N FERTILIZATION OF FIELD-GROWN FABA BEANS IN MANITOBA

Transcription

1 N FERTILIZATION OF FIELD-GROWN FABA BEANS IN MANITOBA JOHN E. RICHARDS' and R. J. SOPER Department f Sil Science, University f Manitba, Winnipeg, Man. R3T 2N2. Received 24 Mar. 1981, accepted I Sept RrcHnns, J. E. en SpEn, R. J N fertilizatin f field-grwn faba beans in Manitba. Can. J. Sil Sci. 62: 2l-3. Can. J. Sil. Sci. Dwnladed frm by n 11/26/17 Fr persnal use nly. The effect f fertilizer N n yield, prtein cntent and symbitic N, fixatin in faba beans (Vicia faba L.) was studied with nine field trials during 3 yr. Frage and seed yields f ndulated faba beans were.infrequently and unpredictably affected by rate f applicatin at seeding (up t 3 kg N/ha), type f applicatin (34 and 67 kg N/ha surface-bradcast r placed with the seed), and time f applicatin (at full blm r at mid pd-fill). Prtein cntent f faba bean frage material was variably affected by applied N; in ne-half f the harvests cnducted, at least ne f the N applicatin treatments resulted in significantly higher frage prtein cntents. N lgical pattern r reasn fr the frage prtein respnse was fund. Seed prtein cntent was unaffected by applied N up t 15 kg N/ ha, but was significantly increased by 3 kg N/ha in tw ut f three trials. Maximum rate f dry matter accumulatin and N uptake cmmenced at blming and cntinued up t the mid pd-fill grwth stage. In seven trials mnitred, the prprtin f faba bean sht N derived by symbitic N2 fixatin was 547, with values f five ut f the seven trials ranging frm 63 t 7l%. This amunted t kg N/ha. Applied N decreased faba bean symbitic fixatin at all trials but ne where available sil N was very high and symbitic N2 was nt ccurring. L'effet de la fumure N sur le rendement, la teneur en prt6ine et la fixatin azt6e symbitique de la f6verle (Vicia faba L.) a 6,t6, 6tudi6 en neuf essais au champ r6partis sur tris ans. Le rendement furrager et grainier des fbves ndul6es a 6t6 influenc6 de faen infr6quente et impr6visible par la dse de fertilisatin au semis (usqu'ir 3 kg N par hectare), le mde d'6pandage (34 et 67 kg en pleine surface u en lcalisatin avec la semence) et I'apprt de N en v6g6tatin (en pleine flraisn et au milieu du stade de remplissage des gusses). L'apprt de N a eu des effets variables sur la teneur en prt6ine du furrage; dans la miti6 des recltes, au mins un des traitements de fumure a entrain6 un accrissement significatif, bien que sans rdre ni raisn lgiques. Jusqu'h la dse de 15 kg N/ha, la fumure n'a pas influ6 sur la teneur en prt6ine des graines, mais la dse de 3 kg a dnn6 lieu h une augmentatin significative dans deux essais sur tris. La phase la plus active d'accumulatin de matidre sdche et d'absrptin de N a cmmenc6 vers la flraisn pur se pursuivre jusqu'au milieu du stade de remplissage des gusses. Dans sept essais, le N prvenant de la fixatin symbitique repr6sentait 54 7 dl N de cmpsitin des pusses, la prprtin variant de 63 d 71 7 dans cinq de ces essais, sit l'6quivalent de 54 d 11kg d'azte par hectare. La fumure N a diminu6 la fixatin symbitique dans tus les essais sauf un dnt la teneur en N assimilable 6tait trcs 6lev6e et ii la fixatin symbitique 6tait cmpldtement nulle. I hesent address (J. E. R.): Department f Land Resurce Science, University f Guelph, Guelph, Ontari NIG 2W1. Can. J. Sil Sci. 62t 2l-3 (Feb. 1982) I l $2. O 1982 Agricultural Institute f Canada 2l

2 22 CANADIAN JOURNAL OF SOIL SCIENCE Can. J. Sil. Sci. Dwnladed frm by n 11/26/17 Fr persnal use nly. Faba bean (Vicia faba L.) is an annual grain legume recently intrduced int Manitba in an attempt t diversify agriculture. Faba beans have the ptential t prduce large quantities f high-prtein grain (Evans et a ), the prductin f which requires large quantities f N. Fr example, in the United Kingdm, a seed yield f 482 kg/ha f faba beans cntained 229 kg N in the seed (McEwen 197). Richards (191'7) determined that 194 kg N/ha ttal plant N was required t prduce a 2 kg/ha seed yield cntaining 37 prtein. Of this 194 kg N/ha, 116 kg N/ha r apprximately 67 f ttal plant N was in the seed, 39 kg N/ha r 27 f the ttal plant N was cntained in leaves, stems and pds, and the remaining 39 kg N/ha was fund in plant rts. Faba beans btain their N frm inrganic sil surces, and when in assciatin with Rhizbium leguminsarium by symbitically fixing atmspheric N2 int plantusable frms. The symbitic relatinship in faba beans appears t be a vigrus ne. McEwen (197) and Sprent (1971) reprted that field-grwn faba beans in the United Kingdm required n fertilizer N fr attainment f ptential yield and prtein cntents. Richards and Sper (1919), using 15N techniques, reprted that faba beans grwn in a N-deficient sil in a grwth chamber experiment did nt respnd t fertilizer N. Faba beans which had nt received fertilizer N fixed 837 f their N requirements, with the sil supplying the remainder. Additin f fertilizer N t these faba beans decreased symbitic N, fixatin, the decrease being prprtinal t the amunt f N added. Faba beans, unlike sybeans (Glycine max. (L.) Merr.) (Sinclair and de Wit 1976), fix cnsiderable quantities f N2 during the pd-fill t senesence grwth stages. Richards and Sper (19'79) reprted that at least 28V f faba beans' ttal seasnal N was fixed after early t mid pdfill grwth stages. Sprent (191-l) als reprted faba beans capable f fixing N2 during later grwth stages. In the Canadian prairie, faba beans have been reprted t respnd t N additins. Seed yield f faba beans grwn n stubble in Manitba was increased by N applicatins up t 52 kglha, while seed yield f faba beans grwn in sil which had been summer fallwed the previus year was unaffected by N additins (Rgalsky 1972). In Saskatchewan, seed yield f faba beans grwn n barley stubble was increased 29V by the applicatin f 9 kg N/ha (Sadler 1975). The experiments reprted in this paper were cnducted t determine the effect f applied N n faba bean yield and prtein cntent thrughut the grwing seasn. and t determine the ability f faba beans t fix N2 symbitically under field cnditins in Manitba. MATERIALS AND METHODS Field trials were cnducted during 1973, 1974 and 1975 at nine lcatins in Manitba. Lcatins f trials, sil classificatin, and selected chemical and physical prperties f sils are presented in Table 1. Previus crps were cereals at all trials. Experimental design was a randmized cmplete blck with five replicatins and a varying number f treatments at all sites. Plt dimensins were 1.6 x 6 m in 19'73 and 19'74 field trials, and 1.6 x 9 m in 1975 field trials. A nine-rw duble-disc press drill with 18- cm rw spacing was used t sw faba beans. Depth f seeding was 1 cm and a seeding rate f 2 kg inculated seed (Nitragin Crp. Q. culture, Nitrgin Crp., Milwaukee, Wiscnsin 5329) per hectare was used. Ackerperle cultivar faba beans were swn at all 1973 field trials and at the 19'74 Altna field trial. In all ther field trials in 19'74 and in all field trials in 19'15, Diana cultivar faba beans were swn. In rder t insure adequate ndulatin' Nitragin Q (Nitragin Crp. Q. culture, Nitragin Crp.' Milwaukee, Wis.) culture inculum was applied in a slurry at 418 9/1 kg faba bean seed prir t seeding. Phsphrus, as mnammnium phsphate, was placed with the seed at 1 kg P/ha in 19'73. ln 1974 and 1975, P as triple superphsphate ryas placed with the

3 RICHARDS AND SOPER - N FERTILTZATTN F FABA BEANs 23 Can. J. Sil. Sci. Dwnladed frm by n 11/26/17 Fr persnal use nly. a q v) F q I9.8 -'- * v IJ] \/? E UeO?i:- 2'.,tu ZE r'5 z N 1 -l -> h6 9 q F U) r+$h\$-a9 r@ hhh * SSd* qtcl?tarcq r+r$*no 6n++ nnc) nd$h\n@n* -6:h@OhnA *ilnn-n n9qqqqqqcj F-r@Sr rr JJJJ-.1(,JJJ?3?Qa\?9u) t YaO i: la ^.8^ tg P"^ *"* E() 9t**tIe6; :6 3: :!;.F F :! E!:5; VA Y;\' -".=:A Fc=+l "y.=a-t$ l'j.:a di E= H dete : :: F:= I tr <6<,Zti<<EE --trtnnnn i-ri-rti\tt\t s-=s33*;ss Efr - -' Ea =6Pa, 5E ;i;se seed at 15 and 2 kg P/ha, respectively. In 1975, K, as KCl, was surface-bradcast at 1 kg K/ha at all sites where sils cntained less than 1 ppm NHTOAc exchangeable K. Sulfur, as CaSOa"2H2O, was surface-bradcast at 3 kg S/ha at the 1975 Teuln trial as sil test results indicated the pssibility f a S deficiency. Sils were examined and sampled at seeding. At each crner f the field trial, sil pits were dug and sil hrizn thickness, sil structure, clr and texture were examined. Sil samples fr chemical analysis were taken near sil pits and in several lcatins within the field trial prir t seeding. Sampling depths used were -15, l5-3, 3-6, 6-9, and 9-12 cm. Samples were frzen as sn after sampling as pssible and kept frzen until drying facilities became available. Samples were subdivided at time f drying. One subsample was air-dried at 3'C fr 4 days and was used fr P, K and S analysis while the ther subsample was ven-dried at 15'C fr 24 h and used fr NO3--N analysis. Nitrate-nitrgen cncentratins, NaHCO3-extractable P, NHaOAc-exchangeable K, SO4--S cncentratins, and ph f sils were determined by techniques then in use by the Manitba Sil Testing Labratry described by Fehr (1973). Nitrgen cntent f harvested plant material was determined by the mdified Kjeldahl-Gunning methd described by Bremner (1965). Nitrgen, as NH,NO3, was surface-bradcast after seeding. Rates applied differed amng years. In 1973, bradcast-n rates used were, 34, 6'1, and 22 kg N/ha. In 1974 field trials, N was surface-bradcast at, 3, 6, 9, 15 and 3 kg N/ha, and in 1975 at, 3, 9, and 15 kg N/ha. In additin, in 1973 field trials N was placed with the seed at 34 and 67 kg/ha. In 1975 field trials, the effect f midseasn N applicatins was investigated. One treatment received 9 kg N/ha when faba beans were in the full-blm grwth stage and anther treatment received 9 kg N/ha when faba beans were in the early pd-fill grwth stage. In all 1974 and 1975 field trials, barley (Hrdeum vulgare 'Cnquest') was swn as a cmparisn crp. Rates f N applied t barley plts were and 9 kg N/ha. At the Seven Sisters and Altna field trials in uninculated faba beans were swn. Rates f N applied t uninculated faba beans were, 9

4 24 CANADIAN JOURNAL OF SOIL SCIENCE Can. J. Sil. Sci. Dwnladed frm by n 11/26/17 Fr persnal use nly. and 3 kg N/ha. These treatments permitted cmparisn f the respnse f a cereal and an annual legume t sil and applied N, and prvided infrmatin whereby the amunt f N, symbitically fixed by ndulated faba beans culd be determined. Previus wrk (Richards and Sper 1979) had shwn that faba beans and barley extracted similar quantities f inrganic sil and fertilizer N. Symbitic N, fixatin f ndulated faba beans was therefre determined by subtracting N cntent f barley shts frm the N cntent f ndulated faba beans shts. Barley was harvested at physilgical maturity. The effect f N fertilizatin n rate f grwth and nutrient uptake was determined by biweekly vegetative sampling f faba beans treated with and 9 kg N/ha at Altna and Seven Sisters in 19'74 and at Carman in Sampling cmmenced 3 wk after seeding and cntinued biweekly until grain harvest. In additin, midseasn vegetative samples f all N applicatln treatments were taken at all sites tn l9'74 and In 1974 field trials, vegetative samples were taken at the pre-blm and pstblm stages f grwth, as we had cnsidered that N demand wuld be greatest during this interval. Based n results btained frm 1974 cntinuus sampling f faba beans treated with and 9 kg/ha, hwever, midseasn harvests in 1975 field trials were cnducted at the fullblm and early pd-fill grwth stages. Samples fr grain and straw yield were taken at maturity frm all N fertilizer treatments. All samples were hand-harvested, and sampling size used was I m2. Plant samples were ven-dried at 7"C fr 24 h. Samples were weighed, and grund t pass thrugh a 2-mm sieve. A statinary thresher was used t separate seed frm straw in grain samples and weights f seed and straw were recrded. The straw samples were then bulked prir t chemical analysis. The cnversin factr used t cnvert percent N t percent prtein was 5.7. RESULTS Average faba bean seed yield was 1643 kg/ha and ranged frm 61 t 3645 kg/ha in inculated plts. Seed yield was generally unaffected by spring-applied N (Tables 2-4). The nly exceptin was at Seven Sisters where the 3 and 3 kg N/ ha applicatin rates significantly increased Table 2. Yield and prtein cntent f faba bean seed in Bt B 34 D+ 67D B 34D 67D N applied (kg/ha) Seed yield (kg/ha) (7") Carberry 34'76 ae 3465 a JZt4A 3339 a 311 a 3443 a Carman 2871 a 2719 a 2971 a 291 a 2593 a 2456 a Seed prtein ' tb - N surface-bradcast after seeding. t D : N drilled in with seed. a$ Numbers fllwed by same letter within clumns are nt significantly different at P :.5 by Duncan's new multiple range test. Values in clumns may be cmpared nly at each lcatin. seed yield (Table 3). Midseasn applicatins f 9 kg N/ha applied at either fullblm r early pd-fill grwth stages had n effect upn seed yield (Table 4). In 1913, 34 and 61 kg N/ha placed with faba bean seed had n effect upn seed yield (Table 2). The quantity f available sil N, as measured by NO3--N cntents at seeding, had n discernable effect upn faba bean seed yield. Fr example, in 1973, seed yield and faba beans at Carman was 237 less than the yield f faba beans at Carberry, even thugh the sil at Carman cntained 2.1 times mre NO3--N t 12 cm than did the sil at Carberry. Faba bean frage material was harvested at the pre-blm and pst-blm grwth stages in 1974 trials and at the full-blm and early pd-fill grwth stages in 1975 field trials. Regardless f harvest stage, faba bean frage yields were nt increased by N fertilizatin (Tables 3 and 4). The nly exceptin was at the pre-blm harvest at Pilt Mund in 1974 where yield f faba beans which had received 6 kg N/ha was significantly higher than yield

5 RICHARDS AND SOPER - N FERTILIZATION OF FABA BEANS 25 Table 3. Frage and seed yields and prtein cntents f faba beans grwn in 1974 Can. J. Sil. Sci. Dwnladed frm by n 11/26/17 Fr persnal use nly. Faba bean experimenl Ndulated Ndulated heblm Nnnndulated Nnndulated Ndulated N applied (kg N/ha) n Pstblm '791 a 915 a 921 a 12 a 148 a 987 a 415 a 698 a '712 a 896 ab 82 ab 762 a 83 ab 841 ab r2r b 912 a 985 a 963 a 824 a 992 ab l1't9 b 913 ab 1129 ab 1O4O ab Yield (kg/ha) Altna 221 ab '745 a 2488 ab 6'7 a 235 ab 95 a 1925 a 85 a 2122 ab 975 a 2'798 a 97 a '722 a 73 a 1257 b 19 a 1994 c 513 b Seven Sisters 381 c l48l a 4226 a 18'7'7 a 4828 a l'7l'7 ab 3923 a 1483 a 4543 a l'78 ab 43 a 1859 b 385 a 645 a 3292 a 1145 b 3528 a 1592 c Pilt Mund 3521 a 1669 ab 2975 a 137 a 2982 a 1863 b 2934 a 1246 a 3886 a 1562 ab 3399 a 1562 ab Prteint Pre-blm Pst-blm (7) (V) 2.O c 19.9 c 18.8 bc 17.6 a 18.7 ab 17.8 ab 12. a r3.'7 b 16.1 c 21.2 a 22.2 ab 24.1 b 22.2 ab 22.6 ab 22.3 ab 2.2 a 2O. a 22.'.7 b 2.4 ab 19-6 a 21.3 b 2.6 ab 21.1 b 19.6 a 12.'7 a l5.l rs.3 b Seed (v) 31.8 bc 28.6 a 3.s D 13.9 ab 32.4 c 14.4 ab 32.6 c 15.6 b 33.r d 1.4 a 28.7 a 11.5 a 28.8 a 13.9 a 32. b 16.'l ab 29.1 a 16.l a 29.3 ab 16.4 ab 29.5 ab 18. bc 29.5 ab l'l.l b 29.6 ab 2.6 c 3.3 b 9.5 a 24.3 a 14.2 b 26.8 b 2.5 c 3.5 c 12.7 a 22.'7 ab 11.9 a 22.1 a 12. a 21.7 a 14. a 24.3 b 13.3 a 23.3 ab 13.2 a 22.5 ab t Prtein calculated n ven-dry misture basis: factr used t cnvert V N a 7a prtein was 5.7. a-c Numbers fllwed by same letters within clumns are nt significantly different at P :.5 by Duncan's new multiple range test. Numbrrs in clumns may be cmpared nly within each experiment. f faba beans which had received n fertilizer N (Table 3). This effect was nt present in the pst-blm harvest. Faba bean seed prtein cntents were high, ranging frm 21.7 t Larye variability ccurred within and amng field trials (Tables 2-4). Generally, seed prtein cntents were nt affected by N up t 15 kg/ha. Hwever, when N was applied at 3 kg/ha in 1974 seed prtein cntent was significantly increased at tw ut f the three sites (Table 3). Prtein cntent f faba bean frage material was variably affected by N fertilizatin. In three ut f six cases in 1974 (3 field trials x 2 sample dates) and in fur ut f the eight cases in 1975 prtein cntent f faba bean frage material was significantly increased by ne f the N fertilizatin treatments (Tables 3 and 4). N relatinship between bserved prtein respnse and frage yield is evident and n relatinship between prtein respnse and specific rates f applied N ccured. In biweekly harvests cnducted frm 3 wk after seeding t senescence at the Altna and Seven Sisters sites in 1974 and at the Carman site in 19'15, neither yield nr N uptake by faba beans was significantly affected by applied N. Based n this, data frm the - and 9-kg N/ha treatments were cmbined and used t de-

6 26 CANADIAN JOURNAL OF SOIL SCIENCE B B B B B B CI ll lj i3 B.S.A CJ A C IJ C B $ B -1 n-9qq '-'qnap9 1c-{T9qq q9qlan O6A6OA N*NNN *- OO*O,6 dndmd 66 NNNN Can. J. Sil. Sci. Dwnladed frm by n 11/26/17 Fr persnal use nly. E >,N ^^ 5S!\ a.92 E zta Od\O\O h@ I I B B ql qj \J-S! (l $r\ *n*- n66 -c]h* s c \l s c! B B s B Ba-b B B's-A \qgq I r qclgt!nnr:.iq19 I I N* **Ni s+ -6$:i dnnoi NNNN NdNd NdNN Nh$ N*i dsn NNdN sssb cbbs, +.+ r -r I r -don, rnn- 6nc) N6NN 66 N B\JS- CS$ll $\JBn BSS 883d,, SFFE r r K$KF r r 883$, ' n6 fi -=9-6@r a +# OhO,O, \ :st* S -i:i ab. N F-.r q sis::sll!ljs sijbbssscssbb\l ra h$c) a!t*- Nrr*F-d :s9!.r6 6:56F N@N* +NN- r r nnn$$* -n O \O --rttttttl 6ha +# n66 O6n6O\ ;t; a{ 3 A,s) E :1J-; XQ- d B; a P = I h: 9i+ > 99 ) c <cy h ZZe* s sf 6 E EZ-,9.9,, > +S B tr

7 RICHARDS AND SOPER - N FERTII,IZATION OF FABA BEANS 27 Can. J. Sil. Sci. Dwnladed frm by n 11/26/17 Fr persnal use nly. velp mathematical mdels describing yield and N uptake frm seeding t senescence f faba beans grwn at the Seven Sisters site. The mdels are: Yield (tnne/ha) : 1.441( e 88t) N uptake (kg N/ha) : 25l( '2e-EEt) where / : time f harvest (days after seeding). The yield and N uptake mdels have cefficients f determinatin f.932 and.915, respectively, and are significant at P :.1. Yield and N uptake curves calculated frm the mdel tgether with the means f 1 bservatins fr each sample date are shwn in Fig. 1. Maximum dry matter accumulatin and N uptake cmmenced at the pre-blm t fullblm grwth stages and ceased during the interval between early pd-fill and mid pd-fill (Fig. l). The perid f maximum N uptake cmmenced befre that f dry matter accumulatin. c E *-- N UPTAKE - YIELD In 19'14 and 1975, barley was used t measure available sil N. Uninculated faba beans were swn at the Altna and Seven Sisters trials in 1914 allwing a cmparisn f N uptake by barley and faba beans. Barley and uninculated faba beans which received n fertilizer N cntained similar quantities f sht N (Table 5). At Altna, abvegrund plant prtins f uninculated faba beans and barley which had received 9 kg N/ha cntained similar quantities f N. Barley grwn at Seven Sisters did nt respnd t applied N while uninculated faba beans did, illustrating the faba bean's higher N requirement. Thus, cnsiderable differences in N uptake by N-fertilized barley and uninculated faba beans ccurred at Seven Sisters (Table 5). Hwever, based n N uptake by N- unfertilized barley and uninculated faba beans, results shw that faba beans were as adept as barley in extracting sil N. The quantity f N in faba bean shts 'Itrn G' c. 1 ; I 5 J z Time frm seeding (days) Fig. 1 Relatinship between N uptake and dry matter accumulatin by ndulated faba beans at the Seven Sisters field trial. P : pre-blm grwth stage; F : full-blm grwth stage; E : early pd-fill grwth stage; M : mid pd-fill grwth stage; S : senescence.

8 28 CANADIAN JOURNAL OF SOIL SCIENCE Table 5. Cmparisn f nitrgen uptake by barley and uninculated faba bean shts at maturity in 1974 field trials Sht nitrgen uptake (kg N/ha) Field trial lcatin Can. J. Sil. Sci. Dwnladed frm by n 11/26/17 Fr persnal use nly. Nitrgen applied (ke/ha) 9 3 Uninc. faba beans Seven Sisters Barley derived frm symbitic fixatin was calculated by the fllwing methd. S:P-B where S : quantity f N derived frm symbitic N2 fixatin in faba bean shts (kg N/ha); P : ttal faba bean sht N (kg/ ha); and B : cntributin f sil N as measured by quantity f N (kg/ha) in barley shts. The prprtin f faba bean N derived frm symbitic fixatin in 1974 and 1975 field trials is presented in Table 6. Faba beans which had received n fertilizer-n derived, n the average, 54V f their abvegrund N by symbitic fixatin (Table 6). Hwever, in five ut f seven field trials symbitic N, fixatin accunted fr 63-llv f sht N. The lw value f symbitically fixed N2 at the Zhda site in 1975 was caused by pr grwth. The Uninc. faba beans Altna Barley aa lw value at Carman in 19'75 was caused by plant-available sil NO:r--N being present in quantities in excess f that required fr maximum faba bean grwth (Table 1). Nitrgen fertilizatin tended t decrease the quantity f N2 fixed faba beans. Fr example, in 1974 at Seven Sisters the prprtin f sht N derived by N2 fixatin was reduced frm 63 I 4lV and subsequently t l47a by the additin f 9 and 3 kg N/ha, respectively. DISCUSSION The large variatin in yield and prtein cntents which ccurred amng the trials in 1974 and 1915 was shwn t be due t differences in sil misture and ambient temperature (Keatinge and Shaykewich 1917). Keatinge and Shaykewich (1977) reprted that the single mst imprtant factr influencing differences in faba bean grwth amng trials was ambient temperature, with temperatures abve 2C during flwering ptentially causing prema- Table 6. Effect f nitrgen applicatins n percent f ttal faba bean sht nitrgen derived frm symbitic fixatin in field trials, l9'74, 1975 Nitrgen applied (kg/ha) 9 3 Altna Percent f faba bean aerial nitrgen derived frm symbrsts Seven Sisters t4 Pilt Mund 68 at Field trial lcatins Carman St. Claude '71 25 Teuln tl 48 JI

9 Can. J. Sil. Sci. Dwnladed frm by n 11/26/17 Fr persnal use nly. ture pd,"'"i";.^:;." ;""",;; maximum temperature in Manitba is 26-28'C, cinciding with the time at which pd frmatin ccurs, Keatinge and Shaykewich's (1911) results explain the inability f faba beans t prduce cnsistently high seed yields in ur experiments. Generally, frage and seed yields f ndulated faba beans were nt affected by applied N. Neither surface-bradcast applicatins up t 3 kg N/ha at seeding nr N fertilizer up t 67 kg Niha placed with the seed resulted in increased seed yields. Applicatins f 9 kg N/ha at fullblm r at early pd-fill grwth stages, stages in which N uptake and grwth were determined t be at a maximum, had n effect upn seed (Table 4). Data indicate that sufficient sil and symbitic fixed N were available t the faba bean during the grwing seasn fr attainment f ptential grwth and seed yield under cnditins tested. Althugh in 5V f the cases mnitred, prtein cntent f faba bean frage material was significantly increased by a N applicatin treatment, n cnsistent N respnse pattern ccurred. N relatinship between prtein respnse and specific rates f N ccurred. The reasns fr the respnses are nt apparent, but culd be due, in part, t the large variability which ccurred in vegetative samples. It shuld be nted that in n case was there a significant prtein cntent difference between faba beans treated with and 9 kg N/ha which were harvested biweekly thrughut the grwing seasn fr yield and N uptake data. Results btained frm ur field trials shwed that uninculated faba beans and barley extracted similar quantities f sil N. Previus wrk cnducted in a grwth chamber using 15N shwed that ndulated faba beans and barley recveted similar quantities f applied N (Richards and Sper 1979). Based n these findings, N uptake by field-grwn, uninculated faba beans and barley was cnsidered t be similar FERTILIZATION OF FABA BEANS 29 t N uptake by ndulated faba beans. This assumptin allwed calculatin f amunt f N symbitically fixed by field-grwn faba beans, and determinatin f the effect f applied N n Nz fixatin. In ur experiments, faba beans were efficient symbitic N2 fixers, fixing between 63 and llt f their abvegrund N in five ut f the seven field trials mnitred (Table 6). Thugh the prprtin f sht N was relatively cnstant at the five sites, actual quantities f N2 symbitically fixed varied frm 54 t I 1 I kg N/ha. Similar results, determined by the acetylene reductin technique, were reprted by Dean and Clark (19'77) in Manitba. Yield and prtein cntent f inculated faba beans which had nt received applied N were similar t thse f uninculated faba beans fertilized with 3 kg N/ha at seeding. Thus, in these tw cases, the quantity f N2 symbitically fixed by ndulated faba beans was rughly equivalent t a fertilizer applicatin f 3 kg N/ha. These results suggest that, in a crp rtatin, the large ptential f faba beans fr fixing N2 is best realized when they are grwn in a N-deficient sil. Thus, the prbability f btaining a grain yield r prtein respnse t applied N in Manitba is lw. BREMNER, J. M Ttal nitrgen. Pages in C. A. Black, ed. Methds f sil analysis. Part II. Chemical and micrbilgical prperties. Agrnmy 9. Am. Sc. Agrn., Madisn, Wis. DEAN, J. R. and CLARK, K. W Ndulatin, acetylene reductin and yield f faba beans as affected by inculum cncentratin and sil nitrate leve1. Can. J. Plant Sci. 57: EVANS, L. E., SEITZER, J. F. and BUSKUK, W Hrsebeans - a prtein crp fr Western Canada? Can. J. Plant Sci. 52: FEHR, P Nutrient requirement tables. Guides t the interpretatin f sil analysis as apprved by Manitba Sil Advisry Cmmittee. Mimegraphed material. Prvincial Sil Testing Labratry, Dep. f Sil Sci., Univ. f Manitba, Winnipeg, Man.

10 3 CANADIAN JOURNAL OF SOIL SCIENCE Can. J. Sil. Sci. Dwnladed frm by n 11/26/17 Fr persnal use nly. KEATINGE, J. D. H. and SHAYKEWICH, C. F Effects f the physical envirnment n the grwth and yield f field beans (Vicia faba minr) in the Canadian prairie. J. Agric. Sci. 89: McEWEN, L 197. Fertilizer nitrgen and grwth regulatrs fr field beans (Vicia faba L.) I. The effects f seed bed applicatins f large dressings f fertilizer nitrgen and residual effects n fllwing winter wheat. J. Agric. Sci. 74: RICHARDS, l. E. 19'17. The effect f fertilizer nitrgen n yield, crude prtein cntent, and symbitic fixatin in Vicia faba L. var. minr. M. Sc. Thesis submitted t the Faculty f Graduate Studies and Research, Univ. f Manitba, Winnipeg, Man. RICHARDS, J. E. and SOPER, R. J Effect f N fertilizer n yield, prtein cntent, and symbitic N fixatin in fababeans. Agrn. J. 71: ROGALSKY, J. R. 19'12. Summary f fababean fertility trials. Papers presented at the 16th Ann. Man. Sil Sci. Meeting, Univ. f Manitba, Winnipeg, Man. pp. 169-l'7. SADLER, J. M Sil, fertilizer and symbitically-fixed nitrgen as surces f nitrgen fr fababeans under prairie cnditins. Papers presented at the 19th Ann. Man. Sil Sci. Meeting, Univ. f Manitba, Winnipeg, Man. pp SINCLAIR, T. R. and de WIT, C. T Analysis f the carbn and nitrgen limitatins t sybean yield. Agrn. J. 68: , SPRENT, JANET I. and BRADFORD, ALISON M Nitrgen fixatin in field beans (Vicia faba) as affected by ppulatin density, shading and its relatinship with sil misture. J. Agric. Sci. (Camb.) 88:

11 This article has been cited by: Can. J. Sil. Sci. Dwnladed frm by n 11/26/17 Fr persnal use nly. 1. Erik S. Jensen, Mark B. Peples, Henrik Hauggaard-Nielsen. 21. Faba bean in crpping systems. Field Crps Research 115:3, [Crssref] 2. C. Aguilera-Diaz, L. Recalde-Manrique Effects f plant density and inrganic nitrgen fertilizer n field beans ( Vicia faba). The Jurnal f Agricultural Science 125:1, 87. [Crssref] 3. P. Ranalli Imprvement f pulse crps in Eurpe. Eurpean Jurnal f Agrnmy 4:2, [Crssref] 4. E. S. Jensen Symbitic N2 fixatin in pea and field bean estimated by15n fertilizer dilutin in field experiments with barley as a reference crp. Plant and Sil 92:1, [Crssref] 5. V.D. Wassermann, Gillian Heyns, A.J. Kruger Effect f nitrgenus fertiliser n the yield f varius annual fdder legumes ndulated by effective rhizbia. Prceedings f the Annual Cngresses f the Grassland Sciety f Suthern Africa 18:1, [Crssref]