ABSTRACT Global warming potential (GWP) of rice paddies depends on straw management. This study evaluated methane (CH4) and nitrous oxide (N2O) emissions and soil C stocks to determine GWP and yield-scaled GWP under different strategies and intensities of rice straw management in a subtropical climate. We hypothesized that decreasing soil management intensity and straw incorporation in the soil would reduce GWP. Methane fluxes were substantially higher during the rice growing season than in the off-season, while the opposite was observed for N2O fluxes. The cumulative emissions of CH4 during the growing season among the straw management strategies evaluated ranged from 165.8 to 586.0 kg ha-1. Annual CH4 emissions were lower when soil and straw received some type of management compared to no-tillage. Daily N2O fluxes ranged from -2.8 to 201.7 g ha-1 day-1; cumulative N2O emissions during the off-season ranged from 455.2 to 2816.5 g ha-1. During the off-season, strategies to reduce N2O emissions include post-harvest straw incorporation using a disc harrow, winter straw removal, and ryegrass cropping. Soil organic C stocks ranged from 35.96 to 38.36 Mg ha-1. Straw management using a disc harrow reduced soil organic C stocks, with more adverse effects than straw removal. Soil and rice straw management did not affect rice grain yield, with an average of 10.4 Mg ha-1. Methane emissions were the main component of GWP in all straw management systems. The contribution of N2O emissions to GWP was small and mostly (>85 %) determined by off-season emissions. Yield-scaled GWP ranged from 0.64 to 1.06 Mg CO2eq Mg-1 yield and was lower when soil and straw management systems occurred shortly after the rice harvest. Our results indicate that soil and straw management immediately after rice harvest reduces CH4 emissions, GWP, and yield-scaled GWP.

Resumen La batata (Ipomoea batatas L.) es una hortaliza de gran importancia económica ya que se puede utilizar para el consumo de natura, para el procesamiento en agronegocios y/o la producción de biocombustibles. El objetivo de este trabajo es evaluar el rendimiento de tres cultivares de batata: BRS Amelia, BRS Cuia y BRS Rubissol en la región noroeste de Rio Grande do Sul. El experimento se realiza en el campo durante dos años consecutivos (cosechas 2014/2015 y 2015/2016). El diseño experimental fue en bloques al azar, evaluando 3 cultivares de camote durante 2 años agrícolas, con 4 repeticiones. Como resultados, se observa que el peso de la papa en el primer año de estudio varía de 272.0 g a 320.2 g. En el segundo año de evaluación, varía de 133.9 g a 247.1 g. En relación con la productividad promedio, los valores obtenidos en el primer año fueron 15.2 t ha-1 para BRS Amelia, 19.8 t ha-1 para BRS Cuia y 16.2 t ha-1 para BRS Rubissol. En el segundo año de evaluación, los valores fueron 12.3 t ha-1 para BRS Amelia, 16.1 t ha-1 para BRS Cuia y 13.1 t ha-1 para BRS Rubissol. Los cultivares presentaron rendimientos más altos que el promedio nacional de Brazil en los dos años evaluados.

Abstract The sweet potato (Ipomoea batatas L.) is a vegetable of great economic importance since it can be used for in natura consumption, for processing in agribusiness and/or biofuel production. The objective of this work was to evaluate the yield of three sweet potato cultivars: BRS Amelia, BRS Cuia and BRS Rubissol in the Northwest Region of Rio Grande do Sul. The experiment was conducted in the field for two consecutive years (harvests 2014/2015 and 2015/2016). The experimental design was in randomized blocks, evaluating 3 sweet potato cultivars for 2 agricultural years, with 4 replications. As results, it was observed that potato weights in the first year of study ranged from 272.0 g to 320.2 g. In the second year of evaluation, it ranged from 133.9 g to 247.1 g. In relation to the average productivity, the values obtained in the first year were 15.2 t ha-1 for BRS Amelia, 19.8 t ha-1 for BRS Cuia and 16.2 t ha-1 for BRS Rubissol. In the second year of evaluation, the values were 12.3 t ha-1 for BRS Amelia, 16.1 t ha-1 for BRS Cuia and 13.1 t ha-1 for BRS Rubissol. Cultivars presented yields higher than the national average from Brazil in the two evaluated years.

RESUMO: Uma alternativa para destinar corretamente o esterco bovino é realizar a compostagem e/ou vermicompostagem e depois adicioná-lo ao solo como fonte de nutrientes às plantas. Porém, este resíduo tem sido utilizado na produção de mudas sem tratamento. O estudo teve por objetivo avaliar o uso de esterco bovino in natura, de composto orgânico e de vermicomposto, produzidos a partir do esterco bovino, em substratos para a produção de mudas de Eucalyptus urograndis. Os tratamentos constituíram-se dos substratos formulados pela mistura dos fertilizantes orgânicos com areia lavada nas porcentagens de 20, 40, 60, 80 e 100 (v/v), em comparação com um substrato comercial (SC). As mudas de Eucalyptus urograndis foram cultivadas em tubetes, em casa de vegetação, e avaliadas aos 120 dias quanto a massa seca da parte aérea e raiz, altura da planta, diâmetro do caule, relação parte aérea/raiz e índice de qualidade de Dickson. O substrato formulado pela mistura de 80% (v/v) de esterco bovino in natura com areia lavada proporcionou o melhor desenvolvimento das mudas de eucalipto. O substrato contendo 100% de vermicomposto de esterco bovino ou composto orgânico produziu mudas com qualidade inferior ao esterco bovino in natura, mas superior ao substrato comercial. Devido aos riscos à saúde associados ao uso de esterco bovino não tratado, o composto orgânico e o vermicomposto são boas alternativas para a produção de mudas de E. urograndis.

ABSTRACT: Composting and vermicomposting before addition to the soil is a viable alternative to the disposal of cattle manure. However, this residue has been used in the untreated form for seedling production. This study evaluated the use of cattle manure in natura, and the organic composted or vermicomposted variants of cattle manure on substrates used in the production of Eucalyptus urograndis seedlings. The treatments consisted of substrates formulated by mixing the organic fertilizers with washed sand in 20, 40, 60, 80 or 100 (v/v) percentages, compared to a commercial substrate. The E. urograndis seedlings were grown in tubes in a greenhouse and evaluated after 120 days for shoot and root dry weights, plant height, stem diameter, shoot/root ratio, and Dickson quality index. The substrate formulated from a mixture of 80% (v/v) of cattle manure in natura and washed sand allows for better development in Eucalyptus seedlings. Substrate containing 100% bovine manure vermicompost or organic compost produced seedlings with lower quality than in natura bovine manure but superior to the commercial substrate. Due to the health risks associated with use of untreated bovine manure, organic compost and vermicompost are good alternatives for the production of E. urograndis seedlings.

ABSTRACT Pork is the most consumed animal protein around the world. The production levels are significant, which results in the generation of large amounts of slaughter waste. Such waste is often disposed of improperly in agricultural areas, causing environmental imbalance by the contamination of soil and water sources with metals and pathogenic organisms. This study evaluates the phytotoxic effects of pig slaughterhouse waste in natura and after stabilization processes on lettuce (Lactuca sativa Linnaeus, 1753), radish (Raphanus sativus Linnaeus, 1753), and rice (Oryza sativa Linnaeus, 1753), in addition to shoot nutrient contents. To do this, the waste was evaluated through phytotoxicity tests on lettuce, radish, and rice plants in natura (PSWin) as well as after aerated composting (PSWa), natural composting (PSWn), and vermicomposting (PSWv). The evaluations were done through germination, root length, plant development, and shoot nutrient analysis. We found that PSWin and PSWa negatively affected germination, root length, and plant development. Shoot nutrient contents varied greatly among treatments, some of which were above, below, or within the recommended limits. Based on these results, we infer that pig slaughterhouse waste in natura and after aerated composting is phototoxic to lettuce, radish, and rice plants. Phosphorus and sulfur exhibited contents above those recommended in all the treatments for lettuce, radish, and rice. On the other hand, potassium and calcium contents were below the recommended thresholds.

RESUMO No estado do Rio Grande do Sul, os reflorestamentos de eucalipto encontram-se, geralmente, em solos de baixa fertilidade natural, favorecendo a associação ectomicorrízica. Neste trabalho, avaliou-se o efeito da inoculação dos isolados de fungos ectomicorrízicos UFSC-Pt116, UFSC-Pt188 e UFSC-SA9, sobre plantas de Eucalyptus grandis, em Neossolo Quartzarênico. As avaliações foram realizadas aos 30, 45, 60, 75 e 90 dias após semeadura. Plantas inoculadas com os isolados UFSC-Pt116, UFSC-Pt188 e UFSC-SA9 alcançaram maior altura, diâmetro do caule, massa seca da parte aérea e volume de raízes em relação ao controle. Plantas inoculadas com o isolado de fungo ectomicorrízico UFSC-Pt188 apresentaram maior teor de fósforo e potássio na parte aérea que as plantas não inoculadas. A inoculação com o isolado fúngico ectomicorrízico UFSC-Pt116 promoveu maior altura e massa seca da parte aérea. Para os teores de nitrogênio e potássio, e para massa seca de raízes não foram observadas diferenças significativas entre os tratamentos. A inoculação com os fungos ectomicorrízicos UFSC-Pt116, UFSC-SA9 e UFSC-Pt188 isoladamente, promoveram maior altura, diâmetro de caule, acúmulo de massa seca da parte aérea e volume de raízes das plantas de Eucalyptus grandis.

ABSTRACT In Rio Grande do Sul state, the eucalyptus planted forests are cultivated in low fertility soils, which contribute to ectomycorrhizal association. This study evaluated the effect of ectomycorrhizal isolates UFSC-Pt116, UFSC-Pt188 and UFSC-SA9 inoculation, individually and in combination, with Eucalyptus grandis in Quartzarenic Neosols. Evaluations were performed at 30, 45, 60, 75 and 90 days after sowing. Plants inoculated with isolates UFSC-Pt116, UFSC-Pt188 and UFSC-SA9 showed highest height, stem diameter, dry mass of shoot and root volume than the control. Plants inoculated with the ectomycorrhizal fungus isolate UFSC-Pt188 showed highest content of phosphorus and potassium in shoots than non-inoculated plants. Inoculation individual ectomycorrhizal isolate UFSC-Pt116 promoted the highest height and shoot dry mass. For nitrogen and potassium, and root biomass have not showed significant differences between treatments. Then inoculation with ectomycorrhizal UFSC-Pt116, UFSC-Pt188 and UFSC-SA9 alone promoted highest height, stem diameter, dry mass of shoot and plant root volume of Eucalyptus grandis.

Eucalypts is one of the main species used for commercial reforestation in the state of Rio Grande do Sul, Brazil. This study aimed to evaluate the survival and early growth of eucalyptus trees in an area subject to sandy process after three years of growth. The Eucalyptus grandis seedlings were grown in a greenhouse, innoculated or not with the isolated ectomycorrhizal Pisolithus microcarpus (UFSC-Pt116), produced in peat or Entisol. After 120 days, the seedlings were transplanted to an area subject to the sandy process, in the city of São Francisco de Assis, RS. The plants have been evaluated regarding survival, height, stem diameter, nitrogen, phosphorus and potassium levels and total phosphorus, inorganic phosphorus, organic phosphorus and wood production on different days after planting. The seedlings grown on the Entisol which was inoculated with the isolated UFSC-Pt116 presented higher survival rates, height, stem diameter, nitrogen concentration and wood production compared to the non-inoculated seedlings. Inoculation with ectomycorrhizal fungi enhanced the production of E. grandis seedlings in survival rates, height, stem diameter.

O objetivo deste trabalho foi avaliar o desenvolvimento de colêmbolos no solo com diferentes níveis de metais pesados, combustíveis e agrotóxicos em condição de laboratório. Os tratamentos foram: Cádmio (1, 10 e 100mg kg-1 de solo); Cobre (50, 500 e 5000mg kg-1 de solo); Zinco (100, 1000 e 10000mg kg-1 de solo); fungicida epoxiconazol + piraclostrobina (1 e 2L ha-1); fungicida epoxiconazol (0,75 e 1,5L ha-1); herbicida glifosato (2 e 4L ha-1); óleo lubrificante queimado (5, 50 e 100mL kg-1 solo) e óleo diesel (5, 50 e 100mL kg-1 solo) e controle. Na dose de 1mg kg-1 de Cd no solo, houve grande aumento na população de colêmbolos e o pH do solo diminuiu à medida que aumentaram as doses de Cd, Zn e Cu no solo. Na presença de combustíveis, os colêmbolos apresentaram incapacidade de reprodução, independente da dose aplicada no solo. O número de colêmbolos apresentou incremento com o aumento da dosagem de glifosato e epoxiconazol. Os metais pesados Cu e Zn têm ação negativa sobre a população de colêmbolos e somente o Cd (1mg kg-1 solo) proporciona aumento na população de colêmbolos no solo. A presença de óleo lubrificante queimado e óleo diesel no solo inibem o desenvolvimento dos colêmbolos no solo. Os agrotóxicos glifosato, epoxiconazol e epoxiconazol + piraclostrobina não influenciam negativamente sobre a população de colêmbolos no solo.

The aim of this research was to evaluate the collembola development in soils with different levels of heavy metals, fuels and pesticides, in laboratory conditions. Treatments were: Cadmium - 1, 10 and 100mg kg-1 soil; Copper - 50, 500 and 5000mg kg-1 soil; Zinc - 100, 1000 and 10000 mg kg-1 soil; fungicide epoxiconazol + piraclostrobina - 1 and 2L ha-1; fungicide epoxiconazol - 0,75 and 1,5L ha-1; herbicide glyphosate - 2 and 4L ha-1; burned lubricating oil - 5, 50 and 100mL kg-1 soil and diesel oil - 5, 50 and 100mL kg-1 soil and control. In the 1mg kg-1 dose of Cd there was a great increase of the collembola population and the soil pH decreased as the Cd, Zn and Cu doses in the soil increased. In the presence on fuels the collembola presented incapacity to procreate regardless the dose applied in the soil. The number of collembola showed an increase with increasing glyphosate and epoxiconazole level. The heavy metal Cu and Zn have negative impact over the collembola population and just Cd (1mg kg-1 soil) offers increase on their population in the soil. The presence of burned oil and diesel in the soil inhibit the collembolan development in the soil. The pesticides glyphosate, epoxiconazol and epoxiconazol + piraclostrobina do not negatively influence the collembola population in the soil.

RESUMO No Estado do Rio Grande do Sul, os reflorestamentos de eucalipto têm se concentrado em solos com baixa fertilidade natural, e o desempenho dessas mudas poderá depender da formação da associação ectomicorrízica. Nesse trabalho, avaliou-se o efeito da inoculação dos isolados de fungos ectomicorrízicos UFSC-Pt116, UFSC-Pt188 e UFSC-SA9, individualmente e em mistura, sobre mudas de Eucalyptus grandis. As avaliações foram realizadas aos 30, 45, 60, 75 e 90 dias após semeadura. A inoculação individual do isolado fúngico ectomicorrízico UFSC-Pt116 promoveu maior altura e massa seca da parte aérea. As mudas inoculadas com mistura dos isolados fúngícos UFSC-Pt116 + UFSC-Pt188 + UFSC-SA9 acumularam maior quantidade de fósforo aos 90 dias. Para os teores de nitrogênio e potássio, e massa seca de raízes não mostrou diferença significativa entre os tratamentos.

ABSTRACT In the Rio Grande do Sul state, where eucalyptus reforestation is common in low fertility soils, the seedling performance may depend on the ectomycorrhizal association. In this paper, the inoculation effects of UFSC-Pt116, UFSC-Pt188 and UFSC-SA9 ectomycorrhizal fungi isolates, individually and in mixture, on Eucalyptus grandis seedlings were evaluated. Evaluations were performed at 30, 45, 60, 75, and 90 days after sowing. The individual inoculation of UFSC-Pt116 isolate promoted highest height and aerial dry mass. The seedlings inoculated with the mixture UFSC-Pt116 + UFSC-Pt188 + UFSC-SA9 accumulated highest amounts of phosphorus at 90 days. The nitrogen and potassium concentrations, and root dry mass did not show significant differences among the treatments.

RESUMO O objetivo deste estudo foi verificar por meio de revisão de literatura, os possíveis impactos do uso do fogo nos atributos físicos, químicos e biológicos do solo. Em relação aos atributos físicos, o fogo pode causar diminuição do volume de macroporos, do tamanho de agregados, da taxa de infiltração de água no solo e, consequentemente, sua umidade, aumento da resistência à penetração de raízes e da densidade do solo. Além disso, o solo torna-se mais susceptível ao processo erosivo pela remoção de sua cobertura vegetal. Nos atributos químicos, muitos trabalhos têm sido desenvolvidos com foco nas propriedades químicas, relatando aumento nos teores de N, P, K, Ca, Mg, entre outros nutrientes mineralizados após a passagem do fogo em consequência das cinzas possuírem alta concentração desses nutrientes. A queima também reduz o aporte de matéria orgânica bruta e, consequentemente, altera o ciclo do carbono, contribuindo para a emissão de gases de efeito estufa para a atmosfera. Nos atributos biológicos, a ação da chama do fogo diminui a disponibilidade de alimento (fonte de energia) para os micro-organismos, diminuindo sobretudo a população da mesofauna do solo. De maneira geral, tomando por base os trabalhos revisados, conclui- se que a queima tanto de pastagens ou campos naturais bem como de resíduos culturais e áreas florestais, deve ser evitada como prática rotineira, pois de maneira geral, degrada direta ou indiretamente o solo. Entretanto, dependendo da situação e do sistema de produção, a queima pode ser uma opção de manejo a ser considerada.

ABSTRACT The aim of this study was to verify through literature review the possible impacts of the use of fire on physical, chemical and biological attributes of soil. In relation to physical attributes, the fire may cause a decrease in the volume of macropores, the size of aggregates, the rate of infiltration of water into the soil and consequently its humidity, and an increase in the resistance to penetration of roots and soil density. Moreover, the soil becomes more susceptible to erosive process due to the removal of its vegetation cover. As for the chemical attributes, many studies focusing on chemical properties have reported an increase in levels of N, P, Ca, Mg, among others mineralized nutrients after the passage of fire because the ashes have high concentrations of those nutrients. Burning also reduces the input of organic matter and therefore alters the carbon cycle, contributing to the emission of greenhouse gases into the atmosphere. In relation to biological attributes, the action of flame fire reduces the availability of food (energy supply) for microorganisms, mainly reducing the population of mesofauna soil. In general, from the works reviewed, it appears that both the burning of pastures and natural fields as well as crop residues and forest areas, should be avoided as a routine practice, because in general, it directly or indirectly degrades the soil. However, depending on the situation and the production system, burning may be an option the be considered.

RESUMO O objetivo deste trabalho foi avaliar a sobrevivência e o crescimento inicial de mudas de eucalipto micorrizadas com o fungo ectomicorrízico Pisolithus microcarpus (UFSC Pt 116), após o transplante para uma área sujeita à arenização no município de São Francisco de Assis, RS. A área foi dividida em quatro blocos, cada qual com quatro tratamentos (turfa fértil com e sem fungo, Neossolo Quartzarênico com e sem fungo). Cada parcela foi composta por 16 mudas dispostas em quatro linhas no espaçamento de 1,5 m x 1,5 m, totalizando em cada bloco 64 mudas. Aos 90 dias após o plantio no campo, as mudas de eucalipto produzidas no substrato turfa fértil com fungo, apresentaram uma taxa de sobrevivência de 100%, enquanto que as produzidas em turfa fértil sem fungo, a taxa de sobrevivência foi de 92%. As mudas produzidas no Neossolo Quartzarênico com e sem fungo tiveram uma taxa de sobrevivência variando em torno de 98 e 89% respectivamente. As mudas produzidas com turfa e fungo apresentaram diferenças significativas no crescimento em altura, e diâmetro do caule. Conclui-se que mudas de Eucalyptus grandis produzidas em substrato turfa fértil e micorrizadas com o isolado Pisolithus microcarpus (UFSC Pt 116), conseguem manter bom estabelecimento e desenvolvimento no campo.

ABSTRACT The aim of this work was to evaluate the survival and the initial growth of mycorrhizated eucalypts with Pisolithus microcarpus (UFSC Pt 116) ectomycorrhizal fungus, after its transplant to area subject to the arenization process in São Francisco de Assis, RS. The area was divided into four blocks, each one with four treatments (fertile turf with and without mycorrhizae, Quartzarenic Neosoil with and without mycorrhizae). Each parcel was composed of 16 seedlings arranged in four lines in the spacing of 1,5 m x 1,5 m, totalizing in each block 64 seedlings. 90 days after the planting in the field, the eucaliptus seedlings produced in turf with fungus in the fertile substratum presented a survival rate of 100 %, whereas for those produced in fertile turf without fingi, the survival rate was 92 %. The seedlings produced in the Quartzarenic Neosoil with and without mycorrhizae had a survival rate varying around 98 and 89 %, respectively. The produced seedlings with turf and fungus showed significant differences in height and stem diameter. This study showed that the Eucalyptus grandis seedlings produced in substratum fertile turf and inoculated with the Pisolithus microcarpus (UFSC Pt 116) isolated may maintain good development and establishment in the field.

RESUMO A inoculação de fungos micorrízicos arbusculares (FMAs) é viável em mudas de espécies florestais. O objetivo deste trabalho foi avaliar o estabelecimento de duas espécies de FMAs na produção de mudas de Acacia mearnsii em diferentes substratos e doses de fósforo. O experimento constou de cinco tratamentos, sendo dois tratamentos de inoculação de espécies de FMAs, (Glomus clarum Nicolson & Schenck e Glomus etunicatum Becker & Gerdemann) e três tratamentos com diferentes substratos (mecplani, turfa fértil e Neossolo Quartzarênico); com cinco doses de fósforo (0, 50, 100, 500 e 1000 mg.kg-1), e dez repetições. Alto nível de P no substrato não impediu colonização micorrízica das raízes. Os isolados G. clarum e G. etunicatum apresentaram alta eficiência na colonização das raízes da A. mearnsii, e os substratos mecplani e turfa-fértil foram os mais eficientes na produção das mudas.

ABSTRACT The inoculation of mycorrhizal arbuscular fungi (FMAs) is viable in forest species. The aim of this study was to evaluate the establishment of two species of FMAs, in Acácia mearnsii production, considering different substracts and phosphour levels. The experiment was carried out with five treatments, with two species of FMAs (Glomus clarum Nicolson & Schenck and Glomus etunicatum Becker & Gerdemann), and three kinds of substracts (Mecplani, Fertil Turfa and Neossolo Quartzarênico) with four phosphour levels, with 10 repetitions. The high level of P in the substract did not influence the mycorrhizal colonization in the roots. These mycorrhizal fungi showed high efficiency in roots colonization of A. mearnsii. The Mecplani and Fertil Turfa substracts were the most efficient ones in seedling growing.