RESUMO
Chemical and physical properties of soil can be altered with the successive application of liquid swine manure (LSM), also known as slurry. Therefore, monitoring the impact of LSM is essential to an assessment of the potential agronomic and environmental benefits and risks associated with management practices. The aim of this study was to evaluate the effects of LSM on the chemical and physical attributes of soil under pasture (Cynodon spp.), located in southern Brazil. Four areas were sampled: three areas cultivated with Cynodon spp. pasture with successive applications of 200 m3 ha1 y1 of LSM for three, eight and 15 years; and untreated native forest as a reference. The soil attributes evaluated were: organic carbon (OC), active (pH water) and potential acidity (H + Al+ 3), nutrient availability (i.e., P, K, Ca, Mg, Cu and Zn), soil bulk density, macro, micro and total porosity. Successive applications of LSM on pasture reduced soil active acidity, and increased the soil organic C and plant-available N, P, Ca, Mg, Cu and Zn contents. These effects were more intense with time and in the shallowest layers, i.e. 0-10 cm. Excessive increases in P, Cu and Zn in the soil should be carefully monitored to minimize the contamination risks to soil, ground and surface waters. Soil physical attribute changes were more associated with land use (pasture versus native forest) than LSM use, and LSM applications induced slight improvements in the soil structural quality over time.
Assuntos
Análise do Solo , Gerenciamento de Resíduos , Líquido Percolado , Pastagens , Química do Solo , Cynodon , SuínosRESUMO
Chemical and physical properties of soil can be altered with the successive application of liquid swine manure (LSM), also known as slurry. Therefore, monitoring the impact of LSM is essential to an assessment of the potential agronomic and environmental benefits and risks associated with management practices. The aim of this study was to evaluate the effects of LSM on the chemical and physical attributes of soil under pasture (Cynodon spp.), located in southern Brazil. Four areas were sampled: three areas cultivated with Cynodon spp. pasture with successive applications of 200 m3 ha1 y1 of LSM for three, eight and 15 years; and untreated native forest as a reference. The soil attributes evaluated were: organic carbon (OC), active (pH water) and potential acidity (H + Al+ 3), nutrient availability (i.e., P, K, Ca, Mg, Cu and Zn), soil bulk density, macro, micro and total porosity. Successive applications of LSM on pasture reduced soil active acidity, and increased the soil organic C and plant-available N, P, Ca, Mg, Cu and Zn contents. These effects were more intense with time and in the shallowest layers, i.e. 0-10 cm. Excessive increases in P, Cu and Zn in the soil should be carefully monitored to minimize the contamination risks to soil, ground and surface waters. Soil physical attribute changes were more associated with land use (pasture versus native forest) than LSM use, and LSM applications induced slight improvements in the soil structural quality over time.(AU)
Assuntos
Análise do Solo , Líquido Percolado , Química do Solo , Pastagens , Gerenciamento de Resíduos , Cynodon , SuínosRESUMO
O objetivo deste estudo foi, a partir da análise de uma populaçao de 31 pacientes portadores de deficiência mental e de 30 pacientes diagnosticados como portadores de autismo, conforme os critérios diagnósticos do DSM-IV, traduzir, adaptar e validar a escala de traços autísticos, construída em Barcelona por Ballabriga e colaboradores. O ponto de corte encontrado foi 15 (p=0,05); o coeficiente de variaçao (confiabilidade), 0,27; a validade externa mostrou baixa concordância (kappa=0,04) e a validade interna foi 100 por cento, mostrando que, em todos os pacientes avaliados, os diagnósticos clínicos concordaram com os realizados através da escala. O índice de correlaçao foi 0,42, mostrando-se específico para os quadros autísticos. Apresentou ainda, capacidade de discriminaçao e consistência interna, com alfa de Cronbach 0,71. Consideramos, assim, que a escala mostra-se confiável para a sua utilizaçao em nosso meio.