Relationships among crop yield, protein, soil properties, and response to nitrogen fertilizer application in an undulating landscape in south central Saskatchewan

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Relationship of crop yield and protein content to soil properties in an undulating landscape in south central Saskatchewan

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Effect of a new physiotherapy concept on bone mineral density, muscle force and gross motor function in children with bilateral cerebral palsy

Copyright @ 2010 The Authors.Objective: The purpose of this study was to determine the effect of a new physiotherapy concept on bone density, muscle force and motor function in bilateral spastic cerebral palsy children. Methods: In a retrospective data analysis 78 children were analysed. The concept included whole body vibration, physiotherapy, resistance training and treadmill training. The concept is structured in two in-patient stays and two periods of three months home-based vibration training. Outcome measures were dual-energy x-ray absorption (DXA), Leonardo Tilt Table and a modified Gross Motor Function Measure before and after six months of training. Results: Percent changes were highly significant for bone mineral density, -content, muscle mass and significant for angle of verticalisation, muscle force and modified Gross Motor Function Measure after six months training. Conclusions: The new physiotherapy concept had a significant effect on bone mineral density, muscle force and gross motor function in bilateral spastic cerebral palsy children. This implicates an amelioration in all International Classification of Functioning, Disability and Health levels. The study serves as a basis for future research on evidence based paediatric physiotherapy taking into account developmental implications

Bioactivity and dissipation of pyroxasulfone herbicide in Saskatchewan soils

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Effect of soil pH on pyroxasulfone bioactivity in soil

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The effect of crop rotation and soil amendments on soil N bioavailability and N2O emissions

Non-Peer ReviewedThe majority of N2O emissions result from bacterial denitrification and to a lesser extent nitrification, occurring in agricultural soils. Therefore, the overall N economy of a system, along with soluble C and limited O2 are the key drivers in the release of N2O. Crop rotations and soil amendments readily add to or deplete the soil N economy depending on the C:N ratio of the biomass returned to the field. This paper synthesizes the results of three varied studies to further elucidate the role of management on key drivers of N2O release. Study one examined how N2O emissions during potato production are influenced by choice of preceding crop in two-year potato rotations. There was a significant effect of preceding crop (PC) on cumulative growing season N2O emissions from the potato crop. Preceding crops of red clover and Italian ryegrass (average of 1.7 kg N2O-N ha-1) produced significantly higher cumulative N2O emissions when compared to preceding crops of corn, canola, soybean, barley and potato (average of 0.8 kg N2O-N ha-1). A second study on potatoes conducted by Lynch et al. (2009) using Plant Root Simulator (PRS)™-probes found that a PC containing red clover increased soil N supply rates compared to a PC containing pea-oat-vetch. This increase in PRS™–N supply rates was associated with increased N2O emission during the five-year potato rotation. The use of by-products from biofuel processing as soil amendments and N2O emissions during canola production was assessed by Schoenau et al. (2009). Wet distillers’ grain and thin stillage resulted in the greatest N2O production compared with soil amendments of alfalfa powder and glycerol. PRS™–N supply rates were closely linked with these patterns of N2O emissions. These results suggest that selection of rotation crops and soil amendments can have significant effects on N2O emissions as affected by soil N bioavailability

The effect of nitrogen fertilization and no-till duration on soil nitrogen availability and greenhouse gas emissions

Non-Peer ReviewedWith a world population now greater than seven billion, it is imperative to conserve the arable land base, which is increasingly being leveraged by global demands for producing food, feed, fibre, and fuel. A key component of sustainable agriculture involves the restoration of unproductive lands that have been rendered unsuitable for agricultural production through anthropogenic soil degradation. The objective of this study was to determine the effect of varying fertilizer N rates on soil N availability and N2O and CO2 emissions of three soils collected at adjacent locations with contrasting management histories: native prairie or short-term (10 years) and long-term (32 years) no-till continuous multi-crop (wheat-pea-canola) cropping systems receiving five fertilizer N rates (0, 30, 60, 90, and 120 kg N/ha) for the previous nine years. Intact soil cores were collected from each site, maintained at field capacity, and incubated (22 oC) for six weeks. Weekly assessments of soil nutrient availability and N2O and CO2 emissions were completed to assess the impact of prolonged variable rates of fertilizer N and duration of no-till management of degraded agricultural soil relative to an adjacent native prairie soil. At the end of the six-week incubation, there was no significant difference (P > 0.15) in cumulative soil N supply rate between the unfertilized long-term no-till soil and native soil. Annual fertilizer N additions of 120 kg N/ha for the previous nine years were required to restore the N supplying power of the short-term no-till soil to that of the native soil, through the build-up of mineralizable N levels. As expected, repeated applications of fertilizer N increased the residual soil N levels in the cultivated soils compared to the native soil. The estimated cumulative CO2-C and N2O-N emissions at the end of the six-week incubation ranged from 231.8-474.7 g/m2 to 183.9-862.5 mg/m2, respectively. Repeated applications of ≥ 60 kg N/ha supported larger N2O-N fluxes in the long-term no-till soil compared to the unfertilized control. Highest CO2-C fluxes from the native prairie soil are consistent with its high organic matter content and contributions from root respiration. Surprisingly, the native prairie soil N2O-N emissions were equal to those from LTNT and STNT soils receiving repeated fertilizer N applications at typical agronomic rates and is probably characteristic of rapid denitrification rates during the dormant vegetative period after snow melt prior to the growing season within temperate native grassland environments. The use of modern no-till continuous multi-crop cropping systems, along with application of fertilizer N, enhances the soil N supplying power over the long-term through the build-up of mineralizable N and appears to be an effective management strategy for improving degraded soils, thus enhancing the productive capacity of agricultural ecosystems. However, accounting for N2O emissions associated with repeated fertilizer N applications is imperative for properly assessing the net global warming potential of any land management system

A confounding effect of ammonium toxicity on bioassay detection of thiencarbazone in soil

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Group 2 herbicide interactions and approaches to detection in soils

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Determination of thiencarbazone in soil by the mustard root length bioassay

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