FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / As tortas resultantes da extraÃÃo do Ãleo das sementes de PinhÃo manso e Mamona constituem-se excelentes fontes de matÃria orgÃnica, ricas em nitrogÃnio, fÃsforo, potÃssio e outros nutrientes. No entanto, o problema està relacionado ao direcionamento dado a esses resÃduos vegetais, quando gerados em grande escala, pois a destinaÃÃo inadequada desses subprodutos pode limitar a eficiÃncia da produÃÃo e a preservaÃÃo do ambiente. Nesse sentido, buscou-se atravÃs deste trabalho, conhecer os efeitos da aplicaÃÃo desses subprodutos no solo de duas Ãreas: uma sobrepastejo e, outra de exclusÃo de sobrepastejo, ambas localizadas na regiÃo de IrauÃuba-CE, sobretudo nos parÃmetros quÃmicos e biolÃgicos que quantificam a qualidade do solo. O experimento foi conduzido em casa de vegetaÃÃo do Departamento de CiÃncias do Solo da Universidade Federal do CearÃ, Campus do Pici, em Fortaleza-CE e analisado, considerando-se cada torta individualmente dentro de cada Ãrea, utilizando-se um delineamento inteiramente casualizado em esquema fatorial 2 x 3 (2 Ãreas e 3 doses de torta), com seis tratamentos e quatro repetiÃÃes, totalizando 24 parcelas experimentais para cada torta, sendo cada parcela constituÃda por um vaso contendo duas plantas. ApÃs 45 dias da incorporaÃÃo das tortas ao solo dos vasos, semeiou-se feijÃo caupi [Vigna unguiculata (L.)] e, ao final de 30 dias de cultivo, foram determinados os valores de pH da soluÃÃo do solo, teores de NPK no solo e na planta, Carbono OrgÃnico Total (COT), densidade de esporos de FMA no solo, Carbono da Biomassa Microbiana (CBM), RespiraÃÃo Basal do Solo (RBS) e os quocientes metabÃlico (qCO2) e microbiano (qMIC). Os resultados demonstraram que a Ãrea sobrepastejo (Ãrea 1) foi a mais favorecida pela aplicaÃÃo das tortas de mamona e pinhÃo manso, especialmente na dose 5% (D2) e a que teve os maiores valores de qCO2, enquanto que a Ãrea de exclusÃo (Ãrea 2) apresentou os maiores valores de CBM do solo. A adiÃÃo das tortas de pinhÃo manso e mamona elevaram os teores de COT e de NPK no solo e nas plantas, indicando que a aplicaÃÃo dessas tortas pode ser uma alternativa na reabilitaÃÃo de Ãreas degradadas. / The residue resulting from the oil extraction of jatropha and castor seeds is considered an excellent source of organic matter, which is rich in nitrogen, phosphorus, potassium and other nutrients. However, the problem is concerned to the fate given to this seed residue, as generated in large scale, since the improper disposal of it may limit the efficiency of production and the environment conservation. In this sense, it was set a research with the objective to evaluate the effects of the application of these seed residues in the soil collected from two areas: an overgrazing site and other conserved as exclusion site, both located in IrauÃuba county of Ceara State, Brazil. The study focused especially on chemical and biological parameters which are related to the soil quality. The experiment was conducted under greenhouse conditions belonging to the Department of Soil Science, Federal University of CearÃ, Campus do Pici, Fortaleza-CE. Plant and soil were analyzed considering each site that received the seed residue. The experimental design was a completely randomized blocks in a 2 x 3 factorial (two areas and three doses of pie), with six treatments and four replicates, totalizing 24 experimental units for each seed residue; each unit consisted of a pot containing two plants. After 45 days of the seed residue application, the pots were sown with cowpea [Vigna unguiculata (L.)] and, after a 30 days growing period, it was determined the pH of the soil solution, the soil and plant NPK contents, Total Organic Carbon (TOC), density of spores in the soil microbial biomass carbon (MBC), soil basal respiration (SBR) and both metabolic (qCO2) and microbial (qMIC) quotients. The results showed that the overgrazing of the area (area 1) was favored by the application of the castor bean and jatropha seed residues, especially at the rate of 5% (D2) which had the highest values of qCO2, while the exclusion area (Ãrea 2) showed the highest values of soil MBC. The addition of jatropha and castor seed residues, at both rates, reduced the density of spores of the soil in both areas, but increased the TOC and NPK soil and plants contents, indicating that the application of these seed residues can be an alternative for rehabilitating degraded soil areas.

Controlled tile drainage (CTD) is an agricultural management practice with well-documented water quality and agronomic benefits, however, by virtue of its effect upon soil hydrology, CTD could potentially impact soil greenhouse gas (GHG: CO2, CH4, N2O) emissions. This study aimed to determine whether: (1) CTD affects soil GHG emissions throughout a dry (2012) and a wet (2013) growing season for corn, soybean, and forage fields in eastern Ontario, and (2) the location in a field with respect to a tile drain (over tile (OT) versus between tile (BT)) is important in GHG emissions. Non-steady state chambers were used for sampling soil GHG emissions in order to analyze GHG fluxes, the δ13C of soil-respired CO2 (RT), and for separating total soil respiration into its rhizosphere and soil components. There was no significant difference in average GHG emissions from CTD and UTD fields (except for 1/5 field pairs studied for N2O) and from OT and BT locations. The means of δ13C of RT were not statistically different (p>0.05) between 4/5 CTD and UTD field pairs, and between OT and BT locations in 4/5 CTD fields. The mean contributions from rhizosphere respiration and soil respiration did not differ (p>0.05) in 3/4 CTD and UTD field pairs. This lack of difference in GHG emissions is believed to have resulted from their being no difference in surface soil water contents among CTD and UTD fields and among OT and BT locations. It is believed that surface soil moisture did not vary because: (1) the water table was too low in 2012 for effective water table control, and (2) significant precipitation created equally wet surface soil in 2013. In 2013, the surface soil moisture was approximately 10% greater and this may be why there was an approximate 5 kg C/ha/day greater CO2 flux from soybean fields in 2013 than in 2012. δ13C was useful for distinguishing the source of CO2 emissions (rhizosphere versus soil respiration) in CTD fields when the crop and plant δ13C signatures varied. The results are useful for helping to capture the carbon footprint of tile drainage management practices imposed at field-scale.

Orientador: Jairo Osvaldo Cazetta / Resumo: Frente ao constante crescimento populacional mundial e o aumento da demanda por alimentos, atividades agrícolas e de produção animal encontram-se cada vez mais pressionadas a aumentar suas produtividades com o mínimo de impacto ambiental. Por isso o grande interesse em usar os resíduos gerados na produção animal para produzir fertilizantes para a agricultura, tendo em vista as altas concentrações de nutrientes minerais para as plantas e pelo pouco conhecimento sobre as alterações desses resíduos no solo em função do tempo após sua aplicação. O objetivo desse trabalho foi avaliar o efeito da aplicação de um composto orgânico produzido com resíduos animais da aquicultura associado à maravalha de madeira, sobre a fertilidade do solo, respiração basal e as perdas de N na forma de amônia, bem como a nutrição e o crescimento das plantas em função do tempo após a aplicação do composto orgânico no solo. Os experimentos foram realizados em casa de vegetação, no período entre maio a novembro de 2018. No primeiro experimento, foram estudados cinco períodos de incorporação do composto orgânico no solo (0, 30, 60, 90 e 120 dias) a uma dose de 20 t ha-1, além de um tratamento sem adubação. No segundo experimento foi monitorado a respiração basal e a volatilização de amônia do citado solo, com (20 t ha-1) e sem a aplicação do composto, por 17 semanas consecutivas. Os resultados foram submetidos à análise de variância pelo teste F e as médias comparadas. Os resultados revelaram que a aplicaç... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Faced with the constant growth of world population and the increased demand for food, agricultural activities and the animal production industry are increasingly pressure to increase their productivity with a minimum environmental impact.For this is big the interest in use the wastes derivingin animal productions for produce fertilizers for agriculture, given the high concentrations of mineral nutrients for plants and the little knowledge about the changes of these residues in the soil as a function of time after their application. The aim of this study was to evaluate the availability the effect of a fish waste-based organic compostassociate with maravalha of wood, about soil fertility, soil basal respiration and N lossesin ammonia form, as well as plant nutrition and growth as a function of time after application of organic compost to the soil. The experiments were performed in a greenhouse between May and November 2018.In the first experiment, five periods of incorporation of organic compost into the soil (0, 30, 60, 90, 120 days) at a dose of 20 t ha-1, as well as a treatment without fertilization were studied. In the second experiment, the basal respiration and ammonia volatilization of the mentioned soil were monitored with (20 t ha-1) and without the application of compost for 17 consecutive weeks. The results were submitted to a variance analysis by the F test and the means compared. The results revealed that the application of the organic compost increased the organi... (Complete abstract click electronic access below) / Mestre

In natural ecosystems, like deciduous and coniferous forests, soil CO2 flux or soil respiration is highly variable and influenced by multiple factors including temperature, precipitation, dissolved soil organic carbon (DOC), dissolved organic matter (DOM), and bacterial and fungal biomass and diversity. However, as the human population continues to grow rapidly, so too do urbanized landscapes with unknown consequences to soil respiration. To determine the extent urbanization influences seasonal shifts in microorganisms and environmental drivers alter soil respiration, we evaluated bacterial and fungal communities, soil physiochemical characteristics, and respiration in forested and urbanizing ecosystems in three watersheds across northern Utah, USA. Based on the next-generation sequencing of the 16s DNA and RNA, we found that montane bacteria were predominantly structured by season while urban bacteria were influenced by degree of urbanization. There was no apparent effect of season on montane fungi, but urban fungal communities followed patterns similar to urban bacterial communities. Bacterial diversity was sensitive to seasonality, especially in montane ecosystems, declining 21-34% from spring to summer and staying relatively low into fall, and fungal diversity was generally depressed in spring. Urban bacterial communities were differentiated by substantially more bacterial taxa with 62 unique OTUs within families structing phylogenetic differences compared with only 18 taxa differentiating montane communities. Similar to bacteria and fungi, DOC and ammonium concentrations fluctuated predominantly by season while these same parameters where highly variable among urban soils among the three watersheds. Structural components of DOM via parallel factor analysis (PARAFAC) of fluorescence excitation-emission matrices show varying patterns between montane and urban systems with humic substance resistance to biodegradability found more dominantly in montane systems. Incorporating all soil chemical parameters, daily temperature and moisture, and fungal and bacterial diversity and richness in mixed linear effects models describing daily CO2 over all seasons, we found that a single model best described montane soil respiration, while individual watershed models best described urban respiration. Montane respiration was related to the availability of DOC, different DOM components, and rRNA-based bacterial diversity . Alternatively, urban respiration was influenced by either bacterial diversity and richness in our rapidly urbanizing environment, DOM characteristics and soil O2 in the more agricultural urban soils, or the DOM parameter humification index (HIX) in highly urbanized soils. Our results suggest that urbanization creates distinct bacterial and fungal communities with a single soil biotic or chemical parameter structuring soil respiration, while montane ecosystems select for similar bacterial and fungal communities with respiration sensitive to fluctuations in soil moisture, bacteria and the recalcitrance of carbon (C) resources.

This study is part of a larger collaborative effort to determine the overall environmental sustainability of intercropping pine (Pinus taeda L.) and switchgrass (Panicum virgatum L.), both of which are promising feedstock for bioenergy production in the Lower Coastal Plain in North Carolina. We measured soil CO₂ efflux (RS) every six weeks from January 2012 to March 2013 in four-year-old monoculture and intercropped stands of loblolly pine and switchgrass. RS is primarily the result of root respiration (RA) and microbial decomposition of organic matter (RH) releasing CO₂ as a by-product and is an important and large part of the global carbon (C) cycle. Accurate estimates of the two components of total soil respiration (RS) are required as they are functionally different processes and vary greatly spatially and temporally with species composition, temperature, moisture, productivity, and management activities. We quantified RA and RH components of RS by using a root exclusion core technique based on root carbohydrate depletion, which eliminates RA within the cores over time. We determined the relationship between RS, RA and RH measurements and roots collected from the cores. We took fresh soil cores in July 2012 to compare root productivity of loblolly pine and switchgrass in monoculture versus the co-culture. Additionally, CH₄ and N₂O fluxes were monitored quarterly using vented static chambers. Pure switchgrass had significantly higher RS rates (July, August, September), root biomass and root length in the top 0-35 cm relative to switchgrass in the co-culture, while loblolly pine with and without switchgrass had no significant changes in RS and roots. Correlations between RA and roots showed significantly positive correlation of RA to grass root biomass (r = 0.37, p ≤ 0.001), fine (r = 0.26, p ≤ 0.05) and medium root surface area (r = 0.20, p ≤ 0.1). The estimated portions of RS attributed to RA in the intercrop stand were 31% and 22% in the summer and fall, respectively. No significant treatment differences were observed in either CH₄ or N₂O flux. Our study indicates a decrease in switchgrass root productivity in the intercropped stand versus the monoculture stand which could account for differences in the observed RS. / Master of Science

Climate change and extreme weather events have impacted global forest ecosystems’ ability to sequester atmospheric carbon dioxide. In this study, the temporal and spatial dynamics of soil CO2 efflux or soil respiration (Rs) was measured in a temperate coniferous (TP74) and a deciduous forest (TPD) over a six-year period (2014 to 2019). Analysis of Rs trends showed a strong positive correlation with soil temperature (Ts) and soil moisture (SM) at TPD and TP74 causing large pulses of Rs. The average annual temperature sensitivity (Q10) was found to be 2.06 for TPD and 1.87 for TP74. Coherence analysis for both sites from 2017 to 2019 showed that in extreme weather events, TP74’s carbon pool was less stable than that of TPD. Dynamics of Rs at both forest sites was further analyzed using thirteen different Rs models (e.g. Ts only, SM only, Ts and SM models, neural network) to evaluate their performance in simulating observed patterns of soil CO2 effluxes. As compared to other models, the Gaussian – Gamma model consistently reproduced observed dynamics of Rs where on average 70% of variability in Rs was explained. This study showed that Ts and SM are key determinants of Rs in both forests. Models that incorporate the influence of SM on Rs and were able to better simulate Rs dynamics as compared to Ts only models. Results also suggest that coherence analysis can be utilized to understand temporal variations in Rs. The knowledge of environmental drivers of Rs can be used to determine the impact of climate change and extreme weather events on Rs and assist in developing ecosystem models. / Thesis / Master of Science (MSc)

The main goals of this study were to document the structural and functional recovery of differently restored areas, to understand better the relationship between the two, and to determine which types of measurements are best for assessing restoration success. To address these questions, an experimental system was created through topsoil removal and subsequent restoration in a blocked, completely randomized design using two levels of soil amendment (with or without 10 kg of leaf mulch per m2) and three levels of seeding treatment (no seed, a standard reclamation mix, and an alternative, wildflower dominated reclamation mix). All measurements were designed to document responses due to restoration treatment in comparison to adjacent, undisturbed, reference sites. Vegetation structure in amended sites, as measured by total vegetation cover and species richness, recovered to levels similar to references within the two years of the study. Plant community composition did not develop similarity to references in any experimental treatments. Both soil amendment and seeding type affected cellulose decomposition rates, with amended plots showing higher decomposition rates than unamended, and seeded plots exhibiting higher rates than unseeded. Enzyme activities were largely determined by soil amendment, but the reference plots consistently had higher enzymatic activity. Amended sites exhibited significant increases over time in soil respiration, reaching or surpassing the rates observed in reference areas. Methane oxidation rates were generally increased in disturbed plots compared to undisturbed references due to increased atmospheric diffusion into the soil. Amended areas exhibited depressed rates relative to unamended, and seeding level had no significant effect on methane oxidation. Over all measurements, restoration of ecosystem function was most facilitated by the addition of the soil amendment. Seeding treatment significantly altered the resultant plant community, which may have substantial, long-term consequences for succession. The inclusion of functional parameters into restoration assessment provides for better overall information concerning ecosystem performance and may add to the ability to predict long-term success of restoration efforts. / Ph. D.

The objective of this research was to determine how genetics and nutrient availability influence C cycling in intensively managed southern pine forests. This work consisted of a two year field and a complimentary one year greenhouse study each split into above- and below-ground pools and fluxes. Both the greenhouse and field experiment showed differences between contrasting genotypes in gas exchange parameters and C partitioning patterns, but genetic by nutrient availability interactions were only observed in the field. In the field study, some genotypes were better able to tolerate nutrient limitations due to more favorable canopy architecture and lower N demand. Our results clearly show that contrasting ideotypes have the potential to respond differently to differences in nutrient availability in terms of biomass partitioning, leaf physiology, and leaf biochemistry (Chapter 3). Both experiments showed short-term improvements to soil physical and chemical properties, which have been shown to correlate with higher site quality. In both the greenhouse and field experiment, we concluded that increased C loss by way of total soil CO₂ efflux (FS) made up only a small percent total C incorporated as LR. Short-term results led us to conclude that combining LR treatments and planting of genotypes with low nutrient demand or high nutrient use efficiency may increase soil organic matter (SOM) while avoiding loss of stem volume from nutrient immobilization. Data from our field study showed a strong genotype by soil amendment interaction for FS over all sampling dates with the relative importance of contributing factors (heterotrophic or root respiration) also changing (Chapter 5). Overall, logging residue incorporation increased total system C gain per ha more than did fertilization alone, but there were differences between genotypes planted (Chapter 6). Data from the field experiment show that although LR incorporation did not decrease overall net primary productivity, it did decrease biomass partitioning to merchantable products (main stem) depending on genotype. These data underline the importance of matching appropriate genotypes to specific site conditions and silvicultural prescriptions. / Ph. D.

An understanding of ecosystem-level carbon (C) sequestration, or net ecosystem production (NEP), requires the separation of heterotrophic, microbial respiration (RH) from autotrophic, root-derived respiration (RA) as the components of RS (i.e., NEP = NPP - RH). However, separating these two sources in situ has been problematic since they are closely coupled. This study utilizes two similarly aged Pinus taeda L. stands, 8 and 9 years-old, aimed at quantifying these two respiration components through in-situ root severing. In order to use root-severing treatments to separate RS into RH and RA components, confirmation of carbohydrate depletion coupled to RA decline is crucial. This study evaluated the changes in CO2 flux rates and carbohydrate supply upon root severing in Pinus taeda L. using a controlled laboratory validating a two-part field study. The first field study used root-severing cores to test in-situ if respiration components can be attained based on the depletion of carbohydrate supply. The second field study was aimed at how future changes in climate might affect the ability of forests to store C and how modern forestry practices might affect changes and was conducted over the course of two installations, spring and summer 2012. In this study we examined the effects of fertilization (0 and 100.9 kg N ha-1 ) and throughfall reduction (0 and -30%) on total soil respiration (RS) as well as the heterotrophic contribution to RS, in a fully replicated (n=4), 2x2 factorial design. In the controlled lab experiment RS and RA declined by 86% and 95% respectively by the end of an 86 day trial and NSC carbohydrates declined by 60% for soluble, 29% for insoluble, and 43% for total (soluble + insoluble). The decline of RA was highly correlated to with the decline of NSC’s at 0.90, 0.69 and 0.93 for soluble, insoluble and total, respectively. The companion field study revealed a mean decrease 21±0.5% of over the final three dates when severed root respiration stabilized. In the second study, testing throughfall reduction and fertilization levels there were no fertilization by throughfall reduction interactions on the contribution of RH to RS in either the spring or summer; however, the main effect of throughfall reduction was significant in the spring. During the spring, the mean contribution of RH to RS for ambient throughfall plots was 96±6.4%, while the mean contribution under throughfall reduction was 68±1.9%. During the summer, there were no differences among treatments and the overall contribution of RH to RS was 78±1.6%. Collectively, both of these studies revealed that the severing of roots from their primary energy source and the subsequent depletion of stored NSC that the use of in-situ methods allows for the quantification of soil respiration components RA and RH. Using these estimates to model NEP in the short-term can be variable by season, however, long-term monitoring may simplify future NEP modeling scenarios / Master of Science

The thinning of loblolly pine plantations has a great potential to influence the fluxes and storage of carbon within managed stands. This study looked at the effects of thinning on aboveground carbon and mineral soil carbon storage, 14-years after the thinning of an 8-year-old loblolly pine plantation on the piedmont of Virginia. The study also examined soil respiration for one year following the second thinning of the same stand at age twenty-two. The study was conducted using three replicate .222 hectare stands planted using 3.05 by 3.05 meter spacing in 1980 at the Reynolds Homestead in Critz, VA. Using two different sample collection methods it was determined that soil carbon was evenly dispersed throughout thinned plots, and that random sampling techniques were adequate for capturing spatial variability. Soil carbon showed a significant negative correlation with soil depth (p=0.0001), and by testing the difference between intercepts in this relationship, it was determined that thinning significantly increased soil carbon by 31.9% across all depths (p=0.0004). However, after accounting for losses in aboveground wood production, thinning resulted in an overall 10% loss in stand carbon storage. However, this analysis did not take into account the fate of wood products following removal. Soil respiration, soil temperature, and soil moisture were measured every month for one year near randomly selected stumps and trees. In order to account for spatial variation, split plots were measured at positions adjacent to stumps and 1.5 meters away from stumps. Soil temperature and moisture were both significantly affected by thinning. Regression analysis was performed to determine significant drivers in soil CO2 efflux. Temperature proved to be the most significant driver of soil respiration, with a positive correlation in thinned and unthinned stands. When modeled using regression, thinning was a significant variable for predicting soil respiration (p < 0.0009), but explained only 3.4% of the variation. The effects of thinning were responsible for decreased respiration, however, when coupled with increased temperatures, soil respiration was elevated in thinned stands. / Master of Science