Shabtai Bittman - Academia.edu (original) (raw)
Papers by Shabtai Bittman
Although shorebirds spending the winter in temperate areas frequently use estuarine and supratida... more Although shorebirds spending the winter in temperate areas frequently use estuarine and supratidal (upland) feeding habitats, the relative contribution of each habitat to individual diets has not been directly quantified. We quantified the proportional use that Calidris alpina pacifica (Dunlin) made of estuarine vs. terrestrial farmland resources on the Fraser River Delta, British Columbia, using stable isotope analysis (δ13C, δ15N) of blood from 268 Dunlin over four winters, 1997 through 2000. We tested for individual, age, sex, morphological, seasonal, and weather-related differences in dietary sources. Based on single- (δ13C) and dual-isotope mixing models, the agricultural habitat contributed approximately 38% of Dunlin diet averaged over four winters, with the balance from intertidal flats. However, there was a wide variation among individuals in the extent of agricultural feeding, ranging from about 1% to 95% of diet. Younger birds had a significantly higher terrestrial contri...
This draft chapter to a planned Guidance Document on integrated sustainable nitrogen management h... more This draft chapter to a planned Guidance Document on integrated sustainable nitrogen management has been prepared for the Task Force on Reactive Nitrogen under the UNECE Air Convention, with support from the European Commission. The process of drafting the Guidance Document started in connection to a workshop "Towards joined-up nitrogen guidance for air, water and climate co-benefits", hosted in Brussels, 11-12 October 2016. The current chapter draft is based on the results from that workshop and on discussions and developments since then. It will be presented and discussed in Brussels on 30 September-1 October at a second workshop jointly organised by the Task Force on Reactive Nitrogen and the European Commission. The content of the draft paper reflects the views only of the authors and the European Commission cannot be held responsible for any use which may be made of the information.
Canadian Journal of Animal Science, 2015
Sheppard, S. C., Bittman, S., Donohoe, G., Flaten, D., Wittenberg, K. M., Small, J. A., Berthiaum... more Sheppard, S. C., Bittman, S., Donohoe, G., Flaten, D., Wittenberg, K. M., Small, J. A., Berthiaume, R., McAllister, T. A., Beauchemin, K. A., McKinnon, J., Amiro, B. D., MacDonald, D., Mattos, F. and Ominski, K. H. 2015. Beef cattle husbandry practices across Ecoregions of Canada in 2011. Can. J. Anim. Sci. 95: 305–321. Beef production in Canada is diverse in many dimensions with numbers of cattle per operation ranging over 10 000-fold, pasture usage from nil to 100%, and types of operations from solely cow–calf to exclusively feedlot finishing. This study summarizes management information obtained from a survey conducted in 2012 (about 2011) on 1009 beef operations in Canada. Many of the results clearly differentiate the practices in the Prairies from those in Ontario and Quebec. Compared to eastern Canada, the Prairies had earlier and shorter calving seasons, higher weaning weights, utilized more winter grazing with a variety of strategies, grew and fed more barley than corn, used...
Modeling Carbon and Nitrogen Dynamics for Soil Management, 2001
Plant and Soil
Defining the long-term effects of liquid dairy manure (LDM) applied by a recommended low emission... more Defining the long-term effects of liquid dairy manure (LDM) applied by a recommended low emission method is important to ensure sustainable grass production and dairy operations. We used natural abundance δ15N and conventional measurements in a long term field experiment to better understand the long-term fate of N applied as LDM, mineral fertilizer (MIN) and both (ALT). We investigated the effects of long-term applications of LDM (with low-emission trailing shoe), MIN, and alternating LDM and MIN (ALT) on grass N uptake, soil N stocks, N losses and δ15N natural abundance in grass, soil and fine heavy fraction (silt + clay size heavy soil). Nominal annual rates of total N were 200 and 400 kg ha−1 for MIN and 400 and 800 kg ha−1 for LDM. MIN and LDM (at 400 kg N ha−1) had similar NUE but LDM accumulated more total soil N (13% of applied) with less losses than MIN; ALT had high yields and losses. Herbage δ15N of MIN declined to near MIN levels after 10–15 years, indicating influence of pre trial management. Herbage δ15N of LDM was consistently lower than applied LDM, implying uptake of depleted urine N. High rates of enriched LDM had little effect on soil δ15N suggesting soil N was quite stable and enriched N was lost by non discriminating pathways like leaching. The physically protected fine heavy fraction contained most soil N. Clearer understanding of long-term N dynamics can improve sustainability of heavily fertilized perennial grasses on dairy farms.
Climate Change and Soil Interactions, 2020
Abstract Good soil quality implies the maintenance of properties at levels capable of ensuring an... more Abstract Good soil quality implies the maintenance of properties at levels capable of ensuring an equilibrated and healthy ecosystem, with sustained agricultural production to supply the world population. Climate change, land-use change, and agriculture intensification are causing a decline in soil quality, which in most parts of the world is becoming severe (desertification). Land-use changes, the associated loss of soil organic matter (SOM), and beneficial microbial diversity are major reasons for deteriorating soil fertility and declining agricultural productivity, as well as affecting water, air, and biodiversity. Adaptation towards climate-resilient and climate-smart agriculture is necessary to cope with climate change and extreme events. This requires the following measures: (1) sustainable production (integrated livestock and cropping systems, including agroforestry); (2) increased soil organic matter (SOM) (bio-based and organic fertilizers, crop rotations, crop associations, no-till, conservation agriculture, C sequestration, and microbial processes); (3) reduced greenhouse gas emissions, less nutrient losses from agriculture, and increased nutrient use efficiency (NUE) (precision agriculture).
Environmental Research Communications, 2021
With increasing demand for land and food, there is growing interest in sustainable intensificatio... more With increasing demand for land and food, there is growing interest in sustainable intensification of agricultural production. Here we investigated sustainable intensification of grass and corn production for dairy farms using a system of semi-virtual farmlets that combine replicated field research plots with feed modelling. We improved manure N capture by spreading separated liquid fraction with a low emission sliding shoe applicator on grass, and manure P capture by precision injecting separated sludge into corn. Reducing the number of annual harvests (5 to 3) increased grass yield and inter-seeding Italian ryegrass in early maturing corn increased fall growth of the cover crop, thus helping to protect soil over winter and providing additional high quality herbage in spring. Irrigation improved yield and potentially yield stability of corn and grass, and adding a nitrification inhibitor to reduce N2O emission may help reduce pollution swapping especially from injected manure. Over...
Canadian Journal of Soil Science, 2019
The lower Fraser Valley is one of the most intensively cropped regions in Canada. Yet, how soil h... more The lower Fraser Valley is one of the most intensively cropped regions in Canada. Yet, how soil health indicators respond to long-term intensive agricultural management is poorly documented in this region. Thus, we evaluated a suite of soil health indicators in response to 21 growing seasons of continuous silage corn (Zea mays L.) under conventional tillage or no-tillage (0–20 cm soil layer). Wet aggregate stability, available water capacity, active carbon (permanganate oxidizable, POXC), and extractable potassium and extractable magnesium were significantly greater with no-till than conventional tillage, whereas 8 of 13 indicators were similar. Soil health indicators responded more favourably to no-till than conventional tillage.
Agricultural and Forest Meteorology, 2018
Ammonia (NH3) emission from animal manure contributes to air pollution and ecosystem degradation,... more Ammonia (NH3) emission from animal manure contributes to air pollution and ecosystem degradation, and the loss of reactive nitrogen (N) from agricultural systems. Estimates of NH3 emission are necessary for national inventories and nutrient management, and NH3 emission from field-applied manure has been measured in many studies over the past few decades. In this work, we facilitate the use of these data by collecting and organizing them in the ALFAM2 database. In this paper we describe the development of the database and summarise its contents, quantify effects of application methods and other variables on emission using a data subset, and discuss challenges for data analysis and model development. The database contains measurements of emission, manure and soil properties, weather, application technique, and other variables for 1899 plots from 22 research institutes in 12 countries. Data on five manure types (cattle, pig, mink, poultry, mixed, as well as sludge and "other") applied to three types of crops (grass, small grains, maize, as well as stubble and bare soil) are included. Application methods represented in the database include broadcast, trailing hose, trailing shoe (narrow band application), and open slot injection. Cattle manure application to grassland was the most common combination, and analysis of this subset (with dry matter (DM) limited to <15%) was carried out using mixed-and fixed-effects models in order to quantify effects of management and environment on ammonia emission, and to highlight challenges for use of the database. Measured emission from cattle slurry ranged from < 1% to 130% of applied ammonia after 48 hours. Results showed clear, albeit variable, reductions in NH3 emission due to trailing hose, trailing shoe, and open slot injection of slurry compared to broadcast application. There was evidence of positive effects of air temperature and wind speed on NH3 emission, and limited evidence of effects of slurry DM. However, random-effects coefficients for differences among research institutes were among the largest model coefficients, and 4 showed a deviation from the mean response by more than 100% in some cases. The source of these institute differences could not be determined with certainty, but there is some evidence that they are related to differences in soils, or differences in application or measurement methods. The ALFAM2 database should be useful for development and evaluation of both emission factors and emission models, but users need to recognize the limitations caused by confounding variables, imbalance in the dataset, and dependence among observations from the same institute. Variation among measurements and in reported variables highlights the importance of international agreement on how NH3 emission should be measured, along with necessary types of supporting data and standard protocols for their measurement. Both are needed in order to produce more accurate and useful ammonia emission measurements. Expansion of the ALFAM2 database will continue, and readers are invited to contact the corresponding author for information on data submission. The latest version of the database is
Canadian Journal of Soil Science, 2008
Over half the slurry manure produced on dairy farms in the high-rainfall, coastal region of Briti... more Over half the slurry manure produced on dairy farms in the high-rainfall, coastal region of British Columbia (BC), Washington State and northern Oregon is applied from mid-February to early May. This study was conducted to compare the emissions of nitrous oxide (N2O) after manure application during this period on perennial forage grass or winter fallow land. The experimental site soil was moderately well- to well-drained medium-textured river deposit of the Monroe series. Treatments consisted of liquid dairy manure applied either at 270 (Early) or 450 (Late) Tsum (accumulation of average air temperatures above 0ºC from Jan. 01) on bare land or a perennial stand of tall fescue (Festuca arundinacea Schreb.) at a rate of 55.5 m3 ha-1 giving a total ammoniacal N (TAN) loading of 100 and 111 kg ha-1 in 2001 and 2002, respectively. An additional grass treatment consisted of split applications (Split) of manure at half the rate on each of the two application dates. Untreated (Control) bare...
Forages have a high N demand, a long growing season, and an effective root system all contributin... more Forages have a high N demand, a long growing season, and an effective root system all contributing to effective nutrient capture. However forages are restrictive in methods available for mitigating gaseous losses both as NH3 and as N2O, due to both practical and cost considerations. Strategies are needed to address the challenges of both N efficiency and N losses. Agronomic techniques in long term experiments can enhance estimates of N loss pathways and N efficiency, and demonstrate the importance of integrated multinutrient approaches. The dual manure stream concept divides manure into a thin fraction suitable as an N source for grass and a sludge fraction suitable as a P source for corn. While this represents an integrated approach, questions remain about alternate loss pathways. While grazing greatly reduces ammonia emissions it is not clear that grazing improves N use relative to confinement systems. The current levels of prospective mitigation of emissions are perhaps modest. H...
Grass and Forage Science, 2019
Sainfoin (Onobrychis viciifolia) is a forage legume of renewed interest in western Canada, with e... more Sainfoin (Onobrychis viciifolia) is a forage legume of renewed interest in western Canada, with equally weighted advantages and disadvantages. In agronomic attributes, sainfoin is, at best, equal in yield, crude protein content and persistence to alfalfa (Medicago sativa). Sainfoin is equally or more palatable than alfalfa to ruminants, with comparable levels of animal productivity per unit forage consumed. The advantages it has compared to alfalfa include the following: (a) mitigation of frothy bloat; (b) reduced ammonia emissions (more faecal nitrogen (N) and less urinary N); (c) equal or better N retention by ruminants; and (d) anthelmintic protection from intestinal parasites. These advantages may be attributed to the presence of condensed tannins (CT), in legumes such as sainfoin. Emphasis on agronomic characteristics in breeding programmes appears to have led to the inadvertent reduction in the efficacy of CT characteristics. Persistence of sainfoin appears to be dependent on minimal pressure from competing plants, harvest or grazing, and good growth conditions from midsummer into fall, allowing for adequate root reserves for survival. It is possible that judicious use of glyphosate in late season might lessen competition in that critical period as sainfoin is more glyphosate-tolerant than alfalfa. Otherwise, sainfoin may be best considered a short-lived forage and best adapted for early season harvest or grazing to eliminate the risk of bloat.
Meeting the dietary demands of humans while protecting Earth's ecosystems is among the greate... more Meeting the dietary demands of humans while protecting Earth's ecosystems is among the greatest challenges of the Anthropocene. Sustainable intensification is expanding as a response to this grand challenge, but success will require an improved understanding of regional, national, and international agricultural systems, including spatial relationships among system components, land use changes that influence the spatial relationships, and optimal approaches to distributing resources. Agricultural specialization and intensification of the 19th and 20th centuries are central considerations, as these advancements led to monumental increases in production and efficiency, but also resulted in uneven geographic distribution of agriculture types and an uncoupling of nutrient biogeochemical cycles. Now, concentrations of animals in certain regions produce manure nutrient accumulations that contribute to air and water pollution, while concentrations of crops in other regions result in nut...
Costs of Ammonia Abatement and the Climate Co-Benefits, 2015
In this chapter we examine techniques for reducing NH3 emissions from stored manure, including: c... more In this chapter we examine techniques for reducing NH3 emissions from stored manure, including: covers, storage design, and manure processing. Most techniques are for liquid manure stores, whereas there are few methods for solid manures and more research is needed. The cost effectiveness for reducing NH3 emissions by each technique was estimated using installation and operating cost data from several sources and published data on baseline emissions and emission reductions of the techniques. A key uncertainty in these cost-efficacy estimates is the baseline emission used to calculate the quantity of N conserved. It is therefore important to obtain regional baseline emission factors (consistent with national emission inventories) to ensure accurate cost estimates.
Atmospheric Ammonia: Detecting Emission Changes and Environmental Impacts, 2009
To date, most attention in modelling NH3 dispersion and deposition has focused on the regional an... more To date, most attention in modelling NH3 dispersion and deposition has focused on the regional and European scale, and little attention has been given to dealing with NH3 in hot-spot areas. The Working Group addressed the issue of hot-spots with four main objectives: • Identify what are the main issues of hot-spots and their consequences at different scales. • Review
Although shorebirds spending the winter in temperate areas frequently use estuarine and supratida... more Although shorebirds spending the winter in temperate areas frequently use estuarine and supratidal (upland) feeding habitats, the relative contribution of each habitat to individual diets has not been directly quantified. We quantified the proportional use that Calidris alpina pacifica (Dunlin) made of estuarine vs. terrestrial farmland resources on the Fraser River Delta, British Columbia, using stable isotope analysis (δ13C, δ15N) of blood from 268 Dunlin over four winters, 1997 through 2000. We tested for individual, age, sex, morphological, seasonal, and weather-related differences in dietary sources. Based on single- (δ13C) and dual-isotope mixing models, the agricultural habitat contributed approximately 38% of Dunlin diet averaged over four winters, with the balance from intertidal flats. However, there was a wide variation among individuals in the extent of agricultural feeding, ranging from about 1% to 95% of diet. Younger birds had a significantly higher terrestrial contri...
This draft chapter to a planned Guidance Document on integrated sustainable nitrogen management h... more This draft chapter to a planned Guidance Document on integrated sustainable nitrogen management has been prepared for the Task Force on Reactive Nitrogen under the UNECE Air Convention, with support from the European Commission. The process of drafting the Guidance Document started in connection to a workshop "Towards joined-up nitrogen guidance for air, water and climate co-benefits", hosted in Brussels, 11-12 October 2016. The current chapter draft is based on the results from that workshop and on discussions and developments since then. It will be presented and discussed in Brussels on 30 September-1 October at a second workshop jointly organised by the Task Force on Reactive Nitrogen and the European Commission. The content of the draft paper reflects the views only of the authors and the European Commission cannot be held responsible for any use which may be made of the information.
Canadian Journal of Animal Science, 2015
Sheppard, S. C., Bittman, S., Donohoe, G., Flaten, D., Wittenberg, K. M., Small, J. A., Berthiaum... more Sheppard, S. C., Bittman, S., Donohoe, G., Flaten, D., Wittenberg, K. M., Small, J. A., Berthiaume, R., McAllister, T. A., Beauchemin, K. A., McKinnon, J., Amiro, B. D., MacDonald, D., Mattos, F. and Ominski, K. H. 2015. Beef cattle husbandry practices across Ecoregions of Canada in 2011. Can. J. Anim. Sci. 95: 305–321. Beef production in Canada is diverse in many dimensions with numbers of cattle per operation ranging over 10 000-fold, pasture usage from nil to 100%, and types of operations from solely cow–calf to exclusively feedlot finishing. This study summarizes management information obtained from a survey conducted in 2012 (about 2011) on 1009 beef operations in Canada. Many of the results clearly differentiate the practices in the Prairies from those in Ontario and Quebec. Compared to eastern Canada, the Prairies had earlier and shorter calving seasons, higher weaning weights, utilized more winter grazing with a variety of strategies, grew and fed more barley than corn, used...
Modeling Carbon and Nitrogen Dynamics for Soil Management, 2001
Plant and Soil
Defining the long-term effects of liquid dairy manure (LDM) applied by a recommended low emission... more Defining the long-term effects of liquid dairy manure (LDM) applied by a recommended low emission method is important to ensure sustainable grass production and dairy operations. We used natural abundance δ15N and conventional measurements in a long term field experiment to better understand the long-term fate of N applied as LDM, mineral fertilizer (MIN) and both (ALT). We investigated the effects of long-term applications of LDM (with low-emission trailing shoe), MIN, and alternating LDM and MIN (ALT) on grass N uptake, soil N stocks, N losses and δ15N natural abundance in grass, soil and fine heavy fraction (silt + clay size heavy soil). Nominal annual rates of total N were 200 and 400 kg ha−1 for MIN and 400 and 800 kg ha−1 for LDM. MIN and LDM (at 400 kg N ha−1) had similar NUE but LDM accumulated more total soil N (13% of applied) with less losses than MIN; ALT had high yields and losses. Herbage δ15N of MIN declined to near MIN levels after 10–15 years, indicating influence of pre trial management. Herbage δ15N of LDM was consistently lower than applied LDM, implying uptake of depleted urine N. High rates of enriched LDM had little effect on soil δ15N suggesting soil N was quite stable and enriched N was lost by non discriminating pathways like leaching. The physically protected fine heavy fraction contained most soil N. Clearer understanding of long-term N dynamics can improve sustainability of heavily fertilized perennial grasses on dairy farms.
Climate Change and Soil Interactions, 2020
Abstract Good soil quality implies the maintenance of properties at levels capable of ensuring an... more Abstract Good soil quality implies the maintenance of properties at levels capable of ensuring an equilibrated and healthy ecosystem, with sustained agricultural production to supply the world population. Climate change, land-use change, and agriculture intensification are causing a decline in soil quality, which in most parts of the world is becoming severe (desertification). Land-use changes, the associated loss of soil organic matter (SOM), and beneficial microbial diversity are major reasons for deteriorating soil fertility and declining agricultural productivity, as well as affecting water, air, and biodiversity. Adaptation towards climate-resilient and climate-smart agriculture is necessary to cope with climate change and extreme events. This requires the following measures: (1) sustainable production (integrated livestock and cropping systems, including agroforestry); (2) increased soil organic matter (SOM) (bio-based and organic fertilizers, crop rotations, crop associations, no-till, conservation agriculture, C sequestration, and microbial processes); (3) reduced greenhouse gas emissions, less nutrient losses from agriculture, and increased nutrient use efficiency (NUE) (precision agriculture).
Environmental Research Communications, 2021
With increasing demand for land and food, there is growing interest in sustainable intensificatio... more With increasing demand for land and food, there is growing interest in sustainable intensification of agricultural production. Here we investigated sustainable intensification of grass and corn production for dairy farms using a system of semi-virtual farmlets that combine replicated field research plots with feed modelling. We improved manure N capture by spreading separated liquid fraction with a low emission sliding shoe applicator on grass, and manure P capture by precision injecting separated sludge into corn. Reducing the number of annual harvests (5 to 3) increased grass yield and inter-seeding Italian ryegrass in early maturing corn increased fall growth of the cover crop, thus helping to protect soil over winter and providing additional high quality herbage in spring. Irrigation improved yield and potentially yield stability of corn and grass, and adding a nitrification inhibitor to reduce N2O emission may help reduce pollution swapping especially from injected manure. Over...
Canadian Journal of Soil Science, 2019
The lower Fraser Valley is one of the most intensively cropped regions in Canada. Yet, how soil h... more The lower Fraser Valley is one of the most intensively cropped regions in Canada. Yet, how soil health indicators respond to long-term intensive agricultural management is poorly documented in this region. Thus, we evaluated a suite of soil health indicators in response to 21 growing seasons of continuous silage corn (Zea mays L.) under conventional tillage or no-tillage (0–20 cm soil layer). Wet aggregate stability, available water capacity, active carbon (permanganate oxidizable, POXC), and extractable potassium and extractable magnesium were significantly greater with no-till than conventional tillage, whereas 8 of 13 indicators were similar. Soil health indicators responded more favourably to no-till than conventional tillage.
Agricultural and Forest Meteorology, 2018
Ammonia (NH3) emission from animal manure contributes to air pollution and ecosystem degradation,... more Ammonia (NH3) emission from animal manure contributes to air pollution and ecosystem degradation, and the loss of reactive nitrogen (N) from agricultural systems. Estimates of NH3 emission are necessary for national inventories and nutrient management, and NH3 emission from field-applied manure has been measured in many studies over the past few decades. In this work, we facilitate the use of these data by collecting and organizing them in the ALFAM2 database. In this paper we describe the development of the database and summarise its contents, quantify effects of application methods and other variables on emission using a data subset, and discuss challenges for data analysis and model development. The database contains measurements of emission, manure and soil properties, weather, application technique, and other variables for 1899 plots from 22 research institutes in 12 countries. Data on five manure types (cattle, pig, mink, poultry, mixed, as well as sludge and "other") applied to three types of crops (grass, small grains, maize, as well as stubble and bare soil) are included. Application methods represented in the database include broadcast, trailing hose, trailing shoe (narrow band application), and open slot injection. Cattle manure application to grassland was the most common combination, and analysis of this subset (with dry matter (DM) limited to <15%) was carried out using mixed-and fixed-effects models in order to quantify effects of management and environment on ammonia emission, and to highlight challenges for use of the database. Measured emission from cattle slurry ranged from < 1% to 130% of applied ammonia after 48 hours. Results showed clear, albeit variable, reductions in NH3 emission due to trailing hose, trailing shoe, and open slot injection of slurry compared to broadcast application. There was evidence of positive effects of air temperature and wind speed on NH3 emission, and limited evidence of effects of slurry DM. However, random-effects coefficients for differences among research institutes were among the largest model coefficients, and 4 showed a deviation from the mean response by more than 100% in some cases. The source of these institute differences could not be determined with certainty, but there is some evidence that they are related to differences in soils, or differences in application or measurement methods. The ALFAM2 database should be useful for development and evaluation of both emission factors and emission models, but users need to recognize the limitations caused by confounding variables, imbalance in the dataset, and dependence among observations from the same institute. Variation among measurements and in reported variables highlights the importance of international agreement on how NH3 emission should be measured, along with necessary types of supporting data and standard protocols for their measurement. Both are needed in order to produce more accurate and useful ammonia emission measurements. Expansion of the ALFAM2 database will continue, and readers are invited to contact the corresponding author for information on data submission. The latest version of the database is
Canadian Journal of Soil Science, 2008
Over half the slurry manure produced on dairy farms in the high-rainfall, coastal region of Briti... more Over half the slurry manure produced on dairy farms in the high-rainfall, coastal region of British Columbia (BC), Washington State and northern Oregon is applied from mid-February to early May. This study was conducted to compare the emissions of nitrous oxide (N2O) after manure application during this period on perennial forage grass or winter fallow land. The experimental site soil was moderately well- to well-drained medium-textured river deposit of the Monroe series. Treatments consisted of liquid dairy manure applied either at 270 (Early) or 450 (Late) Tsum (accumulation of average air temperatures above 0ºC from Jan. 01) on bare land or a perennial stand of tall fescue (Festuca arundinacea Schreb.) at a rate of 55.5 m3 ha-1 giving a total ammoniacal N (TAN) loading of 100 and 111 kg ha-1 in 2001 and 2002, respectively. An additional grass treatment consisted of split applications (Split) of manure at half the rate on each of the two application dates. Untreated (Control) bare...
Forages have a high N demand, a long growing season, and an effective root system all contributin... more Forages have a high N demand, a long growing season, and an effective root system all contributing to effective nutrient capture. However forages are restrictive in methods available for mitigating gaseous losses both as NH3 and as N2O, due to both practical and cost considerations. Strategies are needed to address the challenges of both N efficiency and N losses. Agronomic techniques in long term experiments can enhance estimates of N loss pathways and N efficiency, and demonstrate the importance of integrated multinutrient approaches. The dual manure stream concept divides manure into a thin fraction suitable as an N source for grass and a sludge fraction suitable as a P source for corn. While this represents an integrated approach, questions remain about alternate loss pathways. While grazing greatly reduces ammonia emissions it is not clear that grazing improves N use relative to confinement systems. The current levels of prospective mitigation of emissions are perhaps modest. H...
Grass and Forage Science, 2019
Sainfoin (Onobrychis viciifolia) is a forage legume of renewed interest in western Canada, with e... more Sainfoin (Onobrychis viciifolia) is a forage legume of renewed interest in western Canada, with equally weighted advantages and disadvantages. In agronomic attributes, sainfoin is, at best, equal in yield, crude protein content and persistence to alfalfa (Medicago sativa). Sainfoin is equally or more palatable than alfalfa to ruminants, with comparable levels of animal productivity per unit forage consumed. The advantages it has compared to alfalfa include the following: (a) mitigation of frothy bloat; (b) reduced ammonia emissions (more faecal nitrogen (N) and less urinary N); (c) equal or better N retention by ruminants; and (d) anthelmintic protection from intestinal parasites. These advantages may be attributed to the presence of condensed tannins (CT), in legumes such as sainfoin. Emphasis on agronomic characteristics in breeding programmes appears to have led to the inadvertent reduction in the efficacy of CT characteristics. Persistence of sainfoin appears to be dependent on minimal pressure from competing plants, harvest or grazing, and good growth conditions from midsummer into fall, allowing for adequate root reserves for survival. It is possible that judicious use of glyphosate in late season might lessen competition in that critical period as sainfoin is more glyphosate-tolerant than alfalfa. Otherwise, sainfoin may be best considered a short-lived forage and best adapted for early season harvest or grazing to eliminate the risk of bloat.
Meeting the dietary demands of humans while protecting Earth's ecosystems is among the greate... more Meeting the dietary demands of humans while protecting Earth's ecosystems is among the greatest challenges of the Anthropocene. Sustainable intensification is expanding as a response to this grand challenge, but success will require an improved understanding of regional, national, and international agricultural systems, including spatial relationships among system components, land use changes that influence the spatial relationships, and optimal approaches to distributing resources. Agricultural specialization and intensification of the 19th and 20th centuries are central considerations, as these advancements led to monumental increases in production and efficiency, but also resulted in uneven geographic distribution of agriculture types and an uncoupling of nutrient biogeochemical cycles. Now, concentrations of animals in certain regions produce manure nutrient accumulations that contribute to air and water pollution, while concentrations of crops in other regions result in nut...
Costs of Ammonia Abatement and the Climate Co-Benefits, 2015
In this chapter we examine techniques for reducing NH3 emissions from stored manure, including: c... more In this chapter we examine techniques for reducing NH3 emissions from stored manure, including: covers, storage design, and manure processing. Most techniques are for liquid manure stores, whereas there are few methods for solid manures and more research is needed. The cost effectiveness for reducing NH3 emissions by each technique was estimated using installation and operating cost data from several sources and published data on baseline emissions and emission reductions of the techniques. A key uncertainty in these cost-efficacy estimates is the baseline emission used to calculate the quantity of N conserved. It is therefore important to obtain regional baseline emission factors (consistent with national emission inventories) to ensure accurate cost estimates.
Atmospheric Ammonia: Detecting Emission Changes and Environmental Impacts, 2009
To date, most attention in modelling NH3 dispersion and deposition has focused on the regional an... more To date, most attention in modelling NH3 dispersion and deposition has focused on the regional and European scale, and little attention has been given to dealing with NH3 in hot-spot areas. The Working Group addressed the issue of hot-spots with four main objectives: • Identify what are the main issues of hot-spots and their consequences at different scales. • Review