Cropping system effects on soil quality in the Great Plains: Synthesis from a regional project

Soils perform a number of essential functions affecting management goals. Soil functions were assessed by measuring physical, chemical, and biological properties in a regional assessment of conventional (CON) and alternative (ALT) management practices at eight sites within the Great Plains. The results, reported in accompanying papers, provide excellent data for assessing how management practices collectively affect agronomic and environmental soil functions that benefit both farmers and society. Our objective was to use the regional data as an input for two new assessment tools to evaluate their potential and sensitivity for detecting differences (aggradation or degradation) in management systems. The soil management assessment framework (SMAF) and the agro-ecosystem performance assessment tool (AEPAT) were used to score individual soil properties at each location relative to expected conditions based on inherent soil-forming factors and to compute index values that provide an overall assessment of the agronomic and environmental impact of the CON and ALT practices. SMAF index values were positively correlated with grain yield (an agronomic function) and total organic matter (an agronomic and environmental function). They were negatively correlated with soil nitrate concentration at harvest (an indicator of environmental function). There was general agreement between the two assessment tools when used to compare management practices. Users can measure a small number of soil properties and use one of these tools to easily assess the effectiveness of soil management practices. A higher score in either tool identifies more environmentally and agronomically sustainable management. Temporal variability in measured indicators makes dynamic assessments of management practices essential. Water-filled pore space, aggregate stability, particulate organic matter, and microbial biomass were sensitive to management and should be included in studies aimed at improving soil management. Reductions in both tillage and fallow combined with crop rotation has resulted in improved soil function (e.g., nutrient cycling, organic C content, and productivity) throughout the Great Plains

Indicadores de qualidade do solo em sistemas de cultivo orgânico e convencional no semi-árido Cearense.

A qualidade do solo pode mudar com o passar do tempo, em decorrência de eventos naturais ou ações antrópicas. A adoção de práticas de cultivo orgânico reduz o revolvimento do solo, favorecendo a recuperação de suas propriedades físicas e químicas. Este trabalho teve como objetivo comparar propriedades físicas,químicas e biológicas de solos cultivados com algodão em bases orgânicas e no sistema convencional, assim como identificar as que possam ser utilizadas como indicadores de qualidade do solo. Selecionaram-se seis áreas submetidas ao cultivo orgânico e três ao cultivo convencional para coleta de amostras de solo deformadas e indeformadas, nas camadas de 0–10, 10–20 e 20–30 cm. Técnicas de estatística univariada e multivariada foram utilizadas para análise dos dados. Os resultados mostraram que os indicadores físicos e químicos testados individualmente não foram sensíveis para diferenciar as áreas sob sistema de cultivo orgânico daquelas sob cultivo convencional. No entanto, a aplicação de técnicas de análise multivariada – no caso, componentes principais e a discriminante de Anderson – permitiu a distinção entre algumas áreas cultivadas sob cultivo orgânico comparativamente às convencionais, até mesmo as que estavam em transição.Dos indicadores biológicos, a fauna edáfica mostrou-se mais precisa na avaliação da qualidade do solo, distinguindo de forma satisfatória as áreas sob sistema de cultivo orgânico das que estavam sob sistema convencional

Randomized Clinical-Trial of Manipulative Therapy and Physiotherapy for Persistent Back and Neck Complaints - Results of One Year Follow-Up

Objective - To compare the effectiveness of manipulative therapy, physiotherapy, treatment by the general practitioner, and placebo therapy in patients with persistent non-specific back and neck complaints. Design - Randomised clinical trial. Setting-Primary health care in the Netherlands. Patients-256 patients with non-specific back and neck complaints of at least six weeks' duration who had not received physiotherapy or manipulative therapy in the past two years. Interventions - At the discretion of the manipulative therapists, physiotherapists, and general practitioners. Physiotherapy consisted of exercises, massage, and physical therapy (heat, electrotherapy, ultrasound, shortwave diathermy). Manipulative therapy consisted of manipulation and mobilisation of the spine. Treatment by general practitioners consisted of drugs (for example, analgesics), advice about posture, home exercises, and (bed)rest. Placebo treatment consisted of detuned shortwave diathermy (10 minutes) and detuned ultrasound (10 minutes). Main outcome measures - Changes in severity of the main complaint and limitation of physical functioning measured on 10 point scales by a blinded research assistant and global perceived effect measured on a 6 point scale by the patients. Results - Many patients in the general practitioner and placebo groups received other treatment during follow up. Improvement in the main complaint was larger with manipulative therapy (4·5) than with physiotherapy (3·8) after 12 months' follow up (difference 0·9; 95% confidence interval 0·1 to 1·7). Manipulative therapy also gave larger improvements in physical functioning (difference 0·6; -0·1 to 1·3). The global perceived effect after six and 12 months' follow up was similar for both treatments. Conclusions - Manipulative therapy and physiotherapy are better than general practitioner and placebo treatment. Furthermore, manipulative therapy is slightly better than physiotherapy after 12 months

Percepção ambiental dos produtores e qualidade do solo em propriedades orgânicas e convencionais.

O sistema orgânico de produção deve resultar na utilização mais racional dos recursos naturais, sobretudo do solo. Os produtores orgânicos devem adotar práticas conservacionistas, além de atender a outros princípios deste sistema de produção. Neste trabalho foram avaliadas as práticas de manejo e conservação do solo adotadas por produtores orgânicos e convencionais nas regiões dos municípios de Socorro (Serra da Mantiqueira e Mogiana) e Ibiúna, situados no Estado de São Paulo. O objetivo dessa pesquisa foi verificar o grau de adoção de práticas conservacionistas pelos produtores e avaliar a qualidade do solo na agricultura orgânica e convencional. Foi elaborado e aplicado um questionário, com visitas locais para verificação das práticas conservacionistas e ocorrência de erosão, em 30 propriedades. Os resultados foram expressos em índices indicadores de diversidade de uso do solo, atitude conservacionista, percepção de erosão e do impacto sobre os recursos hídricos. Foram também realizadas análises de atributos químicos, físicos e biológicos indicadores da qualidade do solo. Concluiu-se que os produtores orgânicos têm maior percepção quanto à atitude conservacionista e nas propriedades orgânicas há maior diversidade de cultivos, embora não haja maior diversidade geral de uso do solo. A produção orgânica de alface, em Ibiúna proporcionou maior atividade biológica no solo e maior colonização por fungos micorrízicos arbusculares. O sistema orgânico possui maiores teores de matéria orgânica e menores de potássio e não houve diferença entre os atributos físicos do solo dos sistemas orgânico e convencional

Temporal evolution of solar energetic particle spectra

During solar flares and coronal mass ejections, solar energetic par- ticles (SEPs) may be released into the interplanetary medium and near-Earth locations. The energy spectra of SEP events at 1 AU are typically averaged over the entire event or studied in a few snapshots. In this paper we analyze the time evolution of the energy spectra of four large selected SEP events using a large number of snapshots. We use a multi-spacecraft and multi-instrument approach for the observations, obtained over a wide SEP energy range. We find large differences in the spectra at the beginning of the events as measured by different instruments. We show that over time, a wave-like structure is observed traveling through the spectra from the highest energies to the lowest energies, creating an “arch” shape which then straightens into a power law later in the event, after times of the order of 10 hours. We discuss the processes that determine SEP intensities and their role in shaping the spectral time evolution