter mmonium, temperture n win spee. As with floowter mmonium, mgnitues of mmoni loss from eep-ple tretments were negligile. They were signifintly higher from rost tretments ompre with eep-ple tretments, whih inrese with inresing N rtes (Tle 3). Rie growth, yiel n gronomi effiieny Biomss umultion t pnile initition (PI), heing n mturity stges uring ifferent riegrowing sesons re shown in Figs. 3 n 4. In generl, totl iomss umultion t ll growth stges inrese with N rte irrespetive of metho of pplition. At eh growth stge, response of inresing N rte on iomss umultion ws more istint t PU tretments (exept uring Aus 212) ompre with eep-ple tretments. In eepple tretments, inrese in totl iomss umultion ws higher t lower N rtes; therefore, inresing N rtes h lower response, initing more effiient use of N t lower rte. The ANOVA of grin yiel n yiel omponents n their men omprison is shown in Tle 4. Response of N rtes on grin yiel ws not onsistent mong the sesons. Generlly, grin yiel inrese with N rte in PU uring Amn n Boro sesons ut not uring the Aus seson; while for FDP tretments, inresing N rte i not hve signifint effets on grin yiel in ny seson. Nevertheless, in Amn seson, eep plement of UB52 n NPK 52 signifintly inrese grin yiel y 8 15 % ompre to PU78. However, uring the Aus seson, grin yiel inrese of 5 12 % ws not signifintly ifferent for UB52 n NPK52 versus PU78. During the Boro seson, UB78 or NPK78 inrese grin yiel y 4 46 % in 212 n y % in 213 over PU78. Deep plement of UB156 inrese yiel y only 11 % over PU156. Though the NPK eep plement inrese grin yiels signifintly over rost PU, it i not hve signifint yiel Fig. 3 Aumultion of iomss (ry mtter) n nitrogen t ifferent growth stges of rie in Boro, Aus n Amn sesons in 212. Vertil r inites stnr error of men (n = 3). Within growth stge n response vrile, mens followe y sme letters re not signifintly ifferent t P B.5. All experiments were onute uner CSW onitions. PU rost prille ure, UB eep plement of ure riquettes, NPK eep plement of NPK riquettes; in x-xis, numers followe y N represent kg N h -1 Dry mtter (t h -1 ) Dry mtter (t h -1 ) Dry mtter (t h -1 ) Dry mtter umultion PI Mturity N N78 N156 N78 N14 N156 N78 N12 PI Heing Mturity N N78 N12 N52 N78 N14 N51 N PI Heing Mturity e N N78 N12 N52 N78 N14 N51 N78 Boro 212 N uptke (kg h -1 ) Aus 212 N uptke (kg h -1 ) Amn 212 N uptke (kg h -1 ) N uptke PI Mturity N N78 N156 N78 N14 N156 N78 N12 PI Heing Mturity N N78 N12 N52 N78 N14 N51 N PI Heing Mturity N N78 N12 N52 N78 N14 N51 N78

10 Author's personl opy 6 Nutr Cyl Agroeosyst (216) 14:53 66 Fig. 4 Aumultion of iomss (ry mtter) n nitrogen t ifferent growth stges of rie in Boro 213 uner CSW n AWD onitions. Vertil r inites stnr error of men (n = 3). Within growth stge n response vrile, mens followe y sme letters re not signifintly ifferent t P B.5. PU rost prille ure, UB eep plement of ure riquettes, NPK eep plement of NPK riquettes; in x-xis, numers followe y N represent kg N h -1 Dry mtter (t h -1 ) Dry mtter (t h -1 ) Dry mtter umultion N uptke CSW PI Heing Mturity e N N78 N156 N78 N14 N156 N78 N14 PI Heing Mturity AWD 12 e N N78 N156 N78 N14 N156 N78 N14 N uptke (kg h -1 ) N uptke (t h -1 ) CSW PI Heing Mturity e N N78 N156 N78 N14 N156 N78 N PI Heing Mturity e e e e f N N78 N156 N78 N14 N156 N78 N14 inrese over UB eep plement. The higher grin n strw yiel in eep-ple tretments were ssoite with higher numers of pniles (effetive tillers) per hill n spikelet per pnile (Tle 4). Agronomi effiieny of N (AE N ) ws signifintly ffete y fertilizer tretment in ll rie-growing sesons. In eep-ple tretments, the highest AE N ws oserve t its lower N rtes (Tle 4). In Aus n Amn sesons, signifintly higher (2 25 kg kg -1 N) AE N ws oserve with UB52 or NPK52 ompre to PU78 (1 12 kg kg -1 N). In Boro seson, AE N of UB78 or NPK78 ws signifintly higher (38 46 kg kg -1 N) thn rost PU78 (19 22 kg kg -1 N). Nitrogen uptke n reovery N uptke t ifferent rop growth stges inrese with N rte irrespetive of its metho of pplition (Figs. 3, 4). Highest totl N uptke (grin n strw) ws oserve t UB14 in Aus Amn sesons n t UB156 uring Boro seson. Though mgnitue of uptke inrese with growth stges, the pttern of uptke mong fertilizer tretments ws similr etween PI n heing n mturity stges. However, in Amn 212, slightly lower N umultion ws oserve t mturity stge thn t heing stge. Aross fertilizer tretments, higher N uptke ws oserve uring Boro thn uring Aus Amn sesons. Contrry to fertilizer tretments, N uptke from N plot ws higher uring Aus Amn sesons thn uring Boro seson, proly ue to inrese N supply from iologil N fixtion, rinwter n inrese N minerliztion (Cssmn et l. 1996; Timsinetl.21). Nitrogen reovery (RE N ) t mturity showe similr tren with AE N, higher in lower N rtes prtiulrly in UB n NPK tretments (Tle 5). Deep plement of UB52 or NPK52 uring Aus Amn inrese RE N up to 54 6 % from % of PU78. Similrly, RE N t UB78 or NPK78 in Boro seson inrese up to % from % of PU78. RE N erese with inresing N rte exept t NPK78 uring Aus 212. Deep plement of UB n NPK, prtiulrly t its lower N rte inrese RE N onsistently over PU t ll rie growth stges in Aus Amn 212 n Boro 213. Moreover, RE N in eep-ple tretments inrese onsistently with plnt growth stges uring Boro seson. On the other hn, RE N for ll tretments erese t mturity stge ompre to heing stge uring the Aus seson. RE N for PU remine lmost similr t ll growth stges uring the Amn n Boro sesons. Effets of wter regimes on grin yiel n nitrogen use effiieny Rie ultivtion in Aus n Amn (wet seson) ws rinfe. Wter sving irrigtion (AWD) ws prtie only uring Boro seson. For Boro 213, ANOVA of

11 Author's personl opy Nutr Cyl Agroeosyst (216) 14: Tle 4 Grin yiel, yiel omponents n gronomi effiieny (AE N ) in ifferent fertilizer tretments in Boro, Aus n Amn 212 n Boro 213 N soure N rte Grin yiel (t h -1 ) Effetive tillers hill -2 Spikelets pnile -1 1 grin weight (g) Agronomi effiieny (AE N ) Boro 212 Control PU UB NPK Aus 212 Control PU UB NPK Amn 212 Control PU UB NPK Boro 213 (Averge of CSW n AWD) Control PU UB NPK ANOVA (Boro 213) Wter regime (W) NS NS NS NS NS Fertilizer tretment (T) * * * * * W 9 T NS NS NS NS NS Within olumn n seson, mens followe y sme letters re not signifintly ifferent t 5 % proility level y Tukeys s honest signifint ifferene (HSD) test AE N gronomi effiieny (kg grin/kg N), CSW ontinuous stning wter, AWD lternte wetting n rying, PU prille ure, UB ure riquette, NPK fertilizer riquette ontining NPK * Signifint ifferene t P B.5 Grin yiel is t 14 % moisture ontent

12 Author's personl opy 62 Nutr Cyl Agroeosyst (216) 14:53 66 Tle 5 Chnges in reovery effiieny of fertilizer N over rop growth stges, N tretments n sesons N soure N rte Reovery effiieny (RE N ) PI Heing Mturity Boro 212 PU UB NPK Aus 212 PU UB NPK Amn 212 PU UB NPK Boro 213 (CSW) PU UB NPK Within olumn n seson, mens followe y sme letters re not signifintly ifferent t 5 % proility level y Tukeys s honest signifint ifferene (HSD) test RE N reovery effiieny (kg N uptke/kg N), PU prille ure, UB ure riquette, NPK fertilizer riquette ontining NPK iomss yiel, N uptke n AE N ws one seprtely to see the effet of wter mngement n its intertion with fertilizer tretments (Tle 4). Though ll the prmeters were ffete y fertilizer tretments, none of them ws ffete y wter mngement. However, signifint intertion ws oserve etween fertilizer tretment n wter regime on ovegroun iomss (Fig. 4). Strw yiel n totl ovegroun iomss were signifintly higher in UB N156 uner CSW onition. Disussion Dynmis of mmonium in floowter n mmoni voltiliztion Deep plement of UB n NPK signifintly reue the mount of NH? 4 -N in floowter (Fig. 2). When fertilizer riquettes were eep-ple, the movement of NH? 4 from the eep soil lyer to the soil s surfe or floowter ws very slow (Fig. 2; Rohette et l. 213). Therefore, very low to negligile mount of floowter NH? 4 -N ws oserve in UB n NPK. On the other hn, in rost PU, signifint mount of NH? 4 from ure hyrolysis ws present in floowter n oul e lost vi NH 3 voltiliztion n surfe run off. The mount of floowter NH? 4 -N oul e goo initor to estimte potentil NH 3 voltiliztion loss (Hyshi et l. 26; Rohette et l. 213). This ws evient from estimte NH 3 voltiliztion whih showe similr tren with floowter mmonium, i.e., signifintly higher emissions from PU tretments ompre to eep-ple tretments (Tle 3). This tren ws onsistent ross ll rie-growing sesons. However, in ition to floowter NH 4 -N, the NH 3 voltiliztion n e ffete y other ftors inluing ph, wter temperture, wter epth n win spee (Hyshi et l. 28). Sine these ftors hnges with seson (n site), the mgnitues of NH 3 voltiliztion my vry ross sesons. The shrp eline in the mount of floowter NH? 4 -N from 2 to 3 ys fter ure rost my e ttriute to voltiliztion loss, iffusion of NH? 4 -N into soil, n/or nitrifition in the oxiize soil lyer (Kpoor et l. 28). Wtne et l. (29) oserve similr results, peks in the mmoni flux t 1 3 ys of ure pplition followe y shrp eline. This lerly suggests tht the NH? 4 -N present in floowter is voltilize, nitrifie to nitrte, n plnt uptke (Figs. 3, 4); thus, its mgnitue erese shrply fter its pek t 2 3 ys of pplition. Sine there is negligile floowter NH? 4 -N in UB n NPK

13 Author's personl opy Nutr Cyl Agroeosyst (216) 14: tretments irrespetive of N rtes n sesons, eep plement n signifintly reue potentil N losses from mmoni voltiliztion n surfe run off over rost PU. Effets of FDP on rie growth n yiel The enefits of UB eep plement (ommonly lle ure eep plement, UDP) inrese NUE, 3 % ure-svings n inrese grin yiel ompre to rost pplition in lowln rie fiels re well oumente. In this stuy, eep plement of either UB or NPK signifintly (P \.5) inrese the grin yiel t 52 kg N h -1 uring Aus Amn n t 78 kg N h -1 uring Boro ompre with rost PU. These results re in lose greement with previous stuies (Kpoor et l. 28; Mohnty et l. 1999) tht UB eep plement sves ure y up to 5 % ompre to rost PU without signifint yiel loss. The yiel vntge, prtiulrly t lower N rte, oul e ttriute to inrese plnt uptke or ouling of the fertilizer N reovery (Tle 4).There ws signifint positive orreltion etween grin yiel n N reovery (R 2 =.52, P \.1), prtiulrly uring Boro seson. Severl fiel reserh onute in Bnglesh showe tht UB eep plement with 3 % less ure proue up to 2 % higher yiel (Svnt n Stngel 199; Gregory et l. 21; IFDC 213). Therefore, reommene N rte for rie in this region, se on pst fertilizer trils, ws juste to 3 % less t 52 n 78 kg N h -1 forubeepplement,ompreto78 n 112 kg N h -1 of rost PU, for Aus Amn n Boro sesons, respetively (FRG 212). Our results onfirm tht the UB52 n UB78 reommentions oul ontinue for inresing grin yiels n NUE in Aus Amn n Boro, respetively, in res with limte, soils n mngement similr to this experimentl site. Though UB eep plement hs een prtie for long time in Bnglesh, the eep plement of NPK riquettes to frmers hs reently een introue. One of the mjor enefits of NPK eep plement over UB eep plement is to ensure lne fertiliztion. Aprt from the gronomi n environmentl enefits tht re hieve with UB, NPK eep plement elimintes the nee for multiple fertilizer pplitions, s is the stnr prtie, n onsolites the lor requirement ompre to UB eep plement n rost inorportion of P n K. Deep plement of NPK in Bnglesh is eing prtie not only in rie, ut lso in upln rops (Azm et l. 212; Islm et l. 211; IFDC 215; Mih et l. 215). Moreover, its pplition is expning in other south-est Asin ountries suh s Cmoi (Bhttri et l. 21). The use of multi-nutrient fertilizer riquettes is lso reporte in Ini where eep plement of ure-dap riquettes inrese grin yiel y % over frmers prtie n y % over reommene mngement prtie (Dftrr et l. 1997). Similrly, Kpoor et l. (28) oserve inrese grin yiels n NUE y NPK eep plement over UDP in estern Ini. Contrry to their stuy, NPK response ws similr to UDP in this stuy, proly euse the soil h low ville P (3 mg kg -1 ), whih might hve ffete plnt P uptke ue to the time lg for the roots to ess eep-ple P versus uniformlyrost P, prtiulrly uring erly plnt estlishment. This my result in poor rop growth n ffet yiels. Suh n effet will e ruil for soils with low to very low P sttus (Kpoor et l. 28). Thus, the eep plement of P n K shoul e site speifi n generlly not reommene for soils with very low P n K sttus in terms of rie yiel response. In spite of low P sttus, our results showe tht the eep plement of NPK i not hve ny signifint negtive effets on the yiels ompre with UB eep plement n signifintly inrese rie yiels over rost PU. Nevertheless, NPK my hve signifint effets over UB in frmers fiels euse frmers use more N n less P n K fertilizers. Use of NPK ensures lne supply of nutrients n inrese yiels s well s soil fertility. Mih et l. (215) evlute UB n NPK ross ifferent istrits in southern Bnglesh where NPK inrese grin yiel n eonomi returns ompre to UB. Comprison of NUE etween rost n eep plement Aross ll the sesons, totl N uptke ws higher with FDP (UB n NPK) t eh pplition rte ompre with rost PU following the sme tren with totl iomss. Higher N uptke in eep-ple tretments might e ue to inrese vilility of pplie N (lower N losses) for plnt growth resulting in inrese N ontent of strw n grin (t not shown) n inrese ovegroun iomss (Figs. 3, 4). The totl N uptke (inluing strw) in this stuy rnge from 13 to 18 kg per ton of rough rie similr

14 Author's personl opy 64 Nutr Cyl Agroeosyst (216) 14:53 66 with the rnges reporte in previous stuies (Chouhury n Kenney 25; Kpoor et l. 28; Dong et l. 212). UB n NPK inrese N reovery effiieny y lmost oule n gronomi N effiieny y up to 29 % (kg grin kg -1 N) over rost PU. At 78 kg N h -1 (Boro), UDP inrese N reovery up to % from 35 % of rost PU. Even with single fertilizer pplition, N reovery onsistently inrese up to heing to mturity stges (Tle 4) suggesting tht eep plement supplie N ontinuously throughout the growing perio. These results lso onfirme tht eep plement of NPK is eqully effetive s UB for inresing fertilizer N use effiieny in lowln rie fiels s ompre with the rost PU. The inrese in NUE oul e minly ue to reution of losses from NH 3 voltiliztion, surfe run off, nitrifition n enitrifition (Svnt n Stngel 199; Mohnty et l. 1999), whih ws evient from negligile mount of NH 4? in floowter (Fig. 2), estimte NH 3 voltiliztion loss n inrese plnt uptke n N reovery (Tle 3). When N is eep-ple in reue zone (neroi zone), most of the N is retine in soil s NH 4? -N for longer time, ensuring ontinuous vilility of N for the rie rop (Kpoor et l. 28). Inrese NUE with UB ws lso reporte in West Afri (Bnogo et l. 214). In generl, erese AE N n RE N re expete when N rte is inrese eyon the reommene rtes with greter opportunities for N losses. Generlly, losses inrese when N is pplie in exess of plnt uptke (Ling et l. 213). Effets of wter regimes Most previous stuies hve shown tht the wtersving AWD irrigtion prtie hs no signifint effet on grin yiel ompre to frmer prtie, i.e., ontinuous flooing. In reent review stuy, Lmpyn et l. (215) reporte tht AWD sves irrigtion wter y up to 38 % without reuing grin yiels. In this stuy, wter regime h no signifint effet on grin yiels in ny fertilizer tretments euse soil rying in AWD plots ws very mil, whih i not ffet rie growth. However, only one seson of t woul not e suffiient to see the long-term effets of AWD on rie proution s well s hnges in soil fertility sttus suh s orgni C n N. More stuies re neee to unerstn the intertion effet of AWD n FDP for sustinle rie proution while oping with wter srity. Conlusions Deep plement of UB n NPK signifintly reue floowter NH 4 -N n NH 3 voltiliztion ompre with rost PU. Aross sesons n yers, UB n NPK inrese grin yiels n NUE (AE N n RE N ) over rost PU. The effet of eep plement on grin yiel ws istint n signifint t lower N rtes thn tht of higher rtes n in Boro seson thn in Aus Amn. Among ll rie-growing sesons (exept Aus 212), inrese N rte in PU inrese yiels signifintly. But in eep-ple tretments, the effets of inresing N rtes on grin yiels were not signifint, onfirming the urrent N reommention rte for FDP s use in this stuy is pproprite. Signifintly higher N reovery effiieny (P \.5) ws oserve in eep-ple tretment t its reommene N rtes (52 kg N h -1 in Aus Amn n N78 kg N h -1 in Boro) thn rost PU (64 72 vs %). Sine grin yiel t UB or NPK t 52 kg or 78 kg N h -1 ws not signifintly ifferent ompre with PU12 or PU156, eep plement my sve up to 5 % ure without ny yiel penlty. The ifferene in grin yiels n NUE etween UB n NPK were not signifint. However, eep plement of NPK in frmers fiels inrese grin yiel n nutrient use effiieny n net eonomi returns (Mih et l. 215). Bse on grin yiel n NUE, the existing reommene N rte 52 kg N h -1 for Aus n Amn sesons n 78 kg N h -1 for Boro s UB or NPK oul e ontinue for rie proution in the res with soils, limte n mngement similr to this stuy site. On the other hn, AWD i not hve signifint effets on grin yiels n NUE, suggesting tht eep plement is eqully effetive uner AWD onitions. Comintion of oth FDP n AWD tehnologies in rie ultivtion oul inrese fertilizer use effiieny, sve wter (Boro seson) n inrese grin yiels. However, these results were from the experiment onute in one lotion, more stuies ross ifferent soils, limte n mngement prties re neee to unerstn the site n seson speifi response of fertilizer n wter mngement n their possile intertion effets on yiels, NUE n soil fertility.

15 Author's personl opy Nutr Cyl Agroeosyst (216) 14: Aknowlegments The Unite Sttes Ageny for Interntionl Development (USAID) provie support for this reserh through the projet Aelerting Agriulture Proutivity Improvement-Integrting Greenhouse Gs Emissions Mitigtion into the Fee the Future Bnglesh Fertilizer Deep Plement Rie Intensifition (oopertive greement numer AID-388-A-1-2). Referenes Azm MG, Mhmu JA, Ahmm KU, Gulnz MA, Islm M (212) Profiieny n profitility of potto s ffete y ure super grnule (USG) s soure of nitrogen in high Gnges river flooplin of Bnglesh. Int J Sustin Crop Pro 7:28 3 Bnogo A, Bijokzo F, Youl S, Sfo E, Aioo R, Anrews O (214) Effet of fertilizer eep plement with ure supergrnule on nitrogen use effiieny in Sourou Vlley (Burkin Fso). Nutr Cyl Agroeosyst. oi:1.17/ s Bhttri SP, Pl MC, Mimore DJ, Wu D, Sls R (21) On-frm evlution of fertilizer riquettes n low-ost rip irrigtion for smllholer vegetle proution in Cmoi. Irrig Drin 6: oi:1.12/ir.571 Buresh RJ, Rey KR, vn Kessel C (28) Nitrogen trnsformtion in sumerge soils. In: Shepers JS, Run WR (es) Nitrogen in griulturl systems. Agronomy monogrph 49, ASA, CSSA, n SSSA, Mison, p 41 Cssmn KG, Doermnn A, St Cruz PC, Gines GC, Smson MI, Deslsot JP, Alntr JM, Dizon MA, Olk DC (1996) Soil orgni mtter n the inigenous nitrogen supply of intensive irrigte rie systems in the tropis. Plnt Soil 182: Chien SH, Prohnow LI, Cntrell H (29) Reent evelopment of fertilizer proution n use to improve nutrient effiieny n minimize environmentl impts. Av Agron 12: oi:1.116/s (9)18-6 Chouhury ATMA, Kenney IR (25) Nitrogen fertilizer losses from rie soils n ontrol of environmentl pollution prolems. Commun Soil Si Plnt Anl 36: Dftrr SY, Wgle SM, Svnt NK (1997) Agronomi performne of ure riquettes ontining immonium phosphge in rinfe trnsplnte rie on frmers fiels. J Agri Si 128: Dong NM, Brnt KK, Sorenson J, Hung NN, Hh CV, Tn PS, Dlsgr T (212) Effets of lternte wetting n rying versus ontinuous flooing on fertilizer nitrogen fte in rie fiels in the Mekong Delt, Vietnm. Soil Biol Biohem 47: Freney JR, Simpson JR, Denme OT (1983) Voltiliztion of mmoni. In: Freney JR, Simpson JR (es) Gsesous losses of nitrogen from plnt-soil systems. Mrtinuss Nijhoff, The Hgue, pp 1 52 Freney JR, Trevitt ACF, De Dtt SK, Oeme WN, Rel JG (199) The interepenene of mmoni voltiliztion n enitrifition s nitrogen loss proesses in flooe rie fiels in the Philippines. Biol Fertil Soils 9:31 36 FRG (212) Fertilizer reommention guie. Bnglesh Agriulturl Reserh Counil (BARC), Frmgte, Dhk 1215 Gihre YK, Singh U, Islm SMM, Hu A, Islm MR, Stter MA, Snri J, Islm M R, Shh AL (215) Impts of ure eep plement on nitrous oxie n nitri oxie emissions from rie fiels in Bnglesh. Geoerm : Gregory DI, Hefele SM, Buresh RJ, Singh U (21) Fertilizer use, mrkets, n mngement. 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