R Y SZ A R D T U R SK I, JA N M A G IE R SK I, M A R IA F L IS -B U J A K
THE ELEMENTARY COMPOSITION OF HUMIC ACIDS AND THE CONTENT OF MICROELEMENTS IN THEIR ASH, AS EXEMPLIFIED
BY DIFFERENT POLISH SOILS
D ep artm en t of S o il S cien ce and A g ricu ltu ra l C h em istry, A g ricu ltu ra l of L ublin
IN T R O D U C TIO N
One of the methods of investigations of differentiation of humic acids is the analysis of elem entary composition and the calculation on its basis of appropriate indices. A lthough the above m ethod is, according to O r l o v [5] and among Polish authors to R o s z y k [6], insufficient for indentification of humus compounds of different soil types, non the less this method is applied for characteristics of sole humic acids [1, 5]. It m ust not be m aintained th a t we dispose already of a sufficient num ber of results allowing to discontinue the respective investigations [6]. There are relatively scarce data concerning the content of m icroelements in various components of humus compounds.
In the present work results of the investigations on the elem entary composition and the content of m icroelem ents in ash of the fraction of hum ic acids separated from different Polish soils, are presented.
IN V E ST IG A T IO N R A N G E A N D M ETH ODS
The following soil kinds have been chosen for the investigations : 1 — humous cretaceous rendzina soil, 2 and 3 — chernozem developed from loess, 4 and 5 — soil lessivé developed from loess, 6 — soil lessivé developed from loesslike formation, 7 — soil lessivé w ith pseudogleying symptoms, developed from silts of aqueous origin, 8 — podzolic solid developed from loose sand. The soils m entioned under 1, 3, 5, 6 and 7 rep resen t arable soils, 2, 4 and 8 — forest soils. From accum ulation horizons of soils, except for podzolic soils, samples were taken, in which hum us compounds were analyzed and humic acids separated. From podzolic soil identical separation was made in the sample taken from the B H horizon.
Soils and humic acids were prepared by the methods usually applied at their separation, cleaning and drying. Total С in samples and
frac-60 R. Turski at al.
tions of humus compounds, the elem entary composition of humic acids, were determ ined by the methods generally asumed.
By the analytical methods applied microelements contained in hetero- polar complexes and p artly also in adsorptive organic-m ineral complex es can be determ ined in ash of humic acids.
A full rem oval of m ineral compounds off humic acids is not possible w ithout drastic m easures, whereas the drop of ash down toi 5®/o is assumed as satisfactory for regarding preparations as pure ones. Despite the above reservations, the results obtained allow to define the bounding range of m icroelements in th a t im portant component of the soil.
The determ inations of m icroelements were made by the spectro- graphic method on the Zeiss PGS-2 spectrograph.
D ISC U SIO N OF R ESU L TS
Results of the analysis of humus compounds of the soils investigated (Table 2) do not deviate from earlier data. The present work was aimed, among other things, at the determ ination of the percentage of humic acids in the extracted p art of hum us compounds. Namely, beside the differentiation of the content of m icroelements in the ash p art of humic acids, the variability of their percentage in humus compounds can
T a b l e 1 К З е т э г Л а т у c o m p o s i t i o n o f h u m i c .'.c.idu
Profile
No. С H N 0 c /i: C/ff /.ah, % (J
1 ?5-43 38.50 4 .8 7 40.6 3 .2 ? 1 .9 36. 4a 19 .0 1 1. *2 17.2 5,024 - 0 .0 7 2 Ь3.91 40 .6 3.90 35.3 3.0 3 2 .0 -,0 2 2 . I 13 .3 2 17.50 5.76 + 0 .2 2 3' ? 0 .7 3 36.9 4.3 6 38.3 3.06 1.9 4 1,85 2 3 .0 11.41 16 < 48 2 .5 0 + 0 .2 1 4 5_3._22 37.6 33 [2 3 .09 1 .9 Л 2 , ; с 2 ? .3 11.78 17.23 4 .1 5 + 0 .1 7 5 54*19 4 1.1 4 .3 6 39.6 3.41 2 .2 y±-JJ. 17.2 11.14 15.90 5.81 - 0 .1 3 6 CO ro 36.7 З. 61 2 .3 l',: .2 12.66 14.49 3.42 0 C J О + 7 52.40 35.2 5 . 37 4 3 .3 3.82 „43.40 19.3 r\ 7 5 1 3.71 З Л 7 - 0 .1 3 8 43.90 37.1 35.7 4 .1 4 2 .7 2 4 .5 12.5 13.60 1.03 + 0 .З 6 dcrlv.-i-iin (.0 o r - w e i g h t % a t o r •- a t o m i c % - o x i d a t i o n e
T a b l e 2 C o m p o sitio n o f numus compounds i n th e s o i l s u n d e r stu d y
O u tc ro p No. T o t a l С % % o f t o t a l С in b i t t e n9 i n h u c ic a c i d s i n f u l v i c a c i d s i n humind9 and u lm in a s 1 2 .1 6 0 4 ,1 7 1 3.4 7 14.02 6 8 .3 4 2 2 .0 4 0 1 .8 2 15.8 8 2 6 .5 4 5 5.76 3 1.6C0 4 .3 5 1 8 .2 0 3 0 .2 4 47.21 4 1.8 0 0 6 .7 3 9.6 8 2 7 .4 9 56.05 5 1 .0 4 0 4 .7 9 17.5 9 2 7 .4 0 50 .3 2 6 0 .7 0 8 3 .3 9 18 .0 7 28 .3 9 5 0.15 7 0 .9 7 6 5 .5 2 7 .6 4 3 6 .0 0 5 0 .8 4 8 0 .5 4 0 11.11 5 .3 7 38.1 9 4 5 .3 3
stress th eir im portance in the accumulation of microelements. P articu larly m any humic acids could be extracted off rendzina soil and,, although less th an in the soil m entioned, off chernozem and soils les sivés cultivated, developed from loes and loess form ation. Their content was m uch less in soils developed from silty form ations of aqueous origin, and p articularly few in the B H horizon of podzolic soil.
Irrespective of origin, humic acids constitute a specific separate group of hum us compounds ; such oouclusion could be draw n also on the basis of analysis of their elem entary composition expressed in w eight per cent.
T i b 1 e 3 C o n te n t o f .microo le.Tn.'nt:! in s o i l h o r iz o n s , from w hich humic a c i d s were so pa r a t .2 ri / г ; л / Sample No. ß Mn Сц Го Cr Mo V ■J'i Co 2,Г 1 1 0 ,0 1 2 6 .0 1 1 . 0 2 9 .0 0 11 .0 1 0 2 .0 » .0 4 .0 •190.0 2 1 5 .0 8 9 . 0 9 .0 4 2 .0 12‘J . ü 1 1.0 8 1 . 0 6 .0 /Î.0 ;5 5 . 0 3 1 7 .0 1 0 0 .0 1 0 .0 6 5 .0 1 1 2 .0 1 2 .0 6 0 .0 6 .0 2 .0 4 0 0 .0 4 2 .0 447*0 7 .0 7 2 .0 112.0 1 ; .0 76 .0 6 ,0 4 .0 389.0 5 3 .0 460.0 1 0 .0 6 5 .0 125.0 12.0 7 4 .0 6 .0 1 .0 417 .0 6 17.0 2 9 5 .0 12 .0 6 9 .0 182.0 Ъ . О 6 5 .0 6 .0 4 .0 5 0 1 .0 7 1 5.0 4 0 0 .0 4 .0 2 6 .0 5 9 .0 1.0 2o .0 2 .0 3.0 3 30 .0 8 2 .0 19 .0 1 .0 9 .0 3 6 .0 1.0 I6 .O n .0. n .0. 100.0
62 R. Turski at al. T a b l e 4 C o n t e n t o f m i c r o e l e m e n t s i n h u m i c a c i d s o f t h e s o i l я u n d e r s t u d y / р о г а / ] e Я bln Cu Pb Cr Ыо b _ I Ii Co J r A:ih,SS i 4 j i iO i j 25 j . b iO ... f " 2 11 7 . 6 24 5 19 0 . 4 1 5 . 5 4 9 1 4 . 4 4 1 : v ; o 3 27 2 . 5 45 17 13 1 . 3 8 . 3 20 10 7 . 6 be l o w 3 3 5 . 7 6 4 17 1 . 3 43 4 24 6 . 9 6 . 9 6 6 7 . 1 be .1 ow J J 4 . 1 5 5 35 3 . 1 50 9 25 4 . 3 1 1 . 5 23 S 5 . 6 76 5 . 8 1 6 14 3 . 5 71 3 11 0 . 3 6 . 2 2 8 7 . 2 be l o w 33 3 . 4 2 7 30 1 . 9 57 6 24 2 . 5 3 . 2 16 13 2 . 6 40 3 . 7 7 Q 26 1 . 2 Ü3 30 13 4 . 4 4 . 8 20 7 0 . 9 76 1 . 0 3
W hen analyzing, nam ely, the above composition, no significant dif ferences could be observed, w hat would confirm the thesis on dif ficulties in its use for draw ing conclusions on differences betw een particu lar soil types [1, 5]. Nevertheless, hum ic acids separated from podzolic soil resem ble fulvic acids — predom inating component of hum us compouds of this soil type. A t the same time it can be concluded on the basis of the C/H ratio tr a t it is hum ic acid w ith a considerable condensation of arom atic nucleus, approxim ating the condensation of preparations separated from the cultivated soils under study and even m uch higher th a n in hum ic acids from the A ± horizon of forest soil lessivé (profile 7). Humic acids from sim ilar horizons of forest soils (profiles 3, 7) have less condensed nucleus th an th a t of cultivated soils (profiles 2, 7), w hat has been confirm ed by earlier data [10].
The acids analyzed are characterized by a considerable differentiation of the oxidation degree calculated by the m ethod of Orlov [5]. This differentiation is very sim ilar to results obtained by this author. The quality estim ation of hum ic acids, based on this criterion, allows to assign them to grey humic acids separated from chernozem, irrespective of utilization, cultivated soil? lessivés developed from loess and silts of aqueous origin and from the B H horizon of podzolic soil. Brown would be hum ic acids separated from forest soil lessivé developed from loess, cultivated soil lessivé developed from loess form ation and rendzina soil. These results are, in view of scarce com parative m aterial, difficult for interpretation, w hat was stressed by both the m ethod’s author and other authors [1, 5].
The results obtained allowed to prove a considerable share of humic acids in the accum ulation of m icroelem ents in the soils under study.
This share was distinctly visible in rendzina soil, cultivated chernozem, soils developed from loess and the B H horizon of podzolic soil. In case of rendzina soils the results obtained could be explained by the soil process specificity in these soils, in consequence of which considerable am ounts of humic acids were formed. The example of podzolic soil confirms the possibility of m igration of microelements connected w ith hum us compounds in the soil profile.
Humic acids from all the soils under study exerted a p articu larly strong effect on the copper and boron accumulation. In case of copper its w ell-known particularly strong bounding w ith humus compounds
has been confirm ed [2, 3, 7, 9]. Owing to th a t copper in such boundings
can m igrate in the profile, of w hat its high am ount in the B H horizon
of podzolic soil (profile B) can bear evidence [8].
The boron accumulation, beside organic compounds, can be affected to a certain extent also by im possibility of a full cleaning of prep ara tions of humic acids. Boron is, namely, strongly connected als»o w ith clayey m aterial, first of all, w ith illite, commonly occurring in Polish soils.
The effect of humic acids on the lead accum ulation in the A x horizon m anifested itself only in rendzina soils and in cultivated chernozems, as soils w ith stable forms of these acids. In chernozem from under forest no such phenom enon was observed. Probably the exogenic lead was accum ulated in litte r and did not p enetrate into the Ax horizon. Also the effect of humic acids on the Pb accum ulation in the B H horizon of podzolic soil has been proved, w hat, however, suggests the possibility of translocation of this elem ent jointly w ith hum us compounds.
Considerable am ounts of cobalt in hum ic acids, except for the sample
8, would also suggest th eir effect on the accum ulation of this element,
although its boundings w ith fulvic acids have been proved to a w ider extent by Stevenson and Simakov (cit. a fter [4]). It is probably a con sequence of the unfull cleaning of preparations of humic acids and the presence of clayey fraction, w ith w hich this m icroelem ent is boun
ded. It could be confirmed also by its low content in the sample 8,
most strtongly demineralized. For such in terpretation could speak also the results obtained by S k ł o d o w s k i and S a p e k [9]. Also a lack of the effect о humic acids on the nickel concentration in the soils under study has been proved.
Insignificant appeared to be the effect of humic acids on the m anga nese accumulation. It can be explained by the fact of the form ation by m anganese of rath e r unstable complexes w ith organic compounds, which probably would undergo a disruption a t preparation of humic acids, m anganese being carried away w ith solutions used for this purpose.
64 H. Turski at ai.
C O N C LUSIO N S
1. Making use of the analysis of the elem entary composition of humic acids is, irrespective of forms of presentation of the results, restrained to the estimation of theis certain properties only. It is therefore, necessary to collect fu rth er on analytical m aterials for cor roboration of outlining tendencies in differentation of humic acids of particular soil types.
2. Humic acids participate to a considerable extent in the accumu
lation of m icroelem ents in humus horizons of soils as well as in the B H horizon of podzolic soils.
3. Humic acids p la y a particu larly im portant role in the copper and boron accumulation. Lead in greater am ounts was accum ulated m ainly in humic acids of rendzina soil and chernozems as well as of the BH horizon of podzolic soil. The effect of humic acids on the m anganese concentration in soil was insignificant as compared to other m icro elements mentioned.
REFEREN CES
[1] A l e x a n d r o v a L. N. : O rgan ich esk oe v e sh c h e stv o p o ch v y i p rocessy ego tran sform acii. N auka, L en in grad 1980.
[2] D r o z d o v a B. : Im p ortan ce of h um ic acid s in co n cen tra tio n of rare m icro ele m e n ts in soils. P och v. 1968, 10.
[3] G liń sk i J., T u r s k i R. : D ep en d en ce of the copper con ten t on th e fra ctio n a l com p osition of hu m ic acids. R ocz. glebozn. A ppend, to N. X V , W arsaw 1979. [4] K a b a t a - P e n d i a s A., P e n d i a s H. : T race e le m e n ts in the b iological
m edium . W yd. geol., W arsaw 1979.
[5] O r l o v D. C. : G u m u so v y e k islo ty pochv. Izd. M oscow . U n iv., 1974.
{6] R о s z у к E. : E lem entary com position of hum ic acids from som e soil types. Zesz. nauk. W SR W rocław , R oln. X V I, No. 49, 1962.
[7] S с h 1 i с h t i n g E. : K u p ferv erb in d u n und F ix ie r u n g durch H u m in säu re. Z P fl. Ernähr., D üng. 69 (114), 1955.
[8] S a p e k A. : G etting iron, alu m inium and copper com pounds from hum us su b sta n ces and p odzolic soils. Rocz. glebozn., 21, 1970, 1.
[9] S k ł o d o w s k i P., S a p e k A. : D istrib u tio n of Fe, Zn, Mn, Cu, N i, Co, Pb and Cd in p ro files of fo r e st-ste p p e chern ozem s. Rocz. gleb ozn . 28, 1977. (10] T u r s k i R. : In v e stig a tio n s of organ ic m atter in ty p ica l soils of th e L u b lin
U pland. P art I. S o ils d ev elo p ed from silty form a tio n s. A nn. UM CS, Sec. E 9, 1964, 3.
[11] T u r s k i R. : T he ch a ra cteristics of hum us com pounds of sooil form ed from solid calcareou s rocks in v a rio u s clim a tic zones. P o lish J. S o il Sei. 4, 1971, 2.
K. TURSKI, J. M AGIERSKI, M. F IJA S -B U JA K
SK Ł A D E LEM EN T A R N Y K W A SÓ W H U M IN O W Y C H ORAZ ZA W A R T O ŚĆ W ICH PO PIE L E M IKRO ELEM ENTÓW N A P R Z Y K Ł A D Z IE R Ó Ż N Y C H
GLEB P O L SK I
In sty tu t G leb o zn a w stw a i C h em ii R oln ej A R w L u b lin ie S t r e s z c z e n i e
Zbadano skład e le m e n la r n y k w a só w h u m in o w y ch , a w ich części p o p ieln ej rów n ież zaw artość m ik ro elem en tó w . U zy sk a n e w y n ik i p o zw a la ją w y cią g n ą ć n a stęp u ją ce w n io sk i.
1. W yk orzystan ie an a lizy sk ład u elem en ta rn eg o k w a só w h u m in o w y ch , n ie z a leżn ie od form p rzed sta w ien ia w y n ik ó w , jest ogran iczon e do o cen y n iek tó ry ch ty lk o ich w ła śc iw o śc i. K on ieczn e jest d alsze grom ad zen ie m a teria łó w a n a lity c z n ych w celu p o tw ierd zen ia ry su ją cy ch się ten d en cji zróżn icow an ia k w a só w h u m i n ow ych gleb różn ych typów .
2. K w a sy h u m in o w e m ają duży u d ział w ak u m u la cji m ik ro elem en tó w w p o ziom ach p ró ch n iczn ych gleb, jak rów n ież w poziom ach B H b ielic.
3. K w a sy h u m in o w e o d g ry w a ją szczególn ą rolę w a k u m u la cji m ied zi i boru. O łów w w ię k sz y c h ilo ścia ch b ył a k u m u lo w a n y g łó w n ie w k w a sa ch h u m in o w y ch z ręd zin y, czarn oziem u i z poziom u B R b ielicy . W p ływ k w a só w h u m in o w y ch na k on cen trację w g leb ie m anganu w p orów n an iu do w sp o m n ia n y ch m ik ro elem en tó w n ie b ył istotn y.
P ro f . d r R y s z a r d T u r s k i
i n s t y t u t G v lb o z n a iv s iu c a i C h e m ii R o l n e j AR L.ub.in, ul. lA.'szczyń::Jiirgo 7
