REM ARKS ON SOME M ETHODS
OF A V A ILA BLE M AGNESIUM D ETERM IN A TIO N IN SO IL BY M EANS O F A S P E R G I L L U S N IG E R
D epartm ent of Agrochemistry, College of Agriculture, Kraków
In re c e n t tim es we observ e in a g ric u ltu ra l rese a rc h a r e tu r n to m icro biologic m eth od s in d e te rm in a tio n of th e ab undance of m in e ral soil con s titu e n ts of th e m acro- as w ell as th e m icro elem en t groups. A n u m b er of stud ies w as 'lately p ublish ed dealing w ith d e te rm in a tio n of p lan t-av a ila b le nitro g en, phosphorus, potassium , m agnesium , su lp h u r, and of p a rtic u la r m icro elem ents, as also th e ir c o n ten t in p la n t m a te ria l, in w hich
Aspergillus nig er w as used as te s t o b jec t [1— 15]. In re su lts of th is an d
o th e r rese a rc h w o rk th e m eth od s of m icrobiologic d e te rm in a tio n of p la n t n u trie n ts have un d erg o n e considerable sim plification. G row ing tim e has been red u ced fro m 6— 10 days to 2.5 days, th e in co n venient sterelizatio n of th e soil an d c u ltu re m ed ium th ro u g h in tro d u c tio n of citric or tan n ic acid has b een elim inated, etc. Also th e com position of th e n u trie n t m edia has g re a tly changed. T hus for instance, th e c u ltu re m edium for d e te rm i n a tio n of available m agn esium in soil shows th e follow ing evolution (Tab. 1):
T a b l e 1
Evolution in composition of culture media for Mg determination in s o i l with the A. n iger method
N iklas 1940 Mulder 1948 Nicholas 1951 Gunhold 1957 N ow osielski i 960
Sugar 100,0 g Sugar 50,0 g Sugar 5 0 ,0 g Sugar 50,0 g Sugar 50,0 g
Peptone 1 ,0 KNO3 5 ,0 a О ал о KN03 5 ,0 KNO3 5 ,0
C itr .a c id 10,0 kh2po4 0 ,6 NaH2P04 0 ,6 Na2HP04 2,5 NaH2p04 0 ,6 (nh4 ) 2so 4 6,0 CaS04 .2K20 0,5 Ca(N03) 2 0 ,6 tannin 20,0 tannin 20,0
k2so4 0,37 Microelements Microelements Microelements Microelements
nh4h2po4 1,23 H20 to 1000 ml H20 to 1000 ml H20 to 1000 ml H20 to 1000 ml Microelements
H20 to 1000 ml
A ccording to som e au th o rs those sim plifications have rem ov ed th e prin cip al difficu lties of th e A. niger m ethod, arisin g from th e fa irly com p lex c u ltu re techn iqu e, and have those form ed th e conditions for its w ide ap p licatio n in a g ric u ltu ra l practice.
PURPOSE OF THE STUDY
T he su b sta n tia l sim p lificatio n in m in eral com position of th e m edia 3— 5 (Tab. 1) m ay raise som e dou b ts as to w h e th e r those m edia can re a lly produce th e op tim u m develo pm en tal conditions for A. niger in case of d e te rm in a tio n of av ailab le soil m agnesium . The p re se n t stu d y aim s a t elucidation of th is question.
METHODS
Two stra in s of A. niger w ere used as te s t organism s: stra in a of Czechoslovak origin, obtain ed from th e D e p a rtm e n t of A grotechnology, College od A g ricu ltu re Cracov, and th e ow n s tra in b w hich for a n u m b er of years has been used for tests a t th e D e p a rtm e n t of A g ro chem istry of said college.
The c u ltu re w as g row n on 50 m illilite r m ed ium in conic 300 m l. flasks. The c u ltu re m edium w as inocculated w ith an aqueous suspension of d ry
T a b l e 2
Comparative composition of cu lture media for magnesium determ ination
I . Nicholas (4) I I . Gunhold (3) I I I . Now osielski (7) 17. Medium b (own)
Sugar 5 0,0 g. sugar 50 ,0 g. sugar 50,0 g. sugar 5 0 ,0 g.
OO3 5 ,0 KNO3 5 ,0 KNO3 5 ,0 nh4no3 9 ,6
NaH2P04 0 ,6 Na2HP04 .12H20 2,5 NaH2P04 0,6 1^2 S04 2 ,6
Ca(NO3 )2 0 ,6 tannin 2 0,0 tannin 20,0 КС1 0,75
Microelements : NaH2P04 . 2H20 3,12
PeC1^.6H20 3» Omg. FeS04 .7H20 3 , Omg. FeCl^.ó^O 25, Omg. FeC1^.6H20 5 , Omg.
ZnS04 .7H20 2 ,0 ZnS04 .7H20 2 ,0 ZnS04 .7H20 10,0 ZnS04 .7H20 2 ,0
MnS04 .4H20 0,3 ünS04 .4H20 0,3 llnS04 .4H20 1,5 MnS04 .4H20 0 ,3
CuS04 .5H20 0,6 CuS04 .5H20 0 ,6 CuS04 .5H20 3 ,0 CuS04 .5H20 0 ,6
Na2Mo04 .2H20 0 ,5 Na2Mo04 . 2H20 0 ,5 Na2Uo04 . 2H20 0,75 Na2Mo04 . 2H20 0,15 Ga(N05 ) 2 .8H20 0 ,2
Co(N05 ) 2 .6H20 0 ,1 Ni(N0^ )2 *2H20 0,08
N3703. 4H20 0,08
spores, an d placed in a th e rm o sta t a t 33 °C. A fte r 72 hours th e m ycelium w as decanted, th o ro u g h ly w ash ed w ith d istilled w ater, laid o u t on f ilte r ing p a p e r to elim in ate excess w ater, an d d rie d for 24 hrs. a t 80 °C. The d ry m y celium w as th e n w eighed w ith accu racy + 1 m g. T he n u m b er of rep licatio n s w ith in a series v a rie d b etw e en 3 and 6.
The com position of th e n u trie n t m edia used is given in Tab. 2. A ll c u ltu re m edia w ere p re p a re d w ith tw ice-d istilled w a te r and M erck p. a. reag en ts.
RESULTS
C O M P A R I S O N O F S T A N D A R D C U R V E S F O R R I S I N G M g C O N C E N T R A T I O N ( I N T H E F O R M O F M gS O < ) O B T A I N E D O N C U L T U R E S I - I V W I T H B O T H A . N I G E R S T R A I N S
D iagram 1 an d 2 illu s tra te th e findings. The sta n d a rd cu rves o b tain ed w ith stra in s a an d b on th e sam e c u ltu re are identical, th e curves for th e c u ltu re m edia I— III show ing no significan t differences. E n tire ly d iffe re n t c h a ra c te r th o u g h has th e cu rve obtained in m edium IV. Its course shows th a t th e effect of risin g Mg co n cen tratio n (as MgSO^) on in cre m e n t in m y celium m ass is m u ch g re a te r in m ed ium IV th a n in th e m edia I— III. A ccu rate analysis of th e figs. 1, 2 and th e com position of th e c u ltu re m edia (Tab. 2) allow s to suppose th a t th e s ta n d a rd curves fo r th e m edia I— III re s u lt n o t o nly fro m risin g Mg co n cen tratio n in th e
Fig. 1. Standart curves for culture media I—IV obtained from strains a and w ith application of Mg in the form M a S 0 4. I — m e d i u m I, 2 ■ ■ m e d iu m II, 3 — m e d iu m I II ,
- m e d i u m I V
Fig. 2. Standard curves for culture m e dia I—IV obtained from strain b w ith
application of Mg in the form M g S 0 4 S y m b o l s a s in F i g . 1
mg. noo
Fig. 3. Standard curves for culture media Fig. 4. Standard curves for culture m edia I—IV obtained from strain a w ith appli- I—IV obtained from strain b w ith
appli-su b stra tu m , b u t also fro m some o th e r ag ent conditioned p ro b ab ly by th e m in e ral com position of th e m edia.
The m ost essen tial differen ce b etw e en those m edia consists in th e re la tiv e ly low s u lp h u r co n te n t of m edia I— III in com parison w ith m e diu m IV. It is th e re fo re possible th a t th e fo rm e r do n o t contain enough su lp h u r for A. niger in re s u lt of w hich th e increase in m ycelium m ass w ith rising Mg doses (in th e fo rm of M g S 0 4) is a fu n ctio n no t o n ly of Mg co n cen tratio n b u t also of th e S in th e su b stra tu m .
If th is is tru e , th e s ta n d a rd curves o b tained on th e n u trie n t m edia I— III w ith rising Mg doses in th e form of M gCl2 should d iffer from those o b tain ed on th e sam e m edia w ith M g S 0 4 as m agnesium source, w hile th e co rresponding curves for m ed ium IV should in b oth cases be identical. This surm ise w as ex am in ed by f u rth e r ex p erim en ts.
C O M P A R I S O N O F S T A N D A R D C U R V E S O B T A I N E D O N T H E N U T R I E N T M E D I A I - I V W I T H M g D O S E S I N T H E F O R M O F M g C b
The curves 1— 4 in figs. 3 an d 4 fu lly confirm th e above assum ption. T hence c o n c l u s i o n 1:
In th e d escrib ed ex p e rim e n tal conditions th e su lp h u r co n ten t in th e n u trie n t m edia I— III is in su fficien t fo r n orm al d evelopm en t of A. niger.
cation of Mg in the form MgCl2 S y m b o l s a s in F i g . 1
cation of Mg in the form MgCl2 S y m b o l s a s in F i g . I
Since b oth stra in s show ed id en tical reactio n to changes in com po sitio n of th e n u trie n t m ediu m (as seen in diagr. 1— 4), s tra in b only w as used in th e follow ing tests.
T he n e x t e x p e rim e n ts p u rpo sed to d e te rm in e th e m in im u m S co n ten t in m edia I— III su fficien t for fu ll d ev elo pm ent of A. niger.
T H E E F F E C T O F I N C R E A S I N G S C O N C E N T R A T I O N I N T H E F O R M O F N asS O * O N I N C R E M E N T O F M Y C E L I U M M A S S I N T H E N U T R I E N T M E D I A I - I V
W IT H - F U L L M g D O S E I N T H E F O R M O F M g C h
T he increase of S co n te n t in th e c u ltu re m edia I— III up to 100 jug A (3.2 mg.) causes sy stem atic in crease of th e m yceliu m m ass, w hile in m ed iu m IV th e m yceliu m m ass rem ain s unchanged. S up erp o sitio n of cu rv es 1— 3 of diag;r. 5 on th e co rresponding curves of diagr. 1 shows th e ir com plete sim ila rity (diagr. 6).
fjgA S/50 ml.
Fig. 5. Effect of sulphur addition (as Na2S 0 4) to the media I—IV on the cha racter of the standard curves for Mg in
form MgCl2
1 — m e d i u m 1, 2 — m e d i u m II, 3 — m e d i u m I I I , 4 — m e d i u m I V , 5 — m e d i u m I V w i t h o u t
s u l p h u r
(jgA M g-S/50m l.
Fig. 6. Comparison of standard curve obtained on m edium II for Mg in form M g S 0 4 (curve 2) and the standard curve
for S in form Na2S 0 4 (curve 2')
This p roves th a t in b oth cases those cu rves are functio n s of S con c e n tratio n . This is q u ite u n d e rsta n d a b le since a t th e tim e of m ax im u m g ro w th in te n sity th e m y celiu m req u ires m u ch m ore su lp h u r th a n m ag n e sium . In consequence, th e am o u n t of S given w ith th e Mg in th e form of M g S 0 4 is in su ffic ien t fo r sy n th esis of such a m ass of m y celium w hich m ig h t grow on basis of th e m ag nesiu m content. The m in im u m
(physiolo-gic) Mg : S ratio a ssu rin g n o rm al m y celium g ro w th in th e described e x p e rim e n tal conditions is n a m e ly approx. 0.33.
S tach io m etric com p utation s show s th e follow ing su lp h u r conten ts in th e p a rtic u la r c u ltu re m edia:
n u trie n t m ed iu m I — 0.02 m g. S/50 ml., II — 0.03
III — 0.09 IV — 23.91
F ro m those tests re s u lts c o n c l u s i o n 2:
The o b tain n orm al n u tritio n a l conditions for A. niger, the su lp h u r content in th e m edia I— III m u st be raised to approx. 3.2 mg. S/50 m l.
C O M P A R IS O N O F S T A N D A R D C U R V E S O B T A IN E D O N T H E N U T R I E N T M E D IA I-IV W IT H M g D O S E S I N T H E FO R M M g S 0 4 A N D M g C l2 W IT H A D D IT I O N O F S U L P H U R
(3.2 m g . S/50 m l.)
This com parison fu lly confirm s o u r p reced ing assupm tions (figs. 7 an d 8i). In th e n u trie n t m ed ia I— III a re used for d e te rm in a tio n of available Mg in soils, as w as done b y a u th o rs [4, 5, 8]), th e re su lts a re
Fig. 7. Standard curves for Mg in form Fig. 8. Standard curve for Mg in form M g S 0 4 obtained on m edia I—IV w ith MgCl2 on m edia I—IV w ith addition addition of spulphur (3.2 mg. S/50 ml.) of sulphur
1 to 4 — m e d ia I to IV , 5 — m e d iu m III w it h n o S y m b o ls as in fig . 7 s u lp h u r a d d itio n
b u rd e n e d w ith an e rro r w hose m ag n itu d e is g overned by th re e m ain factors:
— th e k in d of m agn esium sa lt used in p lo ttin g th e s ta n d a rd curve, — th e soil co n ten t of A. niger - av ailab le m agnesium ,
— th e soil co n te n t of s u lp h u r av ailab le to th is m old.
E R R O R M A G N I T U D E I N D E T E R M I N A T I O N O F M g I N N U T R I E N T M E D I A I - I I I I N C A S E O F P R E P A R A T I O N O F S T A N D A R D S W I T H M gS O < O R M g C h
In d e te rm in a tio n of av ailab le m ag n esium in soils using th e sta n d a rd curv es 1 and 2 (fig. 9), th e n a tu re an d m ag n itu d e of th e com m itted e rro r w ill depend on th e conditions discussed in th e follow ing.
fjgA Mg/50ml.
Fig. 9. D ependence of sought Mg concentration on the ob tained m ycelium mass and the Mg form used for preparation
of the m agnesium standard
1 — m e d i u m I I I , s t a n d a r d in f o r m M g C l2, 2 — m e d i u m I I I , s t a n d a r d i n f o r m M g S O é , 3 — m e d i u m I V , s t a n d a r d i n f o r m M g C b
1. In soil w ith high co n te n t of A. niger - available su lp h u r th e m ycelium yield w ill in p rin cip le be g o verend b y th e am o u n t of soil m ag nesiu m availab le to th is m old.
a!) W ith low m agnesiu m co n te n t and m y celiu m m ass n o t exceeding 250 mg./50 m l. (about 20% of m ax im u m yield), th e read in g s of th e sought m ag nesium co n cen tratio n w ill give a p p ro x im ate ly equal values on all th re e curves. F or instance: th e m y celiu m m ass on soil N r. la is 150 m g. — th e Mg co n ten t in d icated b y all th re e curves is a ro u n d 3 mg./100 g. soil.
b) W ith m edium and high m agnesium c o n ten t and th e re fo re m ycelium m ass over 200 mg. th e read in g s cu rve 2 (sta n d a rd form M g S 0 4) w ill show h ig h e r values th a n on cu rv e 3 (real sta n d a rd cu rve fo r Mg) th e resp ective differen ce being th e larg er, th e g re a te r th e m ycelium m ass. C urve 1 can no t by used in th is case since in does n ot cover m yceliu m values in excess of 250 mg.
F o r instance: th e m yceliu m m ass on soil N r. lb is 900 mg., th e Mg co n te n t according to cu rv e 2 is 53 mg./100 g. soil, according to curv e
3 — 16 mg./100 g. soil; cu rve 1 gives no reading.
2. Soil w ith low co n ten t of A. niger-av ailab le su lp h u r. The m ycelium m ass w ill h e re be a fu n ctio n of Mg and S co n centrations in th e su b stra tu m ,
th e values rea d from th e sta n d a rd cu rves 1 and 2 (MgCl2 an d M g S 0 4) being d e p e n d en t o n th e q u a n tity of th e m y celium m ass a b tain ed and th e Mg : S ratio in th e su b stra tu m .
a) If (under the described c u ltu re conditions) th e m ycelium m ass does not exceed 250 mg. and th e m olar ratio Mg : S in th e s u b s tra tu m is below physiologic ratio (1 : 3), th e read ing s on all th re e curves w ill be p rac tic a lly identical. T he ag en t decisive for increase, of th e m ycelium m ass in n am ely is th is case th e m ag n esiu m as th e m in im u m factor. On th e o th e r hand, if th e ratio Mg : S in th e s u b s tra tu m is h ig h er th a n th e physiologic ratio, th e m in im u m facto r w ill n ot be m agn esium b u t su lp h u r, and th e values re a d fro m th e curves 1— 2 w ill be low er th a n fo un d on curve 3.
b) If th e m ycelium m ass o b tain ed on th e n u trie n t m edium w ith th e te ste d soil exceeds 250 mg., no read in g from curve is possible ow ing to its b rea k a t 250 mg., w hile th e read in gs on curve 2 w ill give h ig h er valu es th a n on cu rve 3, irre sp e c tiv e of w h e th e r th e Mg : S ratio in th e s u b s tra tu m is low er or h ig h er th a n th e physiologic ratio .
T he d iffe re n c e s . b e tw e en th e rea l co n ten t of A . nic/er-available Mg in th e exam in ed soil a n d th e resp e c tiv e values found by using th e m edia I— III and M g S 0 4 in p lo ttin g th e sta n d a rd curve, a re p ro p o rtio n al to th e differen ces b etw e en th e m y celiu m m ass o b tain ed on th e c u ltu re m edium IV a n d on th e m edia I— III, resp ectiv ely (at equal m agnesium concen- trationj). T he m ag n itu d e of those differences is in d icated by th e area bou n d b y curves 2 and 3 in diagr. 9, w hile th e ratio of th e v alues found on cu rve 2 to those re a d on cu rve 3 (denoted in diagr. 9 by the le tte rs a and b in d ependence on th e m y celiu m m ass ob tain ed on th e m ediu m w ith th e te ste d soil) is p re se n te d in fig. 10.
T he increase of m yceliu m m ass in th e in te rv a l 250— 1000 m g. is accom panied an in crease in th e ratio — from 1.0 to 3.6. This m eans th a t
Fig. 10. Value of ratio — in relation a
to obtained m ycelium mass
■cl — M g c o n t e n t in s u b s t r a t u m r e a d f r o m r e a l s t a n d a r d c u r v e f o r M g ( c u r v e 3 in d i a g r . 9), b — M g c o n t e n t in s u b s t r a t u m
r e a d f r o m i n c o r r e c t s t a n d a r d c u r v e ( c u r v e 2 in d ia g r . 9)
th e co n cen tratio n v alu e of A. niger-av ailab le Mg in soil o b tain ed und er th e se conditions m ay exceed th e rea l v alue th re e tim es.
T he above d a ta ju stify th e c o n c l u s i o n 3:
T he use of th e n u trie n t m edia I— III for d e te rm in a tio n of A. niger- av a ilab le Mg in soil and co n stru ctio n of sta n d a rd cu rves fro m m agnesium
su lp h a te can lead to erro n eo us resu lts.
To check th e tr u th of th e above conslusions, th e follow ing e x p e ri m en ts w ith soils w ere m ade.
D E T E R M I N A T I O N O F A V A I L A B L E M g I N S O I L U S I N G I II A N D I V O F T H E N U T R I E N T M E D I A
A vailable Mg w as d e te rm in e d in 9 d iffe re n t soils. T h eir c h aracteristics a re given in Tab. 3.
T a b l e 3 C h a ra cteristics of the s o i l s used for determ ination o f a v a ila b le magnesium
S o il Nr. 1 2 3 4 5 6 7 8 . 9
Kind brownmada
(alluv.) black earth mada
podsol mada lo e s s sand humic
acid brown brown mg Mg/100 g .
a fte r Schachtschabel 6,4 39,5 0 ,6 19,3 14,4 2,9 5 ,1 15,7 35,8
M agnesium d e te rm in a tio n w as p e rfo rm e d in 2 g. d ry soil sam ples. The re su lts are show n in Tab. 4.
The d ata p re se n te d in Table 4 give fu ll co n firm ation of o u r preceding conclusions and indicate also th a t deficiency of A. niger-av ailable s u lp h u r m ay occur in soil, as show n b y th e stro n g increase in m y celiu m m ass a fte r ad ditio n of th is elem en t to th e su b stra tu m . It should be n o ted also th a t th e re su lts of avilab le Mg te sts m ad e b y th e S ch achtsch abel and by th e A. niger m eth o d show o n ly poor ag reem en t.
T a b l e 4 S o il content of A. n ig e r -a v a ila b le magnesium determined on n u trient media II I and IV
and with Schachtschabel’ s method
S o il Nr. 1 i Medium 111 Medium IV mg. Ug/100 g. a fte r Schacht schabel with sulphur addition no sulphur added
mg. dry matter mg-. Ug/100 g. mg. dry matter Mg/1§0 g. a c c .to standard with MgS04 H g /îfc g-a c c .to standard with MgCl2 + s mg. dry matter ug/îiô g. a cc.to standard with UgS04 Ug/l§Ô g. a c c .to standard with MgCl2+ S 1 1120 > 1 0 0 > 3 6 528 17 10 1010 19 6,4 2 1090 > 1 0 0 34 5Ю 16 9 1100 > 3 6 39,5 3 15 0 0 17 0 0 10 0 0,6 4 1070 89 28 545 18 10 1058 25 19,3 5 506 16 9 395 10 7 410 7 14,4 6 19 0 0 8 0 0 5 0 2,9 7 420 11 8 360 9 b 370 6 5 ,1 8 1056 84 25 510 16 9 1007 19 15,7 9 1160 >100 > 3 6 490 Ъ 9 1150 > 3 6 35,6
O ur e x p e rim e n ta l series leads to c o n c l u s i o n 4:
T he n u trie n t m ed ia I— III do n o t assure c o rrect re s u lts in d e te rm i n atio n of available Mg in soil ow ing to th e ir in ad e q u a te su lp h u r co n tent. The fact th a t th e su lp h u r deficiency in th e m edia w as not su p p lem en te d in th e e x p e rim e n ts of th e th re e abovem entioned a u th o rs is p resu m a b ly due to an o v e rsig h t involving re g re tta b le consequences, since scientific re se a rc h e rs a re c e rta in ly fam iliar w ith th e prin ciples of th e e x p e rim e n tal m ethods used and even m odified b y th em .
FINAL CONCLUSIONS
1. The c u ltu re m edia m odified by N i c h o l a s , G u n h o l d and N o w o s i e l s k i and recom m ended by th em for d e te rm in a tio n of available soil m agnesiu m co n tain in su ffic ien t q u a n titie s of su lp h u r.
b u rd e n e d w ith an e rro r v a ry in g in w ide lim its, since u n d e r those con ditio n s th e in crease in m y celiu m m ass is a fu n ctio n of co n cen tratio n in th e s u b s tra tu m not of th e m agnesium alone b u t also of th e su lp h u r.
REFERENCES
[1] B o r a t y ń s k i K., R o s z y k o w a S t., Z i ę t e c k a M.: Badania nad zawartością magnezu w glebie. Cz. I i II. Zesz. Probl. Post. Nauk Rolniczych, nr 40a, 1963.
[2] G ó r s k i M.: Nawozy i Nawożenie, t. II, s. 549, W -w a 1961, PWRiL.
[3] G ó r s k i M., N o w o s i e l s k i O., L e k s t o n J.: Przydatność uproszczo nej m etody A. niger do oznaczania zaw artości Mg w roślinie bez uprzedniego jej spopielania i usuw ania innych pierw iastków . Roczn. Glebozn. t. 10, 1961, z. 1. £4] G u n h o l d P., S c h i l l e r H.: Zur Methodik der Bestim m ung der pflan-zenaufnehm baren M agnesium s in Böden. Z.f. Pflanzenernähr., Düng. u.Bdk., Bd 76 (121), H. 1, 1957.
[5] N i c h o l a s D. J. D., F i e l d i n g A. H.: The use A. niger (M)’ for the determ ination of Mg, Zn, Cu and Mo available in soils to crop plants. J. Hortic. Sei., v. 26, Nr. 2. 1951.
[6] N i k l a s H., T o u r s e l O.: D ie Bodenuntersuchung m ittels A. niger. Bdk.u. Pflanzenernähr., Bd 18, 1940, s. 79— 107.
£7] N o w o s i e l s k i О.: W pływ nawożenia na zawartość Mg dostępnego w gle bie. Roczn. Glebozn., t. 8, 1959, z. 2.
[8] N o w o s i e l s k i O.: Oznaczanie Mg za pomocą uproszczonej metody A. niger. Roczn. Glebozn., t. 9, 1960, z. 1.
[9] N o w o s i e l s k i O.: O znaczanie-dostępnej siarki i innych jej form za po mocą A. niger. Roczn. Glebozn., t. 10, 1961, z. 1.
[10] N o w o s i e l s k i O.: Zastosowanie uproszczonej m etody A. niger do analizy chem icznej m ateriałów rolniczych. Roczn. Nauk Rolniczych, t. 87-A-2, 1963. [11] N o w o s i e l s k i O.: Łączne oznaczanie dostępnych p ierw iastków za pomocą
A. niger. Cz. I- P i K. Roczn. Nauk Rolniczych, t. 87-A-4, 1963.
[12] N o w o s i e l s k i O., S i u t a J.: Magnez dostępny dla A. niger a m agnez w ym ienny. Roczn. Glebozn., t. 9, 1962, z. 2.
[13] P i s z c z e k J., B i a ł o u s F r.: Badania nad m etodyką oznaczania Mg łatw o- dostępnego dla roślin. Roczn Glebozn., t. 10 dodat., 1961.
[14] P i s z c z e k J., B i a ł o u s F r.: Oznaczanie magnezu łatwodostępnego w gle bach lekkich. Roczn. Glebozn., t. 9, dodat., 1960.
[15] W i ś n i e w s k a Z., Z e m b a c z y ń s k i A., Ż m i g r o d z k a T.: Zawartość m agnezu w glebach pow iatu Szprotawa. Roczn. Glebozn., t. 10, dodat., 1961.
A . D O M N I C Z
BEMERKUNGEN ZU MANCHEN BESTIMMUNGSMETHODEN DES AUFNEHMBAREN MAGNESIUMS IN BÖDEN
MITTELS ASPER GILLUS NIGER
L e h r s t u h l f ü r l a n d w i r t s c h a f t l i c h e C h e m i e d e r L a n d w i r t s c h a f t l i c h e n H o c h s c h u l e in K r a k ó w
Z u s a m m e n f a s s u n g
D er physiologische Wert von Nährlösungen von N i c h o l a s , G u n h o l d und N o w o s i e l s k i , die für die M agnesium bestim m ung in Böden m ittels Aspergillus niger em pfohlen werden, w urde untersucht. In zahlreichen U ntersuchungen konnte
festgestellt werden, dass der in diesen Nährlösungen enthaltene S ch w efel in zu kleinen Mengen vorkom mt und dass in diesen Bedingungen erzielten B estim m ung sergebnisse des M agnesiums unrichtig sind.
A . D O M N I C Z
PROPOS CONCERNANTS CERTAINES MÉTHODES DE DÉTERMINATION DE MAGNÉSIUM ASSIMILABLE
DANS LE SOL AU MOYEN D 'ASPERGILLUS NIGER C h a i r e d e C h i m i e A g r i c o l e d e l ’E c o l e S u p é r i e u r e d ’A g r i c u l t u r e à C r a c o v i e
R é s u m é
Le travail effectué visait à étudier la valeur physiologique des m ilieux de N i c h o l a s , G u n h o l d et N o w o s i e l s k i , dont l’utilisation est recomm andée lors de la déterm ination du m agnésium assim ilable dans le sol suivant de m éthode Aspergillus niger. Dans de nombreuses expériences ont démontra que ces m ilieu x contiennent une quantité insuffisante du soufre et que les résultats de déterm ination du m agnésium dans de telles circonstances sont erronés.
A . D O M N I C Z
UWAGI DO NIEKTÓRYCH METOD OZNACZANIA PRZYSWAJALNEGO MAGNEZU W GLEBIE ZA POMOCĄ ASPERGILLUS NIGER
K a t e d r a C h e m i i R o l n e j , W S R K r a k ó w
S t r e s z c z e n i e
W pracy zbadano wartość fizjologiczną pożyw ek N i c h o l a s a , G u n h o l d a i N o w o s i e l s k i e g o , zalecanych do stosow ania przy oznaczaniu m agnezu w glebie metodą Aspergillus niger.
W w ielu doświadczeniach wykazano, że pożyw ki te zawierają niedostateczną ilość siarki oraz że otrzymane w tych w arunkach rezultaty oznaczania m agnezu są błędne.
А. дом нич
ЗАМЕЧАНИЯ К НЕКОТОРЫМ МЕТОДАМ ОПРЕДЕЛЕНИЯ УСВОЯЕМОГО МАГНИЯ В ПОЧВЕ С ПОМОЩЬЮ
A SPER GILLUS NIGER
К а ф е д р а А г р о х и м и и К р а к о в с к о й С е л ь с к о х о з я й с т в е н н о й А к а д е м и и Р е з ю м е Изучали физиологическую ценность питательных сред Н и к о л а с а , Г у н о л ь д а и Н о в о с е л ь с к о г о , рекомендуемых для определения магния в почве по методу A. niger. Проведенные опыты показали, что эти среды содерж ат недостаточное коли чество серы и что полученные в этих условиях результаты определения магния ошибочны.
!["Ignacy Chrzanowski jako badacz literatury i profesor", cz. 1, Mieczysław Łojek, Bydgoszcz 1992 : [recenzja]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==)