Catique, Francisco A

Costa, Fernanda Carla Tavares da

Leeuwen, Johannes van

M.Pereira, Márcio

Repositório do INPA

Published as:van Leeuwen J.; Pereira, M.M.; Costa, F.C.T. da; Catique F.A. 1994.  Transforming shifting cultivation fields into productive forests. I Congresso Brasileiro sobre Sistemas Agroflorestais, Porto Velho. Anais, Colombo, PR: EMBRAPA-CNPF, v.2: 431-438.TRANSFORMING SHIFTING CULTIVATION FIELDSINTO PRODUCTIVE FORESTS Johannes van Leeuwen1, Márcio M. Pereira2, Fernanda C.T. da Costa3,Francisco A. Catique21Instituto Nacional de Pesquisas da Amazônia (INPA)2Bolsista do RHAE-CNPq 3Bolsista do CNPqABSTRACT -  The  planting  of  tree  seedlings  can  transform shifting cultivation fields into new forests, which combine the recuperation of soil fertility with production.  This is an important alternative to the common practice of abandoning terra firme fields after two to four years of cropping.  A large number of tree species is of interest for these forests. Grouping  these  species  into  small,  medium-sized  and  large trees,  eases  the  design  of  species  combinations.   The combination  should  allow  for  a  continuous  flow  of  useful products through the years.  First results with participative design  and  establishment  on  fields  of  volunteers  are encouraging.    Key terms: agroforestry, shifting cultivation, fallow, smallholders.A TRANSFORMAÇÃO DE ROÇAS DA AGRICULTURA ITINERANTEEM FLORESTAS PRODUTIVASRESUMO - O plantio de mudas pode transformar as roças da agricultura  itinerante  em  novas  florestas,  que  combinam  a recuperação da fertilidade do solo com a produção.  Trata-se de uma alternativa importante à prática comum de abandonar roças de terra firme depois de dois a quatro anos de cultivo. Um grande número de espécies arbóreas é de interesse para essas  florestas.   Agrupando  essas  espécies  em  árvores  de tamanho pequeno, médio e grande, facilita-se o delineamento de combinações de espécies.  A combinação deve permitir um fluxo contínuo de produtos úteis através dos anos.  Os primeiros resultados com o delineamento participativo e a instalação em roças de voluntários são encorajadores.    Palavras-chave: Termos  para  indexação:  sistemas agroflorestais,  agricultura  itinerante,  pousio,  pequenos produtores.2INTRODUCTIONAgroforestry is generally considered an important land use option for the Amazon, but proven technologies for its promotion are almost not available.  Agroforestry is an extremely broad concept embracing very different systems as: home-gardens, improved fallow, perennial crops with "shade" trees, pasture with trees, alley-farming, etc.  Several hundred plant species, most of them trees, which can be combined in an infinitude of ways, are of potential interest.  However, for most species, little or no agronomic or silvicultural information is available.The  great  many  options  and  the  lack  of  detailed information make it very difficult to develop strategies for the promotion of agroforestry.This paper relates participative on-farm research which aims to develop, on a short-term basis, concrete agroforestry proposals.  It will be limited to presenting proposals on the transformation  of  shifting  cultivation  fields  into  new "forests"  of  economic  interest.   PADOCH  &  DE  JONG  (1987) consider  this  succession  as,  perhaps,  the  most  important system for the humid tropics.MATERIAL AND METHODSWith the help of the extension service EMATER, two small terra  firme (upland)  agricultural  settlements  in  the municipality of Manacapuru (Amazonas, Brazil) were selected for our work.  The settlements are about two hours travel, by asphalt road and ferry, from the city of Manaus.  They were chosen  as  they  are  recent  settlements  without  acute  land tenure  problems,  and  are  representative  of  the  expanding smallholder agriculture  around  Manaus.  At the  same  time, their relatively easy access allows intensive accompaniment.  The settlements were made possible by the opening up in 1986 of two secondary roads which give access to the land.  In most cases farming started several years later.  In 1993 each settlement contained 30-40 small farms.Land use problems and possibilities for the inclusion of more trees into the farming system were discussed during farm visits and meetings with the local community.  During these meetings, farmers interested in participating in the research were identified.A questionnaire for the description of  the  farms  and their forms of land use was developed, tested and improved.Farms belonging to 21 volunteers were visited several times  and  described  in  detail  with  the  help  of  the questionnaire.   Relatively  stable  farms  were  chosen  for further work.A list of interesting tree species was prepared.  The species included are supposed to grow reasonably well on the nutrient  poor  terra  firme soils,  and  to  be  of  economic interest.  Important information sources on species were: FAO (1987), CAVALCANTE (1991), LOUREIRO, SILVA & ALENCAR (1979), many  helpful  farmers,  researchers,  extension  officers  and 3observations by the authors.For each selected farm a special agroforestry proposal was  elaborated  in  cooperation  with  the  farmer.   Final decisions stayed with the farmer.  As the project aims to do research and not extension, only those proposals which could be expected to provide new information, were followed up.In the 1992/93 rainy season the different agroforestry systems were installed on seven farms.  Land and labor was furnished by the farmer, while the project provided most of the planting material, technical advice and, in most cases, assisted in marking the planting sites.The plots are managed by the farm family.  At regular intervals the plots are described and measured.  Evaluation of the  systems  will  be  based  on  farmer  acceptance,  economic aspects and the evolution of soil fertility and bio-diversity.RESULTS AND DISCUSSIONOf the 21 farms described, 20 belong to smallholders with relative few means -- although there are important differences among them -- the other being owned by a business man with important means to invest in his farm.  This paper refers only to the 20 small-holdings.Five of the farms were found also to cultivate land in the  várzea (flood  land).   The  data  presented  here  are restricted to the terra firme, as várzea land use problems are very different.  Várzea soils are much more fertile, but crop loss by early or high flooding is a serious risk.Table: Land use of 20 terra firme smallholder farmsLand use Number of farmsMean area (ha)Amplitude (ha)Cassava 19 2.41 0.3-6.5Semi-perennials (pineapple, passion fruit, sugar cane) 8 0.64 0.1-4.5Home garden (many tree species, mostly for fruit) 20 1.50 0.4-3.5Perennial plantation (cupuaçu, annatto, citrus) 7 0.44 0.5-3.0Pasture 1 0.05 1.0Capoeira (forest regrowth after cropping) 14 1.59 0.5-6.0High forest 18 8.01 0.5-29.0Young home garden or perennial plantation with cassava (negative, as counted twice in previous categories)9 - 0.74 0.05-6.5FARM SIZE 20 13.90 3.0-40.04Notes on the table1. The  scientific  names  of  the  mentioned  species  are: cassava (Manihot esculenta), pineapple (Ananas comosus), passion fruit (Passiflora edulis), sugar cane (Saccharum officinarum),  cupuaçu (Theobroma grandiflorum), annatto (Bixa orellana), citrus (Citrus spp.).2. Although a land use may not occur on all farms, its mean surface was obtained by dividing by twenty the total area encountered on twenty farms, as this gives an idea of the "average" land use.      3. The cultivated areas per farm are relatively high as in several cases a farm is used by more than one household, e.g., parents and married children.4. In fact all families grow cassava as the only family without cassava grows this crop in the várzea.5. Besides bitter and sweet cassava, very small quantities of cowpea (Vigna unguiculata) and horticultural crops are sometimes grown in the same field.The question of sustainability of these farms depends mostly on the fields with cassava and semi-perennials which exhaust the soil in 2-4 years and have to be replaced by newly cleared forest areas (high forest or capoeira).  The average farm has 3.05 ha under cassava and semi-perennials (2.41 + 0.64), and 9.60 ha under forest (8.01 + 1.59).  The relation of land under cassava and semi-perennials to the sum of land under cassava, semi-perennials and forest is approximately one to  four.   In  other  terms  the  percentage  of  land  under cultivation, the so-called R-index (RAINTREE & WARNER 1986), is approximately 25.  Although it might seem that the farms have much land under forest which they can rotate with cassava and semi-perennials, this is not the case.  In an equilibrium situation the nutrient-poor soils of the humid tropics need very long periods to recover their fertility (MUTSAERS 1981; NYE & GREENLAND 1960).Sustainability  can  be  improved  by  increasing  the importance of productive agroforestry, in detriment to the area occupied by cassava and semi-perennials.Agroforestry  should  contribute  substantially  to  the recovery of soil fertility.  It needs, therefore, to use a high number of trees in order to develop a high biomass and a permanent, dense root web which will increase nutrient storage and cycling.  High litter production will protect the soil against erosion and extreme temperatures.  Resulting higher organic  matter  will  increase  water  and  nutrient  storage capacity and phosphorus availability of the soil.  5A mixture of different species involves less economic risks and may lead to a more efficient use of light, nutrients and water.  It may  also  decrease  the risks  of  pests and diseases.A combination of early and late producing species which guarantees a yearly production, and begins production a few years after  installation, is important  to  keep  the farmer interested.   The  system  should  be  easily  integrated  into actual land use and need little labor for installation and early maintenance.The  transformation  of  fields  with  cassava  or  semi-perennials into mixtures of useful tree species of different precocity fits these conditions.  To reduce costs the trees should be planted together with cassava or other crops.  If this is done in the first year of cropping, the trees will be well developed when the field is no longer used.The  proposal  advanced  here  is  in  agreement  with  the observation of RAINTREE & WARNER (1986 p. 44, figure 1) that in the case of a R-index equal to 25, forest fallow has to be substituted by economically enriched fallow.A system with several spacings and canopy layersThirty one species were selected for use.  Most produce fruit, some fruit and timber, some only timber.To simplify working with such a high number of species, they were divided in three groups.  The first group contains species  such  as  cupuaçu,  guava  (Psidium  guayava),  guaraná (Paullinia cupana var. sorbilis) and citrus.  Species of this group stay small, often start fruiting quite early and can be maintained at a relative dense spacing.The second group contains broad leaved fruit species such as avocado (Persea americana),  biribá (Rollinia mucosa) and jackfruit (Artocarpus integrifolia) and palms such as pejibaye (Bactris gasipaes) and  tucumã (Astrocaryum vulgare).  These species develop into "medium sized" trees, need generally a larger spacing than the first group, and, in most cases, fruit production starts later than in the first group.The  third  group  contains  species  such  as  Brazil  nut (Bertholletia excelsa),  piquiá (Caryocar villosum),  cardeiro (Scleronema micranthum) and mahogany (Swietenia macrophylla). Brazil nut and piquiá produce interesting fruit and valuable timber, while cardeiro and mahogany are only of interest for their timber.  Species of this group develop into large trees, which  in  the  later  stages  generally  will  need  very  large spacings.  Fruiting often starts very late.  Brazil nut starts fruiting after 8 to 12 years and piquiá after 10 to 15 years.To  simplify  the  spatial  combination  of  the  different groups, the  larger  spacings  should  "fit" into the  smaller spacings.  A simple solution is to use for the medium-sized species a spacing twice as large as that of the small species, and for the large trees a spacing two or more times that of the medium-sized ones.  One of the possible solutions is 5 x 5 meter for the small species, 10 x 10 for the medium-sized 6species and 20 x 20 for the large species.  Other solutions are: 4 x 4, 8 x 8 and 16 x 16 meter or 4 x 4, 8 x 8 and 24 x 24 meter.  Many more solutions are possible, including less straightforward ones.By  combining  species  of  the  three  categories  the plantation may develop three different canopy layers: a low canopy layer of trees of the first group, a medium height canopy layer of trees of the second group and a top layer of trees of the third group.  Some species will start producing earlier, others somewhat later, and still others quite late, guaranteeing a yearly harvest which begins a few years after installing the plantation.  Light demanding smaller species may stop producing when the larger species create too much shade, causing a form of succession in the system.At the moment, our list contains 8 small species, 20 medium-sized  species,  of  which  7  are  palms,  and  9  large species.  The composition of the list is in no way definitive, as the knowledge on most species is very incomplete.  The placement of a  species in one  of  the categories is to a certain degree subjective.  The economic importance of the different species varies.  For certain species, the use of a relatively large number of trees per farm seems justified, while for other species it may be advisable to use only a small number of trees.The design of agroforestry systems combining several tree species showed that species choice varies a lot from farmer to farmer.  Some farmers  preferred to exclude, for  instance, cupuaçu, which in other cases constituted the most important species.   Several accepted to include  timber  trees,  while others declined.Four  plots  were  installed  in  cassava  fields,  two  in pineapple fields and one in a young capoeira.  In this way the fields  are  transformed  into  a  forest  of  greater  economic value.Important information on farmers' knowledge and practices was obtained.  The knowledge on tree species characteristics, seedling production and planting techniques vary greatly from farmer to farmer.  Direct seeding of tree species proved to be an important farmers' practice, which gave very good results, especially with rapid germinating species as  cupuaçu.  The planting  on  a  rainy  day  of  on-farm  produced,  bare-root seedlings in the  shade of cassava  was another  interesting technique.CONCLUSIONSUnder actual land use forest is cleared for annual or semi-perennial crops.  After two to four years of cropping the field is no longer productive and is left fallow or abandoned. When tree seedlings are planted in these fields together with the crops, if possible, in the first year, the field is transformed into a new forest which combines the recuperation of  soil  fertility  with  the  production  of  economically interesting tree products.7This  is  an  important  alternative  to  the  very  common practice of abandoning  terra firme fields after two to four years of cropping.Smallholders are receptive to this approach and show much interest  in  the  planting  of  fruit  trees.   Some  also  are interested in the installation of timber trees.Assistance in the marking of the planting sites and the availability of seedlings are important stimuli. A uniform prescription cannot be given as preferences for species and future plans for the field vary greatly between farmers.Methods developed and accumulated species information can be  useful  elsewhere  in  the  Amazon  to  identify  adequate agroforestry proposals.CITED LITERATURECAVALCANTE, P.B. (1991)  Frutas comestíveis da Amazônia. Belém: CEJUP, 5. ed., 279 p.FAO (1987) Especies forestales produtores de frutas y otros alimentos,  3.  Ejemplos  de  América  Latina.  Estudio  FAO Montes n. 44/3, 308 p.FLORES  PAITÁN,  S.  (1983)  Agroforesteria  en  la  Amazonia Peruana,  investigaciones  em  marcha  de  la  Universidad Nacional de la Amazonia Peruana.  Turrialbia: CATIE. 3 p. [mimeografado]LOUREIRO,  A.A.,  SILVA,  M.F.  da,  ALENCAR,  J.da  C.  (1979) Essências madeireiras da Amazônia. Manaus: INPA. 2 v.MUTSAERS H.J.W., (1981) Crop ecology and agroforestry.  In: WIERSUM K.F. (ed.). Viewpoints on agroforestry. Wageningen: Agricultural University, p. 123-128.NYE,  P.H.,  GREENLAND  D.J.  (1960)  The  soil  under  shifting cultivation. Commonwealth Bureau of Soils.  U.K. Technical Communication, n. 51, 156 p.PADOCH,  C.,  JONG,  W.  de  (1987)  Traditional  agroforestry practices  of  native  and  ribereno  farmers  in  the  lowland Peruvian  Amazon.  In:  GHOLZ  H.L.  Agroforestry:  realities, possibilities and potentials. Dordrecht: Martinus Nijhoff, p. 179-194.RAINTREE, J.B., WARNER, K. (1986) Agroforestry pathways for the  intensification  of  shifting  cultivation.  Agroforestry systems, v. 4: p. 39-54.Acknowledgements- This work is partly inspired by the work of Dr. Salvador 8Flores  Paitán  in  Iquitos,  Peru,  by  means  of  information brought by Charles Clement and others.- INPA, CNPq and the Max Planck Institute of Germany gave important support.- Valuable information was given by many farmers, extension officers  of  EMATER,  researchers  of  INPA,  FUNTAC,  and  the EMBRAPA Centers of Belem, Manaus, Porto Velho and Rio Branco.- Mark van der Woude and Cornelie L. Hemmes made an important contribution as trainees.- Useful comments on this paper were given by Robert Miller and by João Batista Moreira Gomes, who also participated in part of the field work.

Transforming Shifting Cultivation Fields Into Productive Forests

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