Made available in DSpace on 2017-05-12T14:47:25Z (GMT). No. of bitstreams: 1 Dercio_ Ceri Pereira - Doutorado.pdf: 841243 bytes, checksum: f3b70d33a9f33b455bc194b5161cde6f (MD5) Previous issue date: 2016-02-11 / Applications of mineral fertilizer, mineral fertilizer with biochar, organic compost and organic compost with biochar were evaluated by leaf analysis to evaluate the performance of fertilizers associated or not to the biochar on lettuce. The results showed that the organic compost and mineral fertilizer meet the nutritional demands of lettuce. The use of biochar in fertilization does not affect lettuce productivity nor soil properties. The organic compost increases lettuce crop yield from the sixth cropping. The residual of the organic compound in the soil increased pH, electrical conductivity, carbon results. They have also shown accumulations of phosphorus potassium, copper, zinc, iron and manganese, as well as improved soil quality. The organic compost provides stability on soil respiration and activities of enzymes such as acid phosphatase, alkaline phosphatase and urease. / Aplicações de adubo mineral, adubo mineral com biochar, composto orgânico e composto orgânico com biochar foram avaliadas por diagnose foliar para avaliação do desempenho das adubações associadas ou não ao biochar na cultura da alface. Os resultados demonstraram que o composto orgânico e a adubação mineral atendem à demanda nutricional da alface. A utilização do biochar nas adubações não interfere na produtividade da alface nem nas propriedades do solo. O composto orgânico aumenta a produtividade da cultura da alface a partir do sexto cultivo. Os remanescentes do composto orgânico no solo elevam o pH, a condutividade elétrica, carbono e apresentam acúmulos de fósforo, potássio, cobre, zinco, ferro e manganês, além de melhorarem a qualidade do solo. O composto orgânico proporciona estabilidade na respiração do solo e nas atividades das enzimas fosfatase ácida, fosfatase alcalina, e urease.

The usage of crop residues, among other lignocellulosic biomass, has being considered a promising alternative feedstock for bioenergy (i.e., second generation ethanol - ethanol 2G and bioelectricity) production. With the adoption of sugarcane-mechanical harvesting in Brazil, in average 15 Mg ha-1 of straw are left on the field annually. Partial straw removal for bioenergy production has become a common practice, while partial straw retention on the field ensures several benefits for the soil-plant system. Efforts have being done in order to establish the best route to straw recovery from the field and defining the amount which meeting both needs. Thus, the aims of this study were: i) to establish a step-by-step guidelines to straw recovery from the field; ii) to determine the implications of increasing rates of straw removal on plant growth, stalk yield and stalk industrial quality; iii) to evaluate the effectiveness of straw-blanket raking practice on plant growth and yield, and iv) to use Soil Management Assessment Framework (SMAF) as a tool to perform an integrated approach of soil quality (SQ) under different rates of straw removal. To achieve the proposed goals, a 2-years experiment was set up within the dry and wet seasons at Valparaíso and Capivari, São Paulo, locations with different edaphoclimatic conditions. Increases of primary extractor fan\'s velocity on the harvester lead to placement and removal of straw rates proportionally to 0, 25, 50, 75 e 100%. After two years, parameters associated to the soil- chemical [(Phosphorus-P, Potassium-K and pH), physical-(bulk density) and biological- (microbial biomass carbon-MBC and SOC)] attributes were analyzed within the 0-5, 5-10, 10-20 and 20-30 cm. Under colder climatic condition, plant tillering improved by the increasing rates of straw removal, however plant growth and stalk yield are slightly affected by the straw management. Stalk harvested in the dry season presented higher industrial quality than those harvested within the wet season but this parameter is unaffected by straw removal. Further, under colder climatic condition, to rake the straw blanket enhanced plant tillering while plant growth and stalk yield were not influenced by raking the straw blanket. No straw removal increases P content on plant tissue, regardless of blanket management, especially under the poorest inherent soil condition. The SMAF tool was able to detect changes on soil quality under different rates of straw removal and Oxisol responds faster to straw removal management than Ultisol in the short term. Total straw removal leaded to Oxisoil physical quality degradation; among the soil attributes, soil-physical attribute within the 0-10 cm is correlated with stalk yield. The partial straw removal for bioenergy production leads to the optimization on sugarcane biomass usage. However, the appropriate rate of straw to be removed is site specific and ranged 4-9 Mg ha-1 under the conditions in which this study was performed. The stalk yield was unaffected by raking the straw blanket. The monitoring of SOC, adoption of traffic controller and application of subproducts from the sugarcane industry are strategies to increase soil quality and, consequently, the sustainability of the crop cultivation. / O uso de resíduos culturais, dentre outros tipos de biomassa lignocelulósica, tem sido considerado uma alternativa promissora para produção de bioenergia (etanol de segunda geração e bioeletricidade). Com a implementação da colheita mecanizada da cana-de-açúcar no Brasil, em média 15 Mg ha-1 palha são deixadas no campo anualmente. A utilização de parte deste resíduo para produção de bioenergia tem se tornado uma prática comum, enquanto a manutenção de parte da palha no campo viabiliza vários benefícios ao sistema solo-planta. Esforços têm sido feitos a fim de estabelecer a melhor rota para remoção da palha do campo e definir a quantidade que atenda ambas demandas. Assim, os objetivos deste estudo foram: i) estabelecer um guia que viabilize a remoção de diferentes taxas de palha; ii) determinar as implicações oriundas da remoção de taxas de palha no crescimento, produtividade e qualidade tecnológica de colmos; iii) avaliar a eficácia do enleiramento da camada de palha sobre o crescimento e produtividade da cultura e, iv) utilizar Soil Management Assessment Framework (SMAF) como ferramenta para avaliar de modo integrado os efeitos da remoção de diferentes taxas de remoção de palha sobre a qualidade do solo (QS). Para tanto, foram conduzidos quatro ensaios, sendo um na estação seca e outro na estação úmida em dois locais: Capivarí e Valparaíso, SP; locais com diferentes condições edafoclimáticas. Crescentes rotações no extrator primário da colhedora viabilizaram a deposição e remoção de taxas de palha proporcionais a 0, 25, 50, 75 e 100%. Após dois anos, análises de parâmetros associados aos atributos químicos [(P, K, pH), físicos (densidade) e biológicos (carbono da biomassa microbiana - MBC e SOC)] do solo foram realizadas nas profundidades 0- 5, 5-10, 10-20 e 20-30 cm. Em condições climática mais fria, a remoção de crescentes quantidades de palha melhora o perfilhamento da cultura; entretanto, o crescimento e produtividade de colmo são pouco afetadas pelo manejo da palha. A qualidade tecnológica de colmos colhidos na época seca é superior aos colhidos na época úmida, entretanto, este parâmetro não é afetado pela remoção de crescentes quantidades de palha. Sobre condições climática mais fria, o perfilhamento é beneficiado pelo enleiramento da palha, ao passo que tanto o crescimento quanto a produtividade são insensíveis à essa prática. A retenção da palha aumenta o conteúdo de P no tecido vegetal, especialmente em solo naturalmente pouco fértil. A SMAF foi capaz de detectar alterações na QS em função da remoção de taxas de palha; sendo o Latossolo Vermelho distrófico típico o mais afetado pela remoção da palha em relação ao Argissolo Vermelho- Amarelo distrófico típico em curto prazo. A remoção total da palha promoveu degradação física do primeiro tipo de solo; dentre os atributos do solo avaliados, o atributo físico na profundidade 0-10 cm está correlacionado com a produtividade da cultura. A remoção parcial da palha de canade- açúcar para produção de bioenergia promove otimização no uso da biomassa da cultura. Entretanto, a taxa de palha a ser removida é intrínseca para cada local e variou de 4-9 Mg ha-1 neste estudo. A produtividade é insensível ao enleiramento da palha. O monitoramento nos teores de carbono do solo, a adoção do controle de tráfego de máquinas e a aplicação de resíduos da agroindústria canavieira podem ser estratégias adotadas para melhorar a QS e, por consequência, a sustentabilidade de cultivo da cana-de-açúcar.

Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2007.

Concerns were raised over the past decades, on the degradation condition of arid and semi-arid rangelands in South Africa, mainly in areas under communal land management. Baseline information on soil quality is essential to monitor changes in land conditions and assess impacts of land uses and management over time. The objectives of this study, initiated within the framework of the Desert Margins Program, were to characterize and establish baseline indicators of soil quality health, and to investigate the potential effects of grazing and exclusion management (hypothesized as grazing effect) on selected soil properties in the western Bophirima District in South Africa. Soils were characterized for physical, chemical, enzymatic activity and microbial biomass properties, and grazing effects were evaluated on selected properties. The aboveground herbaceous species composition and biomass production were also determined. Sandy, poor fertile soils (low organic carbon and phosphorus) characterized all sites. Various levels of enzymatic and microbial biomass were recorded at the sites. Grazing had no significant effects on most of soil chemical properties, but did affect selected enzymatic activities, site-specifically. No significant differences of grazing effects were observed on soil microbial biomass. The inconsistent responses of soil properties across the sites prompt to caution regarding the generalization and/or extrapolation of grazing effects to other areas, without consideration of the prevailing environmental and management characteristics to each site. Notwithstanding the alarming plea about degradation at these communal sites, indicators of soil quality did not significantly differ between communal and surrounding commercial and/or game managed areas, despite their apparent vegetation degradation. The results showed that rangeland under the communal management were characterized by increaser species of low grazing value, but this situation did not necessarily interpret severe soil degradation as tacitly described. Soil degradation depends on land use, management and environmental conditions, and references are needed to assess degradation. Important interrelationships between the aboveground vegetation and soil belowground activity were observed. This emphasized the need to integrate both soil and vegetation into rangeland monitoring, as these interrelationships and associated ecological processes sustain rangeland health. Further research is needed to re-examine the "inferred degradation of rangelands in communal areas, taking into consideration their history, and using appropriate baselines and references sites. Only then, can degradation trends and hotspots be identified and thereof, appropriate management decisions (through participatory research) taken locally to combat degradation and sustain long-term rangeland resources uses. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2007.

Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2017-12-04T13:08:41Z No. of bitstreams: 1 PGCS15MA128.pdf: 1299017 bytes, checksum: c9080a00f46c534b9d0afc73165e1cb8 (MD5) / Made available in DSpace on 2017-12-04T13:08:41Z (GMT). No. of bitstreams: 1 PGCS15MA128.pdf: 1299017 bytes, checksum: c9080a00f46c534b9d0afc73165e1cb8 (MD5) Previous issue date: 2015-07-25 / Capes / Any inappropriate soil management, cause negative environmental impact on the diversity of soil fauna. This dissertation aimed to evaluate the influence of land use systems (LUS) on the morphological diversity of springtails, as well as its relationship with physical and chemical soil attributes. Were studied five LUS on the Plateau of Santa Catarina, Brazil: native forest (F), Eucalyptus plantation (Reu), perennial pasture (P), integrated crop-livestock (ILP) and no-tillage (PD), in two different seasons (winter and summer). The evaluation was performed by installing traps of type Pitfall traps per sampling grid (3 x 3). The same points were evaluated physical and chemical soil attributes. The morphotyping of the springtails consisted in observing five characteristics and each feature has been assigned a partial value of Eco-morphological index (EMI) for Biological Quality of Soil Index (QBS) modified. The data were subjected to multivariate analysis. In winter, the LUS (F) presented the highest abundance of morphotypes due the best values of Ca/Mg ratio, total organic carbon (TOC), bioporos, micropores and soil moisture in comparison to other LUS. ILP systems and PD already correlated with the Macropores. In the summer, again the F showed the highest abundance of morphotypes, however, the greatest diversity of levels of adaptation was found in PD. In summer, the F presented related to the TOC and micropores, while ILP and PD correlated with pH, bioporos and soil density. In winter, the value of QBS was greater in F, followed by Reu, P, PD and ILP, respectively, being smaller the higher the intensification of the LUS. In the summer, the QBS values were higher in F, followed by ILP, Reu, PD and P, respectively. The separation to the level of morphotypes proved an efficient alternative to indicate the level of intensification of land use, especially in combination with other explanatory environmental variables / Todo e qualquer manejo inadequado do solo, causa impacto ambiental negativo sobre a diversidade da fauna edáfica. A presente dissertação objetivou avaliar a influência de sistemas de uso e manejo do solo (SUS) sobre a diversidade morfológica de colêmbolos, bem como sua relação com atributos físicos e químicos do solo. Foram estudados cinco SUS no Planalto Catarinense, Brasil: floresta nativa (F), reflorestamento de eucalipto (Reu), pastagem perene (P), integração lavoura-pecuária (ILP) e plantio direto (PD), em duas épocas distintas (inverno e verão). A avaliação dos colêmbolos foi realizada instalando-se armadilhas do tipo Pitfall traps em um grid amostral (3 x 3). Nos mesmos pontos foram avaliados atributos físicos e químicos do solo. A morfotipagem dos colêmbolos consistiu na observação de cinco características e para cada característica foi atribuído um valor parcial do índice ecomorfológico (EMI) para a obtenção do Índice de Qualidade do Solo (QBS) modificado. Os dados foram submetidos a análises multivariadas. No inverno, o SUS F apresentou a maior abundância de morfotipos devido a melhores valores de relação Ca/Mg, carbono orgânico total (COT), bioporos, microporos e umidade do solo em comparação aos demais SUS. Já os sistemas ILP e PD se correlacionaram com o atributo macroporos. No verão, novamente a F apresentou maior abundância de morfotipos, porém, a maior diversidade de níveis de adaptação foi encontrada em PD. No verão, a F apresentou relação com o COT e microporos, enquanto ILP e PD se correlacionaram com pH, bioporos e densidade do solo. No inverno, o valor de QBS foi maior em F, seguido por Reu, P, PD e ILP, respectivamente, sendo menor quanto maior a intensificação do SUS. Já no verão, os valores de QBS foram maiores em F, seguido por ILP, Reu, PD e P, respectivamente. A separação ao nível de morfotipos se mostrou uma eficiente alternativa para indicar o nível de intensificação de uso do solo, principalmente em conjunto com outras variáveis ambientais explicativas

Gestion de la variation de la qualité des sols par les agriculteurs : enjeux pour la rentabilité et la durabilité des exploitations agricoles françaisesLa qualité des sols constitue un enjeu majeur en termes d’environnement et de préservation du potentiel agronomique et économique des exploitations agricoles. Les pratiques agricoles ont des impacts sur la qualité des sols, dont certains entraînent une dégradation des sols et mènent à une réduction de leur productivité. La thèse a pour objectif de caractériser et d'éclairer les enjeux économiques de moyen et long terme de la variation de la qualité des sols en mobilisant des outils théoriques, statistiques et empiriques. Nous tentons, en simulant différents scénarios économiques, d’identifier les leviers permettant de préserver le potentiel des sols. Nous utilisons un modèle dynamique de contrôle optimal où l'agent-agriculteur rationnel maximise son profit dans le temps sous contrainte de la dynamique de la qualité des sols.Il y a deux facteurs de production : les intrants productifs (tels les engrais minéraux azotés) et la qualité du sol, capturée par sa matière organique (MO). La qualité du sol est impactée par les intrants productifs utilisés par l'agriculteur, qui peut investir dans la qualité de ses sols via l'utilisation des résidus de culture, l'intensité de labour et les choix des rotations. Nos résultats montrent que l'investissement dans la qualité des sols fait partie d'une stratégie optimale de l'agriculteur qui, face à l'augmentation des prix des engrais et de l'énergie, substitue ainsi les fonctionnalités / Soil quality is a major issue for the environment and the preservation of the agronomic and economic potential of farms. Farming practices have substantial impacts on soil quality; some are detrimental and lead to a long-term decrease in productivity. The objective of this thesis is to characterize the mid-term and long-term economic issues related to soil quality changes using theoretical, statistical and empirical tools and to propose a dynamic bioeconomic model that highlights these issues. Using the simulations of different economic scenarios, we seek to identify the levers that make it possible to preserve the agronomic and economic potential of soil. The model used is a dynamic optimal control model where the rational agent-farmer with perfect information maximizes his profits over time under a soil quality dynamics constraint. We consider two production factors: productive inputs (such as mineral nitrogen fertilizers) and soil quality, captured by the quantity of soil organic mSoil quality is negatively impacted by the productive inputs used by the farmer, who can invest in his soil quality (crop residue use, tillage intensity, crop rotation choice). Our results show that soil quality investment is a component of the farmer's optimal strategy. The farmer substitutes the ecosystemic functionalities of his soil for chemical inputs in response to the increase in fertilizers and energy prices. However, the mitigated results of our empirical model in terms of SOM final values show the importance of considering a large range of farming practices. Our results offer a ba

Suite à des usages intensifs d’origines industrielles, des surfaces considérables de sols dégradés, peu fertiles, voire contaminés sont délaissées. Dans un contexte de raréfaction des sols et de pressions foncières et économiques grandissantes, la réhabilitation de ces sols fortement anthropisés et délaissés peut-être un enjeu. Toutefois, pour envisager une réutilisation de ces sols, il est nécessaire de mieux les caractériser. L’étude de la qualité des sols prend rarement en compte la biodiversité et le fonctionnement biologique. Ainsi, l’objectif de ce travail de thèse était de caractériser des sols délaissés, en prenant en compte leurs paramètres abiotiques, biotiques et fonctionnels. Pour cela, six sols fortement anthropisés délaissés du nord-est de la France, correspondant à différentes activités industrielles, ont été étudiés in situ et en laboratoire. Plusieurs groupes biotiques (bactéries, champignons, mésofaune, macrofaune et flore) ont été étudiés afin d’avoir une approche quasi-exhaustive de la biodiversité des sols. Une approche taxonomique et fonctionnelle (basée sur les traits) de la biodiversité a été réalisée pour les champignons, la méso- et la macrofaune. De plus, l’évolution in situ au cours du temps des paramètres abiotiques et biotiques a été prise en compte sur un des six sols délaissés étudiés. Enfin, les interactions biotiques entre une espèce de collembole, de champignon mycorhizien à arbuscules et de plante herbacée ont été étudiées dans deux sols délaissés, en laboratoire. Nous avons montré que les sols délaissés étaient caractérisés par une biodiversité significative, comparable selon les cas, à celles d’autres types de sols, comme les sols forestiers, de prairies ou agricoles. Toutefois, des différences de densité, de richesse et de structures taxonomiques et fonctionnelles entre les sols délaissés existent et dépendent du groupe biotique étudié. Ces différences sont notamment liées aux propriétés physico-chimiques contrastées de ces sols. Ainsi, un sol construit, amendé en compost, était l’écosystème le moins perturbé des sols étudiés, contrairement à un autre sol construit et contaminé en métaux lourds. Nous avons montré que les paramètres physico-chimiques, et surtout biologiques, évoluaient rapidement au cours du temps (environ un an) dans le sol construit contaminé en métaux lourds. Enfin, nous avons mis en évidence, dans les deux sols étudiés en laboratoire, des modifications des interactions biotiques sous l’influence de nombreux paramètres comme le volume de sol, la durée de l’interaction, la présence d’une microflore indigène etc. Finalement, nous avons montré que ces sols pouvaient être le support de services écosystémiques tels que l’habitat pour la biodiversité et qu’ils pouvaient être fonctionnels, permettant ainsi de considérer leur potentielle valorisation / Due to industrial activities intensification, large surfaces of degraded soils, with low fertility and sometimes contamination, are derelict. In the context of land depletion and economic pressure, the rehabilitation of these derelict anthropogenic soils could be a key issue. However, these derelict soils needs to be better characterized before to consider their potential use. Soil quality studies rarely take into account the biodiversity and the biological functioning. Thus, the aim of this PhD work was to characterize derelict soils by considering their abiotic, biotic and functional parameters. To this end, six derelict strongly anthropogenic soils from north-eastern France, resulting from different industrial activities, were studied in situ and in laboratory. Several biotic components (bacteria, fungi, mesofauna, macrofauna and flora) were studied to have an almost complete approach of the soil biodiversity. Taxonomical and functional (trait-based approach) study of biodiversity was performed for fungi, meso- and macrofauna. Moreover, the in situ evolution over time of abiotic and biotic parameters was taken into account in one of the six studied derelict soils. Lastly, biotic interactions between a species of Collembola, of arbuscular mycorrhizal fungi and of herbaceous plant were studied in two derelict soils, in a growth chamber. We showed that derelict soils were characterized by a significant biodiversity, comparable case to case with other kinds of soils like forest, grassland or crop. Nevertheless, differences in terms of density, richness and taxonomical and functional structure community were observed between soils and depend on considered biotic group. These differences were notably linked with contrasting physico-chemical parameters between soils. Thus, a compost-amended constructed soil was the less disturbed among the six studied soils, in contrast with a heavy metal-contaminated constructed soil. We showed that abiotic parameters, notably biotic parameters, evolved quickly (within one year) in the metal-contaminated constructed soil. In the two derelict soils where interactions between Collembola and mycorrhizal fungi were studied, biotic interactions were affected by several parameters like soil volume, time of interaction, indigenous microflora presence etc. Finally, we have shown that these derelict soils support ecosystems services such as biodiversity reserve and could be functional, allowing potential re-use

Sistemas integrados de produção agrícola e pecuária estão sendo cada vez mais adotados no país e existe um grande potencial, no subtrópico brasileiro, de integrar a pecuária nas grandes extensões de pastagens hibernais cultivadas, antecedendo lavouras de verão, como soja e milho. Nesses sistemas, enquanto o animal é considerado o elemento catalizador e o solo é o compartimento que centraliza e captura as modificações impostas pelo manejo. Neste estudo, investigou-se um sistema com produção de soja-bovinos de corte, em um consórcio de azevém + aveia preta, manejada em diferentes alturas de pastejo (10, 20, 30, 40 cm) e uma área sem pastejo. O experimento foi instalado em maio de 2001, em São Miguel das Missões - RS, em Latossolo Vermelho distroférrico, em sistema plantio direto. Foram abordados aspectos relacionados aos impactos do manejo do sistema sobre os teores e os estoques de carbono e nitrogênio após nove anos da instalação do experimento. Também foi estudada a cinética de liberação de carbono, nitrogênio, fósforo, potássio, cálcio e magnésio, em dois ciclos pastejo-soja (2009/11), a partir da decomposição dos resíduos vegetais, em sacos de decomposição (litter bags). Intensidades de pastejo moderadas a leve (20, 30 e 40 cm de altura do pasto) promoveram aumento nos teores e estoques de carbono orgânico e nitrogênio, total e particulado, semelhantemente ao observado na área sem pastejo. Valores do índice de manejo de carbono (IMC), em comparação com os da área tomada como referência (mata nativa e SP), indicam alta degradação da qualidade da matéria orgânica na maior intensidade de manejo (10 cm). A velocidade da ciclagem dos nutrientes foi maior nas intensidades moderadas de pastejo (20 e 30 cm), tanto dos resíduos da pastagem como do esterco. A decomposição dos resíduos da soja, cultivada na sequência, não foi afetada pelo manejo do pasto. As folhas apresentaram uma decomposição mais rápida, e consequente liberação mais rápida de nutrientes, em relação aos caules. A quantidade de nutrientes liberados dos resíduos em um ciclo pastejo-soja é suficiente em relação à demanda das plantas (pastagem e soja) e, majoritariamente, determinada pelos resíduos do pastejo (pasto + esterco), que foram maiores nas áreas com pastejo leve e nas áreas sem pastejo. / Integrated crop-livestock systems are lately being increasingly used in the country, and there is a great utilization potential in brazilian subtropic region, by integrating catlle production in a large area covered by winter pastures, preceeding summer crops, mostly soybean and corn. The animal, in such systems, is considered the catalizing agent, while the soil is the compartment that captures all the modifications imposed by animal and pasture management This research investigated a soybean-cattle system in a pasture mixture (ryegrass + black oat), managed at different plant heights (10, 20, 30 and 40 cm) and no grazed areas. The experiment was established in May, 2001, in São Miguel das Missões county, Rio Grande do Sul state – Brazil, in a clayey Hapludox, under no-tillage system. The impacts of the integrated system management in total and particulated fractions of carbon and nitrogen were studied nine years after the experiment started. Nutrient (carbon. nitrogen, phosphorus, potassium, calcium and magnesium) cycling was also studied in two soybean-livestock cycles (2009/11), by plant and animal residue decomposition in litter bags. Moderately and light (20 and 30 and 40 cm plant height, respectively) pasture pressure resulted in similar increase of total and particulated carbon and nitrogen stocks and contents, as found in no-grazed area. Carbon managements indexes (CMI), as compared with the reference areas, indicated high degradation of organic matter quality under the most instensive grazing intensity (10 cm of pasture height). Nutrient cycling was higher in moderately grazing (20 and 30 cm pastures height), for pasture and cattle residues. Soybean residue decomposition was not affected by pasture and cattle management; however soybean leaves were more readily decomposed, and in this way, fastly release nutrients, as compared with stem decomposition. The amount of released nutrients in a soybean-cattle cycle is high as compared with plants (pasture and soybean) requirement for high yields and mostly determined by cattle and pasture residues that were higher under light and no grazing intensities, due to higher residue production.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The study was carried out to evaluate the changes in the physical and chemical properties of a sandy soil and the tree growth after afforestation of an Eucalyptus forest planted in different spacing. It was accomplished an experiment planted with Eucalyptus dunnii Maiden planted on native grassland. The spacings of cultivation were 3,50x3,50m; 3,50x1,75m; 1,75x1,75m and 1,75x0,87m. The soil studied was an Alfisol located in São Francisco de Assis city. The experimental design was a complete randomized block with four replicates. It was studied physical and chemical properties of the soil before and after 24 and 36 months of old. Soil samples were taken, for each experimental unit, in the layers soil 0,00-0,10m; 0,10-0,20m; 0,20-0,40m to determine physical properties and layers ,00-0,10m; 0,10-0,20m; 0,20-0,40m; 0,40-0,60m; 0,60-1,00m to chemical properties. The soil physical properties measured were: bulk density, total, macro and microporosity and wet aggregate size distribution. The soil chemical properties measured were: water pH, exchange Calcium, Magnesium and Potassium, available Phosphorus, and Total Nitrogen and Organic Carbon. The trees growth was evaluated to 12, 18, 24, 30, 36 and 42 months old, it was measured breast height diameter (DAP) and height of the plants, the survival percentage was determined and calculated the basal area for hectare. The results indicate to Eucalyptus cultivation changed soil structure by reduce the aggregation, the bulk density and the macroporosity. However it is not observed effect of the plant spacing on the physical properties to 24 and 36 months of Eucalyptus cultivation. In the chemical properties the Eucalyptus cultivation reduced pH, Ca and K contents of the surface layers and increase Ca content of the deep layers, increase contents Mg contents of the surface layers and reduced in the 0,60-1,00m layer; reduced contents of the N and C in the surface layers. It is not observed effect of the spacing planting in the survival percentage until 42 months old. It was higher DAP in the large plant space, while the height was higher in the narrower plant spacing, however this resulted can be changed because the forest is in full fledge. The basal area per hectare was higher in the narrower plant spacing because of there are more plants. / O estudo foi realizado com o objetivo de avaliar as alterações ocorridas nas propriedades físicas e químicas de um solo arenoso e o crescimento das árvores após a implantação de povoamentos de eucalipto em diferentes espaçamentos. O trabalho foi realizado a partir da instalação de um experimento implantado com Eucalyptus dunnii Maiden em campo nativo, nos espaçamentos 3,50X3,50m; 3,50X1,75m; 1,75X1,75m e 1,75X0,87m, em um Argissolo Vermelho Distrófico no município de São Francisco de Assis (RS). O experimento foi instalado em delineamento experimental blocos ao acaso, com quatro repetições. As avaliações das propriedades físicas e químicas do solo foram feitas antes do plantio e após 24 e 36 meses de cultivo do eucalipto, em que foram coletadas, em cada unidade experimental, amostras de solo nas camadas 0,00-0,10m; 0,10-0,20m e 0,20-0,40m para a avaliação das propriedades físicas e nas camadas 0,00-0,10m; 0,10-0,20m; 0,20-0,40m; 0,40-0,60m e 0,60-1,00m para as propriedades químicas. As propriedades físicas do solo avaliadas foram: a densidade do solo, a porosidade total, a macroporosidade, a microporosidade, a distribuição do tamanho dos agregados estáveis em água. As propriedades químicas determinadas foram: pH em água, Cálcio, Magnésio e Potássio trocáveis, Fósforo disponível, Nitrogênio e Carbono Orgânico totais. As avaliações de crescimento das árvores foram feitas aos 12, 18, 24, 30, 36 e 42 meses após o plantio, foram feitas medições do diâmetro a altura do peito (DAP) e altura das plantas, determinada a porcentagem de sobrevivência e calculada a área basal por hectare. Os resultados indicam que o cultivo de eucalipto interferiu na estrutura do solo através da redução na agregação, na densidade e na macroporosidade. No entanto não se verificou efeito do espaçamento de plantio nas propriedades físicas do solo aos 24 e 36 meses de cultivo do eucalipto. Quanto às propriedades químicas, o cultivo do eucalipto promoveu redução do pH; e dos teores de Ca e K nas camadas mais superficiais e aumentou o Ca nas camadas mais profundas; aumentou os teores de Mg na superfície do solo e reduziu na camada 0,60-1,00m; reduziu os teores de N e C nas camadas superficiais. Não se verificou efeito do espaçamento de plantio na porcentagem de sobrevivência das plantas até os 42 meses de idade. Em relação ao crescimento, observou-se maior DAP nos espaçamentos mais amplos, enquanto a altura foi maior nos espaçamentos mais densos, entretanto, essa relação pode ser alterada, pois a floresta apresenta-se em fase de pleno desenvolvimento. Em relação à área basal por hectare, os espaçamentos mais densos apresentam área basal mais elevada devido ao maior número de plantas.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The study was carried out to evaluate the changes in the physical and chemical properties of a sandy soil after afforestation of an Eucalyptus forest planted in different spacing resulting in several plant population. The initial plant growth was also monitored. It was accomplished an experiment planted with Eucalyptus dunnii Maiden planted on Alfisol (Red Yellow Podzolic) with native grass. The plant spacing used were: 3,50X3,50; 3,50X1,75; 1,75X1,75 e 1,75X0,87 m. The experimental design was a complete randomized block with four replicates. In the initial twelve months was not observed differences in results of soil properties due Eucalyptus exploration. To explore what may occur in this experiment by end of first or second forest plant cycle it was evaluated three areas, in sites side by side. Site 1 Eucalyptus planted 2x1m with 15 years; Site 2 Eucalyptus planted 3x2m with 20 years; Site 3 natural grass. In the experiment, soil samples were taken before the Eucalyptus planting and after twelve months, and layers of 0,00-0,10; 0,10-0,20; 0,20-0,40; 0,40-0,60; 0,60-1,00 e 1,00-1,50 m. In the area 2 (sites 1 to 3) soil samples were taken in four replicates at same soil layers as the experiment area. The soil physical properties measured were: particle size distribution, bulk and particle density, total, macro and microporosity and wet and dry aggregate size distribution. The soil chemical measured were: water pH SMP, Al+++, Ca++, Mg++, K+, available P, N, C and organic matter. In the experiment was measured the diameter 0,10 m and height of plants at three, six, nine and twelve months of age, at twelve months was measured also the DAP and calculated the basal area for plant and basal area for hectare. In the experiment, measuring at twelve months after installation the soil changes were only for macro and microporosity and for aggregation, mainly due to soil tillage and management involved in installation of forest. In the area 2, the Eucalyptus, as well as the planting spacing adopted did not caused soil physical alteration, except for aggregation, which was smaller at native grass field. The changes in soil chemical properties, in the experiment, area resulted in higher pH, Ca and Mg after twelve months. In the area 2 there were higher levels of Al and smaller pH for Eucalyptus forest, whereas the levels of Ca, Mg, P and K were higher in the natural grass. There were higher Ca, P and K in the site 2, 3x2m spacing, where the organic C were higher at layer 0,2 to 0,6m. The plant spacing for the initial twelve months did not affect plant height and canopy radii, however, did affect plant diameter, basal area for hectare at twelve months age. The higher plant diameter were observed for higher plant spacing whereas, the basal area per hectare were higher for narrower plant spacing. / O estudo desenvolveu-se com o objetivo de avaliar as alterações ocorridas nas propriedades físicas e químicas de um solo arenoso e o desenvolvimento das plantas após a implantação de povoamentos de eucalipto em diferentes densidades populacionais. O trabalho foi realizado a partir da instalação de um experimento implantado com Eucalyptus dunnii Maiden em campo nativo, nos espaçamentos 3,50X3,50; 3,50X1,75; 1,75X1,75 e 1,75X0,87 metros, em um argissolo vermelho distrófico (Área 1). O delineamento experimental utilizado foi o de blocos ao acaso, com quatro repetições. Nos primeiros 12 meses de idade do povoamento os resultados não permitiriam conclusões sobre o efeito do eucalipto nas propriedades do solo. Assim, foi avaliada, concomitantemente, uma área com eucalipto implantado nos espaçamentos iniciais de 2X1 e 3X2 m, com 15 e 20 anos de idade, respectivamente, e comparadas com campo nativo (Área 2). Na área 1 foram coletadas, em cada unidade experimental, amostras de solo nas profundidades 0,00- 0,10; 0,10-0,20; 0,20-0,40; 0,40-0,60; 0,60-1,00 e 1,00-1,50 m antes da implantação e após 12 meses de instalação do experimento. Na área 2 foi realizada a coleta de solo com quatro repetições por tratamento, nas mesmas profundidades utilizadas na área 1. As propriedades físicas do solo avaliadas foram granulometria, densidade do solo e de partículas, porosidade total, macroporosidade, microporosidade, distribuição do tamanho dos agregados estáveis em água e a seco. As propriedades químicas determinadas foram: pH, pHSMP, alumínio, cálcio, magnésio, fósforo e potássio trocáveis, nitrogênio e carbono orgânico total, e matéria orgânica. Na área 1 foram realizadas avaliações de diâmetro a 0,10 m e altura das plantas aos três, seis, nove e doze meses de idade, sendo que aos doze meses também foi medido o DAP das plantas e calculado a área basal individual e área basal por hectare. Na área 1, aos doze meses somente ocorreram alterações na macro e microporosidade e na agregação devido às práticas de preparo do solo e do manejo do povoamento no período inicial. Na área 2, o eucalipto, bem como o espaçamento de plantio, não alteraram as propriedades físicas do solo, exceto a agregação, que foi menor no campo nativo. Para as propriedades químicas do solo, na área 1 houve aumento no pH e nos níveis de Ca e Mg no solo após 12 meses. Na área 2, observou-se maiores níveis de Al e menores valores de pH no solo sob o eucalipto. Os níveis de Ca, Mg, P e K foram mais elevados no campo nativo, o teor de matéria orgânica e carbono foram maiores no eucalipto 3X2 m, na terceira e quarta camadas. Em relação ao desenvolvimento inicial, o espaçamento de plantio do Eucalyptus dunnii afetou o diâmetro e a área basal por hectare aos 12 meses de idade, onde se observou um maior crescimento em diâmetro (0,10 m) nos espaçamentos mais amplos. Entretanto, a área basal por hectare foi maior nos espaçamentos menores.