Soil Biological Activity in Recent Clearcuts in West-Central Alberta

Soil biota response to changes in the soil physical environment following forest harvesting is relatively unknown in boreal forests. Soil biological activity was measured at four sites with Luvisolic soil following clear-cut forest har- vesting. Aerobic respiration rate and cellulose decomposition in flooded soils were measured on soil samples collected from treat- ment plots subjected to tree removal only and tree removal associated with three levels of skidding activity immediately after clear-cut harvesting and after 1 and 2 yr. More than half of variation in respiration and cellulose decomposition rates was related to soil properties. Soil respiration rate increased significantly after 1 yr but was not affected by skidder traffic. Cellulose decom- position was highest in soil with air-filled porosity \u3c0.10 m3 m–3, and increased significantly with skidder traffic. Air-filled porosity measured in the field at the time of harvest indicated a poorly aerated environment that becomes wetter in subsequent years. The results imply that soil had biota well adapted to poor soil aeration. The development of a fully anaerobic soil environment fol- lowing forest harvesting only occurred on compacted soil after heavy precipitation, but partial anaerobiosis of these boreal forest soils was common. Although partial anaerobiosis increased decomposition rate, it is considered sufficient to adversely affect the growth of plant roots and change the availability and mobility of nutrients

Efeito de sistemas de uso e manejo nas propriedades físico-hídricas de um argissolo amarelo de tabuleiro costeiro Effect of use and management systems on the physical and hydraulic properties of a yellow argisol of coastal tablelands

Os diferentes sistemas de manejo com cana-de-açúcar em solos de tabuleiros costeiros podem causar alterações na estrutura original do solo. Os efeitos de diferentes sistemas de manejo com cana-de-açúcar nas propriedades físico-hídricas de um Argissolo Amarelo coeso foram estudados em quatro áreas selecionadas na usina Triunfo, no Estado de Alagoas. Os tratamentos consistiram de uma área não irrigada, uma área irrigada, uma com aplicação de vinhaça e uma sob floresta nativa como condição original. As amostras foram retiradas das profundidades de 0-0,2, 0,2-0,4 e 0,4-0,8 m, para determinar as alterações na densidade do solo, distribuição de diâmetro dos poros, curvas de retenção de água no solo e condutividade hidráulica saturada. O maior grau de dispersão de argila nos solos cultivados com cana-de-açúcar promoveu maior acúmulo desta partícula nas camadas subsuperficiais do solo. Os sistemas de manejo com cana-de-açúcar aumentaram a compactação do solo, com conseqüente redução da macroporosidade e condutividade hidráulica saturada, e aumento da retenção de água disponível do solo.<br>Different sugarcane management systems on soils of coastal tablelands can cause alterations in their original soil structure. Effects of the different sugarcane management systems on the properties of a cohesive Yellow Argisol were studied in four areas of the Triunfo sugar mill in Alagoas State, Brazil. The treatments consisted of a site with and without cultivation irrigation each, one site with vinasse application and another under undisturbed native forest. Samples were collected at depths of 0-0.2, 0.2-0.4 and 0.4-0.8 m to determine the alterations in the bulk density, soil pore size distribution, soil water retention curves, and saturated hydraulic conductivity. The highest degree of clay dispersion in sugarcane-cultivated soils promoted a greater accumulation of clay particles in the subsurface soil layers. Management systems with sugarcane increased soil compaction, with a consequent alteration of the soil pore size distribution, reduced the saturated hydraulic conductivity and increased the retention of available water

Aspects of urinary tract infections and antimicrobial resistance in hospitalized urology patients in Asia: 10-Year results of the Global Prevalence Study of Infections in Urology (GPIU)

10.1016/j.jiac.2017.11.013Journal of Infection and Chemotherapy244278-283JICH