IMMEDIATE AND LONG-TERM EFFECTS OF INSECTICIDE APPLICATION ON PARASITOIDS IN JACK PINE STANDS IN QUEBEC

1972 ◽  
Vol 104 (2) ◽  
pp. 263-270 ◽  
Author(s):  
Peter W. Price
Keyword(s):  
Relative Abundance ◽  
Jack Pine ◽  
Ground Vegetation ◽  
Long Term Effects ◽  
Aerial Application ◽  
Insecticide Application ◽  
Number Of Species ◽  
Adult Parasitoid ◽  
Pine Stands

AbstractParasitoid populations were sampled before, and for 4 years following, an aerial application of the insecticide phosphamidon to control a sawfly outbreak. Adult parasitoid mortality was high because of spraying, but a reservoir of parasitoids in host cocoons remained to repopulate the treated areas. In moister sites the number of species decreased and their relative abundance changed, but moderate numbers of parasitoids remained 4 years after spraying. In a dry site with little ground vegetation, none of the species present before spraying remained by the fourth year.

Long-term effects of repeated N fertilization and straw application in a jack pine forest. 3. Nitrogen availability in the forest floor

1995 ◽  
Vol 25 (12) ◽  
pp. 1991-1996 ◽  
Author(s):  
C.E. Prescott ◽  
B.E. Kishchuk ◽  
G.F. Weetman
Keyword(s):  
Nitrogen Availability ◽  
Jack Pine ◽  
N Fertilization ◽  
Ground Vegetation ◽  
N Availability ◽  
Net N Mineralization ◽  
Long Term Effects ◽  
Forest Floors ◽  
Straw Application

A long-term increase in N availability was evident in higher rates of net N mineralization and lower C/N ratios in jack pine (Pinusbanksiana Lamb.) forest floors that received 672 kg N•ha−1 in six applications or a single application of straw. There was no evidence of increased N availability in plots that received P and K in addition to N. Litter N concentrations were higher in N-fertilized and straw-treated plots, but rates of C mineralization and litter decomposition were not increased. Additions of N in repeated small applications or in conjunction with readily decomposable C in straw likely resulted in high retention of N in the ecosystem. The long-term increase in N availability was attributed to increased recycling of N, retention of added N in the ecosystem, and reductions in the ericaceous ground vegetation.

scholarly journals Long-Term Mootral Application Impacts Methane Production and the Microbial Community in the Rumen Simulation Technique System

2021 ◽  
Vol 12 ◽  
Author(s):  
Johanna Brede ◽  
Manuela Peukert ◽  
Björn Egert ◽  
Gerhard Breves ◽  
Melanie Brede
Keyword(s):  
Microbial Community ◽  
Relative Abundance ◽  
Methane Production ◽  
Solid Phase ◽  
Methane Emissions ◽  
Simulation Technique ◽  
Feed Additive ◽  
Gene Copy ◽  
Long Term Effects

Methane emissions by ruminants contribute to global warming and result in a loss of dietary energy for the animals. One possibility of reducing methane emissions is by dietary strategies. In the present trial, we investigated the long-term effects of Mootral, a feed additive consisting of garlic powder (Allium sativum) and bitter orange extracts (Citrus aurantium), on fermentation parameters and the microbial community in the rumen simulation technique (RUSITEC) system. The experiment lasted 38 days and was divided into three phases: an equilibration period of 7 days, a baseline period (BL) of 3 days, and experimental period (EP) of 28 days. Twelve fermentation vessels were divided into three groups (n = 4): control (CON), short-term (ST), and long-term (LT) application. From day 11 to day 27, 1.7 g of Mootral was added to the ST vessels; LT vessels received 1.7 g of Mootral daily for the entire EP. With the onset of Mootral application, methane production was significantly reduced in both groups until day 18. Thereafter, the production rate returned to the initial quantity. Furthermore, the short chain fatty acid fermentation profile was significantly altered by Mootral application; the molar proportion of acetate decreased, while the proportions of propionate and butyrate increased. Metabolomic analysis revealed further changes in metabolite concentrations associated with the Mootral supplementation period. The methyl coenzyme-M reductase gene copy number was reduced in the liquid and solid phase, whereas the treatment did not affect the abundance of bacteria. At the end of the BL, Methanomicrobia was the most abundant archaeal class. Mootral supplementation induced an increase in the relative abundance of Methanomassiliicoccales and a reduction in the relative abundance of Methanomicrobia, however, this effect was transient. Abundances of bacterial families were only marginally altered by the treatment. In conclusion, Mootral has the transient ability to reduce methane production significantly due to a selective effect on archaea numbers and archaeal community composition with little effect on the bacterial community.

scholarly journals Impact of soil scarification on reindeer pastures

Rangifer ◽  
1990 ◽  
Vol 10 (3) ◽  
pp. 99 ◽  
Author(s):  
Olof Eriksson ◽  
Tuomo Raunistola
Keyword(s):  
Standard Procedure ◽  
Plant Cover ◽  
Point Of View ◽  
Ground Vegetation ◽  
Long Term Effects ◽  
Surface Moisture ◽  
Positive Effects ◽  
Soil Scarification ◽  
Soil Temperatures

During recent years, soil scarification has become a standard procedure for improving seed beds after logging. Around 57 000 ha were treated, primarily through harrowing and ploughing, in the counties of Vâsterbotten and Norbotten during 1985. The positive effects of scarification, from a forestry point of view, are improved access to plant nutrients, raised soil temperatures and reduces surface moisture. The aim of the present study was to describe long-term changes in the ground vegetation following scarification. Harrowing affects 45-55% of the plant cover while ploughing affects 65-90%. 10 years after ploughing and harrowing about 20% of the surface is still without vegetation. Real long-term effects remain in dispute. It has been claimed that ploughing, at least, may lead to irreversible changes.

EFFECTS OF EXPERIMENTAL CRUDE OIL SPILLS ON TAIGA AND TUNDRA VEGETATION OF THE CANADIAN ARCTIC

1975 ◽  
Vol 1975 (1) ◽  
pp. 517-525 ◽  
Author(s):  
T.C. Hutchinson ◽  
W. Freedman
Keyword(s):  
Crude Oil ◽  
Oil Spills ◽  
Black Spruce ◽  
Energy Budgets ◽  
Ground Vegetation ◽  
Long Term Effects ◽  
Tundra Vegetation ◽  
Short And Long Term ◽  
Vegetation Species

ABSTRACT Summer and winter crude oil spills have been made on tundra and taiga sites in arctic Canada. The short- and long-term effects of these spills have been recorded, to date, over a 3-year period. Spills were made by even surface spraying and by high intensity point spills. The vegetation present prior to such spills was carefully recorded. All surface spills had a devastating effect on above-ground vegetation. Species did, however, differ markedly in both their ability to survive an oil spill and their ability to recover. Many species, especially lichens, mosses, and liverworts, were killed outright. Some woody and dwarf shrubs were able to produce new, healthy shoots within a few weeks of initial defoliation. The reduced production of storage material, as a result of foliage (and photosynthetic) loss, caused markedly increased plant losses by winter-killing factors. Flowering and reproduction were severely reduced, even in the third summer following a spill. Winter spills had significantly less effect than summer spills. Permafrost was little affected, despite changes in the site energy budgets. Damage appeared greater in exposed taiga sites than on the tundra. Some species, such as black spruce, died throughout a 3-year period, emphasizing the necessity for long-term studies for accurate assessment.

Long-term effects of repeated N fertilization and straw application in a jack pine forest. 2. Changes in the ericaceous ground vegetation

1995 ◽  
Vol 25 (12) ◽  
pp. 1984-1990 ◽  
Author(s):  
C.E. Prescott ◽  
J.W. Kumi ◽  
G.F. Weetman
Keyword(s):  
Forest Floor ◽  
Negative Relationship ◽  
Jack Pine ◽  
N Fertilization ◽  
Ground Vegetation ◽  
N Availability ◽  
Long Term Effects ◽  
Total N ◽  
N Loading ◽  
Straw Application

The cover of the ericaceous shrub Kalmiaangustifolia L. in a jack pine (Pinusbanksiana Lamb.) forest was reduced after repeated fertilization with N or N–P–K, or a single application of straw. Kalmia reductions were greatest in plots that received the highest total N loading (1344 kg N•ha−1), but were also apparent in plots that received 672 kg N•ha−1. The reductions could not be attributed to shading, since tree volume response was small in the plots that received the highest N loading. There was an overall reduction in the amount of ground vegetation in the fertilized plots, so the decline could not be attributed to increased competition from invading species. There was a general negative relationship between the abundance of Kalmia and N availability in the forest floor, in fertilized and straw-amended plots. The reductions in Kalmia cover were still apparent 14 years after the last fertilization and 24 years after the straw application, as was higher N availability. Treatments such as repeated N fertilization or organic amendments that increase N availability in the forest floor may be an option for control of Kalmia in conifer plantations.

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