S. S. 2002. Boron fractionation in some Saskatchewan soils. Can. J. Soil Sci. 82: 173-179. Knowledge of B fractions is essential for understanding its chemistry and potential contribution to plant uptake. Four different extraction methodologies to determine readily available B were compared, using a four-step sequential B fractionation procedure, to reveal the nature of soil B in nine selected soils from the Brown and Gray Luvisol zones with different textures and management histories. The four soil extraction techniques were: hot water (HW), 0.01M CaCl 2, 1 M NH 4 -acetate and anion exchange membranes (AEM). The other four fractions, specifically adsorbed, oxide bound, organically bound, and residual B were determined sequentially on the same soil samples. On average, HW extracted more B than 0.01M CaCl 2 , 1 M NH 4-acetate, and AEM. In almost every soil, readily soluble B represented only a small proportion of the total B content, regardless of the extraction method used. Most soil B existed in the residual or occluded form, which accounted for between 92 and 99%, with an average of 97%, of the total soil B. The concentration of organically bound B was higher than that of oxide bound B and specifically adsorbed B, irrespective of the readily soluble B extracting solution used. Cation exchange capacity (CEC) appeared to be an important characteristic to predict the B pools. No significant correlation was found between soil organic carbon content and the different B pools, except for hot water soluble (HWS) B. Correlation coefficients between the B pools and particle size distribution were poor and correlation between carbonates and B pools were insignificant. The findings suggest that in Saskatchewan soils, readily soluble B is only a small proportion of the total B, and the majority of B exists as residual or occluded form. Hot water soluble B appears to be a good method to estimate available B. We found this method rather simple, efficient, and consistent. Dans chaque sol ou presque, la quantité de B aisément soluble ne représente qu'une petite partie du B total, peu importe la technique d'extraction employée. Dans le sol, le B se retrouve surtout à l'état résiduel ou occlus, ces deux formes représentant de 92 à 99 % du B total (97 % en moyenne). La concentration du B lié aux composés organiques est plus élevée que celle du B lié aux oxydes et du B spécifiquement adsorbé, peu importe la solution employée pour extraire le B aisément soluble. Le pouvoir d'échange cationique paraît jouer un rôle important dans la prévision des bassins de B. Les auteurs n'ont pu établir de corrélation significative entre la teneur en carbone organique dans le sol et les différents bassins de B, sauf pour le B soluble à l'eau chaude. Les coefficients de corrélation entre les bassins de B et la répartition des particules selon leur granulométrie laissent à désirer et il n'y a pour ainsi dire aucune corrélation entre les carbonates et les bassins de B. Les résultats laissent croire que le B aisément soluble ne constitue qu'une peti...

Photocatalytic CO2 reduction to generate energy-riching fuels through solar energy provides an attractive route to alleviate the global energy crisis and environmental concerns. Searching for various photocatalysts with high catalytic...

. 2003. Feasibility of boron fertilization for yield, seed quality and B uptake of canola in northeastern Saskatchewan. Can. J. Soil Sci. 83: 99-108. Canola (Brassica napus L. and B. rapa L.) grown on the sandy soils of northeastern Saskatchewan has been observed to exhibit symptoms similar to B deficiency, and soil testing laboratories often recommend B fertilization on these soils. The objective of the present study was to determine if yield, seed quality and diseases of canola are related to different rates, times and methods of B fertilization on some northeastern Saskatchewan soils (Gray Luvisol) expected to be B deficient. Two growth chamber and seven field experiments were conducted in 1997, 1998, 1999 and 2000. In the field experiments, the treatments included application of B fertilizers as broadcast followed by incorporation (1 to 4 kg B ha -1 ) prior to seeding, seedrow placement at seeding (0.5 to 2 kg B ha -1 ) and foliar spray at 10-20% bloom stage (0.25 and 0.50 kg B ha -1 ) plus a zero B control treatment. In the growth chamber experiments, rates of 1 to 3 mg B kg -1 soil were tested. In the field experiments, seed and straw yields tended to increase in very few of the treatments, with significant increases from incorporated B fertilization at one site for seed and at three sites for straw. The protein content in the seed was significantly increased by B fertilization at one site, while oil content in the seed was not influenced by B fertilization in any field experiment. The B fertilization treatments either increased or tended to increase the B concentration and uptake of B in seed and straw in most cases, with significant contrasts for control vs. incorporated B and seedrow B methods of applications in many cases. The increase in B concentration and uptake of B was usually greater in straw than in seed. Among the methods of B application, the effectiveness of B application could be considered as incorporated B > seedrow B > foliar B. Averaged across the sites and two treatments for each application method for example, B uptake in seed increased by 6.7, 3.8 and 1.0 g ha -1 with incorporated, seedrow and foliar B treatments, respectively. Corresponding methods showed an increase of B uptake in straw by 46, 33 and 23 g ha -1 . Disease levels were low for sclerotinia stem rot (Sclerotinia sclerotorum) and low to moderate for blackleg (Leptosphaeria maculans) and alternaria pod spot (Alternaria brassica and A. raphani), and B fertilizer treatments had no impact on the amount or severity of infection for these diseases. In the growth chamber experiments, B fertilization tended to increase the yield of seed and straw (up to 13%) in both soils, with significant contrasts for 0 kg B ha -1 vs. 1, 2 and 3 kg B ha -1 in many cases. In conclusion, the findings of this study suggest that canola rarely responds to B fertilization in field conditions on soils suspected to be B deficient, but canola response to B was influenced by the method of B application. . S'y ajoutait un traitement témoin, sans amendeme...

Exposed mine tailing wastes with considerable heavy metals can release hazardous colloidal particles into soil under transient chemical and physical conditions. Two-layered packed columns with tailings above and soils below were established to investigate mobilization and transport of colloidal particles from metal-rich mine tailings into soil under transient infiltration ionic strength (IS: 100, 20, 2 mM) and flow rate (FR: 20.7, 41, and 62.3 mm h(-1)), with Cu and Pb as representatives of the heavy metals. Results show that the tailing particles within the colloidal size (below 2 μm) were released from the columns. A step-decrease in infiltration IS and FR enhanced, whereas a step-increase in the IS and FR restrained the release of tailing particles from the column. The effects of step-changing FR were unexpected due to the small size of the released tailing particles (220-342 nm, being not sensitive to hydrodynamic shear force), the diffusion-controlled particle release process and the relatively compact pore structure. The tailing particles present in the solution with tested IS were found negatively charged and more stable than soil particles, which provides favorable conditions for tailing particles to be transported over a long distance in the soil. The mobilization and transport of Cu and Pb from the tailings into soil were mediated by the tailing particles. Therefore, the inherent toxic tailing particles could be considerably introduced into soil under certain conditions (IS reduction or FR decrease), which may result in serious environmental pollution.

PurposeWheat is the staple food in many parts of the world and bread is one of the most important products of wheat flour. There is a need for innovations in bread making to increase its shelf life and consumer's attraction. Fermentation is mostly done by yeast but it does not produce appreciable amounts of organic acids, which are required to enhance the shelf life of bread. The present study aims to determine the effect of bacterial and yeast culture blends on the quality and shelf life of sourdough bread and to observe the sugar utilization during fermentation.Design/methodology/approachThree treatments were made using different blends of bacterial cultures (homo‐fermentative and hetero‐fermentative) and baker's yeast compared with a control having only baker's yeast. Chemical analysis, sugar utilization (Sucrose, glucose and fructose) through high performance liquid chromatography, sensory characteristics (both internal and external) and microbial count (Bacterial and fungal count) for each treatment were conducted at different storage intervals.FindingsThe hetero‐fermentative bacteria i.e. Lactobacillus plantarum along with baker's yeast exhibited the best results regarding the utilization of sugars during fermentation (after 3 h of fermentation 0.0158 mg/ml sugar remained), objective evaluation of bread and its sensory characteristics. The bread prepared using the blend of hetero‐fermentative bacteria (0.5 per cent) and yeast (0.5 per cent) also showed greater resistance against bacteria (9×101 cfu/g after 60 h of storage) and mold (1.1 ×  102 cfu/g after 60 h of storage) growth.Research limitations/implicationsHetero‐fermentative bacteria along with baker's yeast can be utilized in sour dough to improve major bread characteristics. This study is a step further in improving the shelf life of sourdough.Originality/valuePresently only baker's yeast is being used by bread industry for fermentation purpose but a blend of bacterial culture along with baker's yeast can give better performance for better quality and shelf life of the bread.