Production of new high-yielding canola hybrids has been extremely prolific and, as a consequence, very little work has been performed to assess the fertility requirements of these crops. A series of experiments (14 site-years) was carried out over three years (1999)(2000)(2001), primarily to assess the nitrogen (N) fertility of canola hybrid cultivars and at the same time ascertain whether the associated phosphate and sulfur (S) fertility are influenced by N application. All experiments included 12 rates of N (0 to 220 kg N ha −1 in 20 kg ha −1 increments) and three rates of either P 2 O 5 or S (0, 20, and 40 kg ha −1 ) with blanket application of other nutrients. Although differences in the performance of individual canola hybrid cultivars can be significant in some cases, the term "hybrid" in this study does not refer to the performance of one specific cultivar, but to the group of hybrids tested. Under an identical nutrient regime, on average, hybrid cultivars produced a 17% higher seed yield, but did not reach maximum potential; on average, this result, occurred under a higher N fertility regime at which hybrid cultivars produced 33% higher yields than did conventional cultivars. To maintain maximum yield, hybrids must be supplied with phosphate and S at levels that are similar to those used on conventional cultivars. Hence, it would appear that hybrids are more efficient scavengers of soil nutrients, a fact that may have serious ramifications for the fertility of the following crops.

Manure application supplies plant nutrients, but also leads to trace element accumulation in soil. This study investigated total and EDTA-extractable B, Cd, Co, Cu and Zn in soil after 25 annual manure applications. The residual effect of 14 annual manure applications followed by 11 yr with no applications was also investigated. Manure was applied at 0, 30, 60 and 90 Mg ha(-1) yr(-1) (wet weight) under rainfed (treatments Mr0, Mr30, Mr60, and Mr90) and at 0, 60, 120 and 180 Mg ha(-1) yr(-1) under irrigated conditions (Mi0, Mi60, Mi120, and Mi180). The manure applications had no significant effect on soil B, Cd and Co content under both rainfed and irrigated conditions, but significantly increased total Cu and Zn content under irrigated conditions with Zn in Mi120 and Mi180 reaching the lower maximum concentration (MAC) level set by the European Community. Manure application also significantly increased EDTA-extractable Cd and Zn content in soil. Up to 27% of the total Cd (0.156 mg kg(-1)) and 21% of total Zn (38 mg kg(-1)) are found in EDTA-extractable form (Mi180 at 0-15 cm). EDTA-extractable Cd and Zn content was also significantly elevated in the irrigated residual plots due to the higher manure rates used. Thus, the impacts of cattle manure application on trace elements in soil are long lasting. Elevated Cd and Zn are a concern as other studies have linked them with certain types of cancers and human illnesses.

. 2007. Nitrogen and sulphur fertilizer management for growing canola on sulphur sufficient soils. Can. J. Plant Sci. 87: 201-210. Canola is a crop that demands high nitrogen (N) and sulphur (S) inputs to achieve maximum seed yield. The practice of balancing these two nutrients by applying them in a fixed ratio has shown yield benefits on soils deficient in both these nutrients. A 9 site-year study was conducted between 2002 and 2004 to determine whether this practice is necessary for soils containing sufficient S levels. The practice was tested for both hybrid (HC) and open pollinated (OPC) canola cultivars by applying six rates of N (0, 40, 80, 120, 160 and 200 kg N ha -1 ) and supplementing N rates with S, so that three N:S ratios (1.5, 6 and 12 to 1) were achieved. Seed yield, protein and oil content responses of both HC and OPC cultivars were obtained primarily with N, with no evidence for a need of balancing this nutrient with S additions to achieve a ratio within those applied at this study. Hybrid canola cultivars overall yielded 23.7% more than OPC cultivars when they received the N application rate at which maximum yield of the OPC cultivars was obtained (120 kg N ha -1 ). Application of an additional 30 kg ha -1 to obtain maximum HC seed yield only resulted in an additional 1.5% yield advantage for the OPC. As N application rate was increased, small increases in seed protein levels (≈2.5%) were accompanied by a small reduction (≈2%) in seed oil content. Increased yield by HC compared with OPC canola reduces N residual fertility, hence, assessment of soil fertility status by soil testing after growing HC canola is a highly beneficial management practice. Our results indicate that the practice of balancing N and S to a fixed ratio is unnecessary and wasteful on canola grown on soils containing sufficient S. Le rendement grainier, la concentration de protéines et la teneur en huile des cultivars H et PL réagissent surtout aux engrais N, sans qu'il soit apparemment nécessaire d'équilibrer cet élément nutritif par un apport d'engrais S en vue d'obtenir un ratio situé dans la fourchette examinée. En général, les cultivars H donnent un rendement de 23,7 % supérieur à celui des cultivars PL avec la même quantité d'engrais que celle dont les cultivars PL ont besoin pour atteindre leur rendement maximal (120 kg de N par hectare). Appliquer 30 kg de N de plus par hectare aux cultivars PL comme on le ferait aux cultivars H pour qu'ils parviennent à leur rendement grainier maximal n'accroît leur rendement que de 1,5 %. Lorsqu'on augmente le taux d'application de N, la petite hausse de la concentration de protéines dans la graine (≈ 2,5 %) s'accompagne d'une légère baisse de la teneur en huile (≈ 2 %). Comparativement aux cultivars PL, la hausse du rendement des cultivars H réduit la fertilité résiduelle du N, de sorte qu'une analyse du sol s'avère une pratique très bénéfique après la culture de canola H. Les résultats de l'étude indiquent que vouloir équili-brer le N et le S selon des ratios établis pour cultiver...

Since the Indonesian archipelago is part of the very active and dynamic Pacific Ring of Fires, the volcanic eruptions occur from time to time. Immediately after the eruption of Mount Talang in West Sumatra (April 12, 2005), volcanic ashes, both unleached and leached were collected. The deposits from Mt. Talang were andesitic to basaltic in composition. The volcanic ash consisted of volcanic glass, plagioclase feldspar in various proportions, orthopyroxene, clinopyroxene, olivine, amphibole, titanomagnetite. We conducted the total elemental analysis of the bulk samples of the volcanic ash. The contents of major, trace and rare elements as well as heavy metals were determined by wet chemical methods and xray fluorescence (XRF) analyses. Although the volcanic ash of Mt. Talang are still very new, an evaluation of the geochemical weathering indi ces was performed with the objective of showing the volcanic ash condition at the early stage of weathering. Eight weathering indices were evaluated. The results showed that the unleached volcanic ash has higher Rux ton Ratio (R), Weathering Index of Parker (WIP), Product of Weathering Index (PWI) and Silica Titanium Index (STI) values compared to the leached ash, while the leached ash exhibited higher Chemical Index of Alteration (CIA), Chemical Index of Weathering (CIW), Vogt's Residual Index (VO), and Plagioclase Index of Alteration (PIA). These weathering indices can be used to quantify the condition of the volcanic ashes at the initial stage of weathering, to evaluate their fertility, to provide a better understanding of element mobility during weathering, and predict the source of soil nutrients as well as determine the products of primary min erals alteration.

. 2003. Determining wheat responses to copper in prairie soils. Can. J. Soil Sci. 83: 213-221. Criteria for assessment of the Cu status of prairie soils were developed in the early 1980s and are currently in use with some modifications. Although there appears to be a reasonable agreement on the soil critical value of 0.4 mg kg -1 soil based on DTPA-extractable Cu, a marginal range that extends between 0.4 and 1.2 mg DTPA-Cu kg -1 soil is used to generate fertilizer recommendations. The objective of this study was to verify the existing soil critical value and identify the frequency of agronomic as well as economic response of spring wheat to Cu fertilization on soils with levels both below and above the critical value. We carried out a large number (52) of trials with spring wheat (Triticum aestivum L.) between 1991 and 2000 in all three Prairie Provinces and compiled a large number of spring wheat experiments conducted in western Canada (63) by a number of researchers. Fifty-nine trials carried out on soils containing marginal and sufficient Cu levels were evaluated and were compared to 56 experiments on soils containing deficient levels. A number of methods of placement and products were compared. Agronomic responses were obtained in 41 of the 115 experiments and only by broadcasting either 3 to 5.5 kg Cu ha -1 as CuSO 4 ·5H 2 O or 0.5 to 2 kg Cu ha -1 as Cu-sulphonate and incorporating the product or by foliar application of 0.22 kg Cu ha -1 . Calibration of the DTPAextractable Cu test using a Mitscherlich type of function verified the soil critical value of 0.4 mg Cu kg -1 soil. Statistically significant grain yield responses were obtained in 87, 16 and 0% of trials carried out on soils containing <0.4, 0.4 to 0.8 and >0.8 mg DTPA-extractable Cu kg -1 soil. Economic responses, defined as those where Cu application yielded a 2:1 return on the cost of fertilizer in the year of application, varied depending on the price of wheat and ranged between 19 to 45% in deficient soils for a price range of $100 to $200 t -1 of wheat grain; economic responses on marginal and sufficient soils occurred in 6% and none of the cases, respectively. Hence, fertilization of soils with DTPA-extractable Cu levels >0.4 mg kg -1 is associated with very high risk.

A B S T RA C T: Separate montmorillonite suspensions were treated with CrC13 to give seven Cr(III) concentrations. Each suspension was then titrated with 0.1 N NaOH to give a NaOH/Cr 3+ molar ratio of 2.5. Montmorillonite was an effective sorbent for hydroxy-Cr species up to 1200 cmol(+)/kg; above that concentration, sorption continued, though less efficiently. However, N2-BET specific surfaces and cation exchange capacity measurements indicated that the montmorillonite could sorb significantly more than 1200 cmol(+)/kg. There was virtually no exchangeable Cr in any of the clays, suggesting that this element was covalently bonded to the siloxane surface. Infrared spectroscopy revealed a vibration at 1015-1020 cm -1 in the Cr clays which was not present in the control. This new absorption band was attributed to an attenuation of the Si-O al vibration caused by inner-sphere complexaOon of the interlayer Cr with the siloxane oxygen. Because Cr was strongly held and efficiently sorbed, montmorillonite was shown to be an effective sorbent for hydroxy-Cr polymers.Expandable layer silicates have been proposed as sorbents for both organic and inorganic contaminants. In their native state, clays hold hydrated inorganic cations which give the clay surface a hydrophilic character. In this initial condition, the clays are ineffective sorbents for poorly water soluble organic contaminants. The native inorganic cations on the exchange sites must first be replaced with a variety of organic cations to form organoclays that, unlike native clay, are effective sorbents for removing organic contaminants from water (Boyd et al., 1988;Jaynes & Boyd, 1991).Effective adsorption of inorganic cations, on the other hand, does not require any modification of the clay; the cations readily sorb to the unaltered colloid surfaces. The adsorption of various heavy metals by smectites has received considerable attention in the past. The adsorption of Cd

. 2004. The effect of foliar copper application on the grain yield and quality of wheat. Can. J. Plant Sci. 84: 47-56. Available Cu concentrations in prairie soils (DTPA-extractable Cu) are extremely variable, thus resulting in areas within fields that are Cu deficient. These areas are difficult to characterize by a soil test based on a composite field sample; thus, when they are identified in the growing season, foliar Cu application possibly represents the only method of correcting them. A project, carried out over a period of 8 yr that consisted of four experiments and a total of 22 trials, was designed to ascertain whether foliar Cu applications indeed provide a satisfactory means of correcting Cu deficiency. Experiments included comparison of foliar applications at Feekes growth stages 6 (first node of stem visible at base of shoot) and 6 plus 10 (sheath of last leaf completely grown out) to soil broadcast and incorporation of 4 to 5.5 kg Cu ha -1 as copper sulphate (CuSO 4 ·5H 2 O) or seed placement of 2 kg Cu ha -1 in three forms (two oxysulphates and one sulphate); foliar application of a variety of products representing different chemistries (chelate, lignin sulphonate, humic acid, oxychloride and citric acid) on a number of wheat cultivars at Feekes growth stage 10 or one cultivar at Feekes growth stages 2 (beginning of tillering), 6, 10 and 2 plus 10. Foliar applications appear to provide a solution to Cu deficiency that is identified during the growing season. However, foliar applications were not always as effective as broadcast and incorporation of at least 4 kg Cu ha -1 in the form of CuSO 4 ·5H 2 O, which still remains the preferred method to correct a Cu deficiency. Foliar application at Feekes growth stage 2 was ineffective, whereas a single foliar application at Feekes growth stage 10 was not as satisfactory as a single one at Feekes growth stage 6. Thus, the latter stage appears to be preferable; however, maximum grain yield in some cases was obtained by the combination of two foliar Cu applications, one each at Feekes growth stages 6 and 10. Responses of wheat to foliar Cu application were obtained on soils that contained DTPA-extractable Cu concentration of less than 0.4 mg kg -1 . Foliar Cu applications did not have an appreciable effect on grain quality parameters, such as hectolitre weight, moisture or protein content. La concentration du cuivre (Cu) assimilable varie considérablement dans le sol des Prairies (Cu extractible au DPTA), de sorte que divers endroits peuvent être carencés dans un champ. Il est difficile de repérer ces endroits par analyse d'échantillons de sol composites, si bien que lorsqu'on les repère durant la période végétative, la seule solution pourrait consister en une application foliaire de cuivre. Les auteurs ont conçu un projet de huit ans comprenant quatre expériences et 22 essais pour déterminer si l'application foliaire de Cu peut effectivement corriger une carence de cet élément. Pour cela, ils ont comparé une application foliaire au sixième stade de croissan...

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