J. R. STA R C K , E. TRU O G A N D O. J. A TTOE i
AVAILABILITY OF BORON IN SOILS AND THAT ABSORBED ON ANION EXCHANGE RESIN AND LIGNIN2
In soils one may distinguish total, acid-soluble and water-soluble boron. The total amount of boron in soils is of a minor interest from the agricul tural point of v iew because only a sm all part of it is readily available to plants. The extraction of available boron with boiling water described by B e r g e r and T r u o g [1] is commonly used by investigators in this field. P h i l i p s o-n [8] came to the conclusion that the boiling water extraction gives an idea of the quantity at the imm ediate disposal of plants but does not give an adequate idea of the reserves of boron in the soil which m ay become soluble and available. He developed a method of extraction of available boron in soils using a phosphoric acid solution of pH 2.8 or lower, and clarnis this method gives a truer expression of the boron situatiion in the long-term perspective.
In the experim ents herewith described, the availability of boron rem aining in two soils after extraction with boiling w ater and dilute phosphor ic acid and also the boron absorbed on anion exchange resiin and lignin was investigated.
M A T E R IA L S A N D M ETH ODS
Sunflowers (Helianthus annus L., var. Mammoth Russian) were grown in the greenhouse in four liter plastic pots each of w hich contained 5 kg of quartz sand, and other additions later described. At the beginning of the experim ent onehalf liter of m odified Hoagland’s nutrient solution [3] w ith out boron was added to each pot. During the growing period m ost of the pots (those w ith the larger plants) received an additional one liter of sim ilar nutrient solution. Only onehalf liter of Hoagland’s modified
nut-1 R o ck efeller F ou n d ation F e llo w , E m eritu s professor, and p ro fesso r of so ils, r e sp e c tiv e ly .
2 C on trib u tion from th e D ep a rtm en t o f soils U n iv e r sity of W iscon sin , M adison, U .S.A .
rient solution was added to the two treatm ents showing early boron defi ciency and having sm all plants. This reduction to 0.5 liter was done to pre vent a too high concentration of salts in solution. Reagent grade chemicals and demineralized water containing only 0.02 mg B/l was used. The restr icted or negligible growth of the plants in the pots to which boron was not purposely added is proof that the content of boron as impurities in the water and chemicals used did not appreciably affect the plants.
F igu re 1. S u n flo w e r grow n in quartz sand w ith ad d ition of boron from d iffe r e n t sources. A — control, В — borax, С — subsoil, D — w ater ex tra cted subsoil, E —
H3PO4 ex tra cted su b soil and then lim ed , F — m uck soil, G — w a ter ex tra cted m uck soil, H — H3PO4 ex tracted m uck soil and th en lim ed , I — boron absorbed on anion
ex c h a n g e resin , and J — boron absorbed on lig n in
S ło n eczn ik u p ra w ia n y w p ia sk u k w a rco w y m do k tó reg o dodano bor w różn ych p o staciach : A k on troln e — bez boru, В — boraks, С — podglebie, D — pod gleb ie
w y e k str a h o w a n e w od ą, E — p od gleb ie w y ek stra h o w a n e H3PO4 i potem zw a p n e w a -
ne, F — gleb a m urszow a, G — gleba m u rszow a w y ek stra h o w a n a w odą, H — gleb a
m u rszo w a w y e k str a h o w a n a H3PO4 i potem zw ap n ow an a, I — bor zaad sorb ow an y na ż y w ic y w y m ie n n e j, J — bor zaad sorb ow an y na lig n in ie
The characteristics of the two soils added to the quartz sand are given in table 1. The soils had been pulverized so as to pass a 20-mesh sieve. The available boron was determined by the boiling water extra ction. The Seaton silt loam subsoil had been taken at a depth of 15— 20 feet, and the Carlisle muck was surface material. The pH values given in table 1 were determined in a soil-w ater paste with a glass electrode. Available nitrogen was determ ined by alkaline permanganate digestion [9]. Available phosphorus and potassium were determ ined by extraction with 0.3 N-HC1 [6].
In experim ent I, additions to the quartz sand of borax and the two soils (extracted and not extracted) and of boron absorbed on anion e x change resin (Dowex 2x) and on lignin are given in detail in table 2. All treatm ents w ere made in quadruplicate. The amount of available boron in the soils was determ ined by the boiling w ater extraction method. Extract ion of the soils (added to the pots) with boiling distilled water (ratio soil
T a b l e 1 C h a ra cteristics before and a fte r e x tra ctio n o f the two s o i l s added to the quartz sand
A vailable
S o il pH В H P К
mg/kg ppm
Seaton s i l t loam su b s o il 7.9 0.742 12.5 11.5 4 2.5 Seaton s i l t loam su b s o il extracted with b o ilin g
water 8 .2 - 12.5 9.5 37.5
Seaton s i l t loam su b s o il extracted with H3PO4 6 .5 - 12.5 175.0 5 5 .0
C a r lis le muck 6 .7 4.930 1400 З60.0 360.0
C a r lis le muck extracted with b o ilin g water 6 .9 - 1400 380.0 200.0 C a r lis le muck extracted with H3PO4 3 .6 - 1400 I I 6 0.0 100.0
T a b l e 2 Y ie ld s, boron content and t o ta l amount o f boron uptake by sunflower p la n ts
Treatment of quartz culture
Dry matter g /p o t Boron i n / i g P«r g o f dry matter T otal amount o f В uptake in /ig per pot
Control (quartz sand) no ^ B ^O y 8 .0 16.0 128.0
0 .2 mg B/pot as He2 B40y . 10H20 1 2 .6 20.9 263.3 270 g of Seaton s i l t loam su b so il per pot g iv in g 0 .2 mg a v a ila b le boron 11.0 18.5 203.5 270 g of Seaton s i l t loam su b so il extrated with b o ilin g water per pot 8 .5 17.5 148.8 270 g of Seaton s i l t loam su b so il extracted with H3PO4 per pot 17.1 32.5 4 0 .6 g muck s o i l per pot g iv in g 0 .2 mg a v a ila b le boron per pot 15.3 33.4 511.0 4 0 .6 g muck s o i l extracted with b o ilin g water per pot 14.9 27.7 412.7 4 0 .6 g muck s o i l extracted with H3PO4 per pot 5 .7 16.5 94. I 0 .2 mg absorbed on 0.533 g anion exchange r e s in per pot 15.0 25.7 385.5 0 .2 mg В absorbed on 4 .082 g lig n in per pot 14.5 26.3 381.4
L.S.D. (0 .0 5 ) 1.2 -
-to water 1 : 2) was for 5 m inutes w ith a refluxing condensor; they were then washed several tim es on a Büchner funnel and dried at room tem pe rature. Other portions of each soil w ere extracted with dilute phosphoric acid ( ~ and — malar depending on original acid neutralizing capacity of
20 50
the soil) so as to give a pH of 2.8 to the final extracting solution. In case of the Seaton subsoil it was — M H 3 P O 4 and in the case of the Carlisle muck
20
soil it was — M H 3 P O 4 . A fter extraction the soils were washed on a Büch-
50
ner funel about 10 tim es with distilled water and then drûed at room temperature. The Carlisle muck extracted w ith phosphoric acid rema ined strongly acid even after prolonged washing as shown in table 1. Sam ples of these soils were titrated with Ca(OH)2 and an equivalent amount of С аС О з was added to them so as to adjust their pH to that of the non-extracted soils.
The anion exchange resiin (Dowex 2x 3 obtained from Dow Chemical Co- Midland, Michigan) was dried, ground and passed throught a 100 mesh sieve. After w etting w ith water, 6 ml of w et resin was transferred to a glass column 1 cm in diameter. Through this column was passed slow ly 10 ml of borax solution containing 1 g B/l. The resin was then washed several tim es with distiilled water and dried at room temperature. The amount of boron adsorbed by the resin was determ ined as follows: a 400 mg sample of the resin was transferred to a small column, and 30 ml of 2 N HC1 was passed through. The filtrate was collected in a 1000 m l volum etric flask and the amount of boron present in the filtrate was determ ined. An additional 15 ml of 2 N HG1 was passed through the column and the filtrate w as collected in a 250 ml volum etric flask. This filtrate was found to be free of boron, showing that the previous extract ion w as complete.
Alkali lignin (Indulin A ) 4 produced by W est Virginia Pulp and Paper Company was used. F ifty grams of this lignin was treated in a beaker with 500 ml of borax solution containing 1 g B./l and let stand overnight. The amount of boron present was then determ ined after ignition using the çurcumin procedure [2]. Each treatm ent (five plants per pot) was quadrup licated. Careful, daily observations were made during the growing period. The plants w ere harvested after one month of growth. The roots w ere washed first in tap then in distilled water and all the material dried at 80 °C. Finally the plants were weighed, then ground in a W iley m ill and after ignition the boron was determ ined by the curcumin procedure [2].
R E SU L T S A N D D IS C U S S IO N
Table 2 gives the results of experim ent I. The data show that boiling w ater extraction of soils very low in organic m atter rem oves almost all boron available for plants. This is not true in the case of soil high in organic matter. There was no significant difference in yield of plants grown w ith
3 S tro n g ly basic anion ex ch a n g er.
4 In d u lin A is n a tu ra lly occu rring polym er, ch a racterized by a series of c lo sely lin k ed b en zen e, p yran e and fu ran e rin gs ca rrying m e th o x y l, h y d r o x y l and oth er su b stitu e n t groups.
addition of not-extracted and boiling w ater-extracted muck soil. The amount of boron uptake by plants from treatments which received boiling w ater-extracted muck soil was much higher than in the control. Some bo ron is probably quite tightly bound in organic matter and not easily extractable by boiling water. It may become available to plants after decay of the organic m atter during the growing period.
Yields in treatments w ith boron absorbed on anion exchange resin and on ligniin were even higher than in the treatment w ith borax. Plants w ere able to obtain more boron w hen it was added in the form absorbed on anion exchange resin or lignin than as a form of borax. In quartz sand, there may be present some active silica which may react w ith calcium from the nutrient solution and form secondary minerals. In this case fix ation of boron is possible as was shown by P a r k s and S h a w [7]. Sm all utilization of boron in sand culture was shown also by M a j e w s k i and M a j e w s k a [4]. When the boron was added in anion exchange form on resin and lignin, its fixation w as probably less than w hen added as borax.
The low est yields of plants were obtained in treatments w ith subsoil and muck soil previously extracted w ith phosphoric acid. The amount of boron uptake by plants was much lower than in the control. Very prono unced boron difficiency symptom s occurred in very early stages of growth (figure).
In these treatments, after the acidification of the soils to pH 2.8, pro bably a higher amount of aluminum and silica became active. After ad dition of CaCO.j to adjust the pH to the value as in nonextracted soil, the boron could have been fixed due to the formation of secondary minerals in which substition of boron for aluminum was possible. This mechanism of fixation was suggested by P a r k s and S h a w [7]. Also M i d g 1 e у and D u n k l e e [5] investigating the effect of liming on the fixation of bo rates in soils found that a change of pH from 5 to 6 caused a high increase in boron fiixation. In this pH range aluminum become less active and may be precipitatet, forming with siilica and calcium the secondary minerals in which substitution of boron for aluminum is possible. In the soils ex tracted with phosphoric acid, the amount of available phosphorus (table 1) was much higher than in non-extracted soils. There was the possibility that this higher amount of phosphorus m ight influence the uptake of bo ron. To investigate this possibility, an experim ent II with a different amounts of phosphorus in the nutrient solution was carried out in cult ures similar to those in the previous experim ent. Results of experim ent II are given in table 3.
From the data in table 3 make it apparent that two and eight tim es the normal phosphorus concentration in modified Hoagland’s solution
did not significantly affect the yields of sunflow er. These results indicate that the marked decrease of yield in treatments with soils extracted w ith phosphoric acid was not due to a higher amount of phosphorus in these treatments.
T a b l e 3 Influence of high le v e l o f phosphorus on a v a ila b ilit y of boron and growth
of sunflower
Treatments of quartz cu ltu r es Dry matter g /p o t
Control 9 .7
Borax 1 3.9
Borax + 2 times the normal phosphorus concentration 14.3 Borax + 8 times the normal phosphorus concentration 12.7
L.S.D. (0 .0 5 ) 1 .7
On the basis of these data it is impossible to compare the boiling w ater extraction method w ith Philipson’s method. It seem s that in the case of soils low in organic matter, the extraction by bcdling water may remove most of the boron readily available to plants. Generalization of this reqires tests with more soils. Boiling water extraction of soils high in organic m atter does not give the exact information of the available boron situation in the long-term perspective. Boron absorbed on anion exchange resin or on lignin is easily available for plants.
LIT ER A TU R E CITED
[1] B e r g e r K. C., and T r u o g E.: B oron tests and d eterm in a tio n for so ils and p lan ts. S o il Sei., 57, 1944, 25— 36.
[2] D i b l e W. T., T r u o g E. and B e r g e r K. C.: B oron d eterm in a tio n s in soils and p lan ts. S im p lifie d curcum in proced u re A n al. C hem . 26, 1954, 418— 421. [3] J o h n s o n C. M. et al.: C om p arative ch lorin e req u rem en ts of d ifferen t p lan ts
sp ecies. P la n t and so il 8, 1957, 337— 353.
[4] M a j e w s k i F. and M a j e w s k a W.: B ad an ia nad w p ły w e m boru na p o m i dory. R oczn ik i N au k R oln. 68-A -I , 1953, 65— 84.
[5] M i d g l e y A. R., and D u n k l е е E. D.: T he e ffe c t of lim e on th e fix a tio n of borates in soils. S o il Sei. Soc. A m er. Proc. 4, 1939, 302— 307.
[6] N e l s o n W. L. et al.: S o il te s tin g in th e U n ited S ta tes. N a tio n a l S o il and F ertilizer and R esearch C om m ittee, m ailed from U .S.D .A . S oils D iv isio n , B e lts - v ille , Md. 1951.
[7] P a r k s R. Q., and S h a w В. T.: P o ssib le m ech a n ism s of boron fix a tio n in soils: I: C hem ical. S o il Sei. Soc. A m er. Proc. 6, 1941, 219— 223.
[8] P h i 1 i p s o n T.: B oron in plan t and soil. A cta A gric. Scand. III. 2,1953, 121— 242. [9] S h i h a t ą М. М.: II. T est for a v a ila b le so il n itrogen . P h .D . T h esis, U n iv e r sity
J . R . S T A R C K , E . T R U O G , O . J . A T T O E
D O ST Ę PN O ŚĆ B O R U ZAW A RTEG O W G LEBA C H I BO R U Z A A D SO R B O W A N EG O N A ŻYW ICY W Y M IE N N EJ I L IG N IN IE
S t r e s z c z e n i e
P rzep row ad zon o d o św ia d czen ia w a zo n o w e za sło n eczn ik iem w celu zbadania d o stęp n o ści boru zaw a rteg o w gleb ach oraz boru zaad sorb ow an ego na ży w icy w y m ien n ej i lig n in ie. D o św ia d czen ie sk ła d a ło s ię z 9 k om b in acji.
W azony n a p ełn io n o p ia sk iem k w a rco w y m i dodano zm o d y fik o w a n ą p o ży w k ę H o a g la n d a p o zb a w io n ą boru. Bor dodano w ilo ści 0,2 m g na w azon w postaci:
— boraksu,
— boru za sorb ow an ego na ż y w icy w y m ie n n e j (D o w ex 2x), — boru zasorb ow an ego na lig n in ie,
— boru za w a rteg o w g le b ie m in era ln ej (w ilo ści 0.2 m g В oznaczonego m etod ą ek stra k cji w od ą na gorąco),
— boru za w a rteg o w g leb ie organ iczn ej (rów nież ozn aczon ego m etod ą ek stra k cji w o d ą na gorąco).
W p ozostałych k om b in acjach w p row ad zon o do p iask u k w a rco w eg o te sam e ilo ś ci g leb jak w k o m b in a cji 4 i 5 po uprzed n im w y ek str a h o w a n iu ich w od ą na gorąco lu b H3P O4 na zim no (płyn po ek stra k cji o pH 2,8) w celu u su n ięcia d ostęp n ego boru.
N a p o d sta w ie oznaczeń boru p obranego przez sło n eczn ik stw ierd zon o, że w p rzy p adku g leb y m in era ln ej ek stra k cja w od ą na gorąco (go to w a n ie przez 5 m in u t pod ch ło d n icą zw ro tn ą i p rzem y cie na zim no) u su w a p ra w ie cały d o stęp n y dla roślin bor. E k stra k cja w od ą na gorąco g leb y o dużej za w a rto ści su b sta n cji organ iczn ej n ie o k r eśla d ok ład n ie ilo ści boru d ostęp n ego dla roślin . Z g leb y organ iczn ej n a w et po w y e k str a h o w a n iu w od ą na gorąco ro ślin y p ob rały dużo ilo ści boru.
W k om b in acjach gd zie do p iask u k w a rco w eg o dodano g leb ę uprzed n io e k str a h o w a n ą rozcień czon ym H3PO4 i n a stęp n ie zw a p n o w a n o (w celu d o p row ad zen ia do w y jśc io w e g o pH) sy m p to m y braku boru p o ja w iły się w cześn iej niż w ro ślin a ch k o n troln ych , rosn ących na sam ym p iask u k w a rco w y m . N ie b y ło to jed n a k sp o w o d o w a ne zw ięk szo n ą ilo ścią fo sfo ru w tych k om b in acjach , jak to w y k a za ło d od atk ow e d o św ia d c z e n ie ze zw ięk szo n y m i d a w k a m i fo sfo ru w p ożyw ce.
Bor zaso rb o w a n y na ż y w ic y w y m ien n ej i lig n in ie b y ł dobrze w y k o rzy sta n y przez ro ślin y .
И . Р . Ш Т А Р К , Е . Т Р У О Г , О . И . Э Т О У ДО СТУП НОСТЬ Б О Р А С О ДЕРЖ АЩ ЕГО С Я В П О Ч В А Х И Б О Р А А ДС О РБИ РО ВАН Н О ГО Н А И О Н О О БМ ЕН Н И К Е И Н А ЛИГН ИН Е О т д е л е н и е П о ч в о в е д е н и я У н и в е р с и т е т а в У и с к а н с е н М э д и с о н , С Ш А Р е з ю м е П ров еден а был опыт с п одсолнечн иком дл я и ссл едован и я доступ н ости дл я растеий бора почв и бора адсорбированного на ионообм ен нике и лигнине. Опыт состоял из 9 вариантов. С осуды наполняли кварцевы м песком и дав ал и ви дои зм ен н ую смесь Гог- ланда лиш енную бора. Б ор давал и в к оли честве 0,2 мг В на сосуд в ф орм е: 1) буры , 2) бора адсорбированного на ионообм ен нике (Довекс 2Х), 3) бора ад сор бированного на лигнине, 4) бора сод ер ж ащ егося в м инеральной почве (в к ол и ч естве 0,2 мг В, определенного по м етоду горячей экстракции водой), 5) бора со дер ж а щ его ся в органической почве (так ж е обознач енного по м етоду горячей экстракции водой). В дал ьн й ш и х в ар и ан тах вносили в кварцевы й песок те ж е количества почв как в вари ан тах 4 и 5 но посл е п р еды дущ его экстрагирования почв горячей водой или хол одн ого экстрагирования Н3Р 04 (pH ж и д к ост и п осле экстракции 2,8), чтобы удал и ть доступны й бор. На основании оп р едел ен и я бора усвоен ного подсолнечн иком установлено, что горячая экстракция водой (кипячение в теч ен и е 5 минут под обратны м х о лодильни ком и промы вка х ол одн ой водой) уд а л я ет и з м инеральной почвы почти весь бор доступны й дл я растений. Горячая экстракция водой почвы с вы соким содер ж ан и ем органического вещ ества не дает точного оп р едел ен и я бора д о ступного дл я растений. И з органической почвы экстрагированн ой горячей в о дой бы ло усвоен о растениям и больш ое количество бора. В вари антах, где в кварцевы й песок вносили почвы п р еды дущ е эк страги рованны е Н3РО4 и затем и зв естк ован н ы е до и сходн ого pH, симптомы недостатк а бора обн ар уж и л и сь бы стрее, чем на контрольн ы х растен и ях, вы ращ ев аем ы х на чистом кварцевом песке. О днако это н е бы ло вы звано больш им количеством ф о с ф о р а в д а н н ы х вар и ан тах, как п ок азал д оп ол н и тел ьн ы х опыт с в о зв р а щ а ющ ими дозам и ф о с ф о р а в питательной смеси. Бор адсорбированны й на ионообм ен нике и на лигнине хорош о усвои вал ся растениям и.
