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Permeabilidade ao ar em Latossolo Vermelho sob diferentes sistemas de manejo; Soil air permeability in a Rhodic Hapludox under different tillage systems

RODRIGUES, Sueli; SILVA, Alvaro Pires da; GIAROLA, Neyde Fabíola Balarezo; ROSA, Jadir Aparecido
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica
POR
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56.57%
A permeabilidade ao ar pode ser utilizada para avaliar alterações que ocorrem na estrutura do solo em virtude da adoção de diferentes sistemas de manejo. Este estudo testou a hipótese de que o menor revolvimento do solo sob sistema plantio direto resulta na formação de poros mais contínuos e melhor condição de aeração no solo. O objetivo deste trabalho foi avaliar, por meio da permeabilidade ao ar (Ka), da porosidade de aeração (εa) e dos índices de continuidade de poros (K1 e N), a aeração em um Latossolo Vermelho distrófico sob preparo convencional (PC) e sistema plantio direto (SPD). Oitenta amostras de solo (2 tratamentos x 2 profundidades x 20 repetições) com estrutura indeformada foram coletadas de cada sistema de manejo do solo nas profundidades de 0-0,10 e 0,10-0,20 m em área experimental do Instituto Agronômico do Paraná, no município de Ponta Grossa, Paraná. Depois de saturadas e equilibradas em seis potenciais mátricos (-2, -6, -10, -30, -70 e -100 kPa), determinou-se a permeabilidade ao ar e a porosidade de aeração em cada potencial. Também foram determinados a densidade do solo, a densidade de partícula, o carbono orgânico e a porosidade. A densidade do solo não consistiu em fator limitante...

Permeabilidade ao ar em Latossolo Vermelho sob plantio direto e preparo convencional; Soil air permeability in a Rhodic Hapludox under no-tillage and conventional tillage

Rodrigues, Sueli
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 25/01/2010 PT
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A permeabilidade ao ar (Ka) pode ser utilizada para avaliar alterações que ocorrem na estrutura do solo em virtude de diferentes sistemas de manejo. Este estudo testou a hipótese de que o menor revolvimento do solo sob sistema plantio direto resulta na formação de poros contínuos e melhor condição de aeração no solo. O objetivo do estudo foi avaliar, por meio da Ka, porosidade de aeração (a) e índices de continuidade de poros (K1 e N), a aeração em um Latossolo Vermelho submetido ao preparo do solo convencional (PC) e plantio direto (PD). Amostras de solo indeformadas foram coletadas em cada sistema nas profundidades de 0-0,10 e 0,10-0,20 m em área experimental do Instituto Agronômico do Paraná IAPAR, no município de Ponta Grossa, Paraná. A Ka foi medida pelo método da carga decrescente em seis potenciais mátricos, -2, -6, -10, -30, -70 e -100 kPa. A macroporosidade e a Ka foi maior no PC nas duas camadas avaliadas. A continuidade de poros avaliada pela razão entre Ka e a (K1) foi similar entre os sistemas na camada superficial e foi maior para o PC em subsuperfície. O índice de continuidade N, referente ao coeficiente angular da relação log-log entre Ka e a foi diferente quando determinado para cada amostra individualmente (n=6) e quando obtido com todas as observações (n=120). Os dois métodos revelaram poros mais contínuos no PC em superfície. Na camada de 0...

Persistência do herbicida Acetochlor em função de sistemas de preparo e cobertura com palha; Acetochlor herbicide persistence as function of tillage systems and straw mulch presence

Ferri, Miguel Vicente Weiss; Vidal, Ribas Antonio
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
POR
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56.61%
Diferentes sistemas de manejo do solo alteram a persistência dos herbicidas e influem na atividade biológica, potencial de injúria às culturas em sucessão e risco de contaminação ambiental. O experimento foi conduzido, no ano agrícola de 2000/2001, na Faculdade de Agronomia da Universidade Federal do Rio Grande do Sul, com o objetivo de avaliar a persistência do herbicida acetochlor em Argissolo Vermelho manejado sob o sistema de semeadura direta e preparo convencional na presença e ausência de palha. A dose utilizada do herbicida foi de 5040 g ha-1. A persistência foi avaliada através de bioensaio utilizando-se o trigo (Triticum aestivum L.) como planta teste. Foi avaliada a altura da parte aérea das plantas de trigo. A meia vida (t 1/2 ) do herbicida no solo foi de 29 e 30 dias na presença e de 18 e 16 dias na ausência de palha nos solos conduzidos sob semeadura convencional e direta, respectivamente. A palha, na superfície do solo, aumentou a persistência do herbicida acetochlor no solo.; The different soil management systems affects herbicide persistence and change the biological activity, crop selectivity and potencial to environmental risk. An experiment was carried out at the Universidade Federal do Rio Grande do Sul...

Avaliação de sistemas de preparo e calagem em um Latossolo Bruno alumínico; Evaluation of soil tillage and liming systems in an aluminic oxisol

Albuquerque, Jackson Adriano; Mafra, Álvaro Luiz; Fontoura, Sandra Mara Vieira; Bayer, Cimelio; Passos, João Frederico Mangrich dos
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
POR
Relevância na Pesquisa
56.52%
O objetivo do presente estudo foi avaliar o efeito do preparo do solo e formas de aplicação de calcário em experimento de longa duração, nas características de um Latossolo Bruno aluminíco argiloso e nos componentes do rendimento da cultura da soja. O experimento com sistemas de preparo do solo foi instalado em 1978, e, em 1987, métodos de aplicação de calcário foram introduzidos. Os tratamentos avaliados foram: PC sem - preparo convencional sem calcário; PC inc - com calcário; PD sem - plantio direto sem calcário; PD sup - com calcário superficial e PD inc - com calcário incorporado. O solo e a planta foram analisados na safra de 2002-2003. Os sistemas plantio direto e preparo convencional não apresentaram restrições físico-estruturais no solo. Na camada superficial, o plantio direto sem incorporação de calcário apresentou maior estabilidade dos agregados do que o preparo convencional. No PD inc, a estabilidade dos agregados foi menor do que no PD sem e PD sup. A estabilidade dos agregados mostrou-se positivamente relacionada com o comprimento de micélio fúngico e com o teor de CO. A umidade volumétrica e a água disponível na camada superficial foram maiores no PD sem e PD sup e de 0,20 a 0,30 m o PD sem armazenou mais água do que o preparo convencional. O sistema plantio direto apresentou mais CO e P do que o preparo convencional. O maior teor de P no solo favoreceu sua absorção e acúmulo no tecido da soja. A calagem reduziu o Al e elevou os teores de Ca...

Carbon stock and its compartments in a subtropical oxisol under long-term tillage and crop rotation systems; Estoque e compartimentos de carbono em um latossolo vermelho subtropical sob diferentes sistemas de longo prazo de preparo e rotação de culturas

Campos, Ben-Hur Costa de; Amado, Telmo Jorge Carneiro; Bayer, Cimelio; Nicoloso, Rodrigo da Silveira; Fiorin, Jackson Ernani
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
Relevância na Pesquisa
56.58%
A matéria orgânica do solo (MOS) desempenha papel relevante na qualidade do solo e pode atuar como dreno de C-CO2 atmosférico em solos sob sistemas de manejo conservacionista. Este estudo foi realizado com o objetivo de investigar o efeito de longo prazo (19 anos) de sistemas de preparo do solo (PC-preparo convencional e PD-plantio direto) e de rotação de culturas (R0- sucessão de monoculturas, R1- rotação de culturas de inverno e R2- rotação intensiva de culturas) no estoque de carbono (C) orgânico total, particulado e associado a minerais de um Latossolo Vermelho, originalmente degradado, do Sul do Brasil. O clima é subtropical úmido Cfa 2, segundo a classificação de Köppen, com média anual de precipitação pluvial de 1.774 mm e média anual de temperatura de 19,2 oC. As parcelas experimentais foram divididas em três segmentos, e em cada um destes foram coletadas amostras nas profundidades de 0–0,05, 0,05–0,10, 0,10–0,20 e 0,20–0,30 m. As amostras foram coletadas por meio da abertura manual de pequenas trincheiras. O estoque de C no solo apresentou relação linear com o aporte anual de C, independentemente do sistema de preparo investigado. Assim, o preparo do solo teve pequeno efeito no incremento da taxa de decomposição da MOS. Na camada de 0–0...

Carbon dioxide emissions under different soil tillage systems in mechanically harvested sugarcane

Silva-Olaya, A. M.; Cerri, C. E P; La Scala, N.; Dias, C. T S; Cerri, C. C.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica
ENG
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56.64%
Soil tillage and other methods of soil management may influence CO 2 emissions because they accelerate the mineralization of organic carbon in the soil. This study aimed to quantify the CO2 emissions under conventional tillage (CT), minimum tillage (MT) and reduced tillage (RT) during the renovation of sugarcane fields in southern Brazil. The experiment was performed on an Oxisol in the sugarcane-planting area with mechanical harvesting. An undisturbed or no-till (NT) plot was left as a control treatment. The CO2 emissions results indicated a significant interaction (p < 0.001) between tillage method and time after tillage. By quantifying the accumulated emissions over the 44 days after soil tillage, we observed that tillage-induced emissions were higher after the CT system than the RT and MT systems, reaching 350.09 g m-2 of CO2 in CT, and 51.7 and 5.5 g m-2 of CO2 in RT and MT respectively. The amount of C lost in the form of CO2 due to soil tillage practices was significant and comparable to the estimated value of potential annual C accumulation resulting from changes in the harvesting system in Brazil from burning of plant residues to the adoption of green cane harvesting. The CO 2 emissions in the CT system could respond to a loss of 80% of the potential soil C accumulated over one year as result of the adoption of mechanized sugarcane harvesting. Meanwhile...

Spatial and temporal variability of CO2 emisions in soils under conventional tillage and no-till farming

Carbonell-Bojollo, R.; González- Sánchez, E.; Repullo Ruibérriz De Torres, M.A.; Ordóñez- Fernández, R.; Basch, G.
Fonte: ISTRO Publicador: ISTRO
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
66.65%
Agricultural soils can act as a carbon sink depending on the soil management practices employed. As a result of this functional duality, soil management systems are present in international documents relating to climate change mitigation. Agricultural practices are responsible for 14% of total greenhouse gas emissions (GHG’s) (MMA, 2009)(1). Conservation agriculture (CA) is one of the most effective agricultural systems for reducing CO2 emissions, as it increases the sequestration of atmospheric carbon in the soil. In order to assess the performance of CA in terms of CO2 emissions, a field trial was conducted comparing soil derived CO2 fluxes under No-till (NT) farming and under conventional tillage. Three pilot farms were selected in the cereal-growing area of southern Spain, located in Las Cabezas de San Juan (Seville), Carmona (Seville) and Cordoba. Each pilot farm comprises six experimental plots with an approximate area of five hectares; three of the six plots implement CA practices, while the other three use conventional tillage techniques. The subdivision of each tillage system into 3 plots allowed the simultaneous cropping of the three crops of the wheat-sunflower-legume rotation each year. Results showed that carbon dioxide emissions were 31 to 91% higher in tilled soils than in untilled soils...

Short-term effects of four tillage practices on soil physical properties, soil water potential, and maize yield

Salem, Haytham M.; Valero, Constantino; Muñoz, Miguel Angel; Rodríguez, María Gil; Silva, Luis L.
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.7%
The area cultivated using conservation tillage has recently increased in central Spain. However, soil compaction and water retention with conservation tillage still remains a genuine concern for landowners in this region because of its potential effect on the crop growth and yield. The aim of this research is to determine the shortterm influences of four tillage treatments on soil physical properties. In the experiment, bulk density, cone index, soil water potential, soil temperature and maize (Zea mays L.) productivity have been measured. A field experiment was established in spring of 2013 on a loamy soil. The experiment compared four tillage methods (zero tillage, ZT; reservoir tillage, RT; minimum tillage, MT; and conventional tillage, CT). Soil bulk density and soil cone index were measured during maize growing season and at harvesting time. Furthermore, the soil water potential was monitored by using a wireless sensors network with sensors at 20 and 40 cm depths. Also, soil temperatures were registered at depths of 5 and 12 cm. Results indicated that there were significant differences between soil bulk density and cone index of ZT method and those of RT, MT, and CT, during the growing season; although, this difference was not significant at the time of harvesting in some soil layers. Overall...

Soybean response to starter nitrogen and Bradyrhizobium inoculation on a Cerrado oxisol under no-tillage and conventional tillage systems

Mendes,I. C.; Hungria,M.; Vargas,M. A. T.
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2003 EN
Relevância na Pesquisa
56.52%
In Brazil, Bradyrhizobium inoculation has successfully replaced the use of N fertilizer on soybean [Glycine max (L) Merr.] crops. However, with the expansion of no-tillage cropping systems in the Cerrados region, the idea that it is necessary to use small N rates at the sowing to overcome problems related with N immobilization has become widespread, mainly when soybean is cultivated after a non-legume crop. In this study we examined soybean response to small rates of N fertilizer under no-tillage (NT) and conventional tillage (CT) systems. Four experiments (a completely randomized block with five replicates) were carried out in a red yellow oxisol, during the periods of 1998/1999 and 1999/ 2000, under NT and CT. The treatments consisted of four urea rates (0, 20, 30 and 40 kg ha-1 N). All treatments were inoculated with Bradyrhizobium japonicum strains SEMIA 5080 and SEMIA 5079, in the proportion 1 kg of peat inoculant (1,5 x 10(9) cells g-1) per 50 kg of seeds. In both experiments, soybean was cultivated after corn and the N fertilizer was band applied at sowing. In all experiments, N rates promoted reductions of up to 50 % in the nodule number at 15 days after the emergence. Regardless of the management system, these reductions disappeared at the flowering stage and there was no effect of N rates on either the number and dry weight of nodules or on soybean yields. Therefore...

Carbon stock and its compartments in a subtropical oxisol under long-term tillage and crop rotation systems

Campos,Ben-Hur Costa de; Amado,Telmo Jorge Carneiro; Bayer,Cimélio; Nicoloso,Rodrigo da Silveira; Fiorin,Jackson Ernani
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2011 EN
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56.58%
Soil organic matter (SOM) plays a crucial role in soil quality and can act as an atmospheric C-CO2 sink under conservationist management systems. This study aimed to evaluate the long-term effects (19 years) of tillage (CT-conventional tillage and NT-no tillage) and crop rotations (R0-monoculture system, R1-winter crop rotation, and R2- intensive crop rotation) on total, particulate and mineral-associated organic carbon (C) stocks of an originally degraded Red Oxisol in Cruz Alta, RS, Southern Brazil. The climate is humid subtropical Cfa 2a (Köppen classification), the mean annual precipitation 1,774 mm and mean annual temperature 19.2 ºC. The plots were divided into four segments, of which each was sampled in the layers 0-0.05, 0.05-0.10, 0.10-0.20, and 0.20-0.30 m. Sampling was performed manually by opening small trenches. The SOM pools were determined by physical fractionation. Soil C stocks had a linear relationship with annual crop C inputs, regardless of the tillage systems. Thus, soil disturbance had a minor effect on SOM turnover. In the 0-0.30 m layer, soil C sequestration ranged from 0 to 0.51 Mg ha-1 yr-1, using the CT R0 treatment as base-line; crop rotation systems had more influence on soil stock C than tillage systems. The mean C sequestration rate of the cropping systems was 0.13 Mg ha-1 yr-1 higher in NT than CT. This result was associated to the higher C input by crops due to the improvement in soil quality under long-term no-tillage. The particulate C fraction was a sensitive indicator of soil management quality...

Long-term C-CO2 emissions and carbon crop residue mineralization in an oxisol under different tillage and crop rotation systems

Campos,Ben-Hur Costa de; Amado,Telmo Jorge Carneiro; Tornquist,Carlos Gustavo; Nicoloso,Rodrigo da Silveira; Fiorin,Jackson Ernani
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2011 EN
Relevância na Pesquisa
56.58%
Soil C-CO2 emissions are sensitive indicators of management system impacts on soil organic matter (SOM). The main soil C-CO2 sources at the soil-plant interface are the decomposition of crop residues, SOM turnover, and respiration of roots and soil biota. The objectives of this study were to evaluate the impacts of tillage and cropping systems on long-term soil C-CO2 emissions and their relationship with carbon (C) mineralization of crop residues. A long-term experiment was conducted in a Red Oxisol in Cruz Alta, RS, Brazil, with subtropical climate Cfa (Köppen classification), mean annual precipitation of 1,774 mm and mean annual temperature of 19.2 ºC. Treatments consisted of two tillage systems: (a) conventional tillage (CT) and (b) no tillage (NT) in combination with three cropping systems: (a) R0- monoculture system (soybean/wheat), (b) R1- winter crop rotation (soybean/wheat/soybean/black oat), and (c) R2- intensive crop rotation (soybean/ black oat/soybean/black oat + common vetch/maize/oilseed radish/wheat). The soil C-CO2 efflux was measured every 14 days for two years (48 measurements), by trapping the CO2 in an alkaline solution. The soil gravimetric moisture in the 0-0.05 m layer was determined concomitantly with the C-CO2 efflux measurements. The crop residue C mineralization was evaluated with the mesh-bag method...

Forms of inorganic phosphorus in soil under different long term soil tillage systems and winter crops

Tiecher,Tales; Santos,Danilo Rheinheimer dos; Kaminski,João; Calegari,Ademir
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2012 EN
Relevância na Pesquisa
56.55%
The cultivation of crops with different capacity of P uptake and use under long-term soil tillage systems can affect the distribution of P cycling and inorganic forms in the soil, as a result of higher or lower use efficiency of P applied in fertilizers. The purpose of this study was to evaluate the effect of long-term cultivation of different winter species under tillage systems on the distribution of inorganic P forms in the soil. In 1986, the experiment was initiated with six winter crops (blue lupin, hairy vetch, oat, oilseed radish, wheat and fallow) on a Rhodic Hapludox in southwestern Paraná, under no-tillage (NT) and conventional tillage (CT). The application of phosphate fertilizer in NT rows increased inorganic P in the labile and moderately labile forms, and soil disturbance in CT redistributed the applied P in the deeper layers, increasing the moderately labile P concentration in the subsurface layers. Black oat and blue lupin were the most efficient P-recyclers and under NT, they increased the labile P content in the soil surface layers.

Contribution of macroporosity to water flux of a soil under different tillage systems

Soracco,Carlos Germán; Lozano,Luis Alberto; Balbuena,Roberto; Ressia,Juan Manuel; Filgueira,Roberto Raúl
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2012 EN
Relevância na Pesquisa
56.57%
In view of the importance of the macroporosity for the water transport properties of soils, its quantitative assessment is a challenging task. Measurements of hydraulic conductivity (K) at different soil water tensions and the quantification of water-conducting macropores (θM) of a soil under different tillage systems could help understand the effects on the soil porous system and related hydraulic properties. The purpose of this study was to assess the effects of Conventional Tillage (CT), Chisel Plow (CP) and No Tillage (NT) on θM and on K; and to quantify the contribution of macroporosity to total water flux in a loam soil. A tension disc infiltrometer was used at two soil water pressure heads (-5 cm, and 0) to infer θM and K, during fallow. Macroporosity was determined based on the flow contribution between 0 and -5 cm water potentials (K0, K5, respectively), according to the Hagen-Poiseuille equation. The K0 values were statistically higher for CT than for NT and CP. The K5 values did not differ statistically among treatments. The mean K values varied between 0.20 and 3.70 cm/h. For CT, θM was significantly greater than for CP and NT, following the same trend as K0. No differences in θM were detected between CP and NT. With CT...

Soil carbon and nitrogen mineralization caused by pig slurry application under different soil tillage systems

Balota,Elcio Liborio; Machineski,Oswaldo; Truber,Priscila Viviane
Fonte: Embrapa Informação Tecnológica; Pesquisa Agropecuária Brasileira Publicador: Embrapa Informação Tecnológica; Pesquisa Agropecuária Brasileira
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2010 EN
Relevância na Pesquisa
56.52%
The objective of this work was to evaluate the change in soil C and N mineralization due to successive pig slurry application under conventional tillage (CT) and no tillage (NT) systems. The experiment was carried out in a clayey Latossolo Vermelho eutrófico (Rhodic Eutrudox) in Palotina, PR, Brazil. Increasing doses of pig slurry (0, 30, 60 and 120 m³ ha-1 per year) were applied in both tillage systems, with three replicates. Half of the pig slurry was applied before summer soil preparation, and the other half before the winter crop season. The areas were cultivated with soybean (Glycine max L.) and maize (Zea mays L.) in the summers of 1998 and 1999, respectively, and with wheat (Triticum sativum Lam.) in the winters of both years. Soil samples were collected at 0-5, 5-10, and 10-20 cm depths. Under both CT and NT systems, pig slurry application increased C and N mineralization. However, increasing pig slurry additions decreased the C to N mineralization ratio. Under the NT system, C and N mineralization was greater than in CT system.

Microbial diversity in an Oxisol under no-tillage and conventional tillage in southern Brazil

Babujia,Letícia Carlos; Silva,Adriana Pereira; Nogueira,Marco Antonio; Hungria,Mariangela
Fonte: Universidade Federal do Ceará Publicador: Universidade Federal do Ceará
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 EN
Relevância na Pesquisa
56.52%
The no-tillage (NT) system of soil management is recognized as more sustainable than conventional tillage (CT), with an important role played by soil microorganisms. The objective of this study was to estimate differences in soil microbial diversity under NT and CT at different soil depths. For that, bacterial (16S rDNA) and fungal (18S rDNA) communities were evaluated by denaturing gradient gel electrophoresis (DGGE) in a 20-year field experiment established on an Oxisol in southern Brazil on which soybean has been grown in the summer and wheat in the winter. Soil samples were collected at the depths of 0-5, 5-10, 10-20 and 20-30 cm, and submitted to DGGE analyses. The results revealed lower similarity (28%) between bacterial communities in the NT and the CT systems at the 0-5 cm layer. The Shannon index (H) confirmed higher bacterial diversity with NT at all depths, when compared to CT. In relation to fungal communities, higher diversity was detected with CT, especially at the 0 - 5-cm depth. The results indicate that fungal communities can be more tolerant to environmental stresses related to soil disturbance than bacteria. More emphasis should be given for understanding processes affecting the diversity of microorganisms in agricultural soils...

Survival of pathogens on soybean debris under no-tillage and conventional tillage systems.

ALMEIDA, A.M.R.; SARAIVA, O.F.; FARIAS, J.R.B.; GAUDENCIO, C.A.; TORRES, E.
Fonte: Pesquisa Agropecuaria Brasileira, Brasilia, v. 36, n. 10, p. 1231-1238, out. 2001. Publicador: Pesquisa Agropecuaria Brasileira, Brasilia, v. 36, n. 10, p. 1231-1238, out. 2001.
Tipo: Artigo em periódico indexado (ALICE)
EN
Relevância na Pesquisa
56.68%
A study was conducted in the subtropical area of Southern Brazil to determine the survival of pathogens in soybean residues under conventional and no-tillage cultivation systems from March to September of 1998 and 1999. The pathogens most frequently isolated were Colletotrichum truncatum, Phomopsis spp., Cercospora kikuchii, Fusarium spp., Macrophomina phaseolina, and Rhizoctonia solani. Other fungi isolated were Myrothecium roridum, Penicillium sp., Chaetomium sp., Epicoccum sp., Corynespora cassiicola and Trichoderma sp. The percent of survival of each pathogen varied according to the month and the year. Survival of C. truncatum, Phomopsis spp. and C. kikuchii were significantly reduced (p<0.05) from the first to the last evaluation either on buried debris or maintained on the soil surface. On the other hand, M. phaseolina and Fusarium spp. were either not affected or favored by burying the debris. The frequency of recovery of Fusarium spp. increased specially in debris kept under the soil. The loss of biomass, measured by debris weight along the period of this study, showed a reduction of 44.4% in the conventional system and 34.9% in the no-tillage system in 1998, when rain was better distributed. In 1999, the reduction was 48.2% and 39.0% for the conventional and no-tillage system...

Soil carbon and nitrogen mineralization caused by pig slurry application under different soil tillage systems.

BALOTA, E. L.; MACHINESKI, O.; TRUBER, P. V.
Fonte: Pesquisa Agropecuária Brasileira, Brasília, v.45, n.5, p.515-521, maio. 2010 Publicador: Pesquisa Agropecuária Brasileira, Brasília, v.45, n.5, p.515-521, maio. 2010
Tipo: Artigo em periódico indexado (ALICE)
EN
Relevância na Pesquisa
56.52%
Abstract ? the objective of this work was to evaluate the change in soil C and N mineralization due to successive pig slurry application under conventional tillage (CT) and no tillage (NT) systems. The experiment was carried out in a clayey Latossolo Vermelho eutrófico (Rhodic Eutrudox) in Palotina, PR, Brazil. Increasing doses of pig slurry (0, 30, 60 and 120 m3 ha-1 per year) were applied in both tillage systems, with three replicates. Half of the pig slurry was applied before summer soil preparation, and the other half before the winter crop season. The areas were cultivated with soybean (Glycine max L.) and maize (Zea mays L.) in the summers of 1998 and 1999, respectively, and with wheat (Triticum sativum Lam.) in the winters of both years. Soil samples were collected at 0?5, 5?10, and 10?20 cm depths. Under both CT and NT systems, pig slurry application increased C and N mineralization. However, increasing pig slurry additions decreased the C to N mineralization ratio. Under the NT system, C and N mineralization was greater than in CT system.; 2010

Effects of above-ground herbivory on soil microbial biomass in conventional and no-tillage agroecosystems

Holland, J Nat
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.59%
journal article; The effects of above-ground herbivory on soil microbial biomass associated with maize (Zea muys) roots were measured in field experiments. Different grazing intensities were established by placing grasshoppers (0, 5, 10 and 20) in cages around individual maize plants, and allowing them to graze for 5 days. Soil samples were taken 12 days later at a depth of between 8 and 12 cm. Soil microbial biomass was measured using the chloroform fumigation direct extraction method. Results indicated that intermediate levels of herbivory increased soil microbial biomass in the no-tillage system. However, in a conventional tillage system no significant differences were found among the grazing treatments. It is hypothesized that increases in soil microbial biomass in the no-tillage system were attributable to increases in root exudates resulting from above-ground herbivory.

CHARACTERIZATION OF THE WEED SEED BANK IN ZERO AND CONVENTIONAL TILLAGE IN CENTRAL CHILE

Acevedo Hinojosa, Edmundo; Silva Candia, Paola; Peralta Caroca, Rosa
Fonte: INST INVESTIGACIONES AGROPECUARIAS Publicador: INST INVESTIGACIONES AGROPECUARIAS
Tipo: Artículo de revista
EN
Relevância na Pesquisa
56.49%
Artículo de publicación ISI; We studied the abundance, species composition, and depth distribution of the weed seed bank under no-tillage (NT) and conventional tillage (CT) at two sites, A and B. Soil samples were taken at three soil depths (0-2, 2-5, and 5-15 cm). Germinated, dormant, and total seeds were counted. The total number of seeds was higher (p <= 0.05) under CT treatment at the two sites (CTA = 5175 seeds m(-2), NTA = 3250 seeds m(-2), CTB = 33 770 m(-2), and NTB = 22 437 seeds m(-2)). The number of viable, dormant, and germinated seeds was also higher (p <= 0.05) in CT at the two sites. The percentage of viable seeds was low with 37% (CTA), 34% (CTB), 21% (NTA), and 8% (NTB). Viable seeds of Chenopodium album L. (CHEAL) dominated in the two trials with 67% (CTA), 20% (NTA), 96% (CTB), and 77% (NTB). In a principal component analysis, PC1 separated viable seeds of weed species according to tillage and PC2 separated weed species according to sites. Poa annua L. was the most important species associated with NT followed by Cichorium intybus L., and Sonchus while Euphorbia helioscopia L. and Echinochloa crus-galli (L.) P. Beauv. were associated with CT.; FONDECYT 1050565 Universidad de Chile-SIRDS-SAG-INDAP

Soil quality indicators in a Rhodic Paleudult under long term tillage systems

Souza, Elisângela Dutra de; Costa, Sérgio Ely Valadão Gigante de Andrade; Anghinoni, Ibanor; Carneiro, Marco Aurélio Carbone; Martins, Amanda Posselt; Bayer, Cimélio
Fonte: Universidade Federal de Lavras Publicador: Universidade Federal de Lavras
Tipo: Artigo de Revista Científica
Publicado em 01/02/2014 EN
Relevância na Pesquisa
56.67%
Many investigations have focused in defining soil quality indicator components. However, for understanding better the impact of soil tillage systems on soil quality, a broader approach is demanded, with simultaneous soil attributes evaluations, by using multivariate analysis. The objective of this experiment was to evaluate the long-term effect of two tillage systems on the soil C and N stocks in comparison to those of native grassland and to identify the most suitable soil attributes for characterizing soil quality. The experiment was established in 1988 at the Agronomic Experimental Station of the Federal University of Rio Grande do Sul, Southern Brazil. Treatments consisted of two tillage systems (no-tillage and conventional tillage) and a reference area under native grassland. Soil analysis was performed up to 20 cm. Soil organic matter, C and N, physical fractionation was performed and carbon management index calculated. Microbial biomass C and N was determined as well as soil aggregate stability. From soil aggregation, soil average diameters and mass were grouped, and classes determined to calculate mean weight diameter. After 18 years, conventionally tilled soil showed lower total C and N stocks in comparison to no-tilled soil...