Nutrient Uptake and Short-Term Responses of Phytoplankton and Benthic Algal Communities from a Subarctic Pond to Experimental Nutrient Enrichment in Microcosms

Pre-seeding tillage of long-term no-till (NT) land may alter crop production by changing the availability of some nutrients in soil. Effects of short-term (4 years) tillage (hereafter called reverse tillage [RT]) of land previously under long-term (29 or 30 years) NT, with straw management (straw removed [SRem] and straw retained [SRet]) and N fertilizer rate (0, 50 and 100 kg N ha-1 in SRet, and 0 kg N ha-1 in SRem plots), were determined on plant yield (seed + straw, or harvested as forage/silage at soft dough stage), and N and P uptake in growing seasons from 2010 to 2013 at Breton (Gray Luvisol [Typic Cryoboralf] loam) and from 2009 to 2012 at Ellerslie (Black Chernozem [Albic Argicryoll] loam), Alberta, Canada. Plant yield, N uptake and P uptake tended to be greater with RT compared to NT in most cases at both sites, although significant in a few cases only at Ellerslie. On average over both sites, RT produced greater plant yield by 560 kg ha-1 yr-1, N uptake by 5.8 kg N ha-1 yr-1, and P uptake by 1.8 kg P ha-1 yr-1 than NT. There was no consistent beneficial effect of straw retention on plant yield, N uptake and P uptake in different years. Plant yield, N uptake and P uptake increased with N fertilization at both sites, with up to the maximum rate of applied N at 100 kg N ha-1 in 3 of 4 years at Breton and in 2 of 4 years at Ellerslie. In conclusion, our findings suggested some beneficial impact of occasional tillage of long-term NT soil on crop yield and nutrient uptake.

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Impacts of golf course construction and operation on headwater streams: bioassessment using benthic algae

Canadian Journal of Botany ◽

10.1139/b03-081 ◽

2003 ◽

Vol 81 (8) ◽

pp. 848-858 ◽

Cited By ~ 14

Author(s):

Jennifer G Winter ◽

Peter J Dillon ◽

Carolyn Paterson ◽

Ron A Reid ◽

Keith M Somers

Keyword(s):

Nutrient Enrichment ◽

Headwater Streams ◽

Benthic Algae ◽

Golf Course ◽

Golf Courses ◽

Algal Communities ◽

Precambrian Shield ◽

Filamentous Green Algae ◽

Algal Groups ◽

Under Construction

The influence of golf course operation and construction on benthic algal communities in headwater streams on the Precambrian Shield was investigated using a reference condition approach. Streams were sampled for water chemistry and epilithic benthic algae on operational golf courses, on courses under construction, and from nearby minimally impacted reference locations. Epilithic diatom community structure was different in reference streams than in operational golf course streams, the latter indicating nutrient enrichment, higher pH, and disturbance. Full counts of diatoms and soft algae revealed that there was a lower proportion of diatoms relative to other algal groups, cyanobacteria in particular, in operational golf course streams compared with samples from reference locations. Dominance by a single taxon was also significantly higher in operational golf course streams. Although differences relative to the reference streams were less marked for the streams on courses under construction, full counts of diatoms and soft algae provided evidence of disturbance and nutrient enrichment. In particular, high proportions of filamentous green algae were recorded. Overall, our results indicate that golf course land management on the Shield is associated with significant differences in the abundance of certain benthic algal taxa in headwater streams.Key words: diatoms, periphyton, biomonitoring, golf courses, canonical correspondence analysis (CCA), Precambrian Shield.

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Measurement of short-term nutrient uptake rates in cranberry by aeroponics

Plant Cell & Environment ◽

10.1111/j.1365-3040.1996.tb00246.x ◽

1996 ◽

Vol 19 (2) ◽

pp. 237-242 ◽

Cited By ~ 12

Author(s):

P. BARAK ◽

J. D. SMITH ◽

A. R. KRUEGER ◽

L. A. PETERSON

Keyword(s):

Nutrient Uptake ◽

Short Term ◽

Uptake Rates

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Phytoplankton responses to nutrient and grazer manipulations among northeastern lakes of varying pH

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f97-293 ◽

1998 ◽

Vol 55 (4) ◽

pp. 958-966 ◽

Cited By ~ 7

Author(s):

Paul Bukaveckas ◽

William Shaw

Keyword(s):

Phosphatase Activity ◽

Nonlinear Model ◽

Nutrient Enrichment ◽

Grazing Intensity ◽

Short Term ◽

Good Correspondence ◽

Acidic Lakes ◽

P Limitation ◽

Community Grazing ◽

Enrichment Experiments

Short-term nutrient enrichment and zooplankton exclosure experiments were conducted at 14 lakes representing various stages of acidification (pH 4.6-6.8). We measured changes in chlorophyll as an indicator of the severity of nutrient limitation and grazing intensity and compared these with independent measures of P limitation (cell P quotas and phosphatase activity) and grazing (zooplankton densities and inferred community grazing rates). Results from nutrient enrichment experiments showed good correspondence to measured phosphatase activity but not cell P quotas. Phytoplankton in acidic lakes (pH < 5.0) responded more strongly to nutrient enrichment and exhibited fourfold higher biomass-specific phosphatase activity compared with nonacidic lakes. Phytoplankton responses to the removal of macrozooplankton did not exhibit any consistent pattern among lakes of varying acidity. Although the largest herbivores (Daphnia) were more abundant in nonacidic lakes, their absence in acidic lakes was compensated for by increased abundance of smaller species (principally Diaptomus minutus and Bosmina longirostris). The magnitude of the response to grazer removal was positively correlated with lake zooplankton densities at the time of the experiment, and the use of a nonlinear model enabled us to explain 84% of the variation in this response among the 14 sites.

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