No abstract

. Comparison of N fertilizer, source-separated municipal solid waste compost and semi-solid beef manure on the nutrient concentration in boot-stage barley and wheat tissue. Can. J. Soil Sci. 82: 33-43. Composting of source-separated municipal solid waste (SSMSW) is an option currently used to divert refuse from landfills. There is interest in using this material to alleviate soil constraints. Since many livestock producers ensile their cereals, after harvesting at boot-stage, the purpose of this project was to determine the effect that SSMSW compost and semi-solid beef manure, with and without supplemental N fertilizer, would have on the concentration of minerals in this feed.The addition of N fertilizer increased the concentration of N, K, Ca, Mg, Mn, Cu, and Zn in boot-stage tissue of barley in 1996 and wheat in 1997, but only increased the concentration of B in wheat tissue. Cereal boot-stage N, K, and Mn concentrations were higher in the manure than compost-amended plots. However, boot-stage Mg and Cu concentrations tended to be higher in the compost-amended plots. As manure addition increased, the concentration of N and K in barley and wheat, Ca and Cu in wheat, and Mn in barley increased. As the rate of compost addition increased, the concentration of Mg in barley and wheat decreased, while that of Cu in barley increased. Even though the SSMSW compost was applied at higher than normal agronomic rates, tissue Cu and Zn concentrations were not at levels considered to be harmful to plants or livestock.

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. Effect of rotational grazing on selected physical properties of a Gleyed Brunisolic Gray Luvisol loam in Nova Scotia. Can. J. Soil Sci. 79: 117-125. Low organic matter content and weak soil structure, combined with high annual precipitation, make the soils of the Maritime Provinces extremely susceptible to compaction. Although many pasture studies have been conducted in the Maritime Provinces, none has investigated the impact of pasturing cattle on soil physical properties. Soil properties such as resistance to penetration, bulk density and hydraulic conductivity were monitored on pasture swards receiving various rotational-grazing intensities. These parameters were measured concomitantly on traffic-free areas that had been harvested as conserved forage. Resistance to penetration measurements indicate that a significant amount of compaction by cattle occurred during the 1990, 1991 and 1992 grazing seasons. Penetration resistance was generally greatest in the top 6 cm of soil, but was alleviated by frost action during the subsequent winter and spring. The other soil parameters measured were either more variable (surface and subsurface saturated hydraulic conductivity) or less sensitive (bulk density) to compaction. Although more variable, surface hydraulic conductivity was significantly higher in the traffic-free conserved forage areas than in the pasture paddocks. Rest intervals between grazings had no significant effect on saturated hydraulic conductivity. Seasonal change in resistance to penetration generally increased as rest interval decreased. The timothy/alfalfa swards (little alfalfa was left in the pastures by 1992) had the least seasonal change in resistance to penetration. La basse teneur en matière organique et la faiblesse de la structure du sol, sans parler des fortes précipitations annuelles, rendent les sols des provinces Maritimes excessivement sensibles à la compaction. Bien qu'il se soit réalisé beaucoup de recherches sur les pâturages dans cette région, aucune d'entre elles ne s'est intéressée sur l'impact des bovins au pâturage sur les propriétés physiques du sol. Nous avons donc suivi certaines de ces propriétés : résistance à la pénétration, densité apparente et conductivité hydraulique, dans des pâturages exposés à diverses intensités de paissance en rotation. Ces paramètres étaient simultanément mesurés dans des parcelles non piétinées, dont l'herbe avait été récoltée mécaniquement pour la conservation. Les mesures de la résistance à la pénétration montrent que le piétinage des bovins a donné lieu à un niveau significatif de compaction durant les saisons de pâture de 1990, 1991 et 1992. La résistance à la pénétration présentait habituellement l'intensité la plus forte dans les six premiers cm du sol, mais l'effet était atténué par l'action du gel au cours des hivers et printemps subséquents. Les autres paramètres mesurés étaient, soit plus variables, notamment la conductivité hydraulique à saturation à la surface du sol et immédiatement en dessous, soit moins sensibles (densité apparent...

Thilakarathna, R. M. M. S., Papadopoulos, Y. A., Rodd, A. V., Gunawardena, A. N., Fillmore, S. A. E. and Prithiviraj, B. 2012. Characterizing nitrogen transfer from red clover populations to companion bluegrass under field conditions. Can. J. Plant Sci. 92: 1163–1173. The ability of two red clover (Trifolium pratense L.) cultivars, AC Christie (diploid) and Tempus (tetraploid), to transfer fixed nitrogen (N) to companion bluegrass (Poa pratensis L.) was evaluated under field conditions. Plant samples were harvested three times during the 2009 growing season and N transfer from the red clover cultivars to bluegrass was determined using the natural abundance method for first harvest and 15N dilution techniques for second and third harvests. Soil and soil water samples were used to evaluate cultivar effects on soil N conditions. Both red clover cultivars derived more than 90% of their N from biological N fixation. The proportion of bluegrass N derived from interplant N transfer was 7, 11, and 26% for the first, second, and third harvests, respectively. Soil KCl extractable nitrate increased along the three cuts for Tempus in the 0 to 15-cm soil zone. Soil-water nitrate content increased periodically for AC Christie and remained constant for Tempus throughout the growing season. This result indicates that the two cultivars have distinctly different N cycling patterns.