Park wheat (Triticum aestivum cv. Park) is susceptible to stem melanosis when grown on Cu-deficient soils. Three field experiments were conducted to evaluate the effectiveness of various Cu sources, using different methods and rates of application for reducing the incidence of stem melanosis and increasing the grain yield of Park wheat on a Cu-deficient Black Chernozemic soil in central Alberta. A fourth experiment determined the residual effect of Cu over 4 years. In the first experiment, Park wheat had less disease and higher grain yield when Cu-chelate solution at 2 and 4 kg Cu ha-~ or Cu-sulfate solution at 10 and 20 kg Cu ha-I was applied to the soil surface and incorporated to a depth of 8 cm or was applied at these rates as a foliar spray. The foliar application, however, was phytotoxic and delayed maturity by approximately two weeks. Sidebanding Cu (4 cm to the side and 4 cm below the seed row) was least effective. In the second experiment, Cu-sulfate solution incorporated into the soil was more effective than the soil incorporated granular Cu-sulfate in reducing disease incidence and increasing grain yield in the year of application. In the following year the granular Cu was as effective as solution Cu. The third experiment showed that Cu seed dressings did not have any effect on disease incidence or grain yield of Park wheat. In the fourth experiment, the residual effect of Cu-chelate was evident four years after application. The grain yield in the fourth year was about four times that of the control.

The potential for phytoremediation of high concentrations of petroleum hydrocarbons is poorly understood. This study examines variations in phytoremediation performance for a soil contaminated with diesel at 6400 mg TPH kg-1 dry mixture. Experiments on diesel-contaminated soil were conducted in cups using 200 g of soil, and in columns using 4,000 g. Root development and TPH levels were measured in both experiments. In addition, CO2 soil gas concentrations were measured in the column experiments. The results show that ryegrass enhanced the loss of TPH over controls, and that this benefit only became evident after full root establishment. A comparison of the two experiments shows that rooting intensity (mg root kg-1 soil) is the key factor leading to higher TPH loss rates in the smaller containers. No clear difference in TPH loss occurred at 100 and 260 mm depths. Soil gas CO2 did not correlate well with TPH loss rates. The research concludes that an understanding of root development is crucial to evaluating the potential for ryegrass phytoremediation.

Stem melanosis of spring wheal (Triticum aestivum'Park') has often been found to be associated wittr iu-OJficlent soils. The application of Cu chelate at 3.0 kg ha-t of Cu to a Cu-deficient Black Chernozemic sandy loam soil reduced stem melanosis of Park wheat and increased grain yield.

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