Resumo: Pesquisas têm sido desenvolvidas com intuito de se constatar os benefícios da aplicação da escória de siderurgia em cana-de-açúcar. Em vista disso, com o presente trabalho, buscou-se avaliar o potencial agrícola da escória de siderurgia como corretivo da acidez do solo e fonte de silício, em sistema de colheita sem despalha a fogo, por meio de análises químicas do solo, das plantas e de variáveis biológicas de desenvolvimento, qualidade e produção da cana-de-açúcar, em um Latossolo Vermelho distrófico. O trabalho foi conduzido na Fazenda Experimental da FCAV/UNESP - Campus de Jaboticabal. O delineamento experimental foi o de blocos casualizados, em esquema fatorial 2x4, sendo que os tratamentos foram constituídos por duas fontes de material corretivo (calcário e escória de siderurgia), quatro doses (zero; metade; uma vez; duas vezes a dose recomendada para elevar o V% a 60), totalizando 32 parcelas. O estado nutricional das plantas foi determinado por meio de amostragens das folhas +1 e +3 aos 4 e aos 9 meses. No solo, foram realizadas três amostragens (aos 99 dias após a incorporação do material corretivo, aos 6 meses e 15 meses após o plantio) para fins de fertilidade e determinação de silício "disponível". A escória de siderurgia mostrase semelhante ao calcário na elevação do pH do solo, na neutralização da acidez potencial e na elevação da saturação por bases do Latossolo Vermelho distrófico. A aplicação do material corretivo não afeta o crescimento e a produção da canaplanta. Contudo, as fontes e doses dos materiais corretivos influenciam a nutrição da cultura, afetando os teores foliares, especialmente Ca, Mn e Zn, independente do tipo de folha coletada (+1 e/ou +3). A aplicação da escória de siderurgia não foi suficiente para provocar incrementos a níveis tóxicos nas concentrações de metais pesados no sistema solo-planta / Abstract: Polls have been developed in order to see the benefits of silicate slag in sugar cane. Most of the results were favorable in both the production of stems and in the production of sugar, such as increased productivity and reduction of diseases and pest attack. Therefore, with this work, we attempt to assess the agricultural potential of the steel slag as corrective of soil acidity and a source of silicon in the system without despalha fire, from chemical analysis of soil, plants and biological variables of development, quality and production of sugar cane. The study was conducted at the Experimental Farm of FCAV / UNESP - Campus de Jaboticabal, in an Oxisol. The experimental design was a randomized blocks in factorial scheme 2x4, and the treatments consisted of two sources of remedial material (limestone and silicate slag), four doses (zero, half, once, twice the recommended dose for raise the V% indicated as optimal for each crop of sugar cane), totaling 32 plots. The nutritional status of plants is determined by sampling of leaves. The technological analysis will be performed by the sucrose, fiber, purity and concentration of soluble solids. In soil, the sampling will be conducted every six months, determining the concentration of silicon "available." The slag is shown similar to lime in raising soil pH to neutralize the acidity and the increase in saturation of the soil studied. The implementation of corrective material does not affect the growth and yield of sugarcane. However, the sources and levels of corrective agents influence the nutrition of the crop, affecting the leaf, especially Ca, Mn and Zn, regardless of leaf type collected (+1 and / or +3). The application of slag was not enough to cause increases to toxic levels in the concentrations of heavy metals in soil-plant system / Orientador: Renato de Mello Prado / Coorientador: Jairo Osvaldo Cazetta / Banca: José Carlos Barbosa / Banca: Dirceu Maximino Fernandes / Mestre

O plantio direto (PD), associado a plantas de cobertura, pode melhorar os atributos químicos e a qualidade do solo, dependendo do tipo de solo. O objetivo da pesquisa foi avaliar o impacto do PD, associado a diferentes sistemas de cultura, durante longo período (~30 anos) sobre os atributos químicos e indicadores de qualidade de um solo de clima subtropical e de um solo de clima temperado (Estudos I e II), e da influência de sistemas de cultura sobre a eficiência da calagem superficial em PD em um solo de clima subtropical (Estudo III). Nos estudos I e II foram avaliados experimentos instalados em 1985 em Eldorado do Sul (Brasil) e em Concord (EUA) cultivados em PD e preparo convencional (PC). No experimento em Eldorado do Sul foram utilizados três sistemas de cultura: aveia (Avena strigosa)/milho (Zea mays) (A/M), ervilhaca (Vicia sativa)/milho (V/M) e aveia+ervilhaca/ milho+caupi (Vigna unguiculata) (AV/MC), em duas doses de N (0 e 180 kg ha-1). O experimento em Concord foi conduzido com dois sistemas de cultura: milho contínuo e milho-soja (Glycine max)], em três doses de N (0, 80 e 160 kg ha-1). O Estudo III foi conduzido em um experimento instalado em 1983 em PD, sendo avaliados atributos químicos relacionados à acidez do solo antes e dois anos após a calagem (5,0 Mg ha-1) em cinco sistemas de cultura: pousio/M (P/M), A/M, AV/M, AV/MC, LL (Lablab purpureus)+M (LLM), com e sem calagem e em duas doses de N (0 e 180 kg ha-1). As práticas de manejo de longa duração influenciaram os atributos químicos do solo, principalmente, na camada de 0 a 10 cm de profundidade, na qual o PD aumentou, em média, 23 % o teor de C orgânico do solo (COS), 30 % o teor de nitrogênio total (NT) e 100 % o teor de P disponível, em relação ao PC, nos dois solos. O COS e o NT aumentaram na ordem A/M<V/M<AV/MC, enquanto que, o pH, o P disponível e a saturação por bases reduziram na ordem A/M>V/M>AV/MC. O COS e o NT não foram influenciados, mas o pH e a saturação por bases aumentaram na rotação milho-soja. O COS aumentou 5% na dose de 160 kg N ha-1 no solo temperado. A adubação nitrogenada reduziu o pH e a saturação por bases nos dois solos, contudo reduziu 30 % o P disponível no solo subtropical, mas aumentou 20 % no solo temperado. O PD aumentou o estoque e o índice de estratificação (IE) do COS e do C orgânico particulado (COP) e o índice de labilidade (IL) nos dois solos. A inclusão de leguminosas aumentou o IE do COS e COP, e o IL em PD. Os sistemas com leguminosas de cobertura de solo aumentaram a acidificação e a saturação por Al3+ e reduziram a saturação por bases, comparado com sistemas exclusivamente de gramíneas. Após dois anos da calagem superficial o pH foi maior que 5,0 e a saturação por Al3+ foi < 4,0 % até 5 cm, independente do sistemas de cultura, porém, a saturação por bases aumentou para > 50 % até 7,5.cm. As práticas de manejo apresentam comportamento similar entre os diferentes solos, e os sistemas de culturas não influenciaram na eficiência da calagem na camada superficial do solo. / No-till (NT), associated with cover crops, can improve soil chemical properties and quality, which the magnitude of the effects possibly is dependent of soil type. The objective of this research was to evaluate the impact of NT, associated with different cropping systems, cultivated for long-term (~ 30 years) on soil chemical properties and quality indicators of subtropical soil in Southern Brazil and a temperate soil in Midwest US (Studies I and II), and cropping systems influence on liming efficiency in a subtropical soil under long-term NT (Study III). In Studies I and II were used two long-term experiments installed in 1985 in Eldorado do Sul (Brazil) and Concord (US) carried out under NT and conventional tillage (CT). In Brazil, the experiment was composed by three cropping systems: oat (Avena strigosa) / corn (Zea mays) (O/C), vetch (Vicia sativa)/corn (V/C) and oat+vetch/corn+cowpea (Vigna unguiculata) (OV/CC), with two N rates (0 and 180 kg ha-1). In US, the experiment was conducted with two crop rotations: continuous corn and corn-soybean (Glycine max), with three N rates (0, 80 and 160 kg ha-1). The Study III was conducted in a third experiment under NT and assessed soil chemical attributes related to acidity, before and two years after liming (5.0 Mg ha-1), in five cropping systems: fallow/C (F/C), O/C, OV/C,OV/CC, LL (Lablab purpureus)+C LLM), with and without liming and two N rates (0 and 180 kg ha-1). The long-term management effects on soil chemical properties were confined from 0 to 10 cm depth, in which NT system increased, in average, 23 % of soil organic C (SOC), 30 % of total N (TN), 100 % of available P, compared with CT in subtropical and temperate soil. Subtropical cropping systems increased SOC and TN in the order O/C<V/C<OV/CC, while soil pH, available P and base saturation decreased in the order O/C<V/C<OV/CC. Temperate crop rotation had no effects on SOC and TN, but soil pH and base saturation increased in corn-soybean rotation. Nitrogen fertilization increased 5 % of SOC in the N rate of 160 kg ha-1 in temperate soil. Nitrogen fertilization decreased soil pH and base saturation in both soils, but decreased 30% available P in subtropical soil, but increased 20% in temperate soil. No-till increased SOC and particulate organic C (POC) stocks, SOC and POC stratification ratio (SR) and lability index (LI) in both soils. Legume-based cropping systems increased the SOC and POC SR and LI under NT. Besides, legume-based cropping systems increased soil acidification and Al3+ saturation, and decreased base saturation, compared with grass crops. After two years of superficial liming, soil pH increased to >5.0 and Al3+ saturation decreased to <4.0% up to 5 cm, regardless of cropping systems, and base saturation increased to >50% up to 7.5 cm depth. Long-term management practices have similar behavior in the subtropical and temperate soil, and cropping systems has no influence on liming efficiency in topsoil.

A pecuária de corte do Rio Grande do Sul é baseada na utilização de pastagens naturais, que são caracterizadas pela marcante sazonalidade na produção. Tal cenário, proveniente das variações meteorológicas ao longo do ano, apresenta-se de forma ainda mais intensa em condições edáficas limitantes, como é o caso da Região do Basalto Superficial da Campanha gaúcha. O objetivo do presente trabalho foi avaliar a efetividade de práticas de manejo como o diferimento de primavera associado com a fertilização para minimizar os efeitos do déficit forrageiro do verão decorrentes do balanço hídrico negativo que normalmente ocorre na região. Foram utilizados 12 tratamentos baseados na aplicação em área diferida de diferentes níveis de calcário (0 e 1500 kg ha-1), fósforo (0 e 90 kg ha-1) e nitrogênio (0, 75, 150 e 300 kg ha-1), arranjados num fatorial incompleto. A aplicação dos fertilizantes e o início do diferimento ocorreram no dia 10/10/2009. Foi utilizado o delineamento em blocos casualisados com três repetições, utilizando-se como unidades amostrais parcelas com área de 30m² (3 x 10m). Foram realizadas 5 avaliações de massa de forragem, a intervalos médios de 15 dias (25/10/2009 a 08/01/2010). O tratamento testemunha apresentou uma taxa de acúmulo de forragem média de 17,7 kg ha dia-1 de matéria seca, demonstrando a efetividade do diferimento por si só em tais condições. O aumento dos dias de diferimento gerou diminuição na qualidade bromatológica da forragem. O calcário não proporcionou incrementos na produção de forragem, possivelmente em virtude do curto período de tempo entre a aplicação e o término das avaliações. A aplicação de nitrogênio ou fósforo isoladamente promoveu ganhos relativamente baixos para massa de forragem total e massa de forragem verde, mas a interação entre tais elementos potencializou esses efeitos, atingindo mais cedo a altura que otimiza a taxa de ingestão diária. A quantidade máxima de material verde (kg ha-1) foi atingida aos 75 dias para todos os tratamentos, sendo maior com fósforo e doses crescentes de nitrogênio. / The beef cattle industry in southern Brazil is based on the use of natural pastures, which are characterized by marked seasonality in production. This scenario, derived from weather variations throughout the year, is more intense in the limiting soil conditions, such as the basaltic shallow soils at Campanha region of Rio Grande do Sul. The aim of this study was to evaluate the effectiveness of management practices such as spring deferment associated with fertilization to minimize the effects of summer forage deficit arising from the negative water balance that normally occurs in this region. A total of 12 treatments based on the application of different levels of limestone (0 to 1500 kg ha-1), phosphorus (0 and 90 kg ha-1) and nitrogen (0, 75, 150 and 300 kg ha-1) were arranged in a incomplete factorial design distributed in a randomized complete block design with three replicates. Each plot measured 30 m² (3 x 10m). The start of the resting period and the application of fertilizers was done on 10/10/2009. Herbage mass was evaluated at average intervals of 15 days between 10/25/2009 and 08/01/2010. The control treatment showed a rate of herbage accumulation average of 17.7 kg/ha/day of dry matter, demonstrating the effectiveness of the deferral alone in such conditions. The increase of the resting time caused a decrease in forage quality. Limestone utilization doesn't increased forage production, possibly due to the short time between application and completion of evaluations. The application of nitrogen and phosphorus brought gains for relatively low herbage mass and green forage, but the interaction between these factors potentiated these effects, reaching the optimal height to maximize daily ingestion rate earlier. The maximum amount of green matter (kg/ha) was reached at 75 days for all treatments, being higher with increasing levels of nitrogen when phosphorous was applied.

O plantio direto (PD), associado a plantas de cobertura, pode melhorar os atributos químicos e a qualidade do solo, dependendo do tipo de solo. O objetivo da pesquisa foi avaliar o impacto do PD, associado a diferentes sistemas de cultura, durante longo período (~30 anos) sobre os atributos químicos e indicadores de qualidade de um solo de clima subtropical e de um solo de clima temperado (Estudos I e II), e da influência de sistemas de cultura sobre a eficiência da calagem superficial em PD em um solo de clima subtropical (Estudo III). Nos estudos I e II foram avaliados experimentos instalados em 1985 em Eldorado do Sul (Brasil) e em Concord (EUA) cultivados em PD e preparo convencional (PC). No experimento em Eldorado do Sul foram utilizados três sistemas de cultura: aveia (Avena strigosa)/milho (Zea mays) (A/M), ervilhaca (Vicia sativa)/milho (V/M) e aveia+ervilhaca/ milho+caupi (Vigna unguiculata) (AV/MC), em duas doses de N (0 e 180 kg ha-1). O experimento em Concord foi conduzido com dois sistemas de cultura: milho contínuo e milho-soja (Glycine max)], em três doses de N (0, 80 e 160 kg ha-1). O Estudo III foi conduzido em um experimento instalado em 1983 em PD, sendo avaliados atributos químicos relacionados à acidez do solo antes e dois anos após a calagem (5,0 Mg ha-1) em cinco sistemas de cultura: pousio/M (P/M), A/M, AV/M, AV/MC, LL (Lablab purpureus)+M (LLM), com e sem calagem e em duas doses de N (0 e 180 kg ha-1). As práticas de manejo de longa duração influenciaram os atributos químicos do solo, principalmente, na camada de 0 a 10 cm de profundidade, na qual o PD aumentou, em média, 23 % o teor de C orgânico do solo (COS), 30 % o teor de nitrogênio total (NT) e 100 % o teor de P disponível, em relação ao PC, nos dois solos. O COS e o NT aumentaram na ordem A/M<V/M<AV/MC, enquanto que, o pH, o P disponível e a saturação por bases reduziram na ordem A/M>V/M>AV/MC. O COS e o NT não foram influenciados, mas o pH e a saturação por bases aumentaram na rotação milho-soja. O COS aumentou 5% na dose de 160 kg N ha-1 no solo temperado. A adubação nitrogenada reduziu o pH e a saturação por bases nos dois solos, contudo reduziu 30 % o P disponível no solo subtropical, mas aumentou 20 % no solo temperado. O PD aumentou o estoque e o índice de estratificação (IE) do COS e do C orgânico particulado (COP) e o índice de labilidade (IL) nos dois solos. A inclusão de leguminosas aumentou o IE do COS e COP, e o IL em PD. Os sistemas com leguminosas de cobertura de solo aumentaram a acidificação e a saturação por Al3+ e reduziram a saturação por bases, comparado com sistemas exclusivamente de gramíneas. Após dois anos da calagem superficial o pH foi maior que 5,0 e a saturação por Al3+ foi < 4,0 % até 5 cm, independente do sistemas de cultura, porém, a saturação por bases aumentou para > 50 % até 7,5.cm. As práticas de manejo apresentam comportamento similar entre os diferentes solos, e os sistemas de culturas não influenciaram na eficiência da calagem na camada superficial do solo. / No-till (NT), associated with cover crops, can improve soil chemical properties and quality, which the magnitude of the effects possibly is dependent of soil type. The objective of this research was to evaluate the impact of NT, associated with different cropping systems, cultivated for long-term (~ 30 years) on soil chemical properties and quality indicators of subtropical soil in Southern Brazil and a temperate soil in Midwest US (Studies I and II), and cropping systems influence on liming efficiency in a subtropical soil under long-term NT (Study III). In Studies I and II were used two long-term experiments installed in 1985 in Eldorado do Sul (Brazil) and Concord (US) carried out under NT and conventional tillage (CT). In Brazil, the experiment was composed by three cropping systems: oat (Avena strigosa) / corn (Zea mays) (O/C), vetch (Vicia sativa)/corn (V/C) and oat+vetch/corn+cowpea (Vigna unguiculata) (OV/CC), with two N rates (0 and 180 kg ha-1). In US, the experiment was conducted with two crop rotations: continuous corn and corn-soybean (Glycine max), with three N rates (0, 80 and 160 kg ha-1). The Study III was conducted in a third experiment under NT and assessed soil chemical attributes related to acidity, before and two years after liming (5.0 Mg ha-1), in five cropping systems: fallow/C (F/C), O/C, OV/C,OV/CC, LL (Lablab purpureus)+C LLM), with and without liming and two N rates (0 and 180 kg ha-1). The long-term management effects on soil chemical properties were confined from 0 to 10 cm depth, in which NT system increased, in average, 23 % of soil organic C (SOC), 30 % of total N (TN), 100 % of available P, compared with CT in subtropical and temperate soil. Subtropical cropping systems increased SOC and TN in the order O/C<V/C<OV/CC, while soil pH, available P and base saturation decreased in the order O/C<V/C<OV/CC. Temperate crop rotation had no effects on SOC and TN, but soil pH and base saturation increased in corn-soybean rotation. Nitrogen fertilization increased 5 % of SOC in the N rate of 160 kg ha-1 in temperate soil. Nitrogen fertilization decreased soil pH and base saturation in both soils, but decreased 30% available P in subtropical soil, but increased 20% in temperate soil. No-till increased SOC and particulate organic C (POC) stocks, SOC and POC stratification ratio (SR) and lability index (LI) in both soils. Legume-based cropping systems increased the SOC and POC SR and LI under NT. Besides, legume-based cropping systems increased soil acidification and Al3+ saturation, and decreased base saturation, compared with grass crops. After two years of superficial liming, soil pH increased to >5.0 and Al3+ saturation decreased to <4.0% up to 5 cm, regardless of cropping systems, and base saturation increased to >50% up to 7.5 cm depth. Long-term management practices have similar behavior in the subtropical and temperate soil, and cropping systems has no influence on liming efficiency in topsoil.

Grunda, näringsrika sjöar förekommer i två stadier: antingen ett med grumligt vatten och hög biomassa av växtplankton, eller ett med klart vatten och riklig undervattensvegetation. Det klara stadiet är eftersträvansvärt eftersom det skapar goda förutsättningar för en rad ekosystemtjänster, inklusive vattenkvalitet, rekreation och förutsättningar för biodiversitet. Vid eutrofiering, d v s ökat tillskott av näringsämnen, kvarstår det klara stadiet tills näringsbelastningen blir så hög att sjön övergår till ett grumligt stadium. Sjön Tåkern, i Östergötland, har under de senaste åren blivit alltmer eutrofierad och kalkning av vattnet har diskuterats som en möjlig åtgärd för att bevara det klara stadiet som sjön numera befinner sig i. Undersökningar om kalkning av eutrofierade sjöar har gjorts tidigare, men det har varit få studier av effekterna av kalkning på undervattensvegetation, substratlevande djur och påväxtalger. För att undersöka detta, gjordes ett fält- och ett laboratorieexperiment inriktade på effekter på överlevnad av vattengråsugga, Asellus aquaticus, fysiologisk status (halten klorofyll a) i kransalgen Chara globularis och tillväxt av nyetablerade påväxtalger i sjön Tåkern. Resultaten visar att A. aquaticus hade lägre överlevnad efter kalkning till pH 10 i laboratorieexperiment, men i fältförsöket hade kalkning till detta pH inte någon inverkan. C. globularis hade en högre halt klorofyll a efter kalkning till pH 10 i laboratorieexperimentet, men i fältexperimentet hade kalkning ingen effekt på halten klorofyll a. Påväxtalger hade en lägre tillväxthastighet efter kalkning i fältexperimentet. Slutsatsen är att kalkning kan vara en metod för att motverka eutrofiering av sjön Tåkern. Några inkonsekvenser mellan mesokosm- och laborationsresultaten tyder på att fler studier behövs göras för att undersöka hur kalkning till pH 10 påverkar bentiska organismer. / Shallow, nutrient-rich lakes can occur in two alternative states: either a turbid water state with high biomass of phytoplankton, or a clear water state with abundant submerged vegetation. The clear water state is worth striving for because it creates good conditions for a range of ecosystem services and biodiversity. Lake Tåkern, Östergötland, has in recent years become increasingly eutrophic and liming has been discussed as a method to reduce the phosphorus level and maintain, or trigger a shift to, the clear water state. Investigations regarding the effects of liming of eutrophic lakes on phosphorus level and plankton have been performed in the past, but few studies have examined the effects on submerged vegetation, benthic invertebrates and periphyton. To study this, a field and a laboratory experiment were performed to examine how liming to pH 10 affects survival of the benthic invertebrate Asellus aquaticus, the chlorophyll a content in the stonewort Chara globularis and growth of periphyton. Survival of A. aquaticus was not affected in a field mesocosm experiment in Lake Tåkern, but decreased after liming in a laboratory experiment. The chlorophyll a content of C. globularis was not affected in the field experiment but higher than in the controls in the laboratory experiment. Growth of periphyton was reduced in the field experiment. Based on the field experiment, effects on A. aquaticus and C. globularis were negligible, but the laboratory experiment indicate that liming to pH 10 may under certain conditions affect benthic organisms. The conclusion is, however, that liming can be a suitable method to counteract the eutrophication of Lake Tåkern. Some inconsistencies between the field and laboratory results suggest that more studies needs to be made to see how liming to pH 10 affect benthic organisms.

Liming has been used extensively in Sweden, but the management success has been only partial, mostly mitigating the impact of acidification rather than restoring the ecological communities to a self-maintaining pre-acidified state. Rather than a sound restoration tool, liming is a form of command-and-control management that comprises a significant disturbance in the system, which manifests in the form of profound alterations of biophysical settings of lakes. This thesis aims to assess biological responses to liming with a special focus on resilience by looking at the cross-scale interaction aspects of littoral invertebrate communities in limed lakes within the framework of panarchy theory. The thesis is based on multivariate time series modeling (AEM-RDA) to extract hierarchical temporal fluctuations patterns (temporal scales) in littoral invertebrate communities. This analysis tested for the premise of panarchy theory that complex systems are hierarchically structured. Time series analyses were followed by Spearman rank correlation analysis to test another premise of panarchy theory; namely, that “information” (e.g., management interventions) flows between these hierarchical scales. Specifically, Ca:Mg ratios were used as a surrogate of liming, and correlated with each temporal pattern identified by the AEM-RDA. The result showed the distinct temporal scales in littoral invertebrate communities in limed lakes, fitting the premises of panarchy theory and agreeing with previous studies that found hierarchical temporal organizations in other lake communities. The correlation analyses indicated weak cross-scale manifestation of Ca:Mg ratios in the littoral invertebrate communities, suggesting a weak information flow of liming in managed lakes. This “dilution” of management may provide one mechanism that could explain why liming is not effective in creating a self-organizing, resilient system. The results of this study allow shedding further light on liming as a coerced regime (degraded complex systems forced into a state of desired conditions (e.g., ecosystem service provisioning) through constant management). Most research has so far focused on the evaluation of traditional metrics of biodiversity, which have shown that community structure is substantially altered in limed lakes, deviating from those in circumneutral reference lakes and degraded acidified lakes. This thesis, therefore, concludes that integration of traditional ecological approaches and complexity studies may provide complementary insight into the organization of ecosystems and sustainable resource management.

Alla organismer är beroende av fosfor (P) och kväve (N) för att kunna tillväxa och överleva, därför tillsätts dessa näringsämnen i höga doser till jordbruksmark i form av gödsel. Detta gör att jordbruket tillsammans med en ökad nederbörd kan öka avrinning av näringsämnen (framför allt P och N) från jordbruksmark till vattendrag. Strukturkalkning kan användas för att förbättra markstrukturen så att P stannar kvar i marken och därmed minskar Pbelastningen och övergödning i avrinningsområden. Syftet var att undersöka om strukturkalkningen som genomfördes på Dalboslätten under 2020 och 2021 har haft någon effekt på övergödningen i närliggande vattendrag. Hypotesen var att strukturkalkning har minskat övergödningen i form av minskad mängd total-P i de fyra avrinningsområdena.Tillgång till vattenkemiska data i avrinningsområden har skett via Dalslands miljö- och energiförbund där total-P undersöktes med en-vägs ANOVA samt Kruskall-Wallis för de fyra vattendragen Dalbergsån, Krokån, Lillån och Hakerudsälven under 2019–2021. Eftersom nederbörd kan påverka total-P i vattendragen undersöktes även förhållandet mellan total-P och nederbörd genom linjär regression för respektive vattendrag. Dalbergsån och Krokån hade mindre total-P 2021 jämfört med tidigare år, medan Hakerudsälven och Lillån inte hade någon minskning i total-P. Nederbörden hade inte påverkat mängden total-P i något utav vattendragen under 2019–2021. Detta kan i sin tur betyda att strukturkalkningen har haft effekt i två av vattendragen samt en mer lättarbetad jord, men för att få ett mer tillförlitligt resultat hade studien behövt göras under flera år. När befolkningen ökar sätter det ytterligare press på effektiviseringen av jordbruket där mindre mängd gödsel ska ge större mängd grödor. Genom att välja ut grödor som kräver en mindre mängd tillsatta näringsämnen samt att befolkningen ändrar sin kosthållning till fler vegetariska alternativ kan tillsatt P i jordbruket minska och därmed övergödning i avrinningsområden. Tillsammans med strukturkalkning kan våtmarker och fosfordammar anläggas för att få ett mer långvarigt skydd mot övergödningen på Dalboslätten. / All organisms depend on phosphorus (P) and nitrogen (N) to grow and survive; therefore these nutrients are added in high doses to agricultural land in the form of fertilizers. Agriculture together with increased precipitation can increase the runoff of nutrients (mainly P and N) from agricultural land to watercourses. As part of this, structural liming can be used to improve soil structure so that P remains in the soil, thereby reducing P loading and eutrophication in catchment areas. The aim of this study was to investigate whether the structural liming carried out on Dalboslätten during 2020 and 2021 has had any effect on eutrophication in the nearbywatercourses. The hypothesis was that structural liming has reduced eutrophication in the form of a reduced amount of total P in the four catchment areas. Access to water chemistry data in catchment areas has taken place via Dalsland’s environmental office. Total P was investigated with one-way ANOVA and Kruskall-Wallis for the four watercourses Dalbergsån, Krokån, Lillån and Hakerudsälven during 2019-2021. Since precipitation can affect total P in the watercourses, the relationship between total P and precipitation was also investigated through linear regression for each watercourse. Dalbergsån and Krokån had less total P in 2021 compared to previous years, while Hakerudsälven and Lillån had no reduction in total P. Precipitation did not affect the amount of total P in any of the watercourses during 2019-2021. This, in turn, may mean that the structural liming has had an effect in two of the watercourses as well as a more easily worked soil, but to get a more reliable result the study would have to be conducted over several years. As the population increases, it puts further pressure on the efficiency of agriculture, where less fertilizer should produce more crops. By selecting crops that require a smaller amount of added nutrients and by the population changing their diet to more vegetarian options, added P in agriculture can be reduced and thus eutrophication in catchment areas. Along with structural liming, wetlands and phosphorus ponds can beconstructed to obtain longer-term protection against the eutrophication on Dalboslätten.

For more than 45 years an extensive liming measure has taken place in the southwest of Sweden in Västra Götaland county. The goal with the liming is to improve the aquatic ecosystems and counteract the acidification that has occurred in a large part of catchments in this area. The acidification problem was discovered in the late seventies and had a global impact but was distinctive in northern Europe. To mitigate the problem, it was necessary to find what was causing the acidification and, in this case, it was the emissions of acidic substances. A legislation about decreasing the emissions of sulfuric acid was established by several countries in Europe and after that a change occurred. Most of the aquatic ecosystems responded well to the decreased amount of sulfuric deposition and the liming. An unexpected response to the improved health of the aquatic ecosystems was the increased water color (mgPt·l-1) in surface waters. The change in water color, often called brownification, can be a natural process and an indication that the surface waters are approaching a more natural state. In this study a total of 120 surface waters in Västra Götaland county were studied under a 40-year period. An increasing browning of surface waters and significant differences in water color between limed lakes and reference lakes was discovered. The area with the highest yearly precipitation had the largest percentual increase in water color particularly for limed lakes. The results showed significant differences in water color in limed lakes between two time periods, 1981-1985 and 2015-2020, that indicate an increasing trend in the study area. The results could not answer why the surface waters had this increase in browning and there was not possible to determine all the driving factors. Other studies have shown that increasing water color relates to a decrease in sulfuric deposition and increasing concentration of dissolved organic carbon (DOC) in the surface waters. Climate change can be a part of the explanation due to warmer temperatures, longer vegetation periods and wetter climate. Further, it is necessary to continue investigating this problem to determine the driving factors and detect possible trends.

No description available.

Reclaimed surface mined soils in Appalachia are typically infertile and must be amended for optimum vegetative growth. Fluidized bed combustion residue (FBCR), a by-product of coal-fired power plants, has high levels of Ca, S, Zn, Fe, and Al, and 50% of the neutralizing capacity of limestone. Three treatments were applied to three replicated .81 ha reclaimed mine pastures: control (no amendment), 6760 kg FBCR/ha, and 3380 kg limestone/ha. Based on forage availability, six steers were rotationally grazed on pastures receiving each treatment. Steers were weighed and blood samples collected at 14-d intervals and all animals were sacrificed for tissue sampling at the end of the 114-d trial. Amendment with FBCR or limestone increased soil pH (P < .05) above control levels. Forage yield and steer gain were not significantly affected by treatment. Forage samples collected during the trial indicated that FBCR and limestone amendments elevated forage ash, Ca, Mg, S, Cu and Ca:P ratio (P < .05). Cellulose and NDF were depressed in forage grab samples collected from FBCR- and limestone-amended pastures. The forage sampled the following spring was lower in hemicellulose, Zn, un and Ni; and higher in ash, Ca, S, the Ca: P ratio in the FBCR- and limestone-amended pastures. Mean serum mineral levels of steers were not affected by pasture treatment. The blood packed cell volume was higher in cattle grazing FBCR-amended pastures. Liver levels of Fe, H, Hi and Na were lower in cattle on pastures amended with FBCR or limestone. Bile levels of Mn were depressed in cattle grazing FBCR~ and limestone-amended pastures. The level of Cu in the liver and serum was at deficiency levels and was not detectable in bile, regardless of treatment. Higher kidney levels of Ca, Hg and P were recorded for steers grazing FBCR- and limestone-amended pastures. Hair Zn was higher in cattle grazing the FBCR- and limestone- treated pastures. Rib Cr and long bone Cd levels were lower in animals grazing the limestone- and FBCR-treated pastures. This study suggests that FBCR amendment enhances nutrient quality of forage and mineral status of animals at least as well as limestone application to acidic reclaimed mine pastures. / Ph. D. / incomplete_metadata