Euphytica76 : 1 27-132, 1994 .

127© 1994 Kluwer Academic Publishers. Printed in the Netherlands.

Seed quality of soya bean based on mineral composition of seeds of 45 varietiesgrown in a Brazilian Savanna acid soil

C.R. SpeharEMBRAPA-CPAC, C. Postal 08223, CEP 73301970 Planaltina, DF, Brazil

Received 12 July 1993 ; accepted 22 April 1994

Key words : Glycine max, Cerrado, aluminium, liming, genetics, mineral elements, seed quality, soybean

Summary

The Brazilian Savannas (Cerrados), a vast area covering one fourth of the country's territory, has acidic soilsthat are devoid of nutrients and must be amended before cultivation . Mineral disorder on the soya bean crop hasbeen frequent, mainly due to unbalanced liming and fertilization . There is no information on varietal differencesand the impact of these practices on the seed quality . Chemical analyses were performed to assess the levels ofelements in seed samples of 45 soya bean varieties from an experiment in a partly- and fully-limed acid soil . Thelevels of phosphorus, potassium, iron, aluminium, manganese, zinc and copper were inversely proportional tothe level of liming . Calcium, magnesium, sodium, molybdenum and titanium did not show statistical differencesfor seed accumulation in the liming levels. There was a high frequency of varieties derived from Al-intolerantparents to increased levels of P, K, Ca and Mg, contrasting with respective lower levels in the leaves . The varietaldifferences suggest further investigation on the genetics of mineral element accumulation in the soya bean seeds .Aluminium levels varied between 8.7 to 5.5 mg/kg, respectively, for the partly- and the fully-limed soil, indicatingthat cultivation of soya beans in these acid soils produced little effect on the quality of seeds .

Introduction

The Brazilian Savannas (Cerrados) occupy one fourthof the country's territory and have predominantly acidsoils. However, due to recent research contributions,about 50% of the national soya bean grain is producedon these soils (Spehar et al ., 1993) . Even though tech-nology for sustainable agricultural production is avail-able, bad practices of liming and fertilization amongthe soya bean growers have been commonly found .These have resulted in nutritional unbalance, with setbacks on the crop productivity .

In the Cerrados there are two basic types of soilsthat together account for about 50% of the total, name-ly, Dark Red Latosol, which is classified as TypicHaplustox, fine kaolinitic, isohyperthermic (Grove etal ., 1980) and Red Yellow Latosol, classified as TypicAcrustox, oxidic, kaolinitic, isothermic (Ritchey et al .,1982a) according to the U .S . soil taxonomy . In the for-mer, the deeper layers of the soil contain large amountsof aluminium, which is toxic to the plants ; in the latter

calcium content decreases below critical levels for rootgrowth . Before these soils are improved for intensiveagricultural production, liming is necessary to reachsufficient levels of base saturation (Raij & Quaggio,1983 ; Sousa et al ., 1989) .

In addition to fertility problems, the total rainfall inthe Cerrados, although sufficient for crop production,has erratic distribution . Dry spells are frequent in therainy season and these may cause yield reduction, evenwhen soil fertility problems have been overcome . Theamendments are applied to the ploughed layer, wheremost of the roots of cultivated plants concentrate theirgrowth and the benefits of improvement only reachdeeper layers of the soil through leaching, but this isa long term process (Ritchey et al ., 1980). The lowbuffer capacity of these soils aggravates even more themispractice of liming and fertilization . Mineral com-position of soya bean leaves varies greatly at differentliming rates on a Cerrado soil (Spehar, 1993) .

The study described here aimed to evaluate theeffects of two liming levels on mineral elements accu-

128

Table 1 . Mineral elements in the seeds of 5 soya bean varieties cultivated on a partly-limed acid soil inCentral Brazil

Var P K

Ca Mg Fe Al Mn Cu Zn Mo Na Tig/100 g mg/kg

01 0.601 1 .77 0.212 0.227 90 .6 8.7 39 .1 53 .0 15 .1 1 .30 15 .8 1 .1702 0.606 1 .96 0.212 0 .2 2 97 .1 5 .9 3 .9 59 .5 11 . 1 . 5 19 . 1 .2703 0.637 1 .90 0.219 0.258 108 . 9 .1 3 .1 56 .5 11 .3 1 .61 19 .1 1 .220 0.620 1 .99 0.223 0 .2 80 .9 8 .6 6 . 55 .3 10.5 1 .63 19.9 1 .2305 0.625 1 .85 0.237 0.2 6 101 .5 5 . 9 .0 57 .9 11 .5 1 . 8 - 1 .1306 0 .6 3 1 .95 0.210 0.259 91 .0 12 .0 7 .6 5 .0 11 .6 1 .70 - 1 .2507 0.660 1 .9 0 .227 0.268 10 .3 10.3 .1 58 .8 11 .7 1 .7 1 .0908 0 .581 1 .95 0.229 0.2 3 95 .7 8 .6 39 . 51 . - 1 .38 - 0 .9309 0 .62 1 .93 0.216 0.251 97 .0 9 . .8 56 . 10 .9 1 .57 1 .1610 0 .599 1 .88 0.2 0.2 5 87 .5 9 .7 50 .9 58 .9 12 .0 0.9 18 .1 0.9211 0 .531 1 .88 0.232 0.2 2 102 .1 5 .9 5 .0 55 .6 11 .5 0.71 25 .8 1 .2812 0 .626 1 .91 0.229 0.252 108 .7 7 . 8 .5 57 .5 10 .1 0.93 2 .0 1 .1213 0 .63 1 .8 0.238 0.262 157 .1 6 .9 3 .0 57 .5 11 . 1 .28 20 .1 1 .071 0 .692 1 .92 0.2 3 0 .267 - 7 .0 6 .5 60. 10 .3 1 .30 15 .9 0.8115 0.618 1 .77 0.261 0 .2 2 103 .0 8 .7 6 .5 56 .9 10 .2 0 .89 1 .3216 0.665 1 .86 0.2 3 0 .267 111 .1 10 .9 6 . 60 .7 11 .2 1 .08 0 .9717 0.620 1 .92 0.2 3 0 .2 3 98 .1 8 .3 7 .9 57 .0 9 .9 1 .25 - 1 .0618 0.602 2 .00 0.229 0 .2 9 86 .6 9 .9 8 .6 57 .8 11 .8 0 .77 18 .9 1 . 519 0.627 1 .96 0.220 0.265 10 .7 8 . 8 .0 57 .8 9 .5 1 .10 18 . 0 .9920 0 .6 1 .88 0 .250 0 .278 102 .8 9 .0 7 .3 57 .8 11 .2 1 .03 19 .7 1 .2221 0.657 1 .9 0 .251 0 .2 6 101 .2 6 .6 50 .0 62 .2 9 .9 0 .9 - 1 .222 0.622 1 .9 0 .2 2 0 .26 95 .1 10 .5 6 .5 60 .5 9 .2 1 .29 21 .7 1 .0023 0.659 1 .96 0.200 0.269 101 .0 8 .1 .3 58 .3 10 .0 0 .85 - 1 .182 0 .6 1 2 .01 0 .269 0.269 82 .3 9 .0 2 .5 58 .3 9 .5 1 .03 19 .1 1 .2225 0.557 1 .91 0 .208 0 .2 6 92 .7 11 .0 .1 58 .0 13 .1 1 .97 18 .6 -26 0 .61 1 .80 0 .229 0.270 109 .9 2 .5 59 . 10 .5 2 .32 18 .8 1 .03

27 0.636 1 .89 0.266 0.265 130 .5 11 .8 7 .6 61 .1 11 .3 0 .85 - 0 .9728 0.615 1 .85 0.210 0 .26 99 .1 .3 6 .0 58 .5 9 . 0 .95 22 .3 -29 0.637 1 .90 0 .22 0.263 10 .0 6 .7 1 .1 63 .7 1 .2 1 .36 22 .0 1 .1830 0.613 1 .8 0 .266 0.273 - 5 .3 5 .9 58 .1 10 .5 1 .0 26 .3 0 .9531 0.599 1 .87 0.229 0.258 106 .6 12 . 37 .2 53 .3 10 .5 1 . 8 19 .32 0 .6 2 1 .85 0 .2 2 0 .255 121 .3 8 .2 60 .3 11 .8 - -33 0 .61 1 .81 0 .210 0 .26 160 .1 - 6 .6 57 .9 9 .6 2 .05 -3 0 .60 1 .68 0 .19 0 .2 5 110 .7 10 .9 36 . 55 .6 10 .3 1 .58 -35 0.623 1 .88 0.229 0.257 81 .8 6 .6 3 .0 - - 1 .08 - 1 . 536 0.626 1 .7 0 .312 0.290 98 . 10 . 3 .2 58 .2 13 .3 2 .91 17 .8 1 .3337 0 .6 6 1 .8 0 .212 0 .261 97 .1 10 .1 5 .7 61 .8 11 .6 1 .2 25 .6 1 .5938 0.635 1 .83 0.231 0 .261 110 . 8 .2 6 .9 63 .0 11 .6 1 .60 27 .3 1 . 139 0 .6 6 1 .88 0 .197 0.256 107 .3 10 .1 7 . 62 .0 11 .6 1 .37 1 .380 0.601 1 .78 0 .205 0.256 15 .3 6 .5 0 .1 65 .8 12 .8 0 .73 1 . 0 .761 0 .602 1 .88 0 .201 0.262 92 .3 6 . 38 .3 55 .0 11 .0 1 .03 20 .2 0 .982 0.675 1 .98 0 .21 0 .276 100 .7 10 .3 3 .1 59 .0 10 .9 1 . 0 18 .5 1 .203 0 .691 1 .85 0 .200 0.277 95 . 10 .0 3 .6 60 .0 12 .6 0 .98 13 .8 1 .25

0 .5 6 1 .75 0 .215 0 .217 96 .9 8 .0 .3 55 .3 10 .7 1 . 0 - 1 .295 0.567 1 .95 0.229 0 .237 9 .8 11 .6 3 .8 50 .8 13 . 0 .95 17 .0

mulation in seeds of 5 soya bean varieties cultivatedon partly- and fully limed Dark Red Latosol, with thescope of assessing genetic variability for this trait.

Material and methods

A virgin Dark Red Latosol, representative of the majorCerrado soil classes, under Savanna-like vegetation,was chosen for this experiment . It had the follow-ing particle size distribution : sand = 3 %, silt = 19%and clay = 6%. The latter includes the fine parti-cles of aluminium and iron oxides, which are theultimate products of clay decomposition. The chem-ical characteristics of the soil are : pH (H20 1 : 1) =.7, Al = 1 .90 cmol/kg, (Ca + Mg) = 0 . 0 cmol/kg,

P = 0.9 mg/kg and K = 16 mg/kg . After limingwith dolomitic limestone, the area partly-limed, whichreceived 1,000 kg/ha of lime 100% neutralizing poweror CaCO3 equivalent, had a 35% aluminium saturation,whilst the fully-limed area, which reveived ,000 kg/haof lime 100% neutralizing power or CaCO3 equiva-lent had reduced available Al in the ploughed zone(0.30 cmol/kg) . Calcium carbonate equivalent is theacid neutralizing capacity of lime expressed as weightpercentage of calcium carbonate (Tisdale et al ., 1985) .Potassium, phosphorus and a source of micronutrients(Fritted Trace Elements) were equally applied in thetwo areas. The amendments were incorporated intothe soil, at a depth between 0 and 20 cm, by using arotovator. The chemical analyses of soil samples col-lected after the experiment indicated pH (H20 I : 1)5.1 and 5 .7 ; Al 0.97 and 0.10 cmol/kg ; Ca + Mg 1 .65and 3.56 cmol/kg ; P 3.1 and 3 . mg/kg; K 51 and58 mg/kg, respectively, in the two areas .

The partly- and the fully limed areas were sownwith 5 soya bean varieties on hill plots, with threereplications per liming level . Hill and row plots haveshown equivalent efficiency in field testing (Garland &Fehr, 1981 ; Spehar, 1989) . These varieties originatedfrom crosses among the cultivars Biloxi, Cristalina,IAC-2, IAC-5, IAC-7, IAC-8, IAC-9, V x 5-281 .5 andUFV 1 . Only Biloxi was introduced ; the others wereselected from breeding programmes for the CerradoRegion . Before sowing, the seeds of all treatments wereinoculated with strains of Bradyrhizobium japonicumselected for the Cerrado soils .

Plants were harvested at maturity and evaluated foryield. A sample of 200 seeds was collected to examinethe effect of liming on soya bean seed mineral compo-sition .

129

The seeds were milled and samples containing 0 .5 gof soya flour were placed in a acid-washed silica cru-cible and dry ashed in a muffle furnace at 50° C for12 hours . This combination of temperature and timeturned the fat-rich material into whitish ash, withoutcausing volatilization . After cooling the samples weredissolved in 5 ml 6 M HCl and placed in a steambath until dryness. The process was repeated . Afterthe samples were dry, 5 ml of 3 mol HCl was addedto the crucibles to dissolve the soluble residue. Sam-ples were transferred quantitatively with washings toa 50 ml volumetric flask . After settling of the residue,aliquots were analyzed by an Inductively Coupled Plas-ma Emission Spectrometer (ICPES) . Repeated sam-ples of randomly chosen treatments were used to verifyconsistency of analysis .

Results and discussion

The varieties showed differential accumulation of min-eral elements for the same liming level (Tables 1 and2). Attempts were made to relate the levels of ele-ments in seeds to the ones in leaves of Al-tolerant andAl-intolerant in field and performance in hydroponicsexperiments . Varieties IAC-8, V x 5-281 .5 and UFV 1were intolerant, IAC-5 and IAC-2, were intermediateand IAC-7, IAC-9, Cristalina and Biloxi were tolerantto aluminium (Armiger et al ., 1968 ; Mascarenhas et al .,198 ; Spehar, 1989). UFV 1 was the most intolerant infield and hydroponics evaluations .

Varieties, 20, 21 and 32 originated from both Al-intolerant parents, varieties 3, 6, 1 , 23, 2 , 37, 38,39 and 2 from one Al-intolerant parent and varieties7 and 3 from both tolerant parents had higher lev-els of P that the mean values (Table 3) . The highestlevels of potassium were found in varieties 18, 19, 23and 2 . Varieties 3, 11, 18 to 2 , whose common par-ent is UFV 1, had higher levels than average for Caand Mg, although varieties 2 and 3 originated fromAl-tolerant parents, had higher levels of Mg than aver-age. The data indicate a possible association of higherlevels of these elements in seeds to aluminium intol-erance and that genetic variability for mineral elementaccumulation is present in the soya bean germplasm .However, the exceptions suggest that further analysisshall be carried out to elucidate the genetic differencesof mineral element in the seeds. The results for leafanalysis indicated that varieties which had UFV 1 ascommon parent had reduced levels of these elements,especially Ca and Mg, in contrast with varieties derived

130

Table 2 . Mineral elements in the seeds of 5 soya bean varieties cultivated on a fully-limed acidsoil in Central Brazil

Var P K Ca Mg Fe Al Mn Cu Zn Mo Na Tig/100 g mg/kg

01 0.557 1 .80 0.216 0 .233 77 .8 10 .5 20.8 1 .7 11 .0 0.9 16.6 1 .1702 0.511 1 .81 0.237 0.2 3 82 .8 3 . 2 .6 2 .0 8 . 0.92 - 1 .0203 0.528 1 .68' 0.215 0 .2 5 83 .9 2 .5 23 .6 0.6 9 .9 0.63 18 .5 0.660 0.519 1 .78 0.2 0 0 .2 9 87 .8 3 .2 26 .7 2 .6 7 .2 0 .82 21 . 0 .8605 0.512 1 .69 0.263 0 .2 90 .0 5 .5 26 .3 0 . 9 .906 0.517 1 .70 0.222 0 .258 81 .0 9 .7 26 .1 0 . 7 .9 - 16 .0 -07 0.519 1 .67 0.231 0 .25 - 5 .5 26 .8 2 .2 1 . 2 -08 0 . 9 1 .80 0.210 0 .239 77 .3 5 .0 22 .7 38 . 8 .5 0 .93 18 .1 1 .6109 0 .51 1 .73 0 .231 0 .2 7 86 .9 8 .1 25 .3 1 .0 9 .2 1 .57 -10 0 . 80 1 .87 0 .223 0 .2 1 5 .8 6 . 19 .9 5 .0 10 .1 1 .32 - 1 .111 0 .556 1 .95 0 .28 0 .25 87 .7 .3 30 .2 6 .3 7 .6 1 .03 22 .1 1 .0612 0.517 1 .85 0.262 0.250 90 .3 9 .9 28 . 3 .2 8 .9 - 21 .013 0 . 28 1 .81 0 .2 6 0 .258 91 .2 8 .2 27 .1 0 .3 9 .5 - 23 .8 -1 0 .5 0 1 .75 0 .268 0.261 - 6 .0 27 .6 6 . 7 .7 - 16 .015 0 .506 1 .72 0 .265 0 .25 9 .2 6 . 2 .8 1 .9 8 .816 0.568 1 .8 0 .279 0.270 103 .0 .8 30 .3 9 .0 7 .8 1 .51 15 .7 1 .617 0 .527 1 .86 0 .256 0 .2 2 87 .0 3 .1 27 .3 2 .7 7 .6 0 .83 1 .2318 0 . 81 1 .92 0 .2 6 0.255 80 .8 9 .5 25 .0 3 .1 9 .9 19 .1 1 . 919 0 .5 7 1 .98 0.250 0.253 - 7 .6 25 .8 5 .1 10 .8 0 .79 21 .1 1 .3320 0.538 1 .6 0 .272 0.273 95 .6 5 .8 26 .0 3 .7 8 .1 1 . 9 19 .5 1 .2621 0.565 1 .91 0 .278 0 .26 95 . 27 .7 8 .0 7 .7 1 .01 - 1 .1222 0.518 1 .85 0 .261 0.266 82 .6 .6 27 .0 .7 7 .3 0 .80 19 .8 1 .0023 0.582 1 .88 0.258 0.252 98 .6 8 .1 28 .3 8 .7 8 . 0 .77 0 .892 0.528 1 .93 0 .27 0.259 80 .7 .5 27 . 3 . 6 .8 0 .99 15 .1 0 .7825 0.508 1 .9 0 .233 0.260 86 .2 8 .9 22 .2 5 .1 9 .5 - 1 .8 1 .2726 0.529 1 .78 0.232 0 .25 88 .2 3 .0 25 .7 1 .3 7 . 0 .95 13 .9 0 .7327 0.522 1 .83 0.277 0.257 88 .8 3 .3 25 .0 .6 7 .7 0 .97 - 1 .1028 0.523 1 .78 0 .211 0 .2 8 80 .6 6.1 25 .0 1 .6 7 .7 0 .9 21 .1 0 .5729 0.512 1 .85 0.227 0 .25 88 .5 2.6 25 . 5 .0 9 .3 0 .76 - 1 .0630 0.522 1 .85 0.266 0 .261 83 . 2.5 25 .0 2 .2 8 .8 0 .67 23 .1 1 .1131 0.527 1 .80 0 .2 2 0 .2 3 83 .2 5 .8 21 .0 37 .7 7 .8 1 .57 17 .1 0 .7132 0 .5 0 1 .66 0 .25 0 .2 7 86 .9 .5 30 . 2 .5 7 .3 1 .05 0 .8733 0.523 1 .70 0.207 0.256 10 .2 - 25 .6 36 .7 7 .2 1 .06 0 .693 0.577 1 .75 0 .209 0.252 91 .6 7 .9 25 .8 2 .5 7 .8 0 .72 - 0 .935 0.526 1 .69 0.219 0.258 - 2.5 27 .1 1 .0 7 .5 0 . 0 13 .5 0 .6336 0 . 98 1 .77 0.272 0.282 86 .1 9 . 22 .0 3 . 10 . - 13 . 1 .18

37 0 .571 1 .69 0 .237 0.257 89 .3 2.5 26 .1 5 .8 7 .1 0 .56 15 . 1 .0038 0.518 1 .72 0 .27 0.266 100 .2 2 .5 27 .8 8 .3 8 . 0 .76 21 .1 1 .0139 0.532 1 .69 0.227 0.253 89 .9 3 .6 2 .7 3 .5 8 .2 0 . 5 0 .810 0 . 5 1 .65 0 .195 0.250 72 .6 7 .8 18 .9 1 .8 9 .6 - 13 .0 0 .71 0 .527 1 .72 0 .220 0.252 83 .8 2 .5 23 .7 1 .2 7 .5 0 . 3 13 .0 0 .812 0 .535 1 .78 0 .23 0.255 89 .5 2 .5 27 .3 2 .8 8 .0 - 1 .7 0 .753 0 .551 1 .90 0 .251 0.265 92 .2 25 .6 .1 9 .7 1 .3 13 .2 1 .25

0 . 89 1 .62 0 .223 0 .22 78 .1 .0 22 . 38 .6 8 .1 0 .56 - 0.975 0 .52 1 .92 0 .19 0.239 90 .5 - 21 .5 5 .0 10 . - 15 .3 -

Table 3 . Statistical parameters for mineral elements in soya bean seeds cultivated on a partly- (P) and fully-limed(F) acid soil in Central Brazil

from both tolerant parents (Spehar, 1989) . In generalvarietal differences were more evident at the partly-limed acid soil .

Increased liming resulted in lower levels of phos-phorus, potassium, iron, aluminium, manganese, zincand copper in the seeds of soya beans . Calcium, magne-sium, sodium, molybdenum and titanium did not showstatistical differences for seed accumulation in the lim-ing levels . The greatest reductions were observed withAl and Mn, followed by Zn, Fe, Cu, P and K . Simi-lar reductions have been found in the leaves althoughwith large differences in magnitude for mineral ele-ment content in the leaves when compared to the onesin the seeds (Spehar, 1993) . The amounts of Al, Feand Mn in the leaves were 836, 528 and 113 mg/kgfor the partly-limed area and 5, 3 and 29 mg/kgfor the fully-limed area, respectively. This high sen-

Standard

C.V. (%)

Range'ErrorP

F

P

F

P

F

0.005 0.00 5 . 5 .6 0 .161 0 .15

0.011 0.01 .0 5 .3 0.33 0.36

0 .00 0.00 10 .5 10 .3 0.118 0.090

0.002

0.001

5.5

.1

0.073

0.053

2.75 1 .37 17 .1 10 .0 79 .1 9 .

0 .37 0 . 1 2 .1 7 .0 8 .1 8 .0

0 .59 0 .39 9 .0 10 . 16 .9 11 .5

0 . 7 0 . 1 5.3 6 . 15 .0 12 .3

0 .20 0 .17 11 .6 13 .2 5 .9 .2

0.07 0 .06 33.9 35 .6 1 .2 1 .2

0.67 0.62 17.6 19.2 13 .5 10 .8

0.03

0.0

16.0 26 .

0.83

1 .07

1 Difference between the lowest and the highest mean value among the 5 soya bean varieties .

1 3 1

sitivity of available Mn to increased pH has alreadybeen described and the lower level reported here forthe leaves is above 10 mg/kg, below which plants aredeficient (Ritchey et al ., 1982b). However, the dif-ferences for manganese content in seeds were not ashigh as in leaves. There were statistical differences inseed yield among the varieties, although correlationanalysis indicated no association of mineral elementdifferences in seeds and yield .

Aluminium is abundant in the exchangeable formin the soils in many parts of the world, notably thetropical oxisols . However, only a reduced amount ofAl accumulated in the seeds when the soya beans weregrown in the acid soil . The present results suggest thateven though varieties differ in the content of mineralelements in the seeds, the mineral composition of soya

Element Mean StandardDeviation

P F P F

Phosphorus 0 .623 0.523 0 .037 0.029(g/l00 g)Potassium 1 .88 1 .79 0 .075 0 .095(g/100 g)Calcium 0.22 0 .2 2 0 .02 0.025(g/100 g)Magnesium 0.257 0.253 0 .01 0 .010(g/100 g)Iron 10 .00 86 .91 17 .8 8 .66(mg/kg)Aluminium 8 .69 5 . 7 2 .10 2 .58(mg/kg)Manganese . 0 25 . 0 3 .98 2 .6(mg/kg)Copper 58.10 3 .01 3 .10 2.77(mg/kg)Zinc 11 .22 8 .51 1 .30 1 .12(mg/kg)Molybdenum 1 .31 0.9 0.33 0.

(mg/kg)Sodium 19.90 17 . 6 3 .35 3 .50(mg/kg)Titanium 1 .16 1 .01 .018 0 .27(mg/kg)

132

beans is not negatively affected by cultivation in Al-rich environments .

References

Armiger, W.H ., C.D. Foy, A .L . Fleming & B .E. Caldwell, 1968 .Differential tolerance of soybean varieties to an acid soil high inexchangeable aluminium . Agron . J . 60 : 67-68 .

Garland, M .L . & W.R . Fehr, 1981 . Selection for agronomic charac-ters in hill and row plots of soybeans . Crop Sci . 21 : 591-595 .

Grove, T.L., K.D. Ritchey & G .C . Naderman Jr, 1980. Nitrogenfertilization of maize on an oxisol of the Cerrado of Brazil . Agron .J.72:261-265 .

Mascarenhas, H.A.A., C .E .O. Camargo & S.M.P. Falivene, 198 .Tolerance of soybean cultivars to two levels of aluminium innutrient solutions with different salt concentrations . Campinas,SP, Brazil, Bragantia 3 : 59- 66 .

Raij, B . & J .A . Quaggio, 1983. Methods of soil analysis for fertiliza-tion purposes . Technical Bulletin # 81 . (Campinas AgriculturalInstitute, IAC, Campinas, SP, Brazil).

Ritchey, K.D., D.M.G . Sousa, E . Lobato & O . Correa, 1980. Calciumleaching to increase rooting depth in a Brazilian savannah oxisol .Agron. J . 72 : 0- 3 .

Ritchey, K .D., J .E. Silva & A .U.F. Costa, 1982a. Calcium deficiencyin clayey B horizon of savanna oxisols . Soil Sci . 133 : 378-382 .

Ritchey, K .D ., G. Urben Filho & C.R. Spehar, 1982b . Manganesedeficiency induced by excessive liming in a latossolo vermelho-escuro cerrado soil . In : Proceedings of the 2"d National SoybeanResearch Seminar, 1981, pp . 5 1-5 . Brasilia, DF Londrina,PR, Brazil : EMBRAPA-CNPSo .

Sousa, D.M.G ., L.N. Miranda, E. Lobato & L.H.R. Castro, 1989 .Evaluation of methods to predict lime requirements for cerradosoils . Campinas, SP, Brazil, Revista Bras . Ci . Solo 13 : 193-198 .

Spehar, C.R ., 1989 . The genetics of aluminium tolerance in soyabeans Glycine max (L.) Merrill . D . Phil-Thesis, University ofCambridge, England .

Spehar, C.R ., 1993 . Mineral composition of soya beans cultivated ina Cerrado acid soil with two levels of liming . Brasilia, DF Brazil,Pesq . Agropec . Bras . 28 : 6 5-6 8 .

Spehar, C.R ., PM.FO. Monteiro & N .L. Zuffo, 1993. Soybeanbreeding in Central Brazil . In: N .E . Arantes & P.I .M. Souza (Eds .)Proceedings of the Symposium of Soybean Cultivation in theCerrados (Brazilian Savannas), 1992, Uberaba, MG, Piracicaba,SP, Brazil: EMBRAPA-CNPSo/CPAC . pp . 229-251 .

Tisdale, S .L ., W.L. Nelson & J .D. Beaton, 1985 . Soil Fertility andFertilizers, ` h Ed. Macmillan Publishing Co, New York .