Thesis (MScAgric)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: The Eksteen method of lime requirement determination, based on the ratio of Ca+Mg:H (R-value), is widely used in the Western Cape and has proven to be extremely accurate for most soils. However, the Eksteen method is known to give erroneous predictions of lime requirement for certain soil groups. These include sandy soils (notably pale coloured sandy soils), organic-rich topsoils and strongly structured, Mg-rich subsoils. The objective of this study was to examine the nature of the Eksteen RpH relationship for these problem soils, and to develop appropriate modifications to the Eksteen method, where possible. A population of both normal and problem soils was selected and analysed, the RpH relationships of the soils were determined, and various relationships were examined. The principal findings with regard to the nature of the Eksteen RpH relationship were as follows: 1. The lime requirements of pale coloured sandy soils can be most accurately determined on an equivalent basis relative to the total extractable acidity, after the total extractable acidity has been corrected for residual lime. 2. The previously observed and acknowledged inaccuracy of the Eksteen method on organic-rich soils stems from the pH-dependant acidity component of the organic matter. The accuracy with which the lime requirement of these soils is predicted by the Eksteen method can be greatly improved by the application of an organic matter correction factor (OMCF) to the total extractable acidity, which is the parameter on which the lime requirement is then based. 3. In structured, Mg-rich subsoils the pH-neutralising capacity of Mg is considerably lower than that of Ca, a factor which is not taken into account by the Eksteen method. The Eksteen method can nevertheless be corrected to overcome this discrepancy. The high levels of Mg in the structured, Mg-rich subsoils cannot be attributed to minerals in these subsoils containing brucite interlayers. 4. Toxic levels of AI may only be expected at soil pH values below approximately 4.7 as determined in 1M KC!. Soil organic matter and CEC have marked affects on AI extractability. In accordance with the objective that appropriate modifications to the Eksteen method should be developed if possible, theoretically-based correction factors were developed which will permit the use of the Eksteen method to be confidently extended to those soil groups (pale coloured sandy soils, organicrich topsoils and strongly structured, Mg-rich subsoils) for which it was formerly considered unreliable. / AFRIKAANSE OPSOMMING: Die Eksteen metode van kalkbehoeftebepaling, gebaseer op die verhouding van Ca+Mg:H (R-waarde), word oor die algemeen wyd in die Wes-Kaap gebruik en is baie akkuraat vir meeste gronde bewys. Dit is egter bekend dat die Eksteen metode verkeerde kalkbehoeftes vir sekere grondgroepe voorspel. Hierdie sluit sanderige grande (veral lig gekleurde sandgronde), organiesryke bogrande en sterk gestruktuurde, Mg-ryke ondergronde in. Die doel van hierdie studie was om die aard van die Eksteen R:pH verwantskap vir hierdie probleemgronde te bepaal, waar moontlik. 'n Populasie van beide normaal en probleemgrande is geselekteer en geanaliseer, die R:pH verwantskap van die grande is bepaal en verskeie verwantskappe is ondersoek. Die hoof bevindinge ten opsigte van die aard van die Eksteen R:pH verwantskap was as volg: 1. Die kalkbehoefte van lig gekleurde sandgronde kan akkuraat bepaal word op 'n ekwivalente basis, relatief tot die totale ekstraheerbare suurheid, nadat die totale ekstraheerbare suurheid gekorrigeer is vir residuele kalk. 2. Die voorheen bekende onakkuraatheid van die Eksteen metode op organiesryke gronde het sy oorsprong by die pH-afhanklike suurheid komponent van organiese material. Die akkuraatheid waarmee die kalkbehoefte van hierdie grande met behulp van die Eksteen metode voorspel kan word, kan noemenswaardig verbeter word deur die totale ekstraheerbare suurheid te korrigeer met behulp van 'n organiese materiaal korreksie faktor (OMKF). Die aangepaste totale ekstraheerbare suurheid is dan die parameter waarap die kallkbehoefte gebaseer word. 3. In gestruktuurde, Mg-ryke ondergrande is die pH-neutraliseringsvermoe van Mg aansienlik laer as die van Ca, 'n faktor wat seide in berekening gebring word by die Eksteen metode. Die Eksteen metode kan tog gekorrigeer word om hierdie tekortkoming te oorkom. Die hoe vlakke van Mg in gestruktuurde, Mg-ryke ondergrande kan nie aan die teenwoordigheid van minerale in die ondergrond, wat brusiet tussenlae bevat, toegeskryf word nie. 4. Toksiese AI vlakke sal alleenlik by grond pH waardes laer as ongeveer 4.7, soos bepaal in 1M KCI, verwag word. Grand organiese materiaal en KUK het 'n noemenswaardige effek op ekstraheerbare AI. In ooreenstemming met die doelwitte om toepaslike wysigings aan die Eksteen metode aan te bring, is teoreties gebaseerde korreksiefaktore ontwikkel, wat die gebruik van die Eksteen metode verder verbreed om daardie grondgraepe (lig gekleurde sanderige grande, organies-ryke bogrande en sterk gestruktuurde, Mg-ryke ondergrande) in te sluit waarvoor dit vantevore as onbetraubaar beskou is.

<p>Rich fens are an important, but threatened, habitat type in the boreal landscape. In this thesis I have examined responses of rich fen vascular plants and bryophytes after drainage and restoration. </p><p>The effects of drainage on the rich fen flora were observed in a long time study and the responses were rapid and drastic. During an initial stage a rapid loss of brown mosses was observed, followed by increases of sedges and early successional bryophytes, and later by an expansion of dominants. Initial effects of hydrological restoration showed that rewetting can promote re-establishment of an ecologically functional rich fen flora, but has to be combined with other treatments, such as mowing or surface disturbance. </p><p>After restoration, re-establishment of locally extinct species may be hampered by dispersal limitations. To test if reintroductions could help to overcome dispersal limitations I performed transplantation studies with four common rich fens bryophytes to a rewetted site. The results showed that the species were able to establish, and that survival and growth were promoted by desiccation protection and liming. </p><p>I further examined competition among three of the most common bryophytes in natural boreal rich fens that usually occur mixed in a mosaic pattern but show small but important microtopographical niche separation. The results indicate similar competitive abilities among the species, and no case of competitative exclusion occurred. The results help to explain the coexistence of these species under natural conditions with microtopographic variation and repeated small scale natural disturbances. </p><p>Restoring a functional flora in drained rich fens is a complex task, which requires understanding of underlying causes of substrate degradation in combination with suitable restoration measures. The thesis suggests how the results can be used in practical restoration work, and also stresses the need for monitoring of restoration experiments over longer time. </p>

Na rápida ocupação dos solos do Tocantins pelo cultivo de soja, tem se observado a aplicação de doses elevadas de calcário e em período muito próximo do plantio. O tempo insuficiente para dissolução ou a dose elevada do corretivo promove um desequilíbrio químico no solo, com consequente redução na disponibilidade da maioria dos nutrientes. Assim, objetivou-se com o presente trabalho avaliar o efeito de doses e tempos de incubação do corretivo da acidez nos atributos químicos de solos do Tocantins. O trabalho foi conduzido em delineamento inteiramente casualizado com 10 tratamentos obtidos em um esquema fatorial 5X2, combinando cinco doses de calcário (0; 2,0; 4,0; 6,0 e 8,0 t ha-1) e dois períodos de incubação (15 e 60 dias). Os solos usados na incubação foram: Plintossolo Pétrico, textura argilosa (Buritirana); Latossolo Vermelho, textura argilosa (Buritirana); Latossolo Vermelho-Amarelo, textura média (Gurupi); Neossolo Quartzarenico, textura arenosa (Gurupi) e Neossolo Quartzarenico, textura arenosa (Guaraí). Os teores de alumínio e acidez potencial (H+Al) foram reduzidos e os teores de cálcio e magnésio foram elevados significativamente com o aumento da dose de calcário aplicada. Para a construção da fertilidade do Plintossolo Pétrico (Buritirana) e Latossolo Vermelho (Buritirana) foram necessárias 6 t ha-1 para os alcançar valores ideais de Ca, Mg, Al e pH aos 60 dias após aplicação. Aos 15 dias essa construção é alcançada na dose de 8 t ha-1. A construção da fertilidade do Latossolo Vermelho Amarelo (Gurupi), foi alcançada com a dose de 4 t ha-1 aos 60 dias. Já para o Neossolo Quartzarenico de Guaraí e Gurupi a aplicação de 2 t ha-1 do corretivo de acidez do solo foram suficientes para neutralizar a acidez trocável e elevar o valor de pH aos 60 dias após aplicação, contudo, não foi suficiente para a construção da fertilidade em cálcio e magnésio. / In the fast occupation of Tocantins soils by soybean cultivation, it has been observed in high doses of limestone and in a period very close to the plan. Insufficient time to dissolve or a high dose of the corrective promotes a chemical imbalance in the soil, with consequent reduction in the availability of most nutrients. Thus, the effect of doses and the incubation times of the acidity corrector and the chemical attributes of Tocantins soils were evaluated. The work was conducted in a completely randomized design with 10 treatments obtained in a 5X2 factorial scheme, combining five doses of limestone (0, 2.0, 4.0, 6.0 and 8.0 t ha-1) and two treatments Incubation periods (15 and 60 days). The soils used in the incubation were: Petric Plinthsol, clay texture (Buritirana); Red Latosol, clayey texture (Buritirana); Red-Yellow Latosol, medium texture (Gurupi); Quartzarenic Neosol, sandy texture (Gurupi) and Quartzarenic Neosol, sandy texture (Guaraí). The content of aluminum and potential acid (H+Al) were reduced and calcium and magnesium contents were increased with increasing limestone dose applied. For the construction of the fertility of the Petric Plinthsol (Buritirana) and Red Latosol (Buritirana), 6 t ha-1 are required to reach ideal values of Ca, Mg, Al and pH at 60 days after application. At 15 days this construction is achieved at a dose of 8 t ha-1. The construction of the fertility of the Red- Yellow Latosol (Gurupi), was dosed with a dose of 4 t ha-1 at 60 days. For the Quartzarenic Neosol of Guaraí and Gurupi, an application of 2 t ha-1 of the soil acidity corrector to neutralize the exchangeable acidity and raise the pH value to 60 days after application is not enough for a fertility construction in calcium and magnesium.

Submitted by admin tede (tede@pucgoias.edu.br) on 2016-11-22T18:48:04Z No. of bitstreams: 1 Marinês Honorato Pinheiro.pdf: 1321524 bytes, checksum: 2c939222889101ffb6ea160c1e897cd0 (MD5) / Made available in DSpace on 2016-11-22T18:48:04Z (GMT). No. of bitstreams: 1 Marinês Honorato Pinheiro.pdf: 1321524 bytes, checksum: 2c939222889101ffb6ea160c1e897cd0 (MD5) Previous issue date: 2016-05-31 / The Brazilian cerrado, rich in fauna and flora, is currently busy in his great extension, often subject to degradation pastures due to inadequate management and soil characteristics of the Savannahs that have high acidity levels (pH), aluminum toxicity and few nutrients, reducing the productivity of pastures. These aspects interfere directly in forage quality and, consequently, in cattle breeding, since the state of Goiás has the third herd in the country. Whereas the addition of limestone to the soil, provides an increase in pH reduces toxic aluminum and provides calcium and magnesium necessary for the plants, the research aims to evaluate the chemical properties of cerrado soil, through the measurement of pH and base saturation after the application of solid and liquid limestone. In a distrophic red latosol, was implemented an entirely randomized experimental design with seven replications with plots of 7m2 to the solid limestone, and limestone and liquid. The chemical evaluations considered four depths (0 - 5 cm, 5 - 10 cm, 10 - 20 cm), at thirty, sixty and ninety days with the respective rainfall conditions. The solid limestone was efficient, especially in the embedded layer, increasing pH and base saturation. Net limestone did not respond to chemical changes, for growing a forage species Panicum maximum. It was concluded that, in this research, the solid limestone made the soil correction, seeking pasture management. / O cerrado brasileiro, rico em fauna e flora, está atualmente ocupado, em sua grande extensão, por pastagens frequentemente sujeitas à degradação, devido ao manejo inadequado e às características dos solos dos Cerrados que apresentam altos teores de acidez (pH), toxicidade por alumínio e poucos nutrientes, reduzindo a produtividade das pastagens. Estes aspectos interferem diretamente na qualidade da forragem e, consequentemente, na produção de bovinos, uma vez que o estado de Goiás tem o 3o rebanho do país. Considerando que a adição do calcário ao solo, proporciona um aumento do pH, reduz o alumínio tóxico e fornece cálcio e magnésio necessários às plantas, a pesquisa tem como objetivo avaliar as propriedades químicas do solo do cerrado, por meio da mensuração do pH e da saturação por bases após a aplicação do calcário sólido e do calcário líquido. Em um latossolo vermelho distrófico, implantou-se um delineamento experimental inteiramente casualizado, com sete repetições, com parcelas de 7m2, para os calcários sólido, e calcário líquido. As avaliações químicas analisam três profundidades (0 - 5 cm, 5 -10 cm, 10 - 20 cm), em trinta, sessenta e noventa dias, com as respectivas condições pluviométricas. O calcário sólido se mostrou eficiente, principalmente na camada incorporada, aumentando o pH e a saturação por bases. O calcário líquido não respondeu às alterações químicas, para o cultivo de uma forrageira da espécie Panicum maximum. Concluiu-se que, nesta pesquisa, o calcário sólido efetuou a correção do solo, visando o manejo de pastagens.

Made available in DSpace on 2014-06-11T19:22:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-02-15Bitstream added on 2014-06-13T19:27:18Z : No. of bitstreams: 1 leles_ep_me_botfca.pdf: 520708 bytes, checksum: c1a4bf2287c1b8471d2c1ca21372907b (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O objetivo desse trabalho foi avaliar a influência de doses de calcário e zinco e, a interação destes sobre os atributos químicos do solo, desenvolvimento da cultura da mamona e acúmulo nutricional nos grãos produzidos. A hipótese deste trabalho é que o aumento de doses de calcário diminui a disponibilidade de zinco no solo para a planta. O experimento foi desenvolvido em estufa para cultivo protegido sem controle de temperatura, em vasos com 17 dm3 de um LATOSSOLO VERMELHO distrófico, textura média. O delineamento experimental foi de blocos casualizados, com quatro repetições. Os tratamentos do experimento foram arranjados num esquema fatorial 3 x 5, sendo os fatores: 3 saturações por base (40, 60 e 80%) e cinco doses adicionadas de Zn (0,5; 1,0; 2,0; 4,0; 8,0 mg dm-3 de solo). Foram semeadas oito sementes por vaso da mamona Al Guarani 2002, desbastando-se para duas plântulas dez dias após a emergência. Em cada vaso, uma planta foi colhida aos 79 dias após a emergência (início do florescimento), quando foram avaliados os componentes morfológicos e diagnose foliar. A outra planta foi conduzida até 174 dias após emergência (na maturidade fisiológica do racemo primário), quando foram avaliados os atributos químicos do solo, e na planta foram avaliados os componentes morfológicos, componentes de produção e acúmulo nutricional dos grãos produzidos. Maiores doses de calcário resultaram em maior número de grãos por planta e MS dos grãos por planta. Maiores doses de zinco promoveram maior acúmulo de Zn nos grãos. Houve interação V% e Zn na altura da planta, na massa seca da raiz, no comprimento da parte masculina e total do racemo e, no acúmulo de Ca nos grãos. No entanto, nenhum destes incrementos refletiu em diferença significativa na massa de 100 grãos da mamoneira. / The objective in this work was to evaluate the effects of lime levels and zinc, and the interaction of this on chemical attributes of soil, on development in castor bean plants and nutrients accumulation on produced seeds. The hypothese of this work is that the raise lime levels reduce the zinc availability in soil for the plant. The experiment was carried out under greenhouse conditions without control of temperature, in pots with 17 dm3 of “RED LATOSOIL dystrophic”, medium texture. The statistical design was of randomized blocks, factorial 3 x 5, with four replicates. The treatments consisted of liming to reach three basis saturation of 40, 60 and 80%, combined with five zinc levels (0,5; 1,0; 2,0; 4,0 e 8,0 mg dm-3). Eight castor bean seeds (cv Al Guarani 2002) were sown per pot, roughed-hew for two seedlings ten days after the emergence. Of this, one plant was grown until 79 days after emergence (beginning of flowering), when morphologic components were measured and leaf diagnose had been made. The other plant was grown until 174 days after emergence (first raceme mature), when were evaluated the soil chemical attributes, morphologic components and production components of plants and nutrients accumulation on produced seeds. Higher lime levels resulted in greater number of seeds per plants and dry matter of seeds per plant. Higher zinc levels promoted higher zinc accumulation in seeds.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-09-05T19:19:59Z No. of bitstreams: 2 Silva, Geanderson Nascimento da - 2013.pdf: 943488 bytes, checksum: 802bbc3ff0bdcab9e06d1d8d1e608103 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-09-05T19:19:59Z (GMT). No. of bitstreams: 2 Silva, Geanderson Nascimento da - 2013.pdf: 943488 bytes, checksum: 802bbc3ff0bdcab9e06d1d8d1e608103 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-05-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In integrated crop-livestock under no-tillage, liming is done on the surface, it is possible that changes occur in the handling of the limestone in depth as a function of grazing. This study was conducted to evaluate attributes related to soil acidity after surface liming in integrated crop-livestock under no-tillage, subjected to grazing intensities in the Cerrado. The study was conducted at the Universidade Federal de Goiás/Campus Jataí, of a Red Latosol (Oxisol). The treatments consisted of different heights pasture management: 25, 35 and 45 cm and area without grazing, arranged in blocks randomly. Were applied to 2.4 Mg ha-1 lime with effective neutralization value 80 % in surface soil after the harvest of soybean (March 2012). Soil samples were colleted depths: 0-2.5, 2.5-5.0, 5.0-7.5, 7.5-10.0, 10.0-15.0, 15, 0- 20.0 and 20.0-30.0 cm for the evaluation of chemical attributes before liming, seven months (end of the grazing cycle 2012) and 12 months (end of the cycle of soybeans in 2013) after liming. A greater correction of soil acidity in the system crop-livestock compared without grazing area in the same evaluation time, especially when that 12 months after the realization of liming. The different assessment times crop-livestock improved soil chemical properties in the first layer of soil, and soil acidity conditions worsened in depth in all areas, except in the smallest grazing intensity. Keywords: chemical / Em sistemas de integração lavoura-pecuária sob plantio direto a aplicação do calcário é feita em superfície, sendo possível que ocorra modificações na movimentação do calcário em profundidade em função do pastejo. Esse trabalho foi conduzido objetivando avaliar atributos químicos relacionados a acidez do solo após aplicação superficial de calcário em sistema de integração lavoura-pecuária sob plantio direto, submetido a intensidades de pastejo no Cerrado. O estudo foi conduzido na área experimental da Universidade Federal de Goiás/Campus de Jataí, em um Latossolo Vermelho distroférrico. Os tratamentos consistiram de diferentes alturas de manejo da pastagem: 25, 35 e 45 cm e área sem pastejo,disposto em delineamento em blocos ao acaso. Foram aplicados 2,4 Mg ha-1 calcário com PRNT de 80%, em superfície do solo, após a colheita da cultura da soja (março 2012). Amostras de solo foram coletadas nas profundidades de: 0-2,5; 2,5-5,0; 5,0-7,5; 7,5-10,0; 10,0-15,0; 15,0-20,0 e 20,0-30,0 cm para avaliação dos atributos químicos antes da calagem, sete meses (final do ciclo de pastejo 2012) e 12 meses (final do ciclo da soja 2013) após a calagem. Houve maior correção da acidez do solo no sistema integração lavoura-pecuária comparado área sem pastejo numa mesma época de avaliação, principalmente quando decorridos 12 meses da realização da calagem. Nas diferentes épocas de avaliações a integração lavourapecuária melhorou as propriedades químicas do solo na primeira camada de solo, e as condições de acidez do solo pioraram em profundidade em todas as áreas, exceto na menor intensidade de pastejo.

Made available in DSpace on 2016-04-28T14:56:19Z (GMT). No. of bitstreams: 1 2009 - Ludmila de Carvalho Sampaio.pdf: 1705521 bytes, checksum: a3e7341ce10bb882edcbb905becd1778 (MD5) Previous issue date: 2009-06-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The Restinga is one type of sand coastal ecosystems that are suffering with high anthropic impact and is important the consideration of any action related to the recovery and conservation of the last remaining areas. For that, is necessary to study the grown and the best conditions for seedling production of species that are native from these ecosystems. In this context, the present work had the objectives: 1- study the response of Senna appendiculata and Senna bicapsularis to different sources and amount of nitrogen. 2- study the response of S. appendiculata, Senna bicapsularis and Machaerium lanceolatum to lime and to a changes in the soil pH. The experiments were conduct under greenhouse conditions in pots filled with sand soil with low fertility. For the experiment with different sources and amount of nitrogen, seven treatments were applied: control (without nitrogen), NO3? (10 mg N/ plant), NO3? (20 mg N/plant), NH4+ (10 mg N/plant), NH4+ (20 mg N/plant), NO3NH4 (10mg N/plant) e NO3NH4 (20 mg N/plant). For the experiments with lime and soil pH, four treatments were applied: 0, 2. 4 and 6 t/ha of lime. For each experiment, the following measurement were made: shot and root dry weight, root length, plant height, soil pH, root/shoot ratio, collar diameter and relative growth rate (RGR was estimated only for S .pendula). The results suggest tendency for indicate that the preferential source of nitrogen for S. appendiculata was NH4+. However for S. pendula with the obtained results is not possible to describe the preferential source of nitrogen, although the grown was affected by the nitrogen applied. None of studied plants had the growth limited by acid soil conditions. Senna appendiculata showed preference for growing at low soil pH and the lime was not necessary for the promotion of plant grown. In this conditions if lime is applied can cause a decrease in plant grown. Lime applied showed no effect on the growth of M. lanceolatum. / Devido ao elevado estado de degrada??o dos ecossistemas de restinga ? de extrema import?ncia considerar a??es para a conserva??o e recupera??o dos poucos remanescentes ainda existentes. Para isso faz-se necess?ria a realiza??o de estudos relacionados ao crescimento das esp?cies encontradas nestas ?reas, visando melhores condi??es para a produ??o de mudas. Dentro desta proposta, o presente trabalho teve como objetivos: 1- avaliar o crescimento de Senna appendiculata e Senna bicapsularis, utilizando diferentes fontes e doses de nitrog?nio mineral; e 2- caracterizar a resposta de Senna appendiculata, Senna bicapsularis e Machaerium lanceolatum ? calagem e a mudan?as do pH do solo. Os experimentos foram conduzidos em condi??es de casa de vegeta??o, em vasos contendo como substrato, solo arenoso de baixa fertilidade. Para o experimento de efeito de diferentes doses e fontes de nitrog?nio foram utilizados sete tratamentos: testemunha (sem nitrog?nio), NO3? (10 mg N/planta), NO3? (20 mg N/planta), NH4+ (10 mg N/planta), NH4+ (20 mg N/planta), NO3NH4 (10mg N/planta) e NO3NH4 (20 mg N/planta). No experimento de resposta ? calagem e mudan?a do pH do solo foram utilizados quatro tratamentos: 0, 2, 4 e 6 t de calc?rio/ha. Os par?metros avaliados foram: altura da planta, comprimento da raiz, ac?mulo de mat?ria seca da raiz e da parte a?rea, di?metro do coleto, pH do solo, rela??o raiz/parte a?rea, incremento m?dio em altura (IMA) e taxa de crescimento relativo, este ?ltimo apenas para a esp?cie S. pendula. Os resultados obtidos apresentam uma tend?ncia a indicar que a fonte preferencial de nitrog?nio para a esp?cie S. appendiculata seria o am?nio. O crescimento da esp?cie Senna pendula foi influenciado pela aplica??o de nitrog?nio, no entanto n?o foi poss?vel determinar a fonte de nitrog?nio preferencial. Nenhuma das esp?cies estudadas teve seu crescimento limitado em condi??es de solo ?cido. A esp?cie S. appendiculata demonstrou prefer?ncia por solos ?cidos e a calagem n?o seria necess?ria para a produ??o de mudas desta esp?cie, podendo influenciar negativamente o crescimento da mesma. A calagem n?o influenciou o crescimento de M. lanceolatum.

Orientador: Edson Lazarini / Resumo: Em um sistema plantio direto em processo de estabilização, preconiza o não revolvimento do solo. Neste sentido o uso de gesso agrícola pode ser uma alternativa para viabilizar a aplicação do calcário em superfície sem que seja necessária sua incorporação. Dessa forma, o gesso entra como um insumo complementar ao uso do calcário. Em vista do exposto, o presente trabalho objetivou estudar o comportamento do calcário e/ou gesso reaplicados em superfície, e seus reflexos nos atributos químicos do solo e nas culturas do milho e soja em sucessão. O experimento está sendo desenvolvido desde o ano de 2011 em LATOSSOLO VERMELHO distrófico de textura argilosa, desde o ano de 2011, no qual se apresenta em delineamento em blocos ao acaso, em esquema de parcelas sub-subdivididas com quatro repetições. Como tratamentos nas parcelas, foi instalado o milho em dois sistemas de cultivo, sendo eles, solteiro e consorciado com Urochloa. Para as subparcelas foram utilizadas quatro doses de calcário (0; 2000; 4000 e 6000 kg ha-1) e quatro doses de gesso (0; 1500; 3000 e 4500 kg ha-1) distribuídas ao acaso nas sub-subparcelas. As aplicações foram em superfície manualmente em cada parcela e sendo realizadas as seguintes avaliações: características agronômicas, estado nutricional e produtividade de grãos das culturas do milho e soja e os atributos químicos do solo em diferentes profundidades (0,0 – 0,10; 0,10 – 0,20 e 0,20 – 0,40 m). O efeito residual das maiores doses de calcário reaplicados em 2014... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the process of stabilizing in a no-tillage system, the soil revolving must be minimized. In this sense the application of lime can be an alternative to enable the use of gypsum as an alternative to conditioner the subsurface soil layers in the short term, and it can be used as a complementary product to lime because of its greater solubility and mobility in the soil profile. Therefore, the aim of this experiment was to study the effect of lime and gypsum reapplied in surface and their impacts on maize crop under the sole and intercropped with soybean. The experiment is being developed in a dystrophic Red Latosol with clayey texture, since the year of 2011, and arranged in a randomized block designs, in split-split plots, with four replications. As treatments in the plots, the maize was installed in two cropping systems: sole and intercropped with Urochloa. For the subplots, were used four doses of lime (0; 2000; 4000 and 6000 kg ha-1) and four doses of gypsum (0; 1500; 3000 and 4500 kg ha-1) randomly distributed in the sub-subplots. The applications were manual and in surface in each plot, and being performed the following evaluations: agronomic characteristics, nutritional status and grains yield of maize and soybean and the chemical attributes of soil in three different depth (0,0 – 0,10; 0,10 – 0,20 e 0,20 – 0,40 m). The residual effect of the major gypsum doses reapplied in 2014 provided greater yield on the soybean sown two years after. Higher doses of gypsum reduced ... (Complete abstract click electronic access below) / Mestre

<p>During the last four decades, acidifications has been seen as a great environmental hazard. To combat the effects of the acidification, the Swedish government is funding liming of affected areas. This practice has been questioned in northern Sweden, since there is no general agreement about the origin of the acidity there. This thesis aims to explain the administrative handling of the scientific disputes, and thereby the relation between the responsible authority, the Swedish Environmental Protection Agency (SEPA) and the research exrecised on the matter. Research findings are therefore compared with the content of interviews, performed by civil servants at SEPA. It is concluded that the liming in northern Sweden is a very complicated issue, involving many groups and individuals - so much so that it might not just be an issue of acidification science.</p>

Speciation governs transport and toxicity of trace metals and is important to monitor in natural waters. Geochemical models that predict speciation are valuable tools for monitoring. They can be used for risk assessments and future scenarios such as termination of liming. However, there are often large uncertainties concerning the speciation of iron and aluminium in the models, due to the complicated chemistry of these metals. Both are important in governing the speciation of other metals, due to (i) their capacity to form minerals onto which metals can adsorb and (ii) their ability to compete for binding sites to natural organic matter (NOM). Aluminium is also potentially toxic and is therefore closely monitored in acidified freshwaters. In this study different phases of iron in Swedish lakes were characterised. This required a good method for preconcentrating the iron colloids. A new method was developed in this thesis that uses an anion-exchange column to isolate the iron colloids prior to characterisation with extended X-ray absorption fine structure (EXAFS) spectroscopy. Iron was present as ferrihydrite in particles but was also strongly monomerically complexed to NOM in two Swedish lakes. Based on the results an internally consistent process-based geochemical equilibrium model was presented for Swedish freshwaters. The model was validated for pH (n = 9 400) and inorganic monomeric aluminium (Ali) (n = 3 400). The model could simulate pH and Ali simultaneously, and be used for scenario modelling. In this thesis, modelling scenarios for decreases and complete termination of liming are presented for the 3 000 limed Swedish lakes. The results suggest that liming can be terminated in 30 % of the Swedish lakes and decreased in many other lakes. / <p>QC 20120919</p>