No description available.

No description available.

The impact of tillage and residue management on soil microorganisms was studied over the maize (Zea mays L.) growing season in southwestern Quebec. Tillage and residue treatments were imposed on a sandy loam to loamy sand soil in fall 1991. Treatments consisted of no till, reduced tillage, and conventional tillage with crop residues either removed from (-R) or retained on (+R) experimental plots, laid out in a randomized complete block design. Soil microbial biomass carbon (SMB-C), soil microbial nitrogen (SMB-N) and phospholipid fatty acid (PLFA) concentrations were measured four times, at two depths (0--10 cm, 10--20 cm), over the 2001 growing season. Sample periods were: May 7th (pre planting), June 25 th, July 16th, and September 29th (prior to corn harvest). The effect of time was of a greater magnitude than those attributed to tillage or residue treatments. While SMB-C showed no seasonal change (160 mug C g-1 soil); SMB-N was responsive to mineral nitrogen fertilizer; and PLFA data showed an increase in fungi and total PLFA throughout the season. PLFA profiles showed better distinction between sampling period, and depth, than treatments. Of the two treatments, the effect of residue was more pronounced than that of tillage, with increased SMB-C and SMB-N (6.1% and 96%) in +R plots compared to -R plots. This study illustrated that measuring soil quality based on soil microbial components must take into account seasonal changes in soil physical, chemical conditions, and nutrient supply.

A two year field study was carried out in western Quebec to investigate methods of predicting and reducing NO3--N leaching. Corn (Zea mays L.) was planted on the expel site and them were four treatments: water table controlled at 600 mm and 120 kg/ha of N fertilizer (WT120), water table controlled at 600 mm and 200 kg/ha of N fertilizer (WT200), free drainage and 120 kg/ha of N fertilizer (FD120), and free drainage and 200 kg/ha of N fertilizer (FD200). Drain flow was monitored and water samples were taken and analyzed for NO3- -N. Soil NO3- levels were measured along with led chlorophyll and denitrification throughout the two growing seasons. / Drain flow was dependent on both rainfall and the soil moisture content. In 1996, water table control decreased drain flow. However, in 1997 (a drier year), the drain flows for all treatments were similar. NO3 --N was reduced significantly in the controlled water table plots. In 1996, there was 59.2% less NO3--N in the controlled water table plots than in the free drainage plots and in 1997 this increased to 75.9% less NO3--N in the controlled water table compared to the fire drainage plots. In 1996, denitrification was enhanced by the controlled water table plots, with 72.2% more denitrification occurring in the controlled water table plots than in the free drainage plots. In 1997, there was a 93.2% increase in denitrification occurring in the water table plots than in the free drainage plots. / The controlled water table plots had no effect on plant chlorophyll levels. Chlorophyll contents of the corn plants were higher where fertilizer was applied at 200 kg/ha. Overall, it was shown that water table management can significantly decrease NO3--N pollution in drainage water. (Abstract shortened by UMI.)

Soil phosphate is essential for the development and maturity of crops. Plants absorb phosphate from the soil solution which is continuously replenished by fertilizer application and/or desorption from the soil solid phase. Anion exchange membranes (AEMs), act in a similar way to plant roots, adsorbing P from soil solution. Desorption of available P was studied in 1997 on two Gleysolic soils rich in P, a Ste. Rosalie clay soil and a Duravin sandy loam soil, using fluoride-saturated AEMs let in soil suspension for various contact periods. Determination of available P using these AEMs was compared to P extraction using the Mehlich III extractant for predicting P availability to soybean (Glycine max L.). Desorption from both soils, and subsequent adsorption by AEMs was found to decrease with time. A high P desorption rate was calculated for both soils with the Elovich equation. Different chemical and physical characteristics such as pH, Mehlich III extractable Al, Fe and Ca, sand and clay content were in some cases, positively correlated and in other cases, negatively correlated with various contact periods for both soils. The use of AEMs better predicted P availability than the Mehlich III extractant, although the most important asset of using AEMs is that they showed the desorption effect over time on P availability. It was observed that P remobilization from the vegetative part to the grain was reduced due to the high P concentration in both soils.

No description available.

No description available.

No description available.

No description available.

This study focused on the challenges facing the Ukrainian community in Montreal, within the parameters of their support and mutual aid services. Key informants from the community were interviewed. A mail-in questionnaire was administered to a sample of Ukrainians (N = 145), from the community at large. Key findings: (a) a high level of interest in community planning, (b) for women, social policy and health and social services were more important, (c) 18% were uncertain about remaining in Quebec, and (d) internal conflicts within community infrastructures. Areas of concentration for community development: (a) health and social services for independent elderly and others in need, (b) residential placement for elderly, and (c) counselling and information services for immigrants.