Made available in DSpace on 2016-04-28T14:58:59Z (GMT). No. of bitstreams: 1 2007 - Jos? Eduardo Dias.pdf: 7576584 bytes, checksum: f462c307c38711b0d35ca1237ce04396 (MD5) Previous issue date: 2007-05-18 Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq Agroecological production systems are more complex than conventional ones, since a series of crops follow in sequence or are intercropped to achieve high diversity and maximize soil nutrient recycling. The full understanding of these systems require systemic analyses and therefore, adequate tools. To understand soil fertility evolution, heterogeneity should also be considered. This thesis was performed at Integrated Agroecological Production System, located at Serop?dica, Rio de Janeiro, an area that has been organically managed for 14 years. The first chapter consisted of studying land use from 2003 to 2005. Each land unit use was annotated every three months to generate 12 maps. The information gathered was processed to generate three maps: (i) cultivated species richness; (ii) fallow intensity and (iii) green manure use. High cultivated species richness was observed. In some land units up to 40 plant species were recorded. However, this diversity was not uniformly distributed throughout the terrain. A high intensity of land use, mostly with annuals was also observed in a large part of the area. In most cases, fallow periods were up to 3 months in 3 years. The use of legumes was less frequent on the land units used for annual crops. They were not uniformly distributed throughout the terrain. The objectives of the second chapter were: (i) to generate maps of spatial distribution of soil nutrients (Ca++, Mg++ K++ and P), pH and organic matter; at two soil depths 0-20 and 20-40 cm, in 2004 and 2005 (ii) evaluate the difference of those soil attributes in two years (iii) evaluate the difference of soil fertility between the layers of 20-40 cm and 0-20 cm, (iv) generate two maps of fertility potential , one for each year, for the 0-20 cm layer; (v) to combine maps of all attributes in order to generate maps of potential of gain/loss of nutrients . In general, soil nutrient levels were high and very high, indicating that the 14 years of organic management has built up soil fertility. There was a trend of decreasing soil fertility from 2004 to 2005. The area with higher loss potential coincided with a high intensively used portion of the system. However, on the area used as a control, losses also occurred, in lower intensity. From all nutrients studied, phosphorus was the most spatially and temporally variable. Sistemas de produ??o com base agroecol?gica s?o mais complexos que os convencionais. A heterogeneidade ? uma regra nesses sistemas, pois muitas culturas se sucedem no tempo e no espa?o, compondo assim, alta biodiversidade. A compreens?o desses sistemas requer an?lises de car?ter sist?mico e, portanto, necessita de ferramentas compat?veis. Da mesma forma, estudos de fertilidade do solo, que consideram a heterogeneidade espacial e temporal s?o imperativos para se compreender a din?mica dos nutrientes. O presente estudo foi conduzido no Sistema Integrado de Produ??o Agroecol?gica - SIPA, uma ?rea que vem sendo manejada organicamente por catorze anos, situada no munic?pio de Serop?dica RJ. O primeiro cap?tulo constou do estudo do uso da terra, entre 2003 e 2005. Foram feitos registros trimestrais do uso das glebas, gerando doze mapas de uso. As informa??es contidas nesses mapas foram processadas de forma a gerar tr?s novos mapas: (a) riqueza de esp?cies cultivadas; (b) intens idade de pousio e (3) utiliza??o de leguminosas. Foi verificada alta riqueza de esp?cies cultivadas, havendo algumas glebas com at? 40 esp?cies vegetais. Por?m, esta diversidade encontra-se desuniformente distribu?da no terreno. Houve uma alta intensidade de uso da terra, sendo o per?odo de pousio, em grande parte, relativamente curto, ou seja, de at? tr?s meses, em tr?s anos. Nesses casos, predominaram cultivos anuais. O uso de leguminosas, no sistema, foi menor nas glebas de cultivos anuais e estava desuniformemente distribu?do no terreno. O segundo cap?tulo teve como objetivos: (1) gerar mapas da distribui??o espacial de MO, pH. Ca++, troc?vel, Mg++ troc?vel e K++ troc?vel em quatro glebas selecionadas do SIPA, para as camadas de 0 a 20 e de 20 a 40 cm, nos anos 2004 e 2005; (2) avaliar a evolu??o dos teores daqueles elementos nos dois anos; (3) avaliar a diferen?a de teores entre as camadas 0- 20 cm e 20-40 cm; (4) gerar dois mapas de fertilidade potencial qu?mica , um para cada ano, combinando-se os mapas de todos os nutrientes, para a camada de 0 a 20 cm e (5) gerar dois mapas de potencial de perda/ac?mulo de nutrientes, um, pela combina??o dos mapas de evolu??o da fertilidade e outro, pela combina??o dos mapas de potencial de 2005 e 2004. Os resultados indicaram n?veis dos nutrientes, na faixa de alto a muito alto, na maioria da extens?o da ?rea de estudo, nos dois anos, indicando que o manejo do SIPA, nos catorze anos, desde a sua cria??o, tem constru?do a fertilidade do solo. No entanto, detectou-se uma tend?ncia de diminui??o dos n?veis de nutrientes de 2004 para 2005. O potencial de perda coincide com ?rea de alta intensidade de uso, entretanto a ?rea controle, de uso m?nimo, tamb?m indicou perdas, contudo em propor??es menores.