Upscaling chamber-based measurements of N2O emissions at snowmelt

2005 ◽  
Vol 85 (1) ◽  
pp. 113-125 ◽  
Author(s):  
D. Pennock ◽  
R. Farrell ◽  
R. Desjardins ◽  
E. Pattey ◽  
J. I. MacPherson
Keyword(s):  
Pore Space ◽  
Triticum Aestivum L ◽  
N2o Emissions ◽  
Brassica Napus L ◽  
Antecedent Moisture ◽  
Snowmelt Period ◽  
Crop Type ◽  
Central Canada ◽  
Specific Emissions ◽  
Moisture Conditions

One impediment to accurate national estimation of N2O is the difficulty in upscaling N2O measurements made at discrete points to larger field and regional scales. Our objective was to estimate N2O emissions during snowmelt in 2002 for a township (approximately 92 km2) near Laird, Saskatchewan. Chamber measurements were made at 12 sites in the township: four fields with canola (Brassica napus L.) residues, four with pea (Pisum sativum L.) residues, three with wheat (Triticum aestivum L.) residues, and one field that received cattle manure. Ten sampling chambers were used at each site, and N2O samples were made on 7 d during the snowmelt period (from 2002 Apr. 03 to Apr. 17). Cumulative N2O emissions during the 14 days of the snowmelt period differed between crop residue types: cumulative emissions from sites with wheat residues were 105.6 g N2O-N ha-1 and were significantly higher (P < 0.1) than those from fields with pea and canola residues (79.6 and 75.2 g N2O-N ha-1 respectively). The single manured site assessed had the highest cumulative emissions of 330.7 g N2O-N ha-1. The crop-specific emissions from the chamber-based measurements were multiplied by the area of each crop type in the township to calculate an area-weighted value for emissions. Cumulative emissions were 93.4 g N2O-N ha-1 for the chamber-based measurements. Water-filled pore space and soil temperature were not significantly correlated with cumulative emissions. Cumulative emissions from sites with fall nitrate levels below 8.0 kg ha-1 were consistently lower than those above this threshold. The emissions for the Laird township were well below the emissions calculated for most other studies in the Prairies and in central Canada. The lower emissions were probably due to low soil water contents and soil nitrate levels in the fall of 2001 and below normal snowfall in the winter of 2001-2002. This reinforces the importance in antecedent moisture conditions and soil N levels for modeling of emissions at snowmelt. Key words: Greenhouse gas, landscape-scale

Influence of previous crop type on yield of spring wheat: Analysis of commercial field data

1996 ◽  
Vol 76 (3) ◽  
pp. 457-459 ◽  
Author(s):  
Luc Bourgeois ◽  
Martin H. Entz
Keyword(s):  
Field Data ◽  
Triticum Aestivum L ◽  
Field Pea ◽  
Brassica Napus L ◽  
Yield Data ◽  
Linum Usitatissimum L ◽  
Previous Crop ◽  
Crop Type ◽  
Small Plot ◽  
One Year

Although rotational benefits of non-cereal crops have been observed in small plot research trials few quantitative data are available on a field scale. In this study, field data of farmers from the Manitoba Crop Insurance Corporation were analysed to compare yield of wheat (Triticum aestivum L.) following different crops. The yield of wheat following wheat was used as a basis of comparison among crop sequences. The yield data were collected between 1982 and 1993 from fields 64 ha in size, located throughout the province of Manitoba. During this period, the yield of wheat following flax (Linum usitatissimum L.), peas (Pisum sativum L.), and canola (Brassica napus L.), on average was 16%, 11%, and 8% higher, respectively, than wheat following wheat. In one year, the yield of wheat was increased by as much as 41% following a field pea crop. Key words: Crop rotation, barley, canola, flax, field pea, wheat

scholarly journals Large Variations in N2O Fluxes from Bioenergy Crops According to Management Practices and Crop Type

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 675
Author(s):  
Fabien Ferchaud ◽  
Céline Peyrard ◽  
Joël Léonard ◽  
Eric Gréhan ◽  
Bruno Mary
Keyword(s):  
Management Practices ◽  
Pore Space ◽  
Bioenergy Crops ◽  
N2o Emissions ◽  
Crop Type ◽  
Long Term Experiment ◽  
Crop Types ◽  
N2o Fluxes ◽  
Temperature Water

Field N2O emissions are a key point in the evaluation of the greenhouse gas benefits of bioenergy crops. The aim of this study was to investigate N2O fluxes from perennial (miscanthus and switchgrass), semi-perennial (fescue and alfalfa) and annual (sorghum and triticale) bioenergy crops and to analyze the effect of the management of perennials (nitrogen fertilization and/or harvest date). Daily N2O emissions were measured quasi-continuously during at least two years in a long-term experiment, using automated chambers, with 2–5 treatments monitored simultaneously. Cumulative N2O emissions from perennials were strongly affected by management practices: fertilized miscanthus harvested early and unfertilized miscanthus harvested late had systematically much lower emissions than fertilized miscanthus harvested late (50, 160 and 1470 g N2O-N ha−1 year−1, respectively). Fertilized perennials often had similar or higher cumulative emissions than semi-perennial or annual crops. Fluxes from perennial and semi-perennial crops were characterized by long periods with low emissions interspersed with short periods with high emissions. Temperature, water-filled pore space and soil nitrates affected daily emissions but their influence varied between crop types. This study shows the complex interaction between crop type, crop management and climate, which results in large variations in N2O fluxes for a given site.

scholarly journals Effects of crop type on soil microbial properties in the cropland of the Jianghan plain of China

2018 ◽  
Vol 64 (No. 9) ◽  
pp. 421-426
Author(s):  
Li Jun ◽  
Liu Lixin ◽  
Zhang Chunlei ◽  
Chen Chang ◽  
Lu Guangyuan ◽  
...  
Keyword(s):  
Triticum Aestivum L ◽  
Invertase Activity ◽  
Shannon Index ◽  
Available Phosphorus ◽  
Jianghan Plain ◽  
Brassica Napus L ◽  
Microbial Properties ◽  
Soil Microbial ◽  
Soil Available Phosphorus ◽  
Soil Microbial Properties

Soil microbial properties are varied by growing different crops, ultimately reflecting the growth and reproduction of crops. In this study, two types of oilseed rape (Brassica napus L. ZS11 and ZY821) and wheat (Triticum aestivum L. ZM9023) were planted in the Jianghan plain of China. Rhizosphere soil samples were collected three months after sowing. Soil physicochemical properties, enzyme activities and microbial diversity were determined. The results showed that soil available phosphorus significantly increased from 25.57 mg/kg (ZM9023) to 33.20 mg/kg (ZS11) and 35.72 mg/kg (ZY821), respectively. Invertase activity of ZS821 (0.86 mg glucose/g) was significantly lower than in ZS11 (1.04 mg glucose/g). Acid phosphatase activity under planting rapes was significantly higher than that under wheat. Urease activities significantly increased from 40.88 mg NH<sub>4</sub><sup>+</sup>-N/g soil/24 h (NFP) to 49.04 mg NH<sub>4</sub><sup>+</sup>-N/g soil/24 h (FNP) and 51.28 mg NH<sub>4</sub><sup>+</sup>-N/g soil/24 h (ZM9023), 51.60 mg NH<sub>4</sub><sup>+</sup>-N/g soil/24 h (ZY821) and 52.28 mg NH<sub>4</sub><sup>+</sup>-N/g soil/24 h (ZS11), respectively. The ACE (abundance based coverage estimator) and Chao1 indexes of bacteria of ZS11 were lower than ZY821, which were similar to ZM9023. Fertilization increased soil bacterial ACE and Chao1 indexes. However, ACE and Chao1, Shannon and Simpson indexes of soil fungi for ZS11 were significantly higher than in ZY821, which were similar to ZM9023 (except for the Shannon index).

Simulating Antecedent Moisture Conditions to Calibrate Rainfall Derived Inflow and Infiltration for Sanitary Systems

2012 ◽  
Vol 2012 (16) ◽  
pp. 1296-1317
Author(s):  
Ben Gamble ◽  
Eric Saylor ◽  
Joseph Koran ◽  
Susan Moisio ◽  
Nancy Schultz ◽  
...  
Keyword(s):  
Antecedent Moisture ◽  
Moisture Conditions ◽  
Antecedent Moisture Conditions

Site-specific wild oat (Avena fatua L.) management

2012 ◽  
Vol 92 (5) ◽  
pp. 923-931 ◽  
Author(s):  
H. J. Beckie ◽  
S. Shirriff
Keyword(s):  
Specific Treatment ◽  
Triticum Aestivum L ◽  
Avena Fatua ◽  
Slope Position ◽  
Wild Oat ◽  
Herbicide Application ◽  
Brassica Napus L ◽  
Site Specific ◽  
Lower Slope ◽  
Upper Slope

Beckie, H. J. and Shirriff, S. 2012. Site-specific wild oat ( Avena fatua L.) management. Can. J. Plant Sci. 92: 923–931. Variation in soil properties, such as soil moisture, across a hummocky landscape may influence wild oat emergence and growth. To evaluate wild oat emergence, growth, and management according to landscape position, a study was conducted from 2006 to 2010 in a hummocky field in the semiarid Moist Mixed Grassland ecoregion of Saskatchewan. The hypothesis tested was that wild oat emergence and growth would be greater in lower than upper slope positions under normal or dry early growing season conditions. Three herbicide treatments were imposed on the same plots each year of a 2-yr canola (Brassica napus L.) – wheat (Triticum aestivum L.) sequence: (1) nontreated (weedy) control; (2) herbicide application to upper and lower slope positions (i.e., full or blanket application); and (3) herbicide application to lower slope position only. Slope position affected crop and weed densities before in-crop herbicide application in years with dry spring growing conditions. Site-specific wild oat herbicide application in hummocky fields in semiarid regions may be justified based on results of wild oat control averaged across slope position. In year 2 of the crop sequence (wheat), overall (i.e., lower and upper slope) wild oat control based on density, biomass, and dockage (i.e., seed return) was similar between site-specific and full herbicide treatment in 2 of 3 yr. Because economic thresholds have not been widely adopted by growers in managing wild oat, site-specific treatment in years when conditions warrant may be an appropriate compromise between no application and blanket herbicide application.

scholarly journals A case study on the use of appropriate surrogates for antecedent moisture conditions (AMCs)

2010 ◽  
Vol 7 (3) ◽  
pp. 3329-3363 ◽  
Author(s):  
G. A. Ali ◽  
A. G. Roy
Keyword(s):  
Soil Moisture ◽  
Point Scale ◽  
Nonlinear Regression Models ◽  
Terrain Attributes ◽  
Antecedent Moisture ◽  
Triggering Conditions ◽  
Linear And Nonlinear ◽  
Active Processes ◽  
Moisture Conditions ◽  
Antecedent Moisture Conditions

Abstract. While a large number of non-linear hillslope and catchment rainfall-runoff responses have been attributed to the temporal variability in antecedent moisture conditions (AMCs), two problems emerge: 1) the difficulty of measuring AMCs, and 2) the absence of explicit guidelines for the choice of surrogates or proxies for AMCs. This paper aims at determining whether or not multiple surrogates for AMCs should be used in order not to bias our understanding of a system hydrological behaviour. We worked in a small forested catchment, the Hermine, where soil moisture has been measured at 121 different locations at four depths on 16 occasions. Without making any assumption on active processes, we used various linear and nonlinear regression models to evaluate the point-scale temporal relations between actual soil moisture contents and selected meteorological-based surrogates for AMCs. We then mapped the nature of the "best fit" model to identify 1) spatial clusters of soil moisture monitoring sites whose hydrological behaviour was similar, and 2) potential topographic influences on these behaviours. Two conclusions stood out. Firstly, it was shown that the sole reference to AMCs indices traditionally used in catchment hydrology, namely antecedent rainfall amounts summed over periods of seven or ten days, would have led to an incomplete understanding of the Hermine catchment dynamics. Secondly, the relationships between point-scale soil moisture content and surrogates for AMCs were not spatially homogeneous, thus revealing a mosaic of linear and nonlinear catchment "active" and "contributing" sources whose location was often controlled by surface terrain attributes or the topography of a soil-confining layer interface. These results represent a step forward in developing a hydrological conceptual model for the Hermine catchment as they indicate depth-specific processes and spatially-variable triggering conditions. Further investigations are, however, necessary in order to derive general guidelines for the choice of the best surrogates for AMCs in a catchment.

The ecology of terricolous lichens of the Northern Conifer – Hardwood forests of central Eastern Canada

1968 ◽  
Vol 46 (8) ◽  
pp. 1043-1078 ◽  
Author(s):  
J. D. H. Lambert ◽  
P. F. Maycock
Keyword(s):  
Environmental Conditions ◽  
Ground Level ◽  
Hardwood Forests ◽  
Deciduous Tree ◽  
Eastern Canada ◽  
Central Canada ◽  
Terricolous Lichens ◽  
Moisture Conditions ◽  
Tree Composition ◽  
Lichen Growth

A quantitative analysis of the terricolous (ground) lichens in the Northern Conifer – Hardwood forests of central Canada is presented. Seventy-one forest stands were sampled to determine the composition of the tree and lichen strata. Tree composition was expressed in terms of a series of importance values determined from measures of frequency, density, and dominance on a relative basis, with the importance values for all trees in a stand totalling 300. A statistical analysis of lichen distribution showed that while lichens reacted in a similar manner to moisture conditions as the trees they were more commonly found in stands on dry sites. An ordination of stands indicated that optimum environmental conditions for lichen growth were found in dry young conifer stands of low absolute dominance with fairly open canopies, with slowly decomposing ground litter of decidedly acidic reaction.The increase of deciduous tree species in the mesic segments of the moisture gradient produced environmental conditions unsuitable for most of the lichen species recorded. The reduced occurrence of lichens in such sites was interpreted as being related to the lack of suitable substrates, reduction in light intensity at ground level, increased litter, and a more rapid turnover of organic matter.

scholarly journals Denitrification Rate and Its Potential to Predict Biogenic N2O Field Emissions in a Mediterranean Maize-Cropped Soil in Southern Italy

Land ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 97 ◽  
Author(s):  
Annachiara Forte ◽  
Angelo Fierro
Keyword(s):  
Pore Space ◽  
Denitrification Rate ◽  
Linear Functions ◽  
N2o Emissions ◽  
Soil Cores ◽  
High Soil ◽  
N2o Fluxes ◽  
Intact Soil Cores ◽  
Intact Soil ◽  
Soil Nitrates

The denitrification rate in C2H2-amended intact soil cores and soil N2O fluxes in closed static chambers were monitored in a Mediterranean irrigated maize-cropped field. The measurements were carried out during: (i) a standard fertilization management (SFM) activity and (ii) a manipulation experimental (ME) test on the effects of increased and reduced application rates of urea at the late fertilization. In the course of the SFM, the irrigations following early and late nitrogen fertilization led to pulses of denitrification rates (up to 1300 μg N2O-N m−2 h−1) and N2O fluxes (up to 320 μg N2O-N m−2 h−1), thanks to the combined action of high soil temperatures and not limiting nitrates and water filled pore space (WFPS). During the ME, high soil nitrates were noted in all the treatments in the first one month after the late fertilization, which promoted marked N-losses by microbial denitrification (from 500 to 1800 μg N2O-N m−2 h−1) every time the soil WFPS was not limiting. At similar maize yield responses to fertilizer treatments, this result suggested no competition for N between plant roots and soil microbial community and indicated a probable surplus of nitrogen fertilizer input at the investigated farm. Correlation and regression analyses (CRA) on the whole set of data showed significant relations between both the denitrification rates and the N2O fluxes with three soil physical-chemical parameters: nitrate concentration, WFPS and temperature. Specifically, the response functions of denitrification rate to soil nitrates, WFPS and temperature could be satisfactorily modelled according to simple Michaelis-Menten kinetic, exponential and linear functions, respectively. Furthermore, the CRA demonstrated a significant exponential relationship between N2O fluxes and denitrification and simple empirical functions to predict N2O emissions from the denitrification rate appeared more fitting (higher concordance correlation coefficient) than the predictive empirical algorithm based on soil nitrates, WFPS and temperature. In this regard, the empirically established relationships between the denitrification rate on intact soil cores under field conditions and the soil variables provided local-specific threshold values and coefficients which may effectively work to calibrate and adapt existing N2O process-based simulation models to the local pedo-climatic conditions.

Stink Bugs Nymph and Adult Biology and Adult Preference on Cultivated Crop Plants in the Southern Brazilian Neotropics

2019 ◽  
Vol 49 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Taynara Possebom ◽  
Tiago Lucini ◽  
Antônio Ricardo Panizzi
Keyword(s):  
Body Weight ◽  
Triticum Aestivum L ◽  
Cultivated Plants ◽  
Stink Bug ◽  
Stink Bugs ◽  
Laboratory Studies ◽  
Brassica Napus L ◽  
Reproductive Structures ◽  
Glycine Max L ◽  
Adult Preference

Abstract Laboratory studies were conducted with Dichelops furcatus (F.), Euschistus heros (F.), and Nezara viridula (L.) (Heteroptera: Pentatomidae) aiming to evaluate nymph and adult biology and adult preference for immature reproductive structures of the cultivated plants, soybean, Glycine max (L.) Merrill (Fabaceae), wheat, Triticum aestivum L. (Poaceae), and canola, Brassica napus L. var. oleifera (Brassicaceae). Considering the survivorship for D. furcatus nymphs, it was greater on soybean and wheat, for E. heros nymphs it was greater on soybean compared to canola and wheat, and for N. viridula nymphs the survivorship was greater on soybean and canola. Dichelops furcatus nymphs developed faster on soybean and wheat, and E. heros and N. viridula nymphs developed faster on soybean and canola. Body weight at adult emergency for D. furcatus was greater on soybean and wheat, and for E. heros and N. viridula, it was greater on soybean. Adult survivorship and longevity were similar on soybean/wheat/canola for D. furcatus and N. viridula, and greater on soybean for E. heros. Reproduction and weight gain of adults were greater on soybean and wheat for D. furcatus, and on soybean for E. heros; N. viridula reproduced only on soybean and tended to gain greater body weight in this food source. As expected, soybean considering its superior nutritional quality was, in general, the best food. These laboratory studies coupled with field observations allow to conclude that the sequence of soybean/wheat/canola crops in the area studied forms a ‘green bridge’ that favor stink bug populations abundance in southern Brazilian neotropics.

Sign in / Sign up

Export Citation Format

Share Document