8
Bio Fertil Soils (1992) 13: 17-24 Biology d Feility 0 rSos © Springer-Verlag 1992 Effects of mineral and organic fertilizers on the microfauna in a high-altitude reafforestation trial E. Aescht and W. Foissner Institut für Zoologie der Universität Salzburg, Hellbrunnerstrasse 34, A-5020 Salzburg, Austria Received March 28, 1991 Summary. Protozoa (testate amoebae, ciliates), small me- tazoa (rotifers, nematodes), and soil enzymes (catalase, cellulase) were investigated in a reafforested fertilized site at the alpine timberline. Side-dressings of mineral and or- ganic fertilizers were applied alone (90 g NPK; 90, 180, 300, and 450 g dried bacterial biomass per spruce seed- ling) and in combination with magnesite (90 g NPK + 300 g Mg; 90, 180, and 300 g bacterial biomass + 300 g Mg each; 30 g dried fungal biomass + 270 g Mg). One-third of each quantity was applied in 1986, and two- thirds in 1988. None of the treatments caused a signifi- cant decrease in the biological parameters investigated in comparison with untreated controls. The soil life was more or less stimulated depending on the amount of or- ganic material contained in the fertilizers and the quanti- ty; 180- 270 g organic material per seedling proved to be the most effective. Dried bacterial biomass increased the pH by about 0.5 units, catalase activity by about 70%, and the number of ciliates and nematodes by 150-400%. The ciliate biomass and the number of ciliate species were likewise increased. The organomineral fertilizers in- creased pH by up to two units and also stimulated the soil life, but where the organic content was less than 180 g per seedling, efficiency decreased markedly. The least biolog- ical activity was observed in the control soil and in soil fertilized with NPK. Testaceans, rotifers, and cellulolytic activities were only slightly (insignificantly) affected by the treatments. A pooled evaluation of the data (organic versus organomineral versus mineral treatments) and community analyses showed that the organic fertilizer caused a more pronounced increase in the soil life and greater changes in community structure than the mineral combinations. Two years after application of the fertiliz- ers, the differences between the treatments and the unfer- tilized controls had diminished. Key words: Protozoa - Nematoda - Rotatoria - Soil enzymes - Organic fertilizers - Subalpine soil - Reaf- forestation Offprint requests to: E. Aescht The major problem of reafforestation at the timberline is the transplantation shock suffered by seedlings under the extreme climatic conditions. A proper nutrient supply is needed to avoid a decline in the annual biomass incre- ment and thus incomplete maturation, which enhances the risk of frost desiccation (Tranquillini 1979; Glatze! and Fuchs 1986). Pot experiments have shown that cer- tain organic fertilizers allow better growth of spruce seed- lings than conventional NPK fertilizers (Glatze! and Fuchs 1986). This has been confirmed by studies on revegetated ski slopes (Köck and Holaus 1981; Insam and Haselwandter 1985; Lüftenegger et al. 1986). The present experiment was designed to study the effects of various fertilizers on the growth of spruce seedlings under field conditions (Glatze! et al. 1991). This paper is concerned with the quantitative and qualitative changes of the mi- cro-edaphon. A further paper will deal with the autecolo- gy of certain protozoan species. Materials and methods Site description and experimental design The study was performed on the Gressensteinalm (Wildschönau, Tyrol; 12 ° 05'E, 47 ° 40'N), 1800 m above sea level. The experimental area is on a southeast-facing slope (inclination 50-60 ° ) in the dwarf pine zone. About 40 years before the present investigation the dwarf pines (Pinus mugo mugo) were felled for oil production. Old tree stumps and clumps of Norway spruce (Picea abies) indicate that the natural timberline is at about 2100 m at this site. The soil is an iron humus podsol on quartz phyllite. About 430 three-year-old pot-grown ("paper pot") Norway spruce seedlings were planted in holes (13 cm deep and at least 1 m apart) to- gether with the paper pot. Treatments were assigned at random to each seedling. The fertilizers and quantities applied are summarized in Tables 1 and 2. Bactosol (Biochemie GmbH, Kundl, Austria) is a fermentation byproduct made from dried bacterial biomass. Biomag (Tiroler Magne- sit AG, Hochfilzen, Austria) consists of 80 crude magnesite (MgC0 3 ), 100 caustic magnesite [GaMg(C0 3 )z + MgO], and 10 bio- sol (dried fungal biomass produced by Biochemie GmbH, Kundl, Aus- tria). The fertilizers were spread in granular form around the seedling (0 ca. 20 cm). The seven bactosol treatments were applied immediately after planting in June 1986. NPK and magnesite, as mineral fertilizers,

Effects of mineral and organic fertilizers on the microfauna in …1 and 2. Bactosol (Biochemie GmbH, Kundl, Austria) is a fermentation byproduct made from dried bacterial biomass

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  • Bio!" Fertil Soils (1992) 13: 17-24 Biology and Fertility 0rSoils

    © Springer-Verlag 1992

    Effects of mineral and organic fertilizers on the microfauna

    in a high-altitude reafforestation trial

    E. Aescht and W. Foissner

    Institut für Zoologie der Universität Salzburg, Hellbrunnerstrasse 34, A-5020 Salzburg, Austria

    Received March 28, 1991

    Summary. Protozoa (testate amoebae, ciliates), small metazoa (rotifers, nematodes), and soil enzymes (catalase, cellulase) were investigated in a reafforested fertilized site at the alpine timberline. Side-dressings of mineral and or

    ganic fertilizers were applied alone (90 g NPK; 90, 180, 300, and 450 g dried bacterial biomass per spruce seedling) and in combination with magnesite (90 g NPK + 300 g Mg; 90, 180, and 300 g bacterial biomass

    + 300 g Mg each; 30 g dried fungal biomass + 270 g Mg).

    One-third of each quantity was applied in 1986, and twothirds in 1988. None of the treatments caused a significant decrease in the biological parameters investigated incomparison with untreated controls. The soil life wasmore or less stimulated depending on the amount of organic material contained in the fertilizers and the quanti

    ty; 180- 270 g organic material per seedling proved to bethe most effective. Dried bacterial biomass increased thepH by about 0.5 units, catalase activity by about 70%,and the number of ciliates and nematodes by 150-400%.The ciliate biomass and the number of ciliate species werelikewise increased. The organomineral fertilizers increased pH by up to two units and also stimulated the soil

    life, but where the organic content was less than 180 g per

    seedling, efficiency decreased markedly. The least biological activity was observed in the control soil and in soil

    fertilized with NPK. Testaceans, rotifers, and cellulolyticactivities were only slightly (insignificantly) affected by the treatments. A pooled evaluation of the data (organicversus organomineral versus mineral treatments) and

    community analyses showed that the organic fertilizercaused a more pronounced increase in the soil life andgreater changes in community structure than the mineralcombinations. Two years after application of the fertilizers, the differences between the treatments and the unfertilized controls had diminished.

    Key words: Protozoa - Nematoda - Rotatoria - Soil

    enzymes - Organic fertilizers - Subalpine soil - Reafforestation

    Offprint requests to: E. Aescht

    The major problem of reafforestation at the timberline is the transplantation shock suffered by seedlings under the

    extreme climatic conditions. A proper nutrient supply is needed to avoid a decline in the annual biomass increment and thus incomplete maturation, which enhances the risk of frost desiccation (Tranquillini 1979; Glatze! and Fuchs 1986). Pot experiments have shown that cer

    tain organic fertilizers allow better growth of spruce seedlings than conventional NPK fertilizers (Glatze! and Fuchs 1986). This has been confirmed by studies on revegetated ski slopes (Köck and Holaus 1981; Insam and Haselwandter 1985; Lüftenegger et al. 1986). The present experiment was designed to study the effects of various fertilizers on the growth of spruce seedlings under field

    conditions (Glatze! et al. 1991 ). This paper is concerned

    with the quantitative and qualitative changes of the mi

    cro-edaphon. A further paper will deal with the autecology of certain protozoan species.

    Materials and methods

    Site description and experimental design

    The study was performed on the Gressensteinalm (Wildschönau, Tyrol; 12 ° 05'E, 47 ° 40'N), 1800 m above sea level. The experimental area is on a southeast-facing slope (inclination 50-60 °) in the dwarf pine zone. About 40 years before the present investigation the dwarf pines (Pinus mugo mugo) were felled for oil production. Old tree stumps and clumps of Norway spruce (Picea abies) indicate that the natural timberline is at about 2100 m at this site. The soil is an iron humus podsol on quartz phyllite.

    About 430 three-year-old pot-grown ("paper pot") Norway spruce seedlings were planted in holes (13 cm deep and at least 1 m apart) together with the paper pot. Treatments were assigned at random to each seedling. The fertilizers and quantities applied are summarized in Tables 1 and 2. Bactosol (Biochemie GmbH, Kundl, Austria) is a fermentation byproduct made from dried bacterial biomass. Biomag (Tiroler Magnesit AG, Hochfilzen, Austria) consists of 800/o crude magnesite (MgC03), 100/o caustic magnesite [GaMg(C03)z + MgO], and 100/o biosol (dried fungal biomass produced by Biochemie GmbH, Kundl, Austria). The fertilizers were spread in granular form around the seedling (0 ca. 20 cm). The seven bactosol treatments were applied immediately after planting in June 1986. NPK and magnesite, as mineral fertilizers,

  • l8

    were side-dressed 6 weeks later. The biomag treatment was applied inI 987. All treatments were reapplied with double quantities in June 1 988.The experiment was planned and conducted by the Institut fürForstökologie, Universität für Bodenkultur, Vienna (Glatzel et al. 1991).

    Sampling ond counting proceduresSamples were taken on 6 September 1986, 19 September 1987, 28 Sep-tember 1988, 16 September 1989,25 June 1990, and 4 October 1990. Oneach sampling day one seedling from each of the 1 1 treatments was se-lected at random, so that a total of 65 different seedlings (treatment Gmissing in 1986) was investigated. About eight soil cores were taken witha steel corer (A 3 cm) from a soil depth of 0- 10 cm around each seed-ling. These eight cores were thoroughly mixed in the laboratory andpooled into one sample. Direct counting according to Lüftenegger et al.(1988) was used to enumerate testaceans, nematodes, and rotifers, whilea culture method (Foissner 1987a) was used to estimate the potentialabundance of the ciliates. The biomass was calculated as described inFoissner (1985).

    Abiotic factors snd soil enzymesSoil moisture was evaluated after air-drying (about 4 weeks at roomtemperature). In the air-dried samples, pH (glass electrode; 0.01 MCaCl2) and catalase and cellulolytic ("cellulase") activity were deter-mined according to Beck (1971) and Hofmann (1979), respectively.

    StatisticsAlthough the arithmetic means obtained from the six sampling dateswere quite different, few were significantly different (P

  • a-

    Catalase dm /3 min)6

    5

    .]3

    ,1

    L

    .l

    8

    6

    4

    2

    0

    6

    4

    2

    0

    25

    9/86 9/87

    Testacea (Ind

    9/88 s/89

    x 1000/9 dm)

    6/90 10/90

    10/90

    9187 9/88

    Biological Index

    9/89 6/s0(Testacea)

    30

    25

    20

    15

    10

    5

    0

    t2

    10

    I

    6

    4

    9/86

    Soil

    10/ 9o

    10/909/85 9/87 9/88Ciliophora (Ind. x

    9/89 6/901000/9 dm)

    9/86 9/87 9/88Soil Eiological Index

    o.'--+p ci.Liates fard

    9/86 9/87 9/88Nematoda (Ind. x 100

    9/89 6/90(Ciliophora)

    9/89

    /g dm)

    707

    106

    10"

    1041

    10"

    toz

    10

    t0.1

    9/86 9/87 9/88 9/8s 6/90 1ol90

    Fig. 1a-h, Effects of organic and mineral fertilizers on pH (a), catalaseactivity (b), testacean abundance (c), testacean Soil Biological Index(d logarithmic scale), ciliate abundance (e), ciliate Soil Biological Index(f logarithmic scale), mycophagous ciliate abundance (g), and nematodeabundance (h). o--- o, unfertilized controls (A); o---o, bac-

    6/90 10/90

    9/86 9187 9/88 s/8e 6/90 10/90

    tosol alone (C-F); o---o, bactosol and magnesite (IKL);A---A, biomag (G; excluding 1986); tr---n, NPK alone (B);I - - - I, NPK and magnesite (H); dm, dry mass of soil; Ind', indi-viduals; month and year of sampling are given' For details oftreatments, see Täble 2

    e/86 sl87 9/88Mycophagous Ciliates

    6/90 10/90100 /g dm)

    9/89

    (Ind. x

    a20

    15

    ?

    0

    1\

    0'

    0

    t

    pH (CaC12)

    19

  • 20

    Soil enqymesCatalase activity increased by 52-84V0 after applicationof the organic fertilizer (CDEF; Täbles 3, 4). An increasedactivity, though less pronounced, was also observed inthose treatments with higher quantities of bactosol andmagnesite (KL; Tables 3-5). However, by October 1990these treatments were approaching the control level (A),indicating that the additional nutrients had been exhaust-ed (Fig. 1b). Biomag (G) and the low level of bactosoland magnesite (I) caused insignificant changes (Täbles 3,4). The NPK treatments (BH) even slightly (insignificant-ly) decreased catalase activity compared to the control(A; Fig. I b; Tables 3 - 5).

    Cellulolytic activity showed no significant fertilizereffects, possibly due to the small sample size (not mea-sured in 1986). However, the activity was usually slightlyhigher in the fertilized treatments than in the control (A;Table 3).

    No correlations between enzyme activities and proto-zoan or nematode abundance were obtained due to in-consistent variations, e.g. different maxima dates(Fig. 1b,c,e,h). However, Foissner (1985) observed a neg-ative correlation (P

  • 2t

    Table4. Abiotic and biotic parameters of fertilized treatments in relation to control (A in Table3:10090)

    Parameter Treatment

    HcDC

    pH (CaCl2)Catalase activity

    (mg oz g-l dm 3 min r;Total Testacea(individuals g I dm)

    Testacea (Corythion dubium\(individuals g I dm)

    Total Ciliophora(individuals g

    '! dm)Total Ciliophora(pgbiomassg rdm)

    Mean Ciliophora(species number)

    Ciliophora (Colpodea)(individuals c I dm)

    Ciliophora (Grossglockneridae)(individuals g- I dm)

    Total Nematoda(individualsC-1dm)

    6852+ 52+

    620

    93 1

    144* 369 +*

    379* 553 "35 * 45*

    450 1226+

    681 5203*

    125*x 744

    26* 20+ 6j***67* 84*r 17

    5t 25 I

    -11 I -70+431 +*r 395 ++* 242*

    845 *** 447* 573**

    89 *** 60 +* 47 **

    1155* 1115+ 609

    2983 8159**+ 2491jl +,u 159x+* 62

    57 *** 64***- 18 19

    -31 -17

    - 5g + -74+254* 393 E*r

    632** 462**

    82r+ 87+**

    412 979+

    14'74 I 838

    9s

    59 *+* 68 **+38 + 46*

    -28 22

    67 + -40+125 152*

    247 278*

    26+ 60*

    171 416

    848 2226

    90* 142**

    8

    -12

    -14

    25

    105

    179

    4g*

    164

    991

    -12

    Data represent percentage difference. For explanation of treatments, see Table2. *P

  • 22

    Ciliophoro

    The abundance, biomass, and species numbers of ciliatedprotozoa increased significantly in most treatments.Compared to the control (A), pure bactosol (EF) causedthe greatest and NPK (BH) the smallest changes (Fig. 1e,2d, f; Täbles 3 - 5). The high abundance in fertilized treat-ments was mainly due to the colpodids (Täbles 4, 5), agroup of specialized, r-selected ciliates which colonizedisturbed and/or extreme biotopes (Lüftenegger et al.1985). Four colpodid (Colpoda inflato, C. maupasi, C.steinii, C. cucullus), a hypotrich (Gonostomum affine),and a microthoracid species (Leptopharynx costatus)contributed most to the increased abundance. These spe-cies are strictly bacterivorous, indicating an increasedsupply of bacteria. The mycophagous colpodids of thefamily Grossglockneridae were significantly increased inthe organically fertilized treatments (DF; Fig. 1g; Täbles4, 5), indicating an increased fungal abundance. Thisgroup showed maximum values 1 year after the fertilizerapplications, and then its dominance decreased slightlyuntil the end of the investigation period. However, theirnumbers were still five times higher than in the control(A; Fie. 1e).

    The changes in ciliate abundance and species compo-sition deviated clearly from control levels (A) in the simi-larity measures (Fig. 2b, d,0. The species composition inthe pure NPK treatments (B) was very similar to that ofthe controls (A; Fig.2b), again suggesting that the NPKfertilization was ineffective. The organic and organomin-eral treatments were fairly consistently grouped into twofurther clusters (Fig. 2b). In the species-abundance simi-larity, the comparatively weak effects of low quantities ofbactosol and magnesite (IK) and of both NPK treatments(BH) were clearly recognizable (Fig. 2d, f). Moreover, theintermediate position of the biomag and high bactosol+ magnesite treatments (LG) was remarkable (see rankingof fertilizers). The pronounced changes in the ciliatecommunity caused by fertilization were also evident fromthe markedly decreased values of the Soil Biological In-dex (Fig. 1f; see Methods for interpretation)' The outlierin treatment H in June 1990 was due to a very low totalabundance and a low species number (Fig. 1e).

    The significant increase in ciliate abundance, bio-mass, and species number, particularly after the applica-tion of organic fertilizer, agrees well with results reportedby Lüftenegger et al. (1986), who studied revegetated skislopes. Foissner (1981) likewise found higher abundances

    100

    80

    100

    80

    60

    40

    8-] 60.d14o

    940.i@

    20

    >60rJL@

    .i 40@

    20

    80

    i60.dtro

    d'e 40.d@

    20

    100

    20

    Fig.2a-f. Similarity in species composi-tion (a,b method, Jaccard 1902) and spe-cies-abundance similarity (c,d method,Bray and Curtis 1957; e,f method, Morisita1959) of protozoans in 1 1 treatments.Tieatments: A, unfertilized controls; CDEF,organic treatments; BGHIKL, organo-mineral treatments (for details see Iäble 2)CILIOPHOBA

    a

    € lilorisita

    TESTACEA

    40

    20

  • and species numbers in manured and fertilized alpinepastures than in natural sites. In another alpine pasture,timing also increased the biomass significantly; NPK andammonium sulphate, however, caused only smallchanges, while thomasphosphate (14.5V0 P2O5, 45VoCaO) decreased ciliate abundance (Berger et al. 1986).Fertilizer effects on protozoa in other habitats, e.9., ara-ble land, have been reviewed in detail by Foissner(1 e87 b).

    Nemqtoda and rotstoria

    The nematode abundance was significantly increased bybactosol with or without magnesite (CEFKL; Täbles 3, 4)'The pooled comparison showed that higher quantities offertilizers were slightly more effective than lower levels(Table 5). Compared to the control (A), pure bactosol(CDEF) caused a more pronounced increase (P

  • 24

    Note. Trade names and company names are included forthe benefit of the reader and do not imply endorsementor preferential treatment of the products by the Universi-ty of Salzburg.

    Acknowledgmenls. We thank Prof. H. Adam, Head of the Institute ofZoology, University of Salzburg, for institutional support. The enzymeanalyses were performed in the laboratory of Dr. T. Peer by Mrs. M.Tiaunmüller (University of Salzburg). We thank Dr. G. Lüftenegger forhelp in counting testaceans, nematodes, and rotifers and Mr. E. Stroblfor improving the English. Financial support was given by the Bio-chemie GmbH, Kundl, Austria.

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