Tropil Grsslnds (23) Volume 37, 11 19 11 Nitrogen fixtion nd growth of owpe (Vign unguiult) nd ym en (Phyrhizus erosus) in sodi soil s ffeted y gypsum nd sulphur inoulted with Thioillus nd rhizoil inoultion N.P. STAMFORD, A.D.S. FREITAS, D.S. FERRAZ, A. MONTENEGRO AND C.E.R.S. SANTOS UFRPE Deprtment of Agronomy, Reife, Brzil Astrt A greenhouse experiment ws rried out to evlute the effets of pplying gypsum nd sulphur inoulted with Thioillus, on nitrogen fixtion nd growth of owpe nd ym en, inoulted with speifi rhizoil strins. A Neosol Fluvi Sli sodi soil from the Brzilin semi-rid region ws sumitted to tretments onsisting of sulphur inoulted with Thioillus (.6, 1.2 nd 1.8 t/h) nd gypsum (1.8 nd 3.6 t/h). A ontrol tretment hd no sulphur or gypsum pplied. Cowpe nd ym en were inoulted with Brdyrhizoium strins NFB 7 nd NFB 45, respetively, seleted for sline onditions. Tretments without rhizoi were inluded s ontrols. Sulphur with Thioillus ws more effiient thn gypsum, in reduing soil ph, eletril ondutivity (EC) nd exhngele sodium. Sulphur with Thioillus redued ph (8.2 to 4.7) nd E C of the soil sturtion extrt (15.3 to 1.7 ds/m) to vlues elow those dopted in sline nd sodi soil lssifitions. Nodultion, dry mtter prodution nd nitrogen nd sodium uptke were ffeted y the meliornts. Rhizoil inoultion with speifi strins ws very effetive nd, when pplied with soil meliornts, inresed nodultion, totl nitrogen nd shoot dry mtter yield in oth legumes. Correspondene: Prof. Newton P. Stmford, Ru Jder de Andrde, 335 Cs Forte, 5261-6 Reife, Brzil. Emil: newtonps@fstmodem.om.r Introdution The glol popultion nd the orresponding need for griulturl produts hve stimulted need to inrese the produtivity of pstures nd field rops. In mny res of the tropis, espeilly in rid nd semi-rid regions, niml prodution is limited y widespred defiieny of protein, prtiulrly in res with prolonged dry seson. The use of legume speies to provide nitrogen to the system nd to supply protein n inrese niml prodution without pplition of nitrogen fertilisers. Slinity is one of the most importnt proesses whih depress plnt produtivity in semi-rid regions, nd the sustinility of griulture depends on the ontrol of slt onentrtion in the soil profile (Ayrs et l.1993). Severl studies hve een rried out to evlute the effet of slinity on growth of ommeril rops nd the pplition of meliornts in soil relmtion nd to estimte the effets in soils nd on produtivity nd qulity of pstures nd field rops (Miymoto et l. 1986; Hoffmn et l. 1989; Ayrs et l. 1993; Shlhevet et l. 1995; Frnçois 1996). More thn 4 M h of Brzilin soils hve een ffeted y slinity (Szols 1989) nd potentilly there re out 9 M h of sline nd sodi soils in north-est Brzil, e.g. solonetz, solonhk, lluvil sline nd solodi soils (Pereir et l. 1985). Irrigtion is the most vile option to inrese plnt yield in the Brzilin semi-rid region, due to the ourrene of frequent wter defiits in soils nd plnts in drought periods. Thus, the use of sline wters ertinly ontriutes to soil slinity, through the grdul proess of slt umultion (Ghssemi et l. 1995). Exess slt redues plnt development, inreses the energy required for nutrient nd wter sorption, nd indues iohemil djustment for survivl under stress onditions
12 N.P. Stmford, A.D.S. Freits, D.S. Ferrz, A. Montenegro nd C.E.R.S. Sntos (Rhodes et l. 1992). Sodi nd sline-sodi soils re frequently physilly degrded, showing hemil hnges tht n lter nutrient umultion in plnts promoting defiieny of some elements nd toxiity from others (Nidu nd Rengsmy 1993). The hemil soil meliornts used in sline nd lkline soils disple sodium nd other ions of the soil exhnge omplex nd leh these tions from the soil profile (Miymoto nd Enriquez 199; Armstrong nd Tnton 1992). When elementl sulphur is used, speies of Thioillus (sulphur oxidtive teri) use iologil retion in soil whih produes sulphuri id nd redues soil ph (Gri Júnior 1992). In soil solution, the dissoited hydrogen ions n disple the sodium from ly prtiles therey promoting its susequent lehing nd reduing the soil sodiity (Rupel nd Turo 1973). The proess of iologil nitrogen fixtion in legumes grown in sline soils t higher tempertures needs to e evluted, espeilly in tropil legumes suh s owpe (Vign unguiult) nd ym en (Phyrizus erosus). The ltter speies is tuer legume originting in Mexio nd the Amzon region. It is dpted to semi-rid onditions, yields protein nd omestile tuers to e used in humn nd niml nutrition (Sorensen 1996) nd n produe higher iomss without ddition of nitrogen fertiliser, when inoulted with speifi nd effetive rhizoil strins (Kjer 1992; Cruz et l. 1997). There is no dout tht the effetiveness of rhizoil strins is importnt. It is ritil tht n understnding is generted of the effets of soil ph nd exhngele sodium on nodultion if we re to understnd the potentil for plnts to fix nitrogen under sline onditions (Stmford et l. 2). The min ojetive of this study ws to evlute the nitrogen fixtion nd growth of owpe nd ym en legumes inoulted with speifi nd effiient strins of Rhizoi in sodi soil mended with sulphur inoulted with Thioillus teri, nd gypsum, nd the intertions etween rhizoil strins nd the meliornts. Mterils nd methods Plnt nd soil hrteristis The experiment ws rried out in greenhouse ontrolled t temperture 3 35 C. The tropil legumes, owpe (Vign unguiult) v. IPA 26 nd ym en (Phyrhizus erosus) from IAC (Cmpins), were used s test plnts. Seeds were surfe-sterilised with 95% ethnol for 1 min, wshed 6 times with sterilised wter, soked overnight to imie wter, nd plnted in trys ontining mixture of pet nd vermiulite (2:1 rtio, w/w). Ten dys lter the seedlings were trnsplnted into pots (2 seedlings/pot). A Neosol Fluvi Sli sodi soil with medium texture (EMBRAPA 1999), from the irrigted re in the Distrit of Pesqueir, semi-rid region loted in Pernmuo Stte in north-est Brzil ws used. Smples were olleted from the 3 m lyer. After sieving (5 m sieve), the smples were mixed nd 5 kg susmples pled in ly pots to minimise the therml shok resulting from exessive exposure to solr rdition. Anlyses of soils, using the EMBRAPA (1997) methodology, re shown in Tle 1. Tle 1. Chemil nd physil ttriutes of the Neosol Fluvi Sli sodi soil of the Brzilin semi-rid region used in the study. Chrteristi / Attriute Soil Exhngele elements (mmol /kg) N + 156 K + 6 C 2+ 22 Mg 2+ 64 Al 3+ ph 1:2.5 (H 2 O) 8.2 P-ville (mg/kg) 9 N totl (mg/kg).9 Eletril ondutivity (ds/m) 15 Porosity (%) 42 Field pity (%) 2 Density (g/m 3 ) 1.5 Hydruli ondutivity (m/h). Texturl lss medium texture Soil meliornts The soil smples were treted with gypsum s CSO 4. 2H 2 O nd elementl sulphur inoulted with the sulphur-oxidising teri Thioillus thiooxidns nd T. ferrooxidns t the sme onentrtions of vile ells (1 6 /ml). Bteril ultures were grown in 125 ml Erlenmeyer flsks using medium 9K (Gri Junior 1991) for 5 dys t 18 rpm in horizontl shker t 3 C. Inoultion ws pplied t rte of 1 ml/g of sulphur. To otin est results for teril oxidtion, the soil ws inuted for 3 dys nd wtered dily using slightly sline irrigtion wter
Soil meliornts for legumes on sline soils 13 soure (.2 ds/m) ontining N +, Mg 2+, C 2+, K +, Cl nd HCO 3, in mount similr to those in the wter used y frmers for irrigtion in the Pesqueir distrit. During the inution period, suffiient wter (2 L/pot) ws pplied, t intervls of 15 dys, to use lehing of slts, prtiulrly sodium. The rtes of gypsum nd sulphur were lulted ording to Brros nd Mglhães (1989), djusted ording to previous ssys (Stmford et l. 2) nd soil hemil nlyses onduted efore the inution period. The rtes of meliornts pplied were:.6, 1.2 nd 1.8 t/h of elementl sulphur; nd 1.8 nd 3.6 t/h of gypsum. There ws ontrol tretment with no sulphur or gypsum pplied. Seed inoultion nd experimentl onditions Seeds of owpe nd ym en were inoulted with speifi rhizoil strins seleted s effetive in previous lortory experiments under sline onditions. Cowpe ws inoulted with strin NFB 7 nd ym en with NFB 45 with vile ells in liquid ulture (YM) greter thn 1 8 /g of pet inoulnt. The liquid ulture ws pplied t 1 ml/pot in tretments with rhizoil inoultion. After 9 dys of the experimentl period, the soil in eh tretment ws ssessed to determine ph (H 2 O), exhngele sodium nd luminium, nd eletril ondutivity (EC) following the EMBRAPA (1997) methodology. Soil wter ws kept t 8% of field pity (pot pity), fter the inution period, monitored y dily weighing, using wter with E C.2 ds/m. Plnts of owpe nd ym en were hrvested 6 nd 9 dys, respetively, fter trnsplnting nd dry weight of nodules nd shoots plus nitrogen nd sodium onentrtions in shoots (Mlvolt et l. 1989) were determined. Results Soil ph, exhngele sodium nd luminium nd eletril ondutivity The effet of the meliornts on soil ph, exhngele sodium nd luminium, nd eletril ondutivity re presented in Tle 2. As there were no speies soil meliornt intertions, vlues re the verges otined for owpe nd ym en. Applying meliornts signifintly (P<.5) deresed ph nd exhngele sodium. While meliornts lowered eletril ondutivity, the effet ws signifint only for the highest rte of sulphur. Soil meliortion with elementl sulphur inoulted with Thioillus signifintly (P =.5) lowered soil ph, nd resulted in the presene of solule luminium, proly due to soil idifition y the sulphuri id formed during sulphur oxidtion promoted y Thioillus, nd following displement of Al +3. The effet ws diretly proportionl to the level of S pplied, nd ould e hrmful to nitrogen fixtion nd plnt growth (Stmford et l. 22). Tle 2. Soil ph, eletril ondutivity, exhngele sodium nd luminium in soil extrt with pplition of gypsum nd sulphur inoulted with Thioillus. Soil meliornt Soil nlyses ph (H 2 O) N + Al +3 E C (mmol / kg) (mmol / kg) (ds/m) Sulphur (.6 t/h) 7.1 1 12.6. 4.6 Sulphur (1.2 t/h) 5.2d 8.1.2 3.5 Sulphur (1.8 t/h) 4.7e 6.8.4 1.7 Gypsum (1.8 t/h) 7.6 12.5. 3.9 Gypsum (3.6 t/h) 7.2 3.5. 4.3 Control (unmended) 8.2 12.6. 9.9 C.V. (%) 2.2 17.9 21.6 1 Within olumns, vlues followed y different letters re signifintly different t P =.5, using the Tukey test. Sttistil nlysis The experiment ws rrnged in ompletely rndomised ftoril design with 4 replitions. An ANOVA ws performed on the dt using the softwre Snest (Zont et l. 1982) nd mens were ompred y the Tukey test t proility P =.5 (Silv nd Silv 1982). Smller vlues of E C in the soil sturtion extrt were otined in soil (Tle 2) when sulphur inoulted with Thioillus ws pplied (1.7 ds/m), resulting in rtes elow the limit for lssifition s sline soil (4. ds/m) (Rihrds 1954).
14 N.P. Stmford, A.D.S. Freits, D.S. Ferrz, A. Montenegro nd C.E.R.S. Sntos Nodules nd shoot dry mtter Dry mtter yields of nodules on owpe nd ym en following pplition of meliornts with nd without rhizoil inoultion re presented in Figure 1. Cowpe filed to nodulte in the sene of soil meliornts regrdless of the pplition of rhizoi. When soil meliornts were pplied, level of nodultion inresed espeilly when rhizoi were pplied. Highest levels of nodultion ourred with 6 kg/h sulphur plus Thioillus or 1.8 t/h gypsum. Higher levels of pplied sulphur signifintly suppressed nodule prodution. Ym en produed no nodules in the tretment without rhizoil inoultion regrdless of wht soil meliornts were pplied nd did not nodulte in the ontrol tretment with rhizoi. When soil meliornts were pplied with rhizoi, vrying levels of nodultion ourred with the est result when 1.8 t/h gypsum ws pplied. As for nodultion, there were speies rhizoi soil meliornt intertions for shoot prodution (Figure 2). Despite the sene of nodultion without inoultion, ym en grew well. Tretments whih reeived sulphur plus Thioillus S 6 S 12 S 18 G 18 G 36 Control Nodule dry mtter (mg/plnt) 25 2 15 1 5 Ym en d Nodule dry mtter (mg/plnt) 8 7 6 5 4 3 2 1 Cowpe Without inoulnt With inoulnt d Figure 1. Effet of sulphur (S) t 6, 12 nd 18 kg/h inoulted with Thioillus nd gypsum (G) t 18 nd 36 kg/h on dry mtter yield of nodules on owpe nd ym en with nd without rhizoil inoultion. Within topis, olumns rrying different letters re signifintly different t P =.5, using the Tukey test. CV for the legumes: ym en = 35.1%; owpe = 16.%.
Soil meliornts for legumes on sline soils 15 outyielded the ontrol nd gypsum tretments. When inoulnt ws pplied, ll soil meliornts produed signifint growth responses. In the sene of soil meliornts, owpe grew poorly. Applition of gypsum produed signifint growth responses with etter growth when inoulnt ws pplied. When sulphur plus Thioillus ws pplied, growth responses ourred with level of response inversely relted to level of S dded. Sodium nd nitrogen uptke The sodium onentrtions nd totl nitrogen yields in owpe nd ym en shoot dry mtter following pplition of either sulphur inoulted with Thioillus or gypsum, nd rhizoil inoultion re presented in Figures 3 nd 4. Overll, sodium onentrtion in oth speies ws redued when soil meliornts were pplied. Cowpe in the ontrol tretment showed higher levels of sodium (1.4 mg/kg) thn ym en (.5 mg/kg). Totl N uptke in shoots of owpe ws signifintly inresed y rhizoi in the presene of soil meliornts. Best results were otined with the lowest level of sulphur plus Thioillus or either level of gypsum. Applition of higher levels of sulphur lowered totl N. Ym en responded to rhizoil inoultion in the pres- S 6 S 12 S 18 G 18 G 36 Control Shoot dry mtter (g/plnt) 6 5 4 3 2 1 Ym en d d Shoot dry mtter (g/plnt) 5 4 3 2 1 Cowpe Without inoulnt With inoulnt d Figure 2. Effet of sulphur (S) t 6, 12 nd 18 kg/h inoulted with Thioillus nd gypsum (G) t 18 nd 36 kg/h on shoot dry mtter of owpe nd ym en with nd without rhizoil inoultion. Within topis, olumns rrying different letters re signifintly different t P =.5, using the Tukey test. CV for the legumes: ym en = 11.7%; owpe = 2.8%.
16 N.P. Stmford, A.D.S. Freits, D.S. Ferrz, A. Montenegro nd C.E.R.S. Sntos ene of soil meliornts. Totl N in shoots of owpe on the etter tretments ws muh greter thn tht in ym en. Disussion This study hs provided vlule informtion on the growth of owpe nd ym en legumes on sline soils, nd the impt of pplying either gypsum or sulphur inoulted with Thioillus, nd the intertion etween these soil meliornts nd rhizoil inoultion. The positive impt of oth gypsum nd sulphur with Thioillus on produtivity of oth legumes, espeilly in the presene of pproprite rhizoil ultures, holds gret promise for improving output from sline soils. The ft tht the lower levels of oth soil meliornts produed exellent results ugers well for the prtil pplition of this tehnology. It is signifint tht ym en grew well in the sene of ny rhizoil inoultion. This ourred even though the plnts filed to nodulte. While ym en responded well to the pplition of oth sulphur nd gypsum, the response to oth soil meliornts ws greter when rhizoi were pplied. This ws ssoited with signifint nodultion ut not in the untreted soil S 6 S 12 S 18 G 18 G 36 Control Sodium onentrtion (mg/kg).6.5.4.3.2.1 Ym en Sodium onentrtion (mg/kg) 1.6 1.4 1.2 1..8.6.4.2 Cowpe Without inoulnt With inoulnt Figure 3. Effet of sulphur (S) t 6, 12 nd 18 kg/h inoulted with Thioillus nd gypsum (G) t 18 nd 36 kg/h on sodium onentrtion in owpe nd ym en with nd without rhizoil inoultion. Within topis, olumns rrying different letters re signifintly different t P =.5, using the Tukey test. CV for the legumes: ym en = 21.8%; owpe = 15.7%.
Soil meliornts for legumes on sline soils 17 with rhizoil pplition. It is ovious tht soil meliornts will enhne growth of ym en on sline soils. Nturlised rhizoi for ym en re not present in the soil nd pproprite rhizoi should e pplied when plnting ym en on these sline soils, ut only if soil meliornts re pplied. In ontrst, owpe grew poorly on these soils in the sene of ny dditives, inditing poorer tolerne of slinity thn ym en. While owpe responded to the pplition of soil meliornts, it ws more sensitive to the level of sulphur nd Thioillus thn ym en. Levels greter thn 6 kg/h used progressively lower yields of dry mtter. Dry mtter yields tended to reflet the level of nodultion otined. The differentil responses of the two legumes to inresing levels of sulphur ppers to e funtion of their tolerne of soil idity. When sulphur inoulted with Thioillus is pplied, sulphuri id is formed y teri, signifintly lowering soil ph (Gri Júnior 1992) s shown y our soil tests fter 9 dys of growth (Tle 2). This inrese in soil idity used redution in growth nd nodultion of owpe without ny mrked effet on growth of ym en. It ppers, therefore, tht ym en is more tolernt of oth soil idity nd slinity thn S 6 S 12 S 18 G 18 G 36 Control Totl N (mg/plnt) 12 1 8 6 4 2 Ym en 25 Cowpe 2 Totl N (mg/plnt) 15 1 5 Without inoulnt With inoulnt Figure 4 Effet of sulphur (S) t 6, 12 nd 18 kg/h inoulted with Thioillus nd gypsum (G) t 18 nd 36 kg/h on totl nitrogen uptke of owpe nd ym en with nd without rhizoil inoultion. Within topis, olumns rrying different letters re signifintly different t P =.5, using the Tukey test. CV for the legumes: ym en = 15.%; owpe = 22.9%.
18 N.P. Stmford, A.D.S. Freits, D.S. Ferrz, A. Montenegro nd C.E.R.S. Sntos owpe. The effet of the sulphur with Thioillus in lowering soil ph is prtiulrly strong nd re should e exerised in pplying this soil meliornt, espeilly when speies sensitive to soil ph re to e grown. Stmford et l. (2) found tht pplying elementl sulphur inoulted with Thioillus lowered soil ph nd inresed luminium toxiity whih redued the growth of oth Mimos eslpiniefoli nd Leuen leuoephl in sline soil in the semi-rid region of Brzil. These uthors reorded deline in soil ph from 7.9 to 3.5 when 1.8 t/h sulphur inoulted with Thioillus ws pplied. Applition of soil meliornts used mrked inrese in totl nitrogen in plnt tops, the mgnitude of the response eing muh greter thn the inrese in shoot dry mtter. Therefore, treted soils not only produed more forge ut it ws lso of higher qulity thn the forge grown on untreted soil. While dry mtter yields of oth speies were similr, espeilly in the presene of inoulnt, nitrogen uptke ws generlly greter in owpe. Muh of this nitrogen in the owpe forge ws provided y nitrogen fixtion s shown y omprisons of inoulted nd uninoulted plnts. Similr results hve een otined in owpe (Lopes et l. 1996) nd in ym en (Stmford et l. 1995; Cruz et l. 1997). Totl nitrogen in plnt tops ws inresed more thn 1 fold in ym en when pproprite rhizoi nd soil meliornts were pplied nd more thn 25 fold in owpe. Cowpe is oviously muh more effiient thn ym en t fixing nd extrting nitrogen when pproprite rhizoil strins nd soil meliornts re used. Brros et l. (1985) found tht slinity hd no effet on nodultion of two ultivrs of owpe ut showed tht inresing slinity redued totl N uptke in shoots, proly y the inhiitory effet of slinity in the tivity of nitrogense, reduing N yield in shoots. The mrked redution in levels of exhngele sodium in the soil omplex in the presene of oth gypsum nd sulphur supports the findings of Holnd et l. (1988) nd Gheyi et l. (1995) who reported signifint redution in exhngele sodium levels fter pplying 3 t/h gypsum or 2 t/h sulphuri id. There were mrked differenes etween owpe nd ym en in terms of sodium onentrtion in shoots. In unmended soil, onentrtion of sodium in owpe ws more thn 2.5 times tht in ym en. In the presene of soil meliornts, these differenes were signifintly redued. If the tul sodium uptke from unmended soil is lulted y multiplying sodium onentrtion y dry mtter yield of plnt tops, it eomes ovious tht totl sodium uptke y ym en tully exeeds tht of owpe. This reinfores our erlier onlusion tht ym en is more tolernt of sline soils thn owpe. We onlude tht pplition of soil meliornts nd inoultion with pproprite rhizoil strins is neessry to improve nitrogen nd dry mtter yields of owpe nd ym en on these sline soils. While oth sulphur with Thioillus nd gypsum re effetive soil meliornts, pplition rtes re muh more ritil for sulphur thn for gypsum s high pplitions of sulphur will lower soil ph nd depress nodultion nd growth of speies whih re sensitive to ph, e.g. owpe. Further work is needed to develop these findings to stge where they might e pplied in prtie on ommeril frms. Aknowledgements We re indeted to Fundção de Apoio à Ciêni e Tenologi do Estdo de Pernmuo FACEPE, nd to Conselho Nionl de Desenvolvimento Científio e Tenológio (CNPq) for finnil support nd the fellowship. Referenes ARMSTRONG, A.S.B. nd TANTON, T.W. (1992) Gypsum pplitions to ggregted sline-sodi ly topsoils. Journl of Soil Siene, 43, 249 26. AYARS, J.E., HUTMACHER, R.B., SCHONEMAN, R.A., VAIL, S.S. nd PFLAUM, T. (1993) Long term use of sline wter for irrigtion. Irrigtion Siene, 14, 27 34. BARROS, M.F.C., STAMFORD, N.P. nd MAGALHÃES, A.F. (1985) Efeito d slinidde em dus ultivres de upi. Revist Omeg, 3, 15 23. BARROS, M.F.C. nd MAGALHÃES, A.M. (1989) Avlição de métodos de determinção d neessidde de gesso em solos slino-sódios. Revist Brsileir de Ciêni do Solo, 13, 119 123. CRUZ, G.N., STAMFORD, N.P., SILVA, J.A.A. nd CHAMBER PEREZ, M. (1997) Effets of inoultion with Brdyrhizoium nd ure pplition on nitrogen fixtion nd growth of ym en (Phyrhizus erosus). Tropil Grsslnds, 33, 23 27. EMBRAPA (1997) Mnul de métodos de nálises de solo. 2nd Edn. (Centro Nionl de Pesquis de Solos: Rio de Jneiro). EMBRAPA (1999) Sistem Brsileiro de Clssifição de Solos. (Centro Nionl de Pesquis de Solos: Rio de Jneiro). FRANÇOIS, L.E. (1996) Slinity effets on four sunflower hyrids. Agronomy Journl, 88, 215 222. GARCIA JÚNIOR, O. (1991) Isoltion nd hrteriztion of Thioillus thiooxidns nd Thioillus ferrooxidns from urnium mines. Revist Brsileir de Miroiologi, 1, 1 6.
Soil meliornts for legumes on sline soils 19 GARCIA JÚNIOR, O. (1992) O enxofre e sus trnsformções miroins. In: Crdoso, E.J.B., Tsi, S.M. nd Neves, M.C.P. (eds) Miroiologi do solo. pp. 319 329. (Soiedde Brsileir de Ciêni do Solo: Cmpins). GHASSEMI, F., JAKEMAN, A.J. nd NIX, H.A. (1995) Sliniztion of lnd nd wter resoures: Humn uses, extent, mngement nd se studies. (Center for Resoures nd Environment Studies: Cnerr). GHEYI, H.R., AZEVEDO, N.C., BATISTA, M.A. nd SANTOS, J.G.R. (1995) Comprção de métodos n reuperção de rroz em solo sódio. Revist Brsileir de Ciêni do Solo, 19, 173 178. HOFFMAN, G.J., CATLIN, P.B., MEAD, R.M., JOHNSON, R.S., FRANÇOIS, L.E. nd GOLDHAMER, D. (1989) Yield nd folir injury responses of mture plum trees to slinity. Irrigtion Siene, 1, 215 229. HOLANDA, J.S., VITTI, G.C., SALVIANO, A.A.C., MEDEIROS, J.D.F. nd AMORIM, J.R.A. (1998) Alterções ns proprieddes químis de um solo luvil slino-sódio deorrentes d susolgem e do uso de ondiiondores. Revist Brsileir de Ciêni do Solo, 22, 387 394. KJAER, S. (1992) Biologil nitrogen fixtion in Phyrhizus hip (Wedd) Prodi. Annls of Botny, 7, 11 17. LOPES, J., STAMFORD, N. P., FIGUEIREDO, M.V.B., BURITY, H.A. nd FERRAZ, E. (1996) Respost d plição de omposto urno, nitrogênio minerl e produtos minerlizntes n fixção do nitrogênio e no rendimento de upi. Revist Brsileir de Ciêni do Solo, 2, 55 62. MALAVOLTA, E., VITTI, G.C. nd OLIVEIRA, S.A. (1989) Avlição do estdo nutriionl ds plnts: prinípios e plições. (Potfós: Piri). MIYAMOTO, S., RILEY, T., GOBRAN, G. nd PETTICLEW, J. (1986) Effets of sline wter irrigtion on soil slinity, pen tree growth nd nut prodution. Irrigtion Siene, 7, 83 95. MIYAMOTO, S. nd ENRIQUEZ, C. (199) Comprtive effets of hemil mendments on slt nd sodium lehing. Irrigtion Siene, 11, 83 92. NAIDU, R. nd RENGASAMY, P. (1993) Ion intertions nd onstrints to plnt nutrition in Austrlin sodi soils. Austrlin Journl of Soil Reserh, 31, 81 819. PEREIRA, J.R., VALDIVIESO, G.L. nd CORDEIRO, G.G. (1985) Reuperção de solos fetdos por sódio trvés do uso de gesso. In: Seminário sore o uso de fosfogesso n griultur, Brsíli, pp. 85 15. RHOADES, J.D., KANDIAH, A. nd MASHAL, A.M. (1992) The use of sline wter for rop prodution. Irrigtion nd dringe pper, No 48, FAO, Rome. 135p. RICHARDS, L.A. (1954) Dignosis nd improvement of sline nd lkli soils. U.S. Deprtment of Agriulture Hndook 6. (U.S. Government Printing Offie: Wshington). RUPELA, O.P. nd TAURO, P. (1973) Utilistion of Thioillus to relim lkli soils. Soil Biology nd Biohemistry, 5, 899 91. SHALHEVET, J., HUCK, M.G. nd SCHROEDER, B.P. (1995) Root nd shoot growth responses to slinity in mize nd soyen. Agronomy Journl, 87, 512 516. SILVA, J.A.A. nd SILVA, J.P. (1982) Esttísti experimentl plid à iêni florestl. (Imprens d Universidde Federl Rurl de Pernmuo: Reife). SORENSEN, M. (1996) Ym Ben: Promoting the onservtion nd use of underutilized nd negleted rops. 2. (Interntionl Plnt Geneti Resoure Institute: Rome). STAMFORD, N.P., CHAMBER PEREZ, M. nd CAMACHO- MARTINEZ, M. (1995) Symioti effetiveness of severl tropil Brdyrhizoium strins on owpe under longterm exposure to nitrte: Reltionships etween nitrogen fixtion nd nitrte redution tivities. Journl of Plnt Physiology, 147, 378 382. STAMFORD, N.P., MEDEIROS, R. nd MESQUITA, J.C.P. (1995) Avlição de estirpes de rizóio pr jtupé em regime de tempertur elevd. Revist Brsileir de Ciêni do Solo, 19, 49 54. STAMFORD, N.P., ARAÚJO FILHO, J.T. nd SILVA, A.J.N. (2) Growth nd nitrogen fixtion of Leuen leuoephl nd Mimos eslpiniefoli in sline soil of Brzilin semirid region s ffeted y sulphur, gypsum nd sline wter. Tropil Grsslnds, 34, 1 6. STAMFORD, N.P., SILVA, A.J.N., FREITAS, A.D.S. nd ARAÚJO FILHO, J.T. (22) Effets of sulphur inoulted with Thioillus on soil slinity nd growth of tropil tree legumes. Bioresoure Tehnology, 81, 53 59. SZABOLCS, I. (1989) Slt-ffeted soils. (Lirry of Congress: Florid). ZONTA, E.P., MACHADO, A.A. nd SILVEIRA JÚNIOR, P. (1982) Sistem de nálise esttísti Snest. (Universidde Federl de Pelots: Pelots). (Reeived for pulition Mrh 25, 22; epted Novemer 1, 22)