ALBERT

Description: Drury, C. F., Reynolds, W. D., Yang, X. M., Tan, C. S., Guo, X., McKenney, D. J., Fleming, R. and Denholme, K. 2014. Influence of compost source on corn grain yields, nitrous oxide and carbon dioxide emissions in southwestern Ontario. Can. J. Soil Sci. 94: 347–355. The impacts of compost type on corn grain yields over 10 yr and N2O and CO2 emissions in the first 3 yr after compost application were evaluated on a Brookston clay loam soil in Woodslee, ON. The treatments included yard waste compost (YWC), kitchen food waste compost (FWC), and pig manure compost (PMC), which were applied once in the fall of 1998 to field plots at a rate of 75 Mg ha−1 (dry weight basis) and no further applications occurred thereafter as well as a fertilized control treatment. Large application rates were examined to see if the various compost sources could have a lasting effect on soil C storage, N2O and CO2 emissions and corn yields. Compost application significantly increased corn grain yields by 12.9 to 19.4% over 3 yr. However, after 10 yr, FWC was the only compost source which significantly increased yields by 11.3% compared with the fertilized control. Emissions of N2O and CO2 varied with compost type, soil water content and time. Greater N2O emissions occurred in 1999 from PMC (5.4 kg N ha−1) than YWC (2.7 kg N ha−1) and FWC (1.3 kg N ha−1); however, the N2O emissions from the PMC were less than from YWC and FWC in 2001. The 3-yr average N2O emissions were significantly greater with PMC (2.7 kg N ha−1) and YWC (2.5 kg N ha−1) compared with the control (1.5 kg N ha−1). Hence, the timing of N2O emissions varied by compost type, but the overall losses were similar as the higher N2O losses in the first year with PMC were offset by the reduced losses with PMC in the third year. Significantly more CO2 was produced from the FWC in 2000 and from PMC in 2001 than the control.

Description: First-season herbicide efficacy and crop tolerance results are presented for a range of glyphosate (VISION®) rates (0–1.00 kg acid equivalent per hectare) aerially applied with two different dispersal systems (AU5000 Micronairs® and conventional hydraulic nozzles). Derivative-free nonlinear regression was used to model post-treatment raspberry cover (Rubusidaeus L. var. strigosus (Michx.) Maxim.) as an exponentially decreasing function of chemical deposit (R2 = 0.87). Similar methods were used to model post-treatment crown area as a function of chemical deposit and pretreatment crown area for pin cherry (Prunuspensylvanica L.f.) (R2 = 0.92), red maple (Acerrubrum L.) (R2 = 0.79), white birch (Betulapapyrifera Marsh.) (R2 = 0.93), elderberry (Sambucuspubens Michx.) (R2 = 0.85), and aspen (Populustremuloides Michx.) (R2 = 0.96). Acceptable first-season control (〉60% cover reduction) of raspberry, pin cherry, elderberry, and aspen was achieved with rates of deposit ≥0.50 kg acid equivalent per hectare. Red maple and white birch crown area reduction averaged 60% at the highest rate tested (1 kg acid equivalent per hectare). Significant differences in efficacy attributable to the different dispersal systems were found only for pin cherry: the Micronair system resulted in 30% greater efficacy on one of the four blocks tested (P 

Description: Disturbance effects on plant communities largely reflect the degree of overstory removal, soil disturbance, and attendant vegetation destruction. We examined initial harvest-related impacts of partial and complete canopy removal, with and without soil disturbance, on north- and south-facing aspects of an older, relatively undisturbed, boreal transition tolerant hardwood forest at Turkey Lakes, Ontario. We recorded vascular plant cover in 180 25 m2 plots in the 3rd postharvest year and analyzed community response using unconstrained (nonmetric multidimensional scaling) and constrained (distance-based (partial) redundancy analysis) ordination, multivariate ANOVA, indicator species analysis and diversity measures. Community composition and diversity measures were related primarily to gradients in soil disturbance and, particularly for herbaceous species, aspect-related radiative exposure. Canopy opening generally played a lesser role. There were, however, notable canopy opening – soil disturbance × aspect interaction effects on both woody and herbaceous composition. In contrast with herbs, proportionately more woody species had indicator value for south- than for north-facing aspects and for disturbed than for undisturbed soils. Understory community response and diversity measures were affected more by logging-related soil disturbance than by the amount of canopy opening associated with the silvicultural system used. Aspect-related effects, however, suggest silvicultural impacts will be both site- and species (functional group) specific.

Description: Application of raw animal manure to agricultural land has resulted in environmental and health problems. Alternatives, such as composting, are now being developed to alleviate this situation. However, very little information is available regarding the fate of composts when added to fine-textured and poorly drained soils, especially with respect to the initial decomposition of composts and their effects on soil-derived CO2 and N2O emissions. We evaluated food waste compost (FW), yard waste compost (YW), liquid pig manure (LPM), LPM + yard waste compost (PMY) and LPM + wheat straw compost (PMS). Red clover (Trifolium pratense L.) (RC) and an unamended control soil were also tested. The solid amendments were divided into ground and unground treatments. Carbon dioxide emissions were increased relative to the control soil for all treatments except PMY. Total CO2 emissions over the 144-h incubation from unground material followed the pattern (P 〈 0.05): YW (849 mg CO2-C kg-1 soil) 〉 RC (554 mg CO2-C kg-1 soil) 〉 LPM (444 mg CO2-C kg-1 soil) 〉 FW (203 mg CO2-C kg-1 soil) ≈ PMS (194 mg CO2-C kg-1 soil) ≈ PMY (157 mg CO2-C kg-1 soil). The RC, YW and PMS significantly increased N2O emissions compared to all other treatments and the control. Total N2O emissions from unground material over the 144-h incubation followed the pattern (P 〈 0.05): RC ≈ YW ≈ PMS (1230–1490 μg N2O-N kg-1 soil) 〉 LPM ≈ FW ≈ PMY ≈ Control (44-404 μg N2O-N kg-1 soil). Grinding was found to increase CO2 emissions from YW, PMY, PMS, and N2O emissions from RC. The CO2 emissions were due primarily to amendment composition and not particle size, as the relative differences in CO2 emission among ground and unground treatments remained nearly constant. Carbon dioxide emissions from LPM were reduced substantially by composting the manure with yard waste (PMY). Key words: Compost, pig manure, carbon dioxide, nitrous dioxide, available N, incubation

Description: Experimental methods and resulting on-target deposit data are presented for an operational field trial designed to evaluate glyphosate (Vision®) efficacy using two different dispersal systems (AU5000 Micronairs® and conventional hydraulic nozzles). A range of glyphosate rates (0, 0.25, 0.50, 0.75, and 1.00 kg acid equivalent per hectare) was aerially applied in a randomized complete block design to four cutover sites in New Brunswick. Formulation, tank-mix, droplet, and chemical analyses were conducted to quantify actual on-target deposit for each treatment. Data for the calibrated portion of each swath suggested that the Micronair system produced a slightly narrower drop-diameter spectrum (0–677 μm, volume median diameter = 300 μm) than the hydraulic system (0–1085 μm, volume median diameter = 425 μm). Analysis of variance and orthogonal contrasts indicated that on-target deposit for the Micronair system (average accountability = 71%) was not significantly different from that of the hydraulic system (average accountability = 82%) for three of four rates tested. Unrepresentative meteorological and site conditions affecting Micronair treatments in two blocks resulted in reduced deposit for the treatment of 1.00 kg acid equivalent per hectare. Substantial variability within treatments was observed for both dispersal systems (41 and 47% coefficient of variation for Micronair and hydraulic systems, respectively). Overall, results suggest no significant differences between the two dispersal systems (as calibrated) in terms of on-target deposit efficiency or variability. Both on-target droplet density and chemical deposit data reflected differences associated with blocks. This fact highlights the need for further studies on meteorological and operational factors on deposit.

Description: Open-grown jack pine (Pinusbanksiana Lamb.) in northern Ontario, ranging in age from 9–20 years, bore an average of 311 receptive seed cones, with the greatest number in the upper midcrown. Generally, counts of receptive seed cones varied more among trees than among directions; most of the variation among trees occurred in the mid to upper crown. The expression F(H) = Hb+1[b + 2 − (b + 1)H], with b = 3.12 (P 

Description: Post-harvest levels of soil disturbance and vegetation regrowth strongly influence microclimate conditions, and this has important implications for seedling establishment. We examined the effects of blading (scalping), soil loosening (ripping) and vegetation control (herbicide), as well as no soil disturbance, on growing season microclimates and 3-yr seedling response on two grass-dominated clearcuts at different elevations in the Southern Interior of British Columbia. Warmer soil temperatures were obtained by removing surface organic horizons. Ripping produced somewhat higher soil temperatures than scalping at the drier, lower-elevation site, but slightly reduced soil temperatures at the wetter, higher-elevation site. Near-surface air temperatures were more extreme (higher daily maximums and lower daily minimums) over the control than over exposed mineral soil. Root zone soil moisture deficits largely reflected transpiration by competing vegetation; vegetation removal was effective in improving soil moisture availability at the lower elevation site, but unnecessary from this perspective at the higher elevation site. The exposed mineral surfaces self-mulched and conserved soil moisture after an initial period of high evaporation. Ripping and scalping resulted in somewhat lower near-surface available soil water storage capacities. Seedling establishment on both clearcuts was better following treatments which removed vegetation and surface organic horizons and thus enhanced microclimatic conditions, despite reducing nutrient supply. Such treatments may, however, compromise subsequent stand development through negative impacts on site nutrition. Temporal changes in the relative importance of different physical (microclimate) and chemical (soil nutrition) properties to soil processes and plant growth need to be considered when evaluating site productivity. Key words: Microclimate, soil temperature, air temperature, soil moisture, clearcut, seedling establishment

Description: Root and butt rots are often implicated as causal factors influencing windfall and mortality of residual trees following partial cutting. Measurements of decay at stump level (i.e., the upward extension of root rot) were made on cross-sectional discs taken from windfallen and standing dead 100- to 130-year-old black spruce (Picea mariana (Mill.) BSP) near Nipigon in northwestern Ontario. Subsequently, causal fungi were identified using laboratory culturing procedures. The incidence and amount of decay in windfallen trees within leave strips following alternate strip clear-cutting was higher than the general stand levels but lower than that found in windfallen trees in uncut forest. The incidence and amount of decay was also higher in windfallen trees near the centres of the leave strips than in those near the edges and corners of these strips. These results indicate a strong association between root rot and windfall and suggest that for comparable windfirmness, trees near the edges of residual stands must have less decay than those in more sheltered locations. Decay levels tended to be lower on poorly drained sites than on well-drained sites. In uncut forest, and especially in the leave strips, more trees were uprooted than died standing or suffered stem breakage. The incidence and amount of decay tended to be lower in uprooted trees than in standing dead trees or those with stem breakage, although in uncut forest virtually all windfallen or standing dead trees had some degree of stump-level decay. Of the 21 wood-rotting Basidiomycetes isolated from windfallen and standing dead trees, Inonotus tomentosus (Fr.:Fr.) Teng was the most frequent, followed in order by Armillaria ostoyae (Romagn.) Herink, Coniophora puteana (Schum.:Fr.) Karst., and Scytinostroma galactinum (Fr.) Donk. The incidence of I. tomentosus, C. puteana, Xeromphalina campanella (Batsch.:Fr.) Kuhner & Maire, and Serpula himantioides (Fr.:Fr.) Karst., but not Armillaria ostoyae, Scytinostroma galactinum, and Sistotrema brinkmanii (Bres.) Erik., was greater in windfallen and standing dead trees from the leave strips than in the general stand populations. In the leave strips, I. tomentosus, Amylostereum chailletii (Pers.:Fr.) Boid., and Trichaptum abietinum (Dickson:Fr.) Ryv. tended to greater relative abundance in standing dead trees, while the relative abundance of C. puteana and Serpula himantioides was greater in trees with stem breakage. Armillaria ostoyae and Scytinostroma galactinum were as abundant in uprooted trees as in standing dead trees or those with stem breakage. Ascocoryne sarcoides (Jacq.:Fr.) G. & W., a staining fungus that may protect against decay fungi, was frequently isolated in this study.