~A ~~~o l/óolQÇMANAGEMENT AND REHABILITATION OF

DEGRADED LANDS AND SECONDARY FORESTS.IN AMAZONIA:

'--{EMBR~PA - CPAA

Biblioteca

An International Symposium/Workshop

April18-22, 1993Hotel Tropical

Santarém, Pará - Brazil

Organized by:

Intemational Institute of Tropical ForestryUSDA - Forest Service

Southem Forest Experiment StationRio Piedras, Puerto Rico, USA

EMBRAPA/CPATUCentro de Pesquisa Agroflorestal da Amazônia Oriental

Belém, Pará, Brasil

In Collaboration with:

Instituto Brasileiro do Meio Ambiente edos Recursos Naturais Renováveis - IBAMA

Santarém, Pará, Brasil

With Support from:

Tropical Forestry ProgramIntemational Forestry

U.S. Department of Agriculture - Forest ServiceWashington, DC, USA

and~:a.

Man and the Biosphere Prograrnrne (MAB)UNESCO

Paris, France

UTILIZATION OF ABANDONED AREAS IN AMAZONIA BY POLYCULTURESOF PERENNIAL USEFUL PLANTS

F.Feldmannl, L. Gasparottoé, R. Lieberei l, H. Preisingerl

lInstitut für Angewandte BotanikHamburg, Federal Republic of Germany

2CPAA/EMBRAPA Ivumaus, AM, Brasil

ABSTRACT

Degraded fallow areas of primarily monocultural plantations will be transferred into a locally-adapteform of utilization through special consideration of soil microbiological factors (funga I and bacterial sym-bionts). In accordance with the heterogeneity of natural plant communities, polycultures of several perennialand annual ecologically adapted useful plants are installed. During the installation phase mycorrhizal fungiare introduced as important biological factors to optimize the ecological fitness of the plant material. After theimplantation of the polyculture the spontaneous secondary vegetation is managed carefully to reach a jointlybeneficial growth of the secondary vegetation with the useful plants. In this type of naturally enrichedpolyculture special regard is paid to a careful use of pesticides and fertilizers in order to come to a plantproduction system with low input and sustaining medium output. Low input systems with a mixture ofannual and perennial plants result in an ecologically and economically equilibrated situation for small scaleproducers. In this contribution the organization of a multidisciplinary project between Brazilian and Germaninstitutions is demonstrated as well as the results of the installation phase of the project.

INTRODUCTION

Although numerous attempts exist to recultivatedegraded sites of formerly utilized areas inAmazonia, the success of reaching to a sustainableland-use is relatively small.

The handling of short nutrient cycles, leachingof nutrients on one hand, bad availability of nutri-ents on the other hand, the importance of the het-erogcneity of the natural plant cover, and the inter-actions between flora, fauna, and microorganismsare so far not well analysed and understood. Thefew data yet available must be supplemented andput into practice rapidly to allow the prompt deve 1-opment of concepts for effective protection of therainforest and simultaneous ensurance of the socialand economic development of the region.

A resolution for the agricultura I probIems ofAmazonia probabIy can be found in a mixed culti-vation of selected, perennial plants adapted to thespecial environmental conditions of the region andcombined with annual and biannual crops. Thepolyculture system may help to create conditions

which are similar to those existing in the primaryplant cover. The function of perennial trees asreservoires for nutrients and their role in the recy-cling of biomass in complex systems was demon-strated (e.g. Shubarth 1977;Sioli 1980;Burger 1986).Especially in Amazonia a consequent transfer ofthese findings to practice is still in its beginnings.

When a recultivation of fallow lying areas in theAmazon region is planned one has to pay regardespecially to pedological and soil-microbiologicalproblems: alI of the areas have been established byslashing the primary forest, impairing the soilcaracteristics, and destroying soil-microorganismsby buming. In nearly all cases the areas have beencleared mechanically afterwards, and were treatedwith a high input of pesticides during the cultiva-tion phase (Fassbender 1990). Soil-biological analy-sis in rubber tree plantations show that a dramaticchange in the populations of the soil-microbesoccured (Feldmann and Lieberei 1992) and that theplants became much more susceptible to stresses.By inoculation of soils with mycorrhizal fungi (self-produced inoculum or soil from natural stands) animprovement of the soi! as substrate for plant growthis possible (Feldmann 1990).

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Several studies indicate, that principally arecultivation of abandoned areas is possible. Themain problems lie in the fact that a recultivation hasto be sustainable for a very long time period andtherefor has necessarily to be profitable for smallscale producers. That means that methods have tobe developed which lower the input into a produc-tion system especially during the critical installationphase - and ensures an output which meliorates thelife standard of the producers without loosing theproductivity of the fields already after a short time.

In the attempt reported here different factors aretaken into account which are stabilizing biologicalcontrolling systems (e.g. for nutrient cycling orepedimiology of diseases). The management prac-tices include treatments for the improvement of bio-logical factors of soils (Feldmann et aI. 1989;Feldmann and Idczak 1992; Feldmann et al. 1993a),e.g. the introduction of symbionts and the utiliza-tion of plants which are mycotroph and living insymbiosis with N-fixing bacteria (Feldmann et al.1993b); beneath that a high number of plant speciestogether with the useful plants is allowed to grow,and the use of pesticides is minimized.

In cooperation with the three large institutionsin Manaus: CPAA, INPA and UNAMAZ/UA thefollowing items will be carried out:

Former plantation areas of the CPAA arerecultivated with polyculture systemsof dif-ferent useful plants.

Symbiontic fungi are multiplied and inocu-lum is prepared using locally adapted meth-ods.

In the initial phase of the project selectedsymbionts are used to optimize the plants'establishing phase, health and growth.

Recultivation is accompanied by studies onthe ecological and economical effect of natu-ral secondary vegetation growing sponta-neously in the polycultural system.

a management concept for the transfer ofthe results into the common practice will bededuced from the results.

THEORETICAL BASIS FOR THE PROJECT

Prior results demonstrated the importance es-pecially of soil-microbiological factors, theadaptedness of the utilized plants and the heteroge-neity of the vegetation for the stability ofagroecosystems. These parameters are the basis fora successful recultivation of lying fallow anddegraded areas and their long-term use.

The plant production system demonstrated heretherefore fulfills the following items:

- An adapted agroecosystem in the Amazon basinhas to be a polyculture with the use of mainlyperennial, indigenous trees.

Degraded areas have only very few essen-tial, symbiontic organisms (see Feldmann etai. elsewhere in this volume). In the initialphase of a recultivation effective symbionts,especially mycorrhizal fungi, have to be in-troduced to the plant production system.

A high soil-microbiological stability andhigh diversity of effective, adapted soil mi-croorganisms is supported by a high num-ber of different host-species. That meansthat the inclusion of the natural secondaryvegetation should have high importance forthe stabilization of populations of soil-mi-croorganisms and therefore for the intro-duced hosts, the useful plants, too.

The management of the plantation has to becarried out in a way that a high diversity ofsoil-microorganisms remains in the soil.That means a low input of pesticides and acontrolled amount of fertilizers (normallymuch less than without rnycorrhization ofthe plants) is recommended.

A high diversity of useful plants/naturalvegetation probably will enhance the dis-ease tolerance of the whole system by chang-ing the microclimate and giving the possi-bility to establish natural controlling sys-tems, as long as the secondary vegetationdoes not contain host plants for pathogensor pests, which attack the crops.

The selected useful plants have to be accept-able for the people of the Amazon region.

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The produced goods must have a commer-cial value.

The products must be suitable for beingtransported.

The installation of the plantation and theproducts must be profitable.

.,. Modificatians of the management practicemust be accepted by producers and mustbe practicable under local conditions.

ORGANIZATlON OF THE PROJECT

The existing warking group is composed of sei-entists from the CPAA, EMBRAPA,Manaus, Brazil,the Institute for Applied Botany of Hamburg Uni-versity, FRG, the Federal Institute for Timber andForestry in Hamburg, FRG, and the INPA, Manaus.It covers areas of several disciplines as shown inFigure 1.

Basic knowledge has been or is being accumu-lated in the field of mycology, bacteriology and veg-etation science; application-orientedness increases in

the direction of the arrow. For this reason, the ac-ceptance studies designed to find out whether farm-ers in the region are in fact willing to apply the testedcultivation systems practice are inpositioned on thefar right of Figure 1.

Description of the field trial

In the 19haplantation, we intend to test the threefollawing ways of stabilizing crops in different testvariants:

Inoculation of the plants with mycorrhizal.spores }.Testing of different mixed cultivatiop sys-temsFertilization in different fertilizer regimesExperiments on management of the spon-taneous vegetation in the crop systems toimprove the competitive conditions for theplanted crops.

Planted crops and plantation systems

14 species of useful plants were planted in theexperimental field (Table 1).

--AGRICULTURAL SCIENCES--

INCREASINGLY APPLlCAT/ON ORIENTED======~~~~~====================~~

FIGURE 1. Scientific disciplines and institutions involved.

r--BIOLOGICAL SCIENCES---_ .._---- ..-Entomology(EMBAAPA)

Agro·Blology(BuFo)

-.---- ECONOMIC SCIENCES ---lAgrTcultunt---- Studlu on I

(lAngBot, scclo-EMBAAPA) Economlc

Aceeptanee I

t:~~~~~~~__..._...::~_::~~~_..1~SOCIA.~

SCIENl/cv

5011 Blology:Myeology (lAngSot)Baeterlology(lNPA, EMBRAPA)

Vegetatlon Selene.(lAngBot;-4NPA)

CllmatologyI(EMBRAPA) J1.... -.- GEOSCIENCES -.,-

Phytopathology I(Et.lBRAPA)

Plant Nutrltlonand 8011 8elenee(Et.lBAAPA)

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TABLE1. List of planted species.

Commonname Scientific name Plant family Use

Seringueria Hevea spp. Euphorbiaceae Rubber production,oil production from seeds

Cupuaçu Theobroma Sterculiaceae Pulp

I grandiflorum (juice, ice, dessert),pods (chocolate)

Pupunha Bactris grandiflorum Arecaceae Fruit, palmito,t

fodder (leaves), foodcolourings (fruit flesh),weaving material

Castanha do Bertholetia Lecythidaceae Brazil nuts, timberBrasil excelsia

Urucum Bixa orellana Bixaceae Dyestuffssunscreens

-Côcos Cocos nucifera Arecaceae Oil, copra, coconut milk,

feeding stuffs (oil cake),weaving material, fibres,

I construction timber, par-ticle board

.._-- ~---Citrus Citrus sinensis Rutaceae Fruit, oil, pectin

Paricá Schizolobium Caesalpiniaceae Timber, charcoalamazonicum

Mogno Swietenia Meliaceae Timber\ macrophylla

Andiroba Carapa guianensis Meliaceae Timber,oil

Mamão Carica papaya Caricaceae Fruit, papain, carpain,feeding stuffs

Mandioca Manihot Euphorbiaceae Starch, vegetables fromesculenia the leaves

Feijão Vigna sinensis Fabaceae Green fodder, starch

Milho Zea mays Poaceae Starch, edible oil,feeding stuffs

Puerária Pueraria Fabaceae Cover cropsphaseoloides

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TABLE 2. Useful plants grown in different plantation systems.

Plantation systems

mixed cultivo f monocultures

1 2 3 4 5 6 7 8 9

Seringueira .. .. .. ....

Cupuaçu .. .. .. ..f.

Pupunha .. .. .. .,..,

Castanha do Brasil .. perennial

Urucum .. use fuI

Côcos .. plants

Citrus .. ..

Paricá .. ..

Mogno ..

Andiroba ..

Mamão .. short

Mandioca .. .. living

Feijão .. use fui

Milho .. plants

Puerária .. .. .. .. .. cover

spontan. vegetation .. .. .. .. crops

f = fallow (for comparisons)

Four different mixed cultivation systems (sys-tems 1-4, see Table 2) and four conventional monoc-ultures (systems 6-9) are to be compared in the fieldtrial. System 5 is land which was prepared in thesame way as the other systems and then left to itsown devices. Perennials, short-term crops for plant-ing between the rows and cover plants are beingused in the systems. The choice of crops was basedlargely on current marketing prospects.

System 1 is a comparatively intensive cultiva-tion system with little space left between the rows,More space was left between rows in systems 2 and3, which can be used for growing short-term cropsin the first year. In practice, this would help farm-ers survive the first years after establishment of theplantation, during which the Ionger-Iived species arenot generating any income. System 4 is the most"extensive" of the test systems. The species planted

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TABLE3. Plantation systems and test variants applied.

n=54 Ofertilizer 30% fertiL 100%fertil.

- + - + - +myc. myc. myc. myc. myc. myc.

system 1 * * * * mixed

system 2 * * * * cultivation

system 3 * * * *

system4 *

system 5 •• fallow

system 6 *

system 7 * monoculture

system 8 ••

system 9 *

- myc. = not inoculated with mycorrhizal fungi spores+ myc. = inoculated with mycorrhizal spores

produce timber. Secondary vegetation is toleratedbetween the trees. In systems 1-3 and in monocul-tures 6-8, on the other hand, cover plants have beensown (Pueraria phaseoloides). For the later transferto practice probably not only one but an appropri-ate combination of different systems will be recom-mended.

Plantation systems and layout on the fields

The nine plantation systems described are be-ing established in different test variants (Table 3).Some of the young plants have been inoculated withmycorrhiza, the remainder have not. The fertiliza-tion variants include zero fertilizer, 30% and 100%of the recommended dose for the respective species.

That gives a total of n=54 possible variants. Inour experiment we implemented the 18 variantswhich promise to give the most meaningful com-parisons.

In the field test the 18variants are being laid outas blocks, with five complete blocks and repeats. Theposition of the variants within the blocks is com-

pletely randomized. The plots have an area of 48 x32 m2 each. The layout of the plots is determinedby the elongated, irregular shape of the experimen-'tal area. A 100 x 100 m2 patch of secondary forestwas left standing at the edge of the area for com-parative studies of the secondary vegetation.

The experimental area concems terra firme landson the EMBRAPAsite, Km 28,Am 010. These areaswere first cleared of primary forest about ten yearsago, then used as rubber tree monocultures and lastleft unattended. In August 1992, the approximatelyeight-year-old secondary forest was cleared andbumt in the traditional manner. Since April 1993the plantation is established.

FIRST RESULTS OF THE PROJECT'SINSTALLATION PHASE

Spontaneous vegetation four months afterclearing

Before the secondary forest on the test area wascleared, a floristic study was carried out, whichyielded 178 species, mainly trees. Four months af-

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---------------------------------------- --. r.-

ter clearing - and after the area had been surveyedand divided into plots - growth form types of thespontaneous vegetation of all 90 plots of the trialwere assessed quantitatively, i.e. on the basis of theirrespective area coverage. The pattems are the re-sult of the former use of the sites and of pedologicaldifferences between sites within the experimentala ea.

A preliminary analysis of the data reveals het-ero~enous vegetation pattems within the plots (ona m scale), but clearly distinguishable pattems in anorth-south direction (from blockA to block E). Thefollowing growth forms show dominance in theblocks of the experimental area as shown in Table4.

A more detailed analysis of the data is yet tocome. So far the pattems are interpreted as pattemsof different intensity of use, or also differences inintensity and frequency of disturbance. Althoughthese differences will in part be cancelled out bysubsequent management measures, the vegetationdifferences observed are important as they representthe starting conditions of the experiment and mustbe included as site differences in the final trialevaluation.

Control ofwíld vegetation in the plantation

The spontaneous vegetation which regeneratesor colonizes the space between the plantation cropscan, on one hand, constitute competition for thecrops (light, nutrients, space) and must be sup-pressed in this case. On the other hand, the wildvegetation can be an important store of nutrients,which become available to the crops after diebackand mineralization of the biomass. As well a highdiversity of the secondary vegetation probably willmean an equiJibration of ecological controlling sys-tems, e.g. occurrcnce of diverse communities of sym-bionts or other beneficia! microbes. Whethe thesetwo opposed processes can be optimized in favor ofthe crops by appropriate control of the wild vegeta-tion, is a question which has to be examined.

Basically there are thrce ways of controllinggrowth of wild vegetation (Figure 2):

the secondary vegetation is allowed to regener-ate, but is occasionally cleared from the spaceimmediately around the crop plants. In this casemainly trees, i.e. long-lived growth forms, wouldbenefit. The species spectrum would be com-pressed due to the occasional disturbance.

TABLE4. Growth form structure of the spontaneous vegetation in thc different blocks 4 months afterclearing.

Growth forms dorninant in block(s):

Trees A,B

Shrubs nowhere dominant

Herbs Tussock grasses B,D, E

Stolon grasses nowhere dominant

upright growing dic. herbs D

creeping, dicotyl. herbs C,D

Fems (bracken) E

dic'; dicotyl. = dicotyledones

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STRESS TOLERATORSANO STRESS TOLERANTCOMPETI TORS

FIGURE2. Three ways of controlling wild vegetation in the plantation.

the cultivation area is kept free of taller growthforms, i.e. the regeneration of secondary forestspecies is frequently disturbed. In this case thelong-lived herbs and grasses would benefit.

herb species with creeping growth forms aresown, e.g. Pueraria. This would lead to a denseundergrowth of one or a very few species.

The three different ways of treating the under-growth each favor different ecomorphological planttypes according to Grirne (1979, 1988): - sowingfavours fast-growing types with a high nutrientrequirement (competitive ruderals).

frequent cutting and hoeing favours short-livedherbaceous species and specieswhich can regen-erate quickly from the buds at the soil surface(ruderals and CSRstrategy types),

minimum management favors regeneration ofpart of the species spectrum of the secondaryforest.

RUOERALS ANOCSR STRATEGISTS

PrimaryForestSpecies

sowncreeping

- herbs(covar crope)

COMPET/T/VERUOERALS

The arrows indicate different competitive situ-ations due to the management of the planting sys-tems. CSR strategists according to Grime (1979,1988).

In the field experiment cover plants have beensown (see above) in some of the test variants, be-cause of the positive experience on the farming sitethat exists with this method; in other variantssecondary vegetation will be tested as cover plants.

Occurrence of mycorrhizal fungus spores beforeand after burning

The highly important symbionts of most of theuseful plants in tropical regions are severly influ-enced by the management practices in Arnazonianplantations (Feldmann and Lieberei 1992). To esti-mate the influence ofburning before the plantations'establishment, 40 soil samples were surveyed tocount the number of spores and to classify the oc-curring spore types before burning. Irnrnediately

51

----------------------~---------------------------------------------------------=~.-,~ ---

evaluated. At the same time a further estimation ofthe most probable number of propagules in the plan-tation soil was done (following the method ofFeldmann and Idczak 1992).

It was found that all over the plantations anaverage of 658 spores per cm soil of vesicular-arbuscular mycorrhizal fungi (VAMF) occurred, butonly one third of them was alive. An infection andrapid colonization of the root systems of catchingplants (Zea mays, Petroselinum crispum) waseasily possible.

A complete identification of the occurring fungiwas not yet possible. But a first classification of thespores is shown in Table 5.

From each spore type single spore isolatesare now prepared for an exact identification ordescription.

Directly after burning no infection and noliving spore was counted in soil sampled from theabove 5 em of the soil surface. Even síx months af-ter buming preliminary examinations (one MPN testwith 5 dilutions and 5 replications with a mixed soilsample from al1 over the plantation) did not showany mycorrhization in the testing plants (Zea mays).This strong impact of fire with regard to the survivalof the mycorrhizal fungi was not expected, but

shows the dramatic changes which come along withthe buming of the fields. Further periodical testswill show how long it will take until the infectionpotential of mycorrhizal fungi arises again in the testfields.

Ilse of mycorrhizal inoculum in the plantproduction

As described above plants of the half of test vari-ants were inoculated with mycorrhizal fungi. Howthe fungi were selected and how the inoculum wasproduced is descr ibed elsewhere in this volume.

Up to row, ali evaluated inoculated plant }pe-cies showed a much better growth than plants with-out inoculation (Figure 3).

CONCLUSIONS

The first results show a growth response of theuseful plants before being outplanted into the fields.Aditionally the preparation of the fields with thecommon practice of buming resulted in a severedeficiency of fungal symbionts in the soil, It is ex-pected that the better growth of the useful plants inthe nurseries due to mycorrhizal fungi will result ina better initial growth in the field, too. Possibly thisadvantage will decide on survival or fading of theplants under the unfavorable conditions of degraded

TABLE 5. Percentage of VAMF spore numbers in soil samples from thc plantations before buming anddistribution on spore type classes.

spore type [%J of total n percentage min percentage max

GlomusA 41,2 ± 9,3 28 62

Glomus B 37,2 ± 7,5 24 ·19-

Scutellospora A 9,9 ± 7,1 O 23

Scutellospora B 3,0 ±3,2 O 11

Acaulospora 3,6 ±3,7 O 12

not ident./others 5,5 ±3,1 O 11

The total spore number was in average 658 + 176 spores / 50cm3 soil in n=40 samples. Only 27% of thesespores were alive, but the infection potential of the soil was high.

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FIGURE 3. Growth response of some useful plant species to inoculation with mycorrhizal fungi innurseries.

HOTVETEVAl.UA~DPupunha

HOTYETEV"'LUA~DParlca

Urucum

Coco

Seringueira

Cupuacu

Castanha

Cumaru

Mogno

Cassava

Mamao

80 100 120604020o

stands. While the introduction and utilization ofmycorrhizal fungi is very cheap and easily made thiswould demonstrate the first step of a new plant pro-duction system which finally will combine a lowinput with a sustainable output.

REFERENCES

Burger, D.O. Uso da terra na Amazônia Oriental. In:Pesquisas sobre utilizaçao e conservaçao do solo naAmazônia Oriental. Belérn, EMBRAPA/CPATU/GTZ, 1986. p. 71.97. (Relatório Final do ConvênioEMBRAPA/CPATU /GTZ).The other steps following from now on in the

growing and producing phase of the systems as wellas the concluded final polycultural system with itsspecial management practices will be published assoon as possible.

Fassbender, H.W. Umweltvertragliche Landnutzung.Tagung der DSE und ATSAF, Feldafing, 1990, p. 23.

Feldmann, F. Die Mykorrhiza des Kautschukbaumes:Vorkommen am Naturstandort und in Plantagen,Auswirkung auf das Resistenzverhalten undNutzung im Plantagenbau Dissertation, TUBraunschweig,1990.

ACKNOWLEDGEMENTS

Wethank our whole group of Brazilian and Ger-man co-workers for their extremely motivated workduring the preparation and installation phase of thisproject.

Feldmann, F., [unqueira, N.T.V., Lieberei, R. Utilizationof vesiculararbuscular mycorrhiza as a faetor ofintegrated plantprotectionAgricult., Ecosyst. and En-vironment,29, 1989, S. 131-135.

The project is included in the bilateral SHIFT-program between Germany and Brazil. It is sup-ported by the Brasilian CNPq and the GermanBMFT.

Feldmann, F., Idczak, E. Inoculumproduetion of VAMfungi for use in tropical nurseries; In: Varrna, A.K.;Norris, ].R.; Read, D.]. (eds.): Methods in Microbiol-ogy 24: Experiments with Mycorrhizae, 1992, S. 339-357.

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