effects of lining and fertilization on soil solution chemistry in north german forest ecosystems

Volunta~paper

EFFECTS OF LIMING AND FERTILIZATION ON SOIL SOLUTION CHEMISTRY IN NORTH GERMAN FOREST ECOSYSTEMS

E. Matzner I and K. J. Meiwes

ForsehungszentrumWald6kosysteme der Universitat G6ttingen

Buesgenweg 2, D-3400 G6ttingen

Niedersachsische Forstliche Versuchsanstalt

Graetzelstrage 2, D-3400 G6ttingen, FRG

Abstract. The effect of aboveground liming and fertilization as well as ploughing and liming of

forest soils on soil solution chemistry was studied in various experimental plots of the Gezr~n Soiling

area. Due to low solubility of limestone, aboveground liming had only moderate effects on soil pH and

base saturation of CEC. Calcium and Mg concentration increased and Ca~A1 and Mg/AI ratios of the soil

solution improved. Despite extreme doses of lime, nitrate leaching did not increase in the case of a

beech plot. Elevated nitrate leaching was found in the case of a spruce and a beech plot previously

fertilized with N. Nitrate concentrations are far from drinking water thresholds in the case of beech.

Nitrate levels of soil solution of the unfertilized spruce plot are in the range of 3 to 8 mg L -I.

Liming did increase these values slightly in the first years, and nitrate levels reached those of the

untreated plot in the following years. Ploughing connected with high liming doses obviously led to

inhomogeneous distribution of lime. No significant deacidification of seepage water at a depth of 100

cm occurred because of leaching of sulfate from the industrial lime used. This was followed by A1-

leaching. Nitrate levels slightly exceeded drinking water standards throughout the first winter

period after the measure. The development of young trees was significsntly improved.

i. Introduction

Over the last decades forest soils of Central Europe have been impacted

by the deposition of air pollutants. Among those, acids (H +) and

potential acids (NH4 +) are of major importance and accelerate soil

acidification which should be defined as a reduction of acid neutralizing

capacity (Van Breemen et al, 1983). Losses of nutrient cations like Ca,

Mg, and K from the exchange complex, as well as possible toxic effects of

Al-ions being mobilized by strong acid inputs, will threaten the

nutritional status of the trees in many "cases. Nutrient imbalances by

high N inputs may furthermore be involved (Oren et al., 1988). For

example, needle yellowing of Norway spruce, which is related to Mg

deficiency, is widespread in North Germany and has been studied in North

Germany in detail in the Harz mountains (Stock, 1988; Matzner et al.,

1989) and elsewhere (Zech and Popp, 1983; Z6ttl and Mies, 1983).

Liming and fertilization of forest soils represent the most important

measures of silviculture to mitigate the effects of acid deposition on

soils and forests. Aboveground liming is now applied at a dose of about

3 t ha -I in Lower Saxony on a large scale. Major objectives of

aboveground liming are: buffering of acid deposition, improvement of

tree rooting, deaeidification of seepage water, improvement of soil

biological state and improvement of tree nutrition and vitality.

1 Author for all correspondence.

Water, Air, and Soil Pollution 54: 377-389, 1990/91. © 1990/91 Kluwer Academic Pt~blishers. Printed in the Netherlands.

378 E. MATZNER AND K. J. MEIWES

However, the effects of forest fertilization and liming on trees, soils and waters are still discussed controversially. Negative effects on soil C- and N- pools, nitrate leaching, soil animals and trees are argued.

This paper will describe the effects of liming and fertilization on the elemental cycling of North German beech and spruce forests by using results from various experiments. Special consideration is given to soil solution chemistry.

2. Site, Treatments and Methods

2.1 Site

SubplOts for fertilization were established adjoining the already well documented (Ellenberg et al., 1986) mature beech (BI) (Fagus siivatica L.) and spruce (FI) stands (Picea abies L. [Karst.]) of the German IBP project in the north German Solling area. The stands grow on acid, podzolic soils derived from loess material mixed with weathered sandstone. The sites are heavily impacted by the deposition of air pollutants. Hydrogen ion deposition reaching 2 to 4, SO4-S deposition 50 to 80, and total N deposition reaching 30 to 50 kg ha -I a -I as long term averages (Matzner, 1989). The amounts of fertilizer applied to subplots BD and FD (B = beech, F = spruce) are given in Table I.

Table I

Amount (kg ha-l), timing and form of fertilizer applied to the plots BD and FD (aboveground)

Time of application Fertilizer NO3-N NH4-N Ca K Na Mg Mn C1

June/July Ca, ammonium, nitrate + 166 150 115 170 24 4 1973 muriate of potash

October 1975 Lime (industrial) 1188 30 12 360 16 December 1980 Lime (dolomitic) 772 5 2 456 1

186

Subplot BK. Liming aboveground in 1982: 30 t ha -I dolomitic lime; 6090 kg ha -I Ca; 3570 kg ha -I Mg. The dose is about ten times the one used in forest practice. The experiment was conducted to study the effect of an extremely high dose of lime. For details see Beese (1989).

Subplot LV (melioration). Soil treatment by deep ploughing (i00 cm) and mixing with 25 t ha -I industrial lime (mainly Ca-silicate) in 1985; aboveground liming of 15 t ha -I industrial lime with subsequent surficial soil treatment; planting of beech and acer mixture in 1986; seeding of Lupinus polyphyllus. The total amount of elements added were

EFFECTS OF LIMING AND FERTILIZATION ON SOIL SOLUTION CHEMISTRY 379

(kg ha -1 ) Ca, 12.300; Mg, 1.820; S, 590 (S content of the industrial lime). The aim of the experiment was to neutralize the whole rooting zone and to study the effects of a drastic change in soil chemical, physical and biological conditions (Wenzel, 1989).

Subplot LN: reference plot. No soil treatment and liming.

2.2 Methods

Soil solution was collected continuously by ceramic tension lysimeters at various depths and analyzed for major elements according to standard methods (Meiwes et ai., 1984; K6nig et a2., 1989).

3. Results

3.1 Effects of aboveground liming

Prenzel (1985) concluded that the solubility of calcite and dolomite is very low when applied on the soil surface. The maximum rates of solubility were estimated to be in the range of 1 t lime ha -I yr -I. In practice, this rate will be much less mainly because leaves and needles will prevent sufficient contact of the lime and the percolating solution. Thus, one could not expect a close dose-effect relationship in the case of aboveground liming. This is of special importance when evaluating the dose that should be used in practice and the risk of applying high amounts.

The low solubility of lime under field conditions is reflected in the changes of soil solution chemistry after liming. Figure 1 shows the development of the Ca and Mg concentrations of the plot BK treated with an extremely high dose of dolomitic lime in 1982 at a depth of I0 cm. For reference, the untreated plot B1 is given. Only minor changes of solution concentration are found in the case of Ca while the effect of liming is more pronounced in the case of Mg. The pH was raised from about 3.8 (BI) to 4.3 (BK) (Beese, 1989). Only slight changes in Ca and Mg concentrations were also found in other liming experiments (Matzner, 1985; Wenzel, 1989).

The Ca/A1 as well as the Mg/AI ratio of the soil solution has been shown to be a critical parameter indicating the risk of Al-toxicity to plant roots and the risk of antagonistic effects on Mg uptake (e.g. Neitzke and Runge, 1985; Rost-Siebert, 1985; Jorns, 1988). One of the major aims of liming is to improve these parameters in order to reduce the stress to root growth and nutrient uptake. The development of these ratios is given for the site FD and the untreated reference plot at a depth of about i00 cm in Figure 2. Tentative threshold values for Norway spruce are in the range of 1 (Ca/Al) and 0.2 (Mg/AI) (Rose- Siebert, 1985; Jorns, 1988). Both ratios decreased with time in the unlimed plots and are significantly raised by liming.

Increased nitrate losses following aboveground liming may occur as a consequence of improved conditions for microorganisms and are a major risk of liming measures because of groundwater pollution. This phenomenon has recently been reported by Schierl and Kreutzer (1988) after liming of a N-rich Norway spruce stand.


Cals.[mg/l] LK 10

12.5-

10

7.5

2.5

II I

"~/ ~ \ \ ~ ,.,\ i \ j % I .

1111111 I l l l l l l l l l l I 1111111111 I I I I I I i i i i 1 I I I I l l l l l l l I I I I I l l l l l l I 1 1 1 1 1 1 1 1 1 1 I I I 1 1 1 1 1 1 1 1 r

0 1982 1983 1984 1985 1986 1987 1988

Hga .[rag/L] ~ LK 10

7.5-

1,5

L /~ " / II /

' IV , / \ J ! , , o - , / I I ~ I d ' ,

I l l I t\ I /~ t'J\ /

,H.,, ,.,HH~H1982119831198Z : , , . , . . , , ,,,H.H,, ,,H,,.H,198561986,,,,,,,,,,, '''''''''''1987 '''''''''''19886

Figure I. Ca and Mg concentration of the soil solution of the plots BK and B1 at a depth of I0 cm


Mg/At [mot/mol ,~ LP 100

I

I I ~'

I ~] \ I '

II I"~ I,'"~'. ' \ / \ ! I ~I[ Jl lJ II I ' l~/'

l / I I1~, ' - '"/ I

IIInlllll IIIIIlUllll I[I.~ ,~ 111111111111.7. 111111111111976 111111111111.77 IllUlllnl|.7. nlllllllll| g~'ll Ilnlltlllll.ll. 111111111111911 111111111111.82 1111111111119.3 lUlllllllll.lal IIIIIIIII111 ~IllS IllUllllll'i 981~ l 111111111111..7 IIIlllUlU~l... I

Ca/At4.5. [motlmot]~

3.75.

3 .

2.25

1.5

0.75

LP 100

i I ) f I i

b I. I // ~l

• p , l \vl

4~i , , + ,, 1, I~ !' , ~ I ~ , ~t'

.......... F S~' 'i S$17,';: T.;;17,;: 7.';ZI ;2T2T,"[ $2]'] ;7[] ;7' 27 SS]' S2T] ;7'

Figure 2. Ca/AI and Mg/AI ratios of the soil solution of the plots F1 and FD at a depth of i00 cm (time period: 1973 to 1988)


NO3-NI: [mg/[] ~ ,

1 0

8 .

6 ,

4 -

2 -

0 ]

LP 100

i I I It I !

NO3-N451 [mg/[] LP 100

3 7 . 5

3O

2 2 . 5

1 5

7 . 5 '

0

I~/"~ ~\ I~ /~,','/" I I ',~ t,~

Figure 3. NO3-eoncentrations of the soil solution of the plots BI, BD, FI and FD at a depth of i00 cm


NO3-N15 ] ling/L]

12.5

10 "4 i

/

7.5 1 , t i ~, ~',Ii. h ] \ H IIi IX I

2.5 ,~/I, ~ !

% / ~,~J"r, ,,,,,., ,,,,,,,,,,T,,,,,,,,I,I,.,.,,.,.

I 1982 I 1983 I 198,4

LK 10

11 /"

/ I I

, , /V

I I I I I 1 1 1 1 1 1 I I I I I 1 1 1 1 1 1 I J l l l l l l l l l I111111

1 9 8 5 1 1 9 8 6 1 9 8 7 19~

/ . i

NO3-N12 ling/I]

10

'(,,/, \ ~ r / \ ~ '~1 ",

LK 20

I

I I

I ~ I

n

\ I ° \ ~ ° ,'k..

Figure 4. NO3-concentrations of the soil solution of the plots B1 and BK at a depth of i0 cm

384 E. MATZNER. AND K. J. MEIWES

A[45 ling/I] LP 100

3 7 . 5

30 "~

2 2 . 5 ;

1 5 -

7.5 "

I

IqI IIli

i a .AL/

IIIIlIIIII IllU111111t974 111111111111973 IllU1111111978 U111111111197~ 11111111111187~ lUlIIIIIII19Z9 111111111111980 IllU1111111981 IIIILU11111982 1111111IIIIt983 I111111U1119154 IllUU1111|985 111III111111999 [11111111111997 111111111111888 I

ALl2 [rag/L]

10

LP 100

81 I,

t ii I 6- i;~ /

4 " I I I ~ ~ '

.................... ..... :;2...2.2;2.̀2:1:.̀2.2;2.772..2.212..2;~2.7.2:22.~.J~2.̀...2;2~.:.222..2~22..~2.~22..2.2:2..2.22;~..2.2~:]~

Figure 5. Al-concentrations of the soil solution of the plots B2, FD, BI and BD at a depth of i00 cm (time period 1973 to 1988 FI, FD; 1969 to 1988 BI, BD)


Mg ling/l] ~ LK 100

3.75 t

3 t /\~

, ' , , L / , . - .

~11 o.75{

o, I . . . . ] . . . . I 'FIHnAnHnJ'J'A'$'Q'N'D J 'F'I'$nA'HJJ'J'A'S'O'N'D J'F'H'A'~I'J'J'A'S'O'N'IJ jn

Co l i n g / l ] 18

LK 100

e x./,x f~,/

o I . . . . I . . . . t 'F 'H'A'H'J 'J 'A'S 'O'N'9 J 'F 'H'A'H'J 'J 'A'$ 'O'N'D J 'F 'H'A'H'J 'J 'A'S 'O'N'D J'

pH LK 100

i 'F 'M'A'M'J 'J 'A'S 'O'N'0 J 'F 'ti'A'WJ 'J 'A'$ 'O'N'D J 'F 'ti'A'M'J '3 'A'$ 'O'N'D J'

I . . . . i . . . . I

A[ [mg/[] ~ LK 100

1o

8 ~ A

°t" / ' %

S O • , - S [mg/U ~ LK 100

16

12

8 V \~- /z \ / /

4

° 1 . . . . I . . . . I 'F 'H'A'M'J 'J 'A'S 'O'H'D J 'F 'H'A'HU 'J 'A'S 'O'N'D J 'F'M'A'M'J 'J 'A 'S 'O'N'D J'

NO3-N ling/|] ~ LK 100

/ - / I /

4 -x x t-J xx ..... "~

'F 'II'A'M'J 'J 'A'S 'o'N'D J 'F 'H'A'H'J 'J '^'S 'O'N'D J 'F 'H'A 'H'J 'J ^'S 'O'N ' ~

Figure 6. Soil solution chemistry of the plots LV

and LN at a depth of i00 cm


Nitrate concentrations of the soil solutions from the various Solling experimental sites show different pictures. Concerning the effect of aboveground liming on the nitrate concentrations of the soil solution and seepage water of the sites BD and FD (Figure 3), one has to take the N- fertilization in 1973 into account which might enlarge the effect. However, only a slightly higher level of nitrate is found after liming in 1975 in these sites and with time nitrate concentrations reach those of the untreated sites in the case of Norway spruce. Nitrate concentrations under the limed beech plot are higher but did not exceed 4 mg NO3-N L -I.

Despite the high liming dose, nitrate eoncentrations of the limed plot BK are equal and sometimes less than those from the unlimed plot at i0 and 20 cm soil depth (Figure 4). This may be caused by N-immobilization by soil microorganisms and by the higher vitality (in terms of growth) and N-uptake of the trees of the BK-site (Roloff, 1989 in Matzner, 1989).

While studying the initial effects of aboveground liming of other Norway spruce sites of the Solling area, Wenzel (1989) found increased nitrate concentrations of the soil solution in the upper part of the profile during winter. Minor effects are also reported from the deeper layer.

3.2. Effectsof aboveground salt fertilizers

Highly soluble fertilizer salts (NH4N03, KCI) were applied in moderate doses on the sites BD and FD in 1973. Cation exchange of fertilizer cations of high exchange selectivity (NH 4 and K) against the dominant cation found at the exchange sites (AI), is reflected in the development of the soil solution chemistry.

Figure 5 shows the total Al-concentrations of the soil solution at i00 cm depth which are extremely high in 1973 and 1974. Unfortunately, the starting phase after fertilization is not completely included. AI- concentrations might have been higher. The A1 accompanying anion is mainly CI, but is also NO 3- to a large extent. Both the nitrate leaching and high A1 concentrations of the soil solution after fertilization should be avoided because of groundwater pollution, acidification of deeper layers (Matzner, 1985), and possible toxic effects to plant roots. Increased A1 concentrations and A1 leaching with seepage water following the fertilization of K2(Mg)SO 4 are also reported by Wiedey and Raben (1988).

3.3 Effects of soil treatment and liming

The development of soil solution chemistry was followed at plots LN and LV at a depth of I00 cm.

The effects of the treatment and liming on soil pH and exchangeable cations are given by Wenzel (1989). The treatment increased the base saturation of the CEC to about 20 to 30~ up to I00 cm soil depth. Only the 0 to 20 cm layer reached a base saturation of 70~. The distribution of lime obviously is rather heterogeneous as indicated by high standard deviation of base saturation and of soil pH. Thus, one major aim of the treatment, to deacidify the whole rooting zone, has not been reached.

The treatment influenced the soil solution chemistry in many ways. The high amount of S that was applied with the industrial lime, leached from the soil leading to increased levels of SO4-S in the soil solution (Figure 6).


Sulfur may be present in the form of sulfate (CaS04), but it is also known that industrial lime contains reduced S (FeS, CuS). Only total S was analyzed in this case. In the case of reduced S, the oxidation and leaching of sulfate will be a proton generating process. The sulfate is accompanied by Al-ions mobilized from the soil (Figure 6). The alcalinization of seepage water, which was another major aim of the treatment, failed so far. Furthermore, the pH of the soil solution of the treated LV plot, is slightly lower compared to the control plot (Wenzel, 1989). Ca and Mg concentration increased as a consequence of the treatment and the Ca/A1 ratios improved slightly despite elevated A1 levels (Wenzel, 1989). Soil treatment and liming caused increased nitrate leaching (Figure 6). Especially during the autumn period of 1986, nitrate levels slightly exceeded drinking water standards, but then decreased continuously in 1987 and 1988.

4. Discussion and Conclusions

Due to the low solubility of limestone, the change of solution chemistry induced by aboveground liming is moderate. Neither drastic pH-changes nor drastic changes of Ca and Mg concentrations occurred. Furthermore, base saturation of CEC is only affected slightly in the upper mineral soil (Wenzel, 1989; Matzner, 1985). Thus, one can conclude that, out of practical reasons the application of a higher dose of lime than the presently used 3 t ha -I will not lead to detrimental effects exceeding those of a low dose significantly. The improvement of the decomposer environment by aboveground liming may be followed by elevated levels of nitrate in seepage water. The results from the Solling area show that this is not always the case. Even very high liming doses did not increase the nitrate concentration in the case of the BK site. Increased nitrate concentration on the FD site at a soil depth of I00 cm will reach those of the unlimed plot with time and may be caused by N-fertilization prior to liming. The long lasting increase of nitrate is found in the case of the BD plot. The levels of nitrate, however, are far lower than drinking water thresholds. The BD site also received N-fertilization prior to liming. Wenzel (1989) also found a moderate increase of nitrate concentration in a 2 yr period after aboveground liming of mature spruce stands.

The factors leading to changes of N-dynamic of limed forest soils are poorly understood in a quantitative way. The role of long lasting atmospheric N-deposition needs an especially careful assessment. Scandinavian liming experiments reveal even less net N-mineralization of limed plots compared to their unlimed references (Andersson and Persson, 1988; Derome et al., 1986).

The risk of inducing unacceptable levels of nitrate by aboveground liming of forest soils is thus assumed to be low and is covered by the positive effects. A high level of nitrate like those reported from Schierl and Kreutzer (1988) seems to be exceptional and might be restricted to specific site conditions like those found in the H6glwald. The zeroplot of the H6glwald had already very high nitrate concentrations of soil solution and seepage water indicating a disturbance of the N cycle of this ecosystem.

Improvement of tree vitality and nutrition by liming was shown for the Solling sites (Matzner, 1985, 1989) and elsewhere (Kaupenjohann and Zeeh, 1987).


As mentioned above, one of the major aims of liming is to improve tree rooting. Especially rooting of Norway spruce in deeper soil layers seems to be restricted by adverse Ca/A1 ratios of the soil solution (Ulrich, 1989; Murach and Matzner, 1989). However, despite increased Ca/A1 ratios after liming, rooting patterns in deeper layers did not change (Andersson and Persson, 1988; Murach and Sch~nemann, 1985) after aboveground liming. Further research is necessary to understand the factors influencing rooting patterns of trees and the possible effects of above-ground liming.

The A1 concentrations and the total acid load (H + + cation acids) of soil solution and seepage water is reduced by liming (Matzner et al., 1983; Matzner, 1985; Beese, 1989). Aboveground liming thus can be used to reduce the risk of water acidification. However, the effects are still moderate and acidity is transferred to deeper layers by seepage water even 15 yr after liming in considerable amounts.

The mobilization of Al-ions with subsequent leaching is a major problem of fertilization of easy soluble salts like sulfates or chlorides on acid soils. This is demonstrated by the development of AI- concentrations of the BD and FD plot as well as by laboratory studies (Hildebrand, 1989). Application of these fertilizers to acid forest soils should be restricted to acute nutrient deficiency symptoms and only relatively low doses should be used.

While the effects of aboveground liming on rooting patterns are minor, the root development and vitality of young trees significantly improved by soil treatment and liming on the plot LV (Wenzel, 1989). Wenzel showed the development of deep reaching root systems of beech, spruce and acer following the treatment, while the roots at the untreated plots stayed superficial. Unfortunately soil solution chemistry has not been followed in the rooting zone. Alcalinization of the seepage water at i00 cm failed at least within 3 yr. The distribution of lime is obviously too heterogeneous and the S content of the industrial lime induced high sulfate and A1 levels of the soil solution at deeper layers.

The applicability of industrial limes with high sulfur content at high doses is thus questionable.

The treatment induced high nitrate concentrations of the seepage water within the first year, nitrate concentrations of the second and third years were already far below drinking water thresholds. The future development will be of great importance. Further evaluation of existing and comparable measures as well as new experiments of this type are necessary to allow better recommendations for forest practice.

References

Andersson, F. and Persson, T.: 1988, Nat. Swed. Envi. Prot. Board Report 3518, 1-131. Solna, (S).

Beese, F.: 1989, Ber.d. Forschungszentr. Wald6kosyst.d.Univ. G6ttingen, Reihe A, Bd. 49, 9.

Derome, J. Kukkula, M. and Malk6nen, E.: 1986 Nat. Swed. Envi. Prot. Board Report 3084, 1-107 Solna (S).

Ellenberg, H.sen., Mayer, R. and Schauermann, J. (eds): 1986, 0kosystemforschung: Ergebnisse des Sollingprojektes 1966-1986. Ulmer Verlag Stuttgart.

Hildebrand E.E.: 1989, 0sterreiehische Forstzeitung 3, 78.


Jorns, A.: 1988, Ber.d.Forschungzentr. Wald6kosyst.d.Univ. G6ttingen. Reihe A, Bd. 42, i.

K6nig N., Loftfield, N. and Lfiter, K.L.: 1989, Ber.d. Forschungszentr. Wald6kosyst.d.Univ. G6ttingen, Reihe B, Bd. 13.

Kaupenjohann, M. and Zech, W.: 1987, in G. Glatzel (ed) "M6glichkeiten und Grenzen der sanierung immissionsgeschadigter Wald6kosysteme". FIN, Univ.f. Bodenkultur Wien (A), 82-98.

Matzner, E.: 1985, AFZ 43, 1143. Matzner, E.: 1989; Ber.d.Forschungszentr. Wald6kosyst.d. Univ. G6t-

tingen, Reihe B, Bd. 15. Matzner, E., Blanck, K., Hartmann, G. and Stock, R.: 1989, in J.B. Bucher

and I. Bucher-Wallin (eds) Proc. 14th Int. Meeting Air Pollution Effects on Forest Ecosystems, IUFRO P2.05, Interlaken (CH), Oct. 2-8 1988, Birmensdorf, 195-199.

Matzner, E., Khanna, P.K., Meiwes, K.-J., Prenzel, J., Lindheim, M. and Ulrich, B.: 1983, Plant and Soil 74, 343.

Meiwes, K.-J., K6nig, N., Khanna, P.K., Prenzel, J. and Ulrich, B.: 1984, Ber.d.Forschungszentr. Nald6kosyst.d. Univ. G6ttingen. Reihe A., Bd. 7.

Murach, D. and Matzner, E.: 1989, IUFRO Symposium "Woody Plant Growth in a Ghanging Physical and Ghemical Environment", Vancouver 1987, in press.

Murach, D. and Schfinemann, E.: 1985, AFZ 43, 1151-1155. Neitzke, M. and Runge, M.: 1985, Flora 177, 237. Oren, R., Schulze, E.-D., Werk, K.J. and Meyer, J.: 1988, Oecologia 77,

163. Prenzel, J.: 1985, AFZ 43, 1142. Rost-Siebert, K.: 1985, Ber.d.Forschungszentr. ~ald6kosyst.d. Univ. G6t-

tingen, Reihe A, Bd. 12, i. Schierl, R. and Kreutzer, K.: 1988, Kali Briefe 19, 417. Stock, R.: 1988, Forst- u. Holzwirt 43, 283. Ulrich, B.: 1989, Adv. Environm. Science, in press. van Breemen, N., Mulder, J. and Driscoll, C.T.: 1983, Plant and Soil 75,

283. Wenzel, B.: 1989, Ber.d.Forschungszentr. Wald6kosyst.d. Univ. G6ttingen.

Reihe A. Bd. 51, i. Wiedey, G. and Raben, G. : 1989 Ber.d.Forschungszentr.

Wald6kosyst.d. Univ. G6ttingen. Reihe A. Bd. 12, i. Zech, W. and Popp, E.: 1983, Forstwiss.Cbl. 102 50. Z6ttl, H.W. and Mies, E.: 1983, Allg.Forst-u.J.Zt E. 154, 110.

effects of lining and fertilization on soil solution chemistry in north german forest ecosystems

Documents