Improving soil health in agricultural soils is vital as the effects of climate change and an increasingly affluent population are putting a strain on land resources. Conservation agricultural practices such as cover cropping and conservation tillage systems (e.g., strip tillage, minimal tillage, or no tillage) are implemented to improve soil properties, but soil health outcomes in Coastal Plain cropping systems have been inconsistent and may take decades or longer to occur. Improving soil health and agricultural prosperity in the region requires: a better understanding of the rate and magnitude of response in soil properties to different types of management; and a better understanding of the interaction between management types, soil health parameters, and crop yield. In this study, four tillage systems (in order of decreasing intensity: conventional tillage > strip tillage > minimal tillage > and no tillage) and three winter cover rotations (in order of decreasing expected biomass input: high-biomass cover crop > winter cash crop > and fallow) were tested in a split plot design. For the first objective of this study, bulk density, penetration resistance (as depth to root restrictive layer), total organic carbon, carbon stocks, saturated hydraulic conductivity, and yield were measured repeatedly over a seven-year period to better understand the longitudinal response of these properties to management. Bulk density and saturated hydraulic conductivity showed a greater temporal variation in the more intensive tillage practices (strip tillage and conventional tillage) in the top 5 cm. Depth to root restrictive layer was consistently highest in the deep tillage treatments (strip tillage and minimal tillage). The change in soil organic carbon concentration between 2018 and 2022 in the top 5 cm was numerically greater in the strip tillage (0.67%) and no tillage (0.68) than the conventional tillage was 0.18%. In 2022, the carbon stocks were significantly increased in all three conservation tillage treatments compared to conventional tillage. Yield was significantly increased by winter cover in the years that a legume/non-legume cover crop mix was implemented. For the second objective of this study, the effects of 6 years of management were evaluated for total organic carbon, active carbon, short-term carbon mineralization, aggregate stability, and crop yield. These parameters were then correlated to determine drivers in soil health outcomes. Total organic carbon was increased in the strip tillage treatment (1.13% in 2021 and 1.61 % in 2022) compared to conventional tillage (0.83% in 2021 and 1.09% in 2022) in the top 5 cm. In 2022, total organic carbon under cover crop (1.51 %) and cash crop (1.46 %) treatments were also significantly higher than the fallow (1.33 %) in the top 5 cm. Active carbon results followed a similar but weaker trend in both years. Percent aggregate stability was improved by minimal tillage (47%) in 2022 compared to conventional tillage (41%). The findings from the correlation analyses suggest that total organic carbon concentration, soil texture, and tillage were all prominent drivers in improving soil health outcomes. These results demonstrate the relatively slow response of many soil physical properties to management, highlight the need for consistent management to improve properties, and emphasize the need to take measurements at different times of the year. This information can be used to develop more sustainable and resilient cropping systems in the Coastal Plain. / M.S. / Centuries of intensive farming practices have degraded agricultural soils, which contributes to the challenge of feeding a growing and increasingly affluent global population. Therefore, understanding which farming practices reverse this degradation and improve soil health is vital for regions such as the southeastern Coastal Plain, where agriculture is a prominent industry. Soil health is defined as the ability of soil to support life sustainably. Conservation agricultural practices, such as planting crops over the winter and conservation tillage systems (where at least 30% of the soil surface is left undisturbed) are implemented to improve soil properties, but soil health outcomes in Coastal Plain farms have been inconsistent and may take decades or longer to occur. Therefore, the improvement of environmental health and agricultural prosperity in this region requires a better understanding of the patterns of change in soil properties in response to different types of management; and a better understanding of the factors that most influence soil health outcomes. This study evaluated the combination of four tillage systems of differing intensities, and three winter crop types on soil health outcomes. For the first objective of this study, soil physical properties, soil carbon, and crop yield were measured repeatedly over a seven-year period to quantify how these properties respond to management. The soil physical properties showed temporary improvement by more intensive tillage but reverted in the months after tillage. The soil carbon increased from 2018 to 2022 in the three least-intensive tillage treatments. Crop yield was significantly increased in years when there was a mix of crop species planted. For the second objective of this study, the effects of management on soil carbon, soil stability, and crop yield were evaluated after six years of management. These soil health parameters were then correlated to determine the most prominent factors influencing change in soil properties. Soil carbon and soil stability were both improved in least-intensive tillage treatments. The findings from the correlation analyses suggest that soil carbon concentration, soil texture, and tillage were all prominent factors in improving soil health outcomes. These results demonstrate the relatively slow response in many soil physical properties to management, highlight the need for consistent management to improve soil health, and emphasize the importance of taking measurements at different times throughout the year. Furthermore, this is information that can be used to develop more sustainable and resilient cropping systems in the Coastal Plain.

Orientador: Bastiaan Philip Reydon / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Economia / Made available in DSpace on 2018-08-27T05:27:00Z (GMT). No. of bitstreams: 1 Telles_TiagoSantos_D.pdf: 2532419 bytes, checksum: 074d49e9f68a6dcd4d343ff801020e43 (MD5) Previous issue date: 2015 / Resumo: Os preços de terras agrícolas podem ser determinados tanto pelos fatores produtivos quanto pelos fatores especulativos. Entre os fatores produtivos, é reconhecido que investimentos na conservação dos solos em áreas destinadas às atividades agropecuárias podem valorizar as terras agrícolas. O plantio direto na palha é uma tecnologia que integra diretrizes da agricultura conservacionista e que garante uma série de vantagens à produção agropecuária, com possíveis impactos no preço das terras, o que contribui para que a adoção desse tipo de preparo do solo esteja crescendo no Brasil. Essa expansão foi de tal grandeza que no Censo Agropecuário 2006, realizado pelo Instituto Brasileiro de Geografia e Estatística (IBGE), foi dedicada uma seção específica para o levantamento de informações sobre os tipos de preparo do solo. Esse levantamento possibilitou o cruzamento de informações sobre os tipos de preparo do solo com o preço das terras agrícolas, oferecendo a possibilidade de verificar se as terras utilizadas com o plantio direto na palha são mais valorizadas do que aquelas utilizadas com outros tipos de preparo, ou seja, cultivo convencional ou cultivo mínimo. Os resultados indicaram que no Estado do Paraná as terras agrícolas em áreas de lavouras temporárias com plantio direto na palha, quando comparadas aos demais tipos de preparo, são mais valorizadas. Essa valorização das terras associada ao plantio direto na palha também pode ser observada em outras Unidades da Federação, tais como Bahia, São Paulo, Rio Grande do Sul, Mato Grosso do Sul, Mato Grosso e Goiás. Mas o fenômeno da expansão do plantio direto na palha e aumento do valor das terras que utilizam a tecnologia pode estar relacionado a outros aspectos técnicos e econômicos inerentes a esta tecnologia, dentre os quais: a redução de risco de perdas de produção associados às questões climáticas e de custos, redução no número de operações agrícolas em comparação aos outros tipos de preparo e simplificação na gestão da propriedade agrícola. Adicionalmente, outro fator que pode ter influenciado essa relação entre plantio direto e valorização das terras agrícolas foram ações governamentais, por meio de programas e políticas públicas com foco na conservação e recuperação dos solos. Isso suscita a questão de que é válido investigar com mais profundidade a repercussão do programas dessa natureza na valorização do ativo terra enquanto fator para a tomada de decisão dos agricultores na adoção de práticas propostas pela agricultura conservacionista / Abstract: The cost of farm lands is determined by both productive and speculative factors. Soil conservation is one such factor that might result in the appreciation of areas dedicated to agriculture. The no-tillage (NT) is a technology integrating the guidelines of conservation agriculture and ensures several advantages to agricultural productions. It also impacts land prices and, in turn, favors the adoption of this type of soil preparation in Brazil. The expansion of the use of the NT was so significant that the 2006 Agricultural Census, carried out by the Brazilian Institute of Geography and Statistics (IBGE), dedicated one specific section for the acquisition of information about the types of soil preparation. The collected data allowed the study of the correlation between the type of soil preparation and the cost of farm lands. In particular, it enabled the comparison between the direct prices of lands using NT or other soil preparation, that are conventional tillage and minimum tillage. The results indicate that, in Parana State, farm lands in large areas of annual crops using NT are negotiated at higher prices comparison with land using other forms of soil preparation. This Brazilian farm land appreciation in association with the NT was also observed in other Federation units, such as Bahia, São Paulo, Rio Grande do Sul, Mato Grosso do Sul, Mato Grosso and Goias. The observed higher prices might also be associated with other technical and economical aspects, inherent to the NT, such as the reduction of risk of yield loss due to climate issues and decreased costs, diminished number of agriculture operations, in comparison with the other types of soil preparation and simplified management of the property. Additionally, another factor that might have influence on this relationship between the NT and the appreciation of the farm lands were governmental actions, represented by public programs and policies focusing on the conservation and restoration of soils. It raises the question that it is important to investigate more deeply the repercussion of such policies in the appreciation of land as an asset in the farmer's decision to adopt practices of the tillage conservation agriculture / Doutorado / Desenvolvimento Economico, Espaço e Meio Ambiente / Doutor em Desenvolvimento Economico

Orientador: Sylvio Luis Honório / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-16T03:54:41Z (GMT). No. of bitstreams: 1 Martins_MarceloLuis_M.pdf: 770308 bytes, checksum: 481ff6a7c14306c173ede0d4ee971464 (MD5) Previous issue date: 2010 / Resumo: Com a finalidade de determinar algumas características físicas e químicas do Hippeastrum hybridus da variedade Apple Blossom durante o armazenamento foi conduzido este experimento na faculdade de Engenharia Agrícola - UNICAMP. O experimento foi realizado no mês de agosto do ano de 2008 em virtude da época de colheita do bulbo. Apos a coleta do material uma parcela dos bulbos foi impactada, todas as parcelas foram curadas até que perdessem cerca de 15% de matéria fresca. Após este tratamento os bulbos foram divididos entre aqueles que foram impactados e os não impactados, ambas as parcelas foram colocadas sob refrigeração a 13ºC durante 3 meses, uma parcela do material não impactado foi mantido a temperatura de 25±3 durante o mesmo período para efeito de comparação. Foram realizadas analises físico-químicas e visuais antes de depois dos tratamentos, e a cada 10 dias durante todo o período de armazenagem a frio do material. Acompanharam-se as alterações físico-químicas, mediante avaliação dos parâmetros, sólidos solúveis, altura, circunferência. A aparência geral do bulbo também foi acompanhada pela presença ou não de vermelhidão por impacto. Os bulbos submetidos ao ensaio de volume apresentaram volume médio igual a 495cm³ com coeficiente de variação igual a 0, 028%, o volume aparente possui valor igual 95,625 kg, a massa específica aparente 0, 617cm³, e o volume intersticial determinado foi igual a 174cm³. A massa específica real possui valor igual a 0,834g/cm³.Os bulbos submetidos à pesagem apresentaram massa média de valor igual a 413g com coeficiente de variação igual a 0,28%, a porosidade equivalente a 27%. Os valores dos coeficientes de variação demonstram que os bulbos apresentaram boa uniformidade de volume e massa e baixa porosidade na massa. Os resultados das analises realizadas permitiram avaliar que os bulbos impactados e mantidos sob refrigeração não apresentam diferenças significativas em nível de significância de 5% para o parâmetro de sólidos solúveis quando comparados aos bulbos não impactados sob mesma condição climática. Entretanto o bulbo colocado fora da refrigeração apresentou diferença significativa em nível de significância de 5% para o parâmetro de lidos solúveis quando comparado ao bulbo não impactado e sob refrigeração. O bulbo é um esferóide oblato com 90,8% de esferificidade / Abstract: It was developed a research to determinate some physical and chemical characteristics of Hippeastrum hybridus (Apple Blossom variety) during storage, the experimental tests were conducted on the UNICAMP lab. The experiment tests were carried out in august, 2008 because of the harvest season of the bulbs. After the harvest part of the material were impacted and the whole material were separated in portions and then received the curing treatment with hot air at 30ºC for twenty four hours making the bulbs lose about 15% of water.After curing treatment the material were divided on "impacted" and "non impacted" both portions were stored for 3 months on 13ºC, one portion didn't receive the cold treatment. After that, some physical and chemical analyses were conducted, a visual analysis was made as well, and the analyses started 10 days after the product was impacted. The following parameters were evaluated: moisture content, soluble solids (ºBRIX), weight, circumference and general appearance. The statistical analysis results showed that the impact did not affect the bulbs soluble solids but the cold chain affects them. In matters of volume the bulbs showed medium volume equal to 495cm³, the variation about 0, 028%, the apparent volume 95,625 kg , specific mass apparent 0, 617cm³ and the interstitial volume equal to 174cm³, the specific real mass it's equal to 0,834g/cm³, porosity it's equal to 27%. The bulb is an oblate spheroid with 90, 8% of sphericity / Mestrado / Tecnologia Pós-Colheita / Mestre em Engenharia Agrícola