Tile drainage water from agricultural fields commonly exceeds environmental guidelines for phosphorus (P) in rivers and streams. The loss of P through artificial drainage is spatially and temporally variable, and is related to local factors. This study characterizes variability in total P (TP) and soluble reactive P (SRP) concentrations in weekly drainage samples from 39 agricultural fields in Nova Scotia, Canada, from April 2002 through December 2003. We examined connections between P concentrations and the factors: (i) soil texture; (ii) discharge flow rate; (iii) soil test P (STP); (iv) manure type; and (v) crop cover. Generally, variability between fields and samples was great, and fields with standard deviations exceeding the mean for TP, SRP, and flow rate were 71, 54, and 79%, respectively. It was evident that poultry and swine manure contributed to high STPs, and to constantly high TP concentrations with high proportions of SRP. Concentrations varied from week to week, and particularly in April, May, October, and November when the greatest TP, SRP, and flow rate averages were measured. Mean TP concentrations exceed the USEPA (1994) TP guideline of 0.10 mg L(-1) at 82% of the fields, and periodically concentrations more than 10 times, and occasionally more than 50 times higher than the guideline were found. The proportion of SRP in TP had a tendency to be higher when TP levels were high in coarse textured soils. In Nova Scotia, dairy manure is most often applied on permanent cover crops, which did not show as much P concentration variability as crop rotations. Daily or hourly observation of short-term increases in P concentrations related to the described factors would help to characterize the changes in P concentrations observed during frequent heavy drainage flow events.

There is strong evidence that Ambiol® (a derivative of 5-hydroxybenzimazole) promotes drought tolerance in many plants; it is often suggested that this is the result of its antioxidant properties. Recent evidence has also shown that several natural antioxidants promote carrot germination under drought stress. Thus, it was hypothesized that seed preconditioning using natural antioxidants might confer drought tolerance. Ambiol®, ascorbic acid, β-carotene, lutein, and lycopene were chosen as antioxidants at concentrations of 0.1 mg·L−1, 1.0 mg·L−1, and 10 mg·L−1. A preconditioning treatment was applied by soaking tomato (Solanum lycopersicum L.) seeds in an antioxidant solution for 24 h. Of the antioxidants tested, 10 mg·L−1 Ambiol®, 1.0 mg·L−1 β-carotene, 1.0 mg·L−1 ascorbic acid, and 0.1 mg·L−1 lycopene were shown to increase shoot dry mass by 114%, 94%, 56%, and 83%, respectively, in droughted seedlings when compared with a droughted control. Similar benefits were observed in root dry mass, leaf area, photosynthesis, and water use efficiency. Proteins were extracted from the seeds of certain treatments, before and after germination, and separated using isoelectric focusing. Specific proteins were found to be induced through all preconditioning treatments, whereas Ambiol® and β-carotene were found to induce specific proteins, independent of those induced through imbibition, both before and after germination. This result suggests that Ambiol® and β-carotene evoke specific proteins that may confer drought tolerance to the key physiological processes studied. In addition, protein profiles of ascorbic acid, β-carotene, and Ambiol® after germination had fewer visible bands than the controls, suggesting an accelerated mobilization or conversion of proteins within the seed.

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. 1999. Effects of deicing salt on lowbush blueberry flowering and yield. Can. J. Plant Sci. 79: 125-128. The effects of deicing salt (NaCl) on buds, blossoms and yields of lowbush blueberry (Vaccinium angustifolium Ait.) were assessed over 3 yr in two commercial fields adjacent to a major Nova Scotia highway. Concentrations of road salt on exposed stems were highest next to the highway, and decreased with distance from the road. Numbers of blossoms, and subsequent fruit yields were low nearest the road, and increased with distance from the highway. Numbers of live blueberry buds and blossoms, and subsequent yields, were inversely related to concentrations of road salt on the stems. Plants under plastic shelters placed near the highway had more live buds and blossoms, as well as higher yields relative to plants exposed to deicing salt. The wild lowbush blueberry (Vaccinium angustifolium Ait.) is forced into a biennial production cycle by regular pruning. Vegetative growth and fruit bud formation occur during the first season. Developed fruit buds overwinter on 15-20 cm upright stems. Flowering, fruit development and harvest follow in the second year (Eaton 1988). Lowbush blueberries are tolerant of low winter temperatures (Quamme et al. 1972), except when affected by factors such as insufficient snow cover and winds (Cappiello and Dunham 1994).The lowbush blueberry is susceptible to winter desiccation (Hall et al. 1971). This results from exposure of stem tips above snow cover, and is particularly severe in the Parrsboro, Nova Scotia, area where salt spray frequently drifts off the Bay of Fundy (Hall et al. 1979). Blueberry yields in this region have been substantially reduced after winters with little snow cover.Major Nova Scotia highways are in close proximity to a number of lowbush blueberry fields. Due to heavy winter snowfall and severe winter conditions, deicing road salt (NaCl) is routinely applied in large amounts. Once dissolved in water it often drifts off highways onto nearby vegetation and can cause considerable plant damage (Westing 1969). Desiccation of foliage and stems occurs when water molecules are moved out of cells following deposition of salt onto plants (Smith 1975). Effects of low temperatures are more damaging to plant cells when they are forced to expand as they are after exposure to salt (Leopold and Willing 1984).The objective of this study was to assess the effects of deicing salt from a major highway in Folly Mountain, Nova Scotia, on flowering and yield of lowbush blueberries over a 3-yr period. MATERIALS AND METHODSBlueberry test fields were on opposite sides (east and west) of Highway 104 (Folly Mountain, Nova Scotia, 45°32′N, 60°32′E, elevation 260 m). Frequent large applications of road salt were applied during winter (33 and 40 t km -1 during 1993-1994and 1994-1995 C. A. Audus, Nova Scotia Department of Transport and Communications, personal communication). The east field was cropped in 1992 and 1994, the west field in 1995.During April of each crop year, blueberry stems wer...