Nutrient Availability and Foliar Nutrient Status of Sugar Maple Saplingsfollowing Fertilization

D. Pare, W. L. Meyer, and C. Camire*

ABSTRACTFoliar analysis of maple sugar (Acer saccharum Marsh.) saplings

having low foliar K (5.4 g kg*1) and P (1.2 g kg'1) was carried outfor 3 yr to investigate the effects of a single application of fertilizer Ptriple superphosphate [TSP], K (K2SO4) and Ca [Ca(OH)2]. Also, soil,water-saturated soil extract, resin sacks buried in situ, and lysimetersolution analysis methods were used. Potassium and P additions sig-nificantly increased foliar K (1.81 g kg-' increase) and P (0.25 g kg-1

increase) for the 3 yr that the observations were conducted. Calciumaddition had no effect on foliar element concentrations. A Diagnosisand Recommendation Integrated System (DRIS) analysis corrobo-rated the foliar analysis: K indices increased with increased K fertil-ization (from -47 to —23) and P indices increased with increased Pfertilization (from —25 to —15). Calcium application significantlyincreased the effective cation-exchange capacity (CEC), exchangeable Caand Mg and water-extractable Ca and decreased the acidity in the root-ing zone for a 3-yr period. Conventional soil analysis and resin sacksdetected significant effects of P and K fertilizers on their respective ele-ments. However, these effects did not last more than 2 yr after fertilizerapplication in the surface soil horizon (Ah). Lysimeter solution analysisshowed that K2SO4 fertilizer caused short-term increases in SO4 and Caleaching. The duration of fertilizer P and K on foliar nutrition and thebehavior of soil nutrients suggested that biochemical cycles are importantmechanisms perpetuating fertilizer effects.

INCIDENCE of forest decline in Europe and North_ America has rapidly increased during the past

decade (Pitelka and Raynal, 1989). In Quebec, sugarmaple stands have shown symptoms of dieback anddecline since the late 1970s. The cause of the declineis still unclear but the interactions of numerous abioticand biotic factors could be involved (Bernier et al.,1989; Hendershot and Jones, 1989). In addition, Ber-nier and Brazeau (1988a) have found low foliar con-centrations of K, P, or both in several declining maplestands in the Appalachian region and low concentra-tions of Mg in the granitic formation of the LowerLaurentians (Bernier and Brazeau, 1988b).

One of the possible solutions to prevent or reversea decline in stands of low nutrient status is the use offertilizers, the belief being that trees supplied withadequate amounts of nutrients will be healthier andtherefore more resistant to stress (Hendershot and Jones,1989). In European coniferous forests, several studieshave indicated that one of the ways to reverse thedecline problem in trees experiencing nutrient defi-ciencies is to provide trees with an adequate nutrientsupply, both in terms of quantity and proportion ofthe essential elements (Hiittl, 1990; Huttl and Wis-niewski, 1987; Zottl, 1987; Zottl and Huttl, 1986).

In Quebec, foliar nutrient concentrations in sugar

D. Pare, Groupe de recherche en ecologie forestiere, Universitedu Quebec a Montreal, C.P. 8888, Succursale A, Montreal, Que-bec, Canada H3C 3P8; and W.L. Meyer and C. Camire', Centrede Recherche en Biologie Forestiere, Faculte de Foresterie et deGeomatique, Pavilion Abitibi-Price, Universite Laval, Sainte-Foy(Quebec), Canada G1K 7P4. Received 4 Mar. 1992. *Corre-sponding author.

Published in Soil Sci. Soc. Am. J. 57:1107-1114 (1993).

maple stands have increased following fertilization(Bernier et al., 1989; Hendershot, 1991; Pare, 1987)but trials to assess the prevention or alleviation ofsugar maple decline symptoms with the addition offertilizers are still ongoing. Although increased foliarnutrient concentrations were observed in many casesfor a single year after fertilization (Bernier et al., 1989;Huttl and Wisniewski, 1986; Pare, 1987), the long-term fertilizer effects on nutrient-deficient sugar ma-ple stands have not been reported. For other tree spe-cies, however, numerous long-term fertilization studieshave been carried out (e.g., Mahendrapa and Salon-ius, 1982; Shoulders and Tiarks, 1980; Nelson andSwitzer, 1990). The recovery of fertilizers in a for-ested ecosystem varies with vegetation type, soil, andfertilizer and as Ballard (1984) summarized, the re-covery of N fertilizer is usually of short duration butthe recovery of P and K may last several years.

Foliar analysis is one of the most common tech-niques used to assess the nutrient status of trees afterfertilization but visual symptoms (as exhibited by dis-colored or damaged leaves) are also useful in assess-ing tree vigor (Bernier and Brazeau, 1988a,b). Althoughcritical-value approaches have been used to assess fer-tilization effects on nutrient levels in plants, the sys-tem is limited by factors such as plant age and growthrates, and one cannot rank the order in which thenutrients are limiting. Tomlinson (1985) has indicatedthat differences in soil and foliar cation ratios may beused to help diagnose deficiency symptoms in declin-ing maple trees. However, the interpretation of suchanalyses is complicated by the number and the inter-relationships among the ratios examined (Sumner,1978). Ingestad (1987) stated that plant nutrient levelsare related to the complete nutrient proportions in plantsand in fertilizer as well as the rate of fertilizer appli-cation required to support current plant growth. Hepostulated that plant nutrient levels are more relatedto the proportions of nutrients available in the soilrather than just the absolute concentrations of the nu-trients. Several studies on tree nutrition and stresses(Ingestad, 1979a,b; Jia and Ingestad, 1984) have re-vealed optimum cation and anion ratios for tree vigorand growth.

The Diagnosis and Recommendation IntegratedSystem (DRIS), developed by Beaufils (1973) andsubsequently modified by Beverly (1987), defines thenutrient status of high-yielding or healthy populationsand compares subsequent tissue analysis to those ob-served optimums. The DRIS method examines the in-terrelationship among plant, soil, environmental, andyield factors. The reactions among these factors aresummarized in terms of indices, which in turn givenan indication of the intensity with which a plant orAbbreviations: TSP, triple superphosphate; DRIS, Diagnosis andRecommendation Integrated System; CEC, cation-exchange capac-ity; PVC, polyvinyl chloride; FIA, flow injection analysis; ICP,inductively coupled plasma; 1C, ion chromatography; ANCOVA,analysis of covariance; NDI, nutrient disequilibrium index.

1107

1108 SOIL SCI. SOC. AM. }., VOL. 57, JULY-AUGUST 1993

soil requires a given nutrient (Sumner, 1978). How-ever, DRIS requires intensive analyses and surveys ofthe population in question and requires healthy, op-timum growing plants to be present. Lozano and Huynh(1989), using a small data base, have had some initialsuccess with this method in examining foliar data ofsugar maple.

The effectiveness of fertilizer treatments to eitherprevent of alleviate the decline problem requires theassessment of the efficiency of tree uptake of the fer-tilizer and the fertilizer's fate in the soil. The primaryobjective of this study was to determine the effects offertilization for a 3-yr period, on foliar nutrient status(including changes in DRIS indices) and on soil nu-trient availability in soils supporting sugar maple sa-plings. The main emphasis was on the fate of K andP fertilizers in plant and soil because of the low K andP foliar levels found in several sugar maple stands insouthern Quebec. A further objective was to examinethe effects that applications of Ca(OH)2 had on theavailability of other nutrients and on soil acidity. Thiswas done because sugar maple stands in this regionare sometimes limed to neutralize soil acidity (pH =4-5.6) and acid precipitation (pH = 3.0-4.5; Gri-mard, 1985) with little or no regard for other effectson soil nutrients. Nitrogen and Mg were not consid-ered low or deficient in this region and were thereforenot added.

MATERIALS AND METHODSThe site chosen for this study was in a thinned area within

a stand of mature (~ 150 yr) sugar maple trees near St. Norbert,Quebec (46°03'N, 71°55'W; 15-20 m above sea level). In thisstand, the dieback, transparency, discoloration and amount ofdwarfed leaves was < 10% and was thereby defined as "weakdecline" (Millars and Lachance, 1989). The decline of maturetrees manifested itself mainly in the form of branch dieback(5-10%). No such dieback could be seen on the saplings.

This stand was chosen because of: (i) the stand's known lowfoliar nutrient levels of P and K; (ii) its potential susceptibilityto future decline (Bernier et al., 1989); and (iii) the fact thatthe fertilization experiment was meant to supply the saplingswith higher amounts of nutrients as prevention rather than cure.Foliar nutrient levels were determined by looking at criticalfoliar concentrations (in g kg-1: N, 15; P, 1.2; K, 6; Ca, 6;and Mg, 1) and by examining the DRIS indices as proposedby Lozano and Huynh (1989) for sugar maple (N index, 15;P index, —27; K index, —39; Ca index, 6; and Mg index,44) prior to fertilization.

The topography in the St. Norbert stand is level to slightlyundulating. Soil is well- to rapidly drained. The soil parentmaterial is an alluvium sand to loamy sand, 60 cm deep over-lying a sandstone and siltstone formation consisting of quartz-ite and dolomite. The topsoil is a Medium Mull Forest humus(10 cm thick). The soil is classified as a Haplorthod (SoilSurvey Staff, 1975) or a Sombric Humo-ferric Podzol (CanadaSoil Survey Committee, Subcommittee on Classification 1978).Physico-chemical properties of the soil profile are given inTable 1.

Fifty-four 2 by 2 m plots were selected among the densesugar maple understory (25 000-35 000 stems ha-1; saplingheight = 1.5-3.0 m; sapling age = 5-10 yr). The criteria forselection was that there be at least 10 saplings present, that aspace of 5 m be left between plots, and that plots were to beat least 10 m away from the base of any mature trees in thearea. The experiment consisted of three levels of P (0 [PO],75 [PI], and 150 [P2] kg ha-1 TSP), three levels of K (0 [KO],

Table 1. Selected physical and chemical properties of St. Norbertsoil.

Particle-sizedistribution pH

_________ Organic Total TotalDepth Horizon Sand Silt Clay H2O CaCl2 C N S

cm0-10 Ah 82 16 2 5.2 4.4 82.0 4.9 0.73

10-13 E 84 13 3 4.5 4.0 7.7 0.5 0.1713-17 Bsl 79 11 10 4.8 4.3 37.2 1.8 0.7317-25 Bs2 84 8 8 5.1 4.5 33.3 1.3 0.7325-58 Bs3 89 5 6 5.2 4.7 14.3 0.7 0.4058-68 BC 95 3 2 5.4 5.0 4.3 0.2 0.17

150 [Kl], and 300 [K2] kg ha-1 K2SO4), and three levels ofCa (0 [CaO], 500 [Cal], and 1,000 [Ca2] kg ha-1 Ca(OH)2—40.7% Ca and 9.5% Mg) fertilizers alone and in combination,providing 27 treatments. Treatment levels were chosen basedon other fertilization studies done in the province (Bernier etal., 1989; Hendershot, 1991). Each treatment was replicatedtwice in a completely randomized factorial experiment. Thefertilizers were applied once by hand on 14 June 1987.

Five saplings were selected and marked for foliar collectionamong those growing near the center in each of the 54 plots.One undamaged, subapical leaf was collected per sapling. Thefive leaves were pooled to form one composite sample perplot, oven dried at 65 °C to a constant weight and ground topass a 425-fim sieve. Total N, P, K, Ca, and Mg were ana-lyzed according to the methods described by Bernier and Bra-zeau (1988a). Foliar samples were collected before (on 14 June1987) and after fertilization (on 14 Sept. 1987, 27 Aug. 1988,and 14 Aug. 1989). The prefertilization sampling served tocreate covariables (statistical control) for the effect of fertilizeron foliar tissue element concentrations and reduced the numberof saplings required for testing.

Single soil samples from the Ah, Bsl, and Bs2 horizonswere collected from each of the 54 plots on 29 Oct. 1987 (138d after fertilization), on 28 Oct. 1988, and on 7 Aug. 1989.Samples were air dried and sieved through a 2-mm screen. Thesamples were analyzed for dichromate-oxidizable C, KjeldahlN, 1 M NH4NO3-extractable K, Ca, Mg, Fe, Mn, and acidity(H + Al) (Stuanes et al., 1984), Bray II-extractable P, andpH (in H2O and 10 mM CaCl2). Effective CEC was estimatedby summing Ca, Mg, K, and acidity. Dichromate oxidizableC was used as a covariable in the statistical analysis.

Duplicate 100-g samples from the Ah horizon were saturatedwith deionized water by capillarity (Longenecker and Lyerly,1964), equilibrated for 12 h at 5 °C and extracted by centri-fugation (Davies and Davies, 1963). The supernatants werefiltered (0.45 fun) and immediately frozen until the inorganicions were analyzed. This analysis was used to estimate indicesof cation availability to plants and of cation leaching potentials(Sharpley and Kamprath, 1988).

Cation and anion exchange resin sacks were prepared ac-cording to Krause and Ramlal (1987). Cation and anion sackswere made by placing 78 cmol,. of Biorex 70 (300-850 nm)(Bio-Rad Laboratories, Richmond, CA) resin and 51 cmolc ofBio-Rad AG3-X4A (300-850 ,14m) resin, respectively in 5 by5 cm polyester fabric sacks that were heat sealed. Cation sackswere cleaned with 1 M HC1 and then reconverted to the Naform with 0.5 M NaHCO3 (Sibbesen, 1977). Anion sacks wereconverted from the Cl form to the bicarbonate form with 0.5M NaHCO3 (Sibbesen, 1977).

Before placing the sacks in the soil, resins (in the sack) werespread out in an attempt to cover the complete sack area. Ineach plot, five sacks of each resin type were installed flat underthe Ah horizon. Sacks were at least 5 cm apart from each otherand the cation sacks were at least 50 cm away from the anionsacks. Resin sacks were installed on 12 June 1987 and col-lected on 22 Oct. 1987. At the time of collection, a fresh set

PARE ET AL.: NUTRIENT SUPPLY AND STATUS OF SUGAR MAPLE AFTER FERTILIZATION 1109

of sacks replaced those removed. This second set was collectedon 26 Oct. 1988. A final, third set replaced the second set atthis latter date and was subsequently collected on 12 Aug.1989. When collected, sacks were stored in individual vials(at 4 °C) and analyzed within 2 d. Anion sacks were extractedwith 0.05 M NaHC03 and cation sacks were extracted with0.1 M HC1 according to the method of Krause and Ramlal(1987).

Round-bottomed porous cup lysimeters (Soil MoistureEquipment Corp., Santa Barbara, CA) cemented to the end of66-cm-long PVC pipes (50 mm i.d., 2 mm thick) were in-stalled in holes drilled to the 30-cm depth (Bs2-Bs3 interface)at each plot, 2 wk before fertilization. The porous cups wereacid washed with 1 M HC1 (Grover and Lamborn, 1970) andleached with deionized water (final conductivity <3 ;uS cm-1).A tension of 25 kPa was applied once a week. Solutions werecollected weekly; averaged concentrations for the frost-freeperiod were used for the computations.

Resin sack extracts, saturated extracts, and lysimeter ex-tracts were analyzed for NH4 by FIA (Tecator FIAstar 5020Analyser, Tecator AB, Hoganas, Sweden), for K, Ca, Mg, Aland Fe by ICP (Perkin Elmer Plasma 40, Perkin Elmer, Nor-walk, CT) and for N03, H2PO4, and SO4 by 1C (Dionex 2120i,Dionex, Sunnyvale, CA). Samples with low phosphate con-centrations (<100 /Ltmolc L-1) were reanalyzed by FIA. Lys-imeter solutions were also analyzed for pH (potentiometricallyusing glass and reference electrodes).

The experimental design for the analysis of the effect offertilizers on soil, lysimeter, or foliar nutrient concentrationswas a split block in time design (Steel and Torrie, 1980) rep-licated two times, with fertilizer P, K, and Ca levels (denotedas 0, 1, and 2) as whole units, and years 1987, 1988, and1989 (Years 1, 2, and 3) as subunits. The design yielded 54replicates for single-treatment effect (18 replicates yr-1, 3 yr);18 replicates for first-order interactions (6 yr-1, 3 yr) and sixreplicates for second-order interactions (2 yr-1, 3 yr). Maineffects were further broken down into linear and quadraticmain effects, P < 0.01 for first-order interactions, and P <0.001 for second- and third-order interactions. Data were log(x+ 1) transformed to obtain homoscedasticity. The SAS soft-ware (SAS Institute, 1985) was used for all the statistical anal-yses (GLM procedure).

RESULTSAn ANCOVA revealed that the prefertilization foliar

concentrations (14 June 1987) in Ca, Mg, and N (ele-ments also found to be unaffected by fertilization) wererelated to their respective foliar concentrations after fer-tilization (P = 0.037, 0.001, and 0.002, respectively).Therefore, corrected values of these elements are re-ported. Results from the foliar analysis that were signif-icant are presented in Fig. 1. Applications of P and Kfertilizers significantly increased their respective elementconcentrations in foliage. Conversely, foliar N signifi-cantly decreased with the application of P fertilizer. Therewas a significant effect of the time (i.e., year) after fer-tilization on foliar P, K, and Mg concentrations; P andMg foliar elements decreased from Year 1 to Year 3; Kdecreased from Year 1 to Year 2; Year 3 was similar toYear 2. The DRIS indices indicated the same trend: Pand K fertilizers caused an increase in their respectiveindices while Ca fertilizer did not. The DRIS indices forK and P remained negative despite the addition of fer-tilizer while the indices for all other elements remainedalways positive (Table 2). The NDI (Walworth and Sum-ner, 1987) was lowest when both K and P fertilizers wereapplied.

—. 20

1987 1988 1989 1987 1988 1989

Fig. 1. Effect of different fertilizer treatments (three levels ofP: 0 [PO], 75 [PI], and 150 [P2] kg ha-' triple superphosphate;three levels of K: 0 [KO], 150 [Kl], and 300 [K2] kg ha-'K2SO4) on N, P, and Mg foliar concentrations and effect ofyear of sampling on P, K, and Mg foliar concentrations.Bars with different letters indicate significant differences atthe 0.05 level of probability.

Conventional soil analysis of the Ah horizon revealedsignificant (positive) effects of fertilizer P on extractableP and of fertilizer Ca on exchangeable Ca, exchangeableMg, exchangeable acidity, and effective CEC (Fig. 2).In general, extractable P increased with the rate of Papplied. The fertilizer P x year interaction revealed adecline of the P fertilizer effect on the amount of ex-tractable P with respect to both time and the amount ofP applied. Figure 2 also reveals that mean values ofextractable P in the Ah horizon were lower in 1987 thanin the following years, irrespective of fertilizer treat-ment. The effect of fertilizer K on exchangeable K inthe Ah horizon was not significant but fertilizer K had asignificant effect on exchangeable K concentrations inthe Bsl and Bs2 horizons and values varied accordingto year (Fig. 2).

Calcium concentrations in saturated extracts linearlyincreased and Al concentrations linearly decreased with

1110 SOIL SCI. SOC. AM. J., VOL. 57, JULY-AUGUST 1993

Table 2. Relationship between fertilizer treatment and DRISindices.

Acidity - Ah

Fertilizer treatmentpt000000000111111111222222222

K*000111222000111222000111222

Ca§012012012012012012012012012

N15221481010711615171416797869161410612586

P-27-21-21-33-27-27-30-21-22-19-30-19-27-23-18-16-17-19-10-12-19-12-14-21-14-14-17

Index

K-39-49-40-27-25-28-20-29-14-43-75-38-46-28-22-24-20-20-34-45-61-31-28-28-30-29-21

Ca6611884581

1116811106914661611041176

Mg444237453541383130367135463325242830293450322634282926

NDIf

131140123121105110100100731242091141461018080747988113160868499888776

t Three levels of P: 0 (PO), 75 (PI), and 150 (P2) kg ha~' triplesuperhosphate.

t Three levels of K: 0 (KO), 150 (Kl), and 300 (K2) kg ha-' K2SO4.§ Three levels of Ca: 0 (CaO), 500 (Cal), and 1000 (Ca2) kg ha-1

Ca(OH)2.11 Nutrient disequilibrium index is the sum of indices irrespective of

sign.

increased levels of Ca application (Fig. 3). The effecton extractable Ca was similar from year to year, whereasthe effect on extractable Al declined slightly but signif-icantly with time. No other significant effects of fertil-izers were measured on water-extractable elements in theAh horizon. However, extractable Ca, Mg, and K sig-nificantly decreased from Year 1 to Year 3 and Mn sig-nificantly increased from Year 1 to Year 3 (Fig. 3).

Resin P and K increased significantly with their re-spective fertilizer applications in 1987 (Fig. 4); increasedresin SO4 was observed in 1987 due to K2SO4 fertiliza-tion (Fig. 4). Fertilizer Ca had no effect on resin-extract-able Ca but significantly increased resin-extractable Kand decreased resin-extractable P (Fig. 4). The fertilizerP x Ca interaction on resin-extractable P was also sig-nificant; P uptake by the anion exchange resins de-creased with increased Ca application. In 1988, P fertilizersignificantly increased resin P and decreased resin NO3with increased P application. It is also noteworthy thatresin-extractable P was found in much lower concentra-tions in 1988 than in 1987 (Fig. 4).

Fertilizer K-K2SO4 significantly increased the Ca andSO4 concentrations in the lysimeter solutions (Fig. 5).In addition, the fertilizer K x year interaction resultedin significant increases of Ca and SO4 with increasingK2SO4 application (mainly for 1987) and a significantdecrease of Ca and SO4 during the second and third yearafter fertilizer application. Lysimeter Mg and K signif-icantly decreased to a minimum by 1988 and continuedas such to 1989, whereas lysimeter H continued to de-crease until 1989 (Fig. 5).

*; 10001

S 40£X 20

LLI

1987 1988 1989

P-Bray II-Ah1987 1988, 1989

,abab

1987 1988 1989

PO P2 PO P2 PO P2P1 P1 P1

Fig. 2. Effect of different fertilixer treatments (three levels ofP: 0 [PO], 75 [PI], and 150 [P2] kg ha-1 triple superphosphate;three levels of K: 0 [KO], 150 [Kl], and 300 [K2] kg ha-1

K2SO4; three levels of Ca: 0 [CaO], 500 [Cal], and 1000[Ca2] kg ha ' Ca(OH)2) on effective cation-exchange capacity(CEC), exchangeable acidity, exchangeable Ca and Mg, andextractable P in the Ah horizon, on exchangeable K in theBsl and Bs2 horizons, and effect of year of sampling onexchangeable K in the Bsl and Bs2 horizons. Bars withdifferent letters indicate significant differences at the 0.05level of probability.

PARE ET AL.: NUTRIENT SUPPLY AND STATUS OF SUGAR MAPLE AFTER FERTILIZATION 1111

1989

S£

si

K-1987

1987 1988 1989 1987 1988 1989Fig. 3. Effect of different fertilizer treatments (three levels of

Ca: 0 [CaO], 500 [Cal], and 1000 [Ca2] kg ha-' Ca(OH)2)on water-extractable Ca and Al and effect of year of samplingon water-extractable K, Ca, Mg and Mn in the Ah horizon.Bars with different letters indicate significant differences atthe 0.05 level of probability.

DISCUSSIONFor the three seasons that the observations were made,

it was found that a single fertilizer application of K andP increased respective foliar concentrations. It is note-worthy that the annual requirements of nutrients are gen-erally low in comparison to the quantities of fertilizerapplied. In a northern haVdwood forest, total above-ground annual P and K uptake have been estimated tobe <10 and <70 kg ha-1 yr-1 respectively (Whittakeret al., 1979); the amount of fertilizer P applied in ourstudy was 0, 16, and 33 kg ha"1; the amount of fertilizerK applied was 0, 67, and 135 kg ha"1.

The lasting effect of P fertilization on foliar P statusmay be attributed to the efficient recycling mechanismsfor P within plants (Ryan and Bormann, 1982) and withinthe soil-plant continuum (Harrison, 1978; Wood, 1980).However, since the effect of fertilizer P on soil extract-able P was not observed for more than two seasons,internal biochemical cycling is probably the most im-portant mechanism perpetuating the effect of fertilizer P.Internal recycling of P by foliar translocation alone wasfound to account for 30% of the annual requirement ina 55-yr-old northern hardwood forest (Ryan and Bor-mann, 1982).

o 2o

i ^oo

PO P2 PO P2 PO P2P1 P1 P1

K-1987 eooa -^

KO K1 K2

SO4-1987

CaO Ca1 Ca2 KO K1

Oo

i

50

40

30

20

10

N03-1988 H2PO4 -1988

0.8

bill

PO P2 PO P1 P2

Fig. 4. Effect of different fertilizer treatments (three levels ofP: 0 [PO], 75 [PI], and 150 [P2] kg ha-' triple superphosphate;three levels of K: 0 [KO], 150 [Kl], and 300 [K2] kg ha 'K2SO4; three levels of Ca: 0 [CaO], 500 [Cal], and 1000[Ca2] kg ha-1 Ca(OH)2) on resin sack nutrients in 1987(H2PO4, K, and SO4) and in 1988 (NO3 and H2PO4). Barswith different letters indicate significant differences at the0.05 level of probability.

The application of fertilizer P did not result in an in-crease of P in extractable form in the B horizons or ingreater P concentrations in lysimeter extracts. This in-dicated that P movement in the soil profile was restrictedso that leaching losses were minimal. Working with apodzolic soil, Wood (1980) demonstrated that quantitiesof P not biologically immobilized in the forest floor werechemically immobilized in the mineral soil. Further-more, Pare and Bernier (1989a,b) found that a Mull-Moder humus type in the same region as this study alsohad the potential to chemically immobilize phosphateions. Consequently, phosphate fixation may occurthroughout the soil profile. Aluminum and Fe oxides,responsible for phosphate immobilization, have ampho-teric charges that tend to become more reactive afteracidic deposition. In such circumstances, phosphate im-mobilization may become exacerbated (Tisdale et al.,1985).

Lime application did not directly affect foliar P status.

1112 SOIL SCI. SOC. AM. J., VOL. 57, JULY-AUGUST 1993

£

—1000

O 800

600

400

g 200

5

Ca1987 a 1988 1989

b

CaO Ca1 Ca2

S04

KO K2 KO K2 KO K2K1 K1 K1

H— 1000ll

o0 800

^§ 600_g•g 40080 200

CA n

r- 19B7

- ab

-

-

b

1

a 1988 1989 ^1.6

uOL2^a.

C•2 0.8E

• 8 0 4

III I.IKO K2 KO K2 KO K2

K1 K1 K1

O

3.

1987 1988 1989 1987 1988 1989

Fig. 5. Effect of different fertilizer treatments (three levels ofK: 0 [KO], 150 [Kl], and 300 [K2] kg ha-1 K2SO4; threelevels of Ca: 0 [CaO], 500 [Cal], and 1000 [Ca2] kg ha-'Ca(OH)2) on lysimeter NH4, Ca, and SO4 concentrationsand effect of year of sampling on lysimeter H, K, and Mgconcentrations. Bars with different letters indicate significantdifferences at the 0.05 level of probability.

This was somewhat surprising since a decrease in aciditygenerally increases soil P availability in acid soils (Beekand van Riemsdijk, 1979; Lopez-Hernandez and Burn-ham, 1974). Lime can also modify rates of soil nutrientcycling by stimulating soil biological activity (Adam etal., 1978). In our study, lime application generally in-hibited the uptake of fertilizer P by resins, perhaps bythe formation of Ca-P minerals (Barrow and Shaw, 1977;Tisdale et al., 1985). It is interesting to note that theinteraction between fertilizer P and fertilizer Ca as wellas the effect of Ca fertilizer on extractable P were notdetected with the Bray II extraction method. This sug-gests that the resin sack technique better estimated con-centrations of labile P in the soil solution than thetraditional extraction methods, which often alter the soilchemical equilibrium. However, since the application oflime had no effect on tree foliar P status, it is hypothe-sized that the fertilizer Ca x fertilizer P interaction ob-served with the resin sack technique is probably of shortduration and of little significance for tree nutrition.

A secondary effect of P fertilizers was observed in thedecrease in foliar N concentrations and may have beencaused by an increased microbial N immobilization fol-lowing the P fertilization. This would suggest that soilmicroorganisms were limiting in P prior to fertilizer ap-plication but not in N or in an energy source (Flanagan,1986). However, studies have shown that the additionof P in forested ecosystems does not result in greatermicrobial biomass (Flanagan, 1986; Kelly and Hender-son, 1978a,b) nor in reduced N availability (Cole andHeil, 1981; Purchase, 1974). In the foliage, the reducedN concentrations resulting from P fertilization may alsohave been caused by an increased growth of saplings.This would suggest that N uptake was in excess of re-quirements before fertilization an that P was limitinggrowth. This interpretation is supported by the DRISindices, which also indicated that N remained positive(i.e., not deficient) after the highest P application.

In red pine (Pinus resinosa Aiton) plantations, thelasting effect of a single application of fertilizer K wasattributed to efficient biogeochemical cycling (Shepardand Mitchell, 1990; Stone and Kszystyniak, 1977). Theseauthors demonstrated that the effects of K fertilizer werestill noticeable 39 and 23 yr, respectively, after fertil-ization. In our study, the measurements of resin sackextractable K, NH4NO3-exchangeable K, and water-ex-tractable K indicate that K did not accumulate in a labileform in the Ah horizon as a result of fertilizer K appli-cation but that K moved down into the Bsl and Bs2horizons, where it accumulated in the exchangeable form.However, the estimated recovery of K in exchangeableform in the Bsl and Bs2 horizons was only 2% of addedfertilizer K. Furthermore, it was still undetermined whetherthe tree could fully exploit the K reservoir in the B ho-rizons since the fine tree roots were mostly located inthe uppermost soil horizons (Lyford, 1975; Meyer andGottsche, 1971; Wood, 1980). Internal cycling of K isnot often mentioned as an important component of theK nutrition of trees since retranslocation of K from shed-ding leaves is often small in comparison to other nu-trients (Alban, 1985; Switzer and Nelson, 1972) althoughit can be significant in some species (van Den Driessche,1984). On the other hand, retranslocation during heart-wood formation has been recognized as an importantmechanism of K efficiency in several species (Attiwill,1980; Bamber and Fukazawa, 1985) and may, in oursituation, help to explain the duration of the fertilizer Keffect in the absence of significant changes in soil avail-able K.

Foliar N and P in black spnice [Picea mariana (Miller)B.S.P.] stands subjected to N and P fertilization in-creased 1 yr after fertilization, but over a 10-yr periodthere was little or no response (Mahendrapa and Salon-ius, 1982). Shoulders and Tiarks (1980) and Nelson andSwitzer (1990) found similar short-term foliar N re-sponse in slash pine (Pinus elliottii Engelm.) and sweetgum (Liquidambar styraciflua L.) foliage, respectively,after N fertilization. In contrast to Nelson and Switzer(1990) who found no foliar response to P fertilizer,Shoulders and Tiarks (1980) found that P (and K) fer-tilization produced significantly higher foliar P (and Klevels, respectively) for up to 8 yr after fertilization.

Results from the lysimeter experiment indicated thatthe SO4 ions contained in K fertilizer moved rapidly

PARE ET AL.: NUTRIENT SUPPLY AND STATUS OF SUGAR MAPLE AFTER FERTILIZATION 1113

downward and were charge-balanced by Ca ions. Theincreased losses of Ca were estimated to be approxi-mately 2% of the exchangeable Ca contained in the soilcolumn underlying the lysimeters. A brief but intenseloss of cations has also been observed following K fer-tilization in other forested ecosystems (Marion and Leaf,1977). The movement of cations down the soil profilesof deciduous forests is strongly related to the leachingof SO4 ions (Courchesne and Hendershot, 1988; Johnsonet al., 1985; Mollitor and Raynal, 1982). Although Kions usually have a greater mobility than Ca ions in thesoil (Wiklander, 1980), the addition of large amounts ofK to the soil probably replaced Ca on the soil exchangesites, thereby allowing Ca to accompany the SO4 as itleached. The high ratio of exchangeable Ca to K in thesoil (35:1 in the Ah horizon, 15:1 in the Bsl horizonand 32:1 in the Bs2 horizon) may favor the movementof Ca ions with SO4 ions once these latter have disso-ciated from fertilizer K. The ratio of exchangeable Cato exchangeable K was estimated to be 15:1 (activity)after addition of the highest dosage of fertilizer K to thesoil column overlying the lysimeters. Finally, the highlyselective absorption of K ions by tree roots (Marschner,1986) and K fixation by clay minerals (Table 1; Sullivan,1977) were additional mechanisms that may have re-stricted K movement beyond the Bs2 horizon.

Fertilizer Ca application had no effect on foliar statusand seldom interacted with other fertilizers. Soil analysisindicated that Ca accumulated in the Ah horizon but notin the Bsl and Bs2 soil horizons where K ions accu-mulated. The amount of fertilizer Ca retained in the Ahhorizon was estimated to be 85% of added Ca. Since Cawas added as Ca(OH)2, it created an increase in effectiveCEC, which in turn may have promoted the retention ofCa ions in exchangeable form. The absence of a Caeffect on vegetation indicated that this element was notlimiting for plant growth. The long term effects of anincreased exchangeable Ca content in the Ah horizon areunknown, but the increased effective CEC in the Ahhorizon as a result of lime application may favor theretention of cations.

Some results of resin sack analysis did not match me-chanistic explanations or observations made with con-ventional soil analysis. Some of the problems encounteredwith the resin method have been examined in Krause andRamlal (1987) and Raison et al. (1987). Fertilizer Cadid not increase resin sack extractable Ca but signifi-cantly increased resin sack extractable K. No explanationcould be found for this phenomenon since the ratio Ca/K in exchangeable and water-extractable forms increasedwith Ca fertilizer application while it decreased on ex-change resins (data not shown). Moreover, fertilizer Papplication caused a reduction of NO3 sorption on resinsacks in 1988. This effect may be caused by competitionbetween these two anions for binding sites on anion ex-change resin, increased biological immobilization of NO3,or a decrease in nitrification rates with P fertilizer ap-plication. Finally, the resin sack measurements indicateda significant effect of P and K fertilizers during the firstseason, whereas conventional and saturated soil extractanalysis did not. This may suggest that the resin sacktechnique is the most precise of the three methods used.However, it should be remembered that the resin sackswere installed prior to fertilizer application and that they

may reflect conditions that do not last until the end ofthe summer, at which time the other soil analyses wereperformed. The rapidly vanishing effect of fertilizers insoil and the time lag between soil measurements maytherefore explain the limited agreement among the dif-ferent measurements of soil nutrient availability.

Variability among years was high for foliar concen-trations and especially high for soil properties. The var-iability in foliar elemental concentrations may be causedby the difference in sample date collection. The varia-bility in soil properties is partly the result of the dimin-ishing availability of fertilizer elements with time as wellas the effect of changing environmental conditions acrossyears. The low 1987 soil extractable P values may beattributed to the low amount of precipitation receivedduring that summer (Meyer, 1991).

In terms of the effectiveness of the fertilizer treatmentsused in this study, it may be concluded that a greater doseof P and K fertilizer than what was used for this study maybe required since the ORIS analysis indicated that defi-ciencies were not fully alleviated. However, since appli-cation in excess of the biological uptake capacity did notpromote significant increases in the available soil nutrientreserves, a more frequent application may be desirable.

ACKNOWLEDGMENTS

This research was supported by the Natural Sciences andEngineering Research Council of Canada and by the Ministeredes forets du Quebec (MFO). We thank S. Boisclair, A. Brous-seau, F. Marquis, R. Mercier, and N. Mercier for their tech-nical assistance.

1114 SOIL SCI. SOC. AM. J., VOL. 57, JULY-AUGUST 1993