Simulated management effects on ammonia emissions from field applied manure

A need exists to improve the utilization of manure nutrients by minimizing NH₃ emissions from land application of manure. Management strategies to reduce NH₃ emissions are available; however, few have been validated under Canadian conditions. A well tested and accurate simulation model, however, can help overcome this challenge by determining appropriate management strategies for a given set of field conditions.     

Nitrogen- vs. phosphorus-based dairy manure applications to field crops: nitrate and phosphorus leaching and soil phosphorus accumulation

Management of animal manures to provide nutrients for crop growth has generally been based on crop N needs. However, because manures have a lower N/P ratio than most harvested crops, N-based manure management often oversupplies the crop-soil system with P, which can be lost into the environment and contribute to eutrophication of water bodies. We examined the effects of N- vs. P-based manure applications on N and P uptake by alfalfa (Medicago sativa L.), corn (Zea mays L.) for silage, and orchardgrass (Dactylis glomerata L.), leaching below the root zone, and accumulation of P in soil. Treatments included N- and P-based manure rates, with no nutrient input controls and inorganically fertilized plots for comparison. Nitrate concentrations in leachate from inorganic fertilizer or manure treatments averaged 14 mg NO(3)-N L(-1), and did not differ by nutrient treatment. Average annual total P losses in leachate did not exceed 1 kg ha(-1). In the top 5 cm of soil in plots receiving the N-based manure treatment, soil test P increased by 47%, from 85 to 125 mg kg(-1). Nitrogen- and P-based manure applications did not differ in ability to supply nutrients for crop growth, or in losses of nitrate and total P in leachate. However, the N-based manure led to significantly greater accumulation of soil test P in the surface 5 cm of soil. Surface soil P accumulation has implications for increased risk of off-field P movement.     

Electromagnetic induction methods applied to an abandoned manure handling site to determine nutrient buildup

Movement of nutrients from livestock manure handling sites has the potential to negatively impact the environment. This study was conducted using electromagnetic induction (EMI) measurements to develop apparent soil electrical conductivity (EC(a)) maps to identify regions of nutrient buildup beneath an abandoned compost site. A trailer-mounted EM-38 coupled with a global positioning satellite system was towed across an area used for composting of feedlot manure. The resulting EC(a) maps were compared with known locations of compost rows confirming the alignment of row locations with high EC(a) regions. The identified rows were cored and compared with the region between the rows. The identified rows with a compost history demonstrated significant (P < 0.05) increases in soluble salts (1.6 times greater), NO3 (6.0 times greater), and Cl (2.0 times greater) compared with the area between the rows at a 1.5-m depth. Image processing techniques were used to display yearly changes that were associated with nutrient movement and transformations in the soil beneath the site. Correlations between EMI measurements and soil core analyses for NO3-N, Cl, and EC provided ancillary support for the EMI methods. The use of EMI for mapping of sites having a history of livestock waste application was effective in delineating high nutrient buildup areas and for observing spatial EC(a) changes over time.     

Phosphorus transport in overland flow in response to position of manure application

Phosphorus (P) loss in overland flow varies with spatial distribution of soil P, management, and hydrological pathways. The effect of flow time, flowpath length, and manure position on P loss in overland flow from two central Pennsylvania soils packed in boxes of varying length (0.5, 1.0, 1.5, 2.75, and 4.0 m long x 15 cm wide x 5 cm deep) were examined by collecting flow samples at 5-min intervals for 30 min (50 mm h(-1) rainfall) without and with 75 kg P ha(-1) applied as swine (Sus scrofa) manure over 0.5 m of the box slope length at distances of 0 to 3.5 m from the downslope collection point. Dissolved reactive P concentration was more closely related to the proportion of clay in sediment of overland flow before (r = 0.98) than after (r = 0.56) manure application. This was attributed to the transport of larger, low-density particles after applying manure. The concentration of dissolved and particulate P fractions decreased with increasing flowpath length, due to dilution rather than sorption of P by surface soil during overland flow. Total P loss (mainly as particulate P) from the Watson channery silt loam (fine-loamy, mixed, active, mesic Typic Fragiudult) was more than from Berks channery silt loam (loamy-skeletal, mixed, active, mesic Typic Dystrudept), even with manure applied. Thus, while P loss in overland flow is affected by where manure is applied relative to flowpath length, initial soil P concentration should not be discounted when looking at areas of potential P loss within a watershed.     

Solids and nutrient removal from flushed swine manure using polyacrylamides

Most of the organic nutrient elements (nitrogen and phosphorus) and carbon compounds in liquid swine are contained in fine suspended particles. Flocculation treatment with polyacrylamide (PAM) followed by screening is one the best methods to separate the liquid fraction from the solid fraction in swine manure, and thus to eliminate nutrient elements associated with solids. In this study, the efficiency of a synthetic polyacrylamide to treat swine manure was evaluated. After polymer treatment samples were sieved and the filtrated liquid was analyzed. TSS, VSS and COD concentrations in the liquid fraction were 2.17, 1.93 and 16.42 g/L respectively, accounting for 94, 94 and 77% removal percentages for TSS, VSS and COD using 30 mg/L of PAM.     

Response of antibiotics and resistance genes to high-intensity and low-intensity manure management

The purpose of this study was to determine the response of antibiotics and antibiotic resistance genes (ARG) to manure management. A pilot field study was conducted using horse manure containing no antibiotics, into which chlortetracycline (CTC), tylosin (TYL), and monensin (MON) were spiked and compared to unspiked controls. Subsequently, a large-scale field study was conducted comparing manure from a dairy with minimal use of antibiotics and a feedlot with regular subtherapeutic use of antibiotics. The manures were subjected to high-intensity management (HIM) (amending, watering, and turning) and low-intensity management (LIM) (no amending, watering, or turning) and were monitored for antibiotic concentrations and levels of tetracycline ARG [tet(W) and tet(O)] using quantitative real-time polymerase chain reaction. All three antibiotics in the pilot study dissipated more rapidly in HIM manure, with half-lives ranging from 4 to 15 d, compared to LIM manure, with half-lives ranging from 8 to 30 d. Levels of tet(W) were significantly higher after 141 d of treatment, but levels of tet(O) were significantly lower in all treatments. In the large-scale study, the feedlot manure had higher initial concentrations than the dairy manure of tetracycline (TC), oxytetracycline (OTC), and CTC as well as tet(W) and tet(O). Tetracycline and OTC dissipated more rapidly in HIM manure, with half-lives ranging from 6 to 15 d, compared to LIM manure, with half-lives ranging from 7 to 31 d. After 6 mo of treatment, tet(W) and tet(O) decreased significantly in feedlot manure, whereas dairy manure required only 4 mo of treatment for similar results.     

Exploring red deer culling strategies using a population-specific calibrated management model

Wildlife management is generally carried out under conditions of uncertainty. The exact population size is unknown, its future dynamics are uncertain and clear management objectives are often not formulated. In order to provide management advice in this situation, a framework is presented for combining different sources of information using a Bayesian approach for calibrating a management model. Harvesting strategies can then be explored based on predictions of future populations size and structure which incorporate parameter uncertainty. This method makes it possible to evaluate the probability of achieving certain objectives with different management strategies. The advantage of the approach presented in this paper lies in that both the model and the harvesting strategies are adaptable to any particular population of interest. The approach is illustrated for two Scottish red deer populations for which culling strategies corresponding to different management objectives are explored and their benefits evaluated. It is found that each population requires different culling rates for keeping population number stable, demonstrating the benefits of the population specific calibration of the management model.     

The guild concept applied to management of bird populations

Alternative ways to apply the guild concept to wildlife management are evaluated here. I reject the idea that indicator species can be selected for each bird guild to reduce costs of environmental assessment and monitoring. Promise is seen, however, in the option of using whole guilds to indicate the capability of habitat zones to support populations of wildlife species. It may be adequate for most management purposes to delineate guilds only for species that use an environment for breeding, because transients and winter residents probably use the same zones of the habitat in the same ways. Potential guilds are identified by cells of a two-dimensional matrix, the axes identifying primary feeding and nesting zones. Some questions may be answered with guilds as delineated by all cells in the matrix. Alternatively, larger guilds can be formed by grouping all species in each column or row of the matrix to identify, for example, all species that depend on tree canopies for foraging, or tree boles for nesting. One can also consider separately the resident breeders, migrant breeders, and winter residents to obtain insights into whether observed changes in numbers of birds in a guild are a result of conditions locally or elsewhere. I conclude that the guild concept probably has a place in wildlife management, but much testing must be done before it is widely applied.     

Novel manure management technologies in no-till and forage introduction to the special series

Surface application of manures leaves nitrogen (N) and phosphorus (P) susceptible to being lost in runoff, and N can also be lost to the atmosphere through ammonia (IH3) volatilization. Tillage immediately after surface application of manure moves manure nutrients under the soil surface, where they are less vulnerable to runoff and volatilization loss. Tillage, however, destroys soil structure, can lead to soil erosion, and is incompatible with forage and no-till systems. A variety of technologies are now available to place manure nutrients under the soil surface, but these are not widely used as surface broadcasting is cheap and long established as the standard method for land application of manure. This collection of papers includes agronomic, environmental, and economic assessments of subsurface manure application technologies, many of which clearly show benefits when comparedwith surface broadcasting. However, there remain significant gaps in our current knowledge, some related to the site-specific nature of technological performance, others related to the nascent and incomplete nature of the assessment process. Thus, while we know that we can improve land application of manure and the sustainability of farming systems with alternatives to surface broadcasting, many questions remain concerning which technologies work best for particular soils, manure types, and farming and cropping systems.     

Landscape planning: A method applied to a growth management example

This article is the first in a series of three. These articles were prepared to document the growth management process undertaken in Teller County, Colorado, USA. In this article, an 11-step method for landscape planning is proposed. In step 1, an issue, or set of related issues, is identified as posing a problem and/or opportunity to people and/or the environment. In step 2, a goal, or several goals, is established to address the problem or opportunity. In steps 3 and 4, inventories and analyses of biophysical and sociocultural processes are conducted, first at the regional level and then at the local level. Step 5 involves detailed studies (such as suitability analyses) that link the inventory and analysis information to the problems or opportunities and goals. Detailed studies link regional and local information to specific sites. Thus, this method involves a regional-local-specific site hierarchy. In step 6, concepts are developed that lead to a landscape plan in step 7. During step 8, the plan is explained through a systematic educational and citizen involvement effort to the affected public. In step 9, detailed designs are developed that again are explained to the specific individuals who will be impacted by the designs. It is in step 10 when the plan and designs are implemented. Step 11 involves the administration of the plan. The method is illustrated through an example of growth management planning for Teller County and the city of Woodland Park, Colorado. Paper 1 in a series of 3.     

Organizational commitment to integrated and collaborative management: matching strategies to constraints

Integrated and collaborative approaches to environmental management are being advocated as a more appropriate and effective approach to decision-making. It is based on collaboration among a range of individuals and organizations that have a stake, role, or responsibility in management outcomes. However, researchers have found that implementation of this approach has encountered difficulties. This paper focuses on the role of organizations and their commitment to implementation. Based on case study and survey research in the United States and Australia, the author examines organizational constraints and the range of strategies used to secure commitment. It is argued that participants must more explicitly address the commitment issue and design implementation strategies that respond to organizational constraints.     

A review of post-modern management techniques as currently applied to Turkish forestry

This paper reviews the effects of six post-modern management concepts as applied to Turkish forestry. Up to now, Turkish forestry has been constrained, both in terms of its operations and internal organization, by a highly bureaucratic system. The application of new thinking in forestry management, however, has recently resulted in new organizational and production concepts that promise to address problems specific to this Turkish industry and bring about positive changes. This paper will elucidate these specific issues and demonstrate how post-modern management thinking is influencing the administration and operational capacity of Turkish forestry within its current structure.     

Additives to reduce ammonia and odor emissions from livestock wastes: a review

This paper reviews the use of additives to reduce odor and ammonia (NH3) emissions from livestock wastes. Reduction of NH3 volatilization has been shown to be possible, particularly with acidifying and adsorbent additives, and potential exists to develop further practical and cost-effective additives in this area. Masking, disinfecting, and oxidizing agents can provide short-term control of malodor, but as the capacity of these additives is finite, they require frequent reapplication. Microbial-based digestive additives may offer a solution to this problem as they are regenerative, but they appear to have been developed without a thorough understanding of microbiological processes occurring in livestock wastes. Currently, their use to reduce odor or NH3 emissions cannot be recommend. If the potential of these types of additives is to be realized, research needs to shift from simply evaluating these unknown products to investigating known strains of bacteria or enzymes with known modes of action. To protect the farmers' interest, standard independent test procedures are required to evaluate efficacy. Such tests should be simple and quantify the capacity of the additive to perform as claimed. The principle use of additives needs to be identified and addressed during their development. Producers may not use effective additives in one area if they further compound other problems that they perceived to be more important. There is the potential to use additives to treat other problems associated with livestock wastes, particularly to improve handling properties, reduce pollution potential to watercourses, and reduce pathogenic bacteria. Further work is required in these areas.     

The reversible process concept applied to the environmental management of large river systems

The wetland ecosystems occurring within alluvial floodplains change rapidly. Within the ecological successions, the life span of pioneer and transient stages may be measured in several years or decades depending on the respective influences of allogenic (water dynamics, erosion, and deposition) and autogenic developmental processes (population dynamics, eutrophication, and terrestrialization). This article emphasizes the mechanisms that are responsible for the ecosystem changes and their importance to environmental management. Two case studies exemplify reversible and irreversible successional processes in reference to different spatial and temporal scales. On the scale of the former channels, the standing-water ecosystems with low homeostasis may recover their previous status after human action on the allogenic processes. On the scale of a whole reach of the floodplain, erosion and deposition appear as reversible processes that regenerate the ecological successions. The concepts of stability and reversibility are discussed in relation to different spatiotemporal referential frameworks and different levels of integration. The reversible process concept is also considered with reference to the energy inputs into the involved subsystems. To estimate the probability of ecosystem regeneration or the cost of restoration, a concept of degrees of reversibility is proposed.     

Demonstration of methods to reduce E. coli runoff from dairy manure application sites

Contamination by bacteria is a leading cause of impairment in U.S. waters, particularly in areas of livestock agriculture. We evaluated the effectiveness of several practices in reducing Escherichia coli levels in runoff from fields receiving liquid dairy (Bos taurus) manure. Runoff trials were conducted on replicated hay and silage corn (Zea mays L.) plots using simulated rainfall. Levels of E. coli in runoff were approximately 10(4) to 10(6) organisms per 100 mL, representing a significant pollution potential. Practices tested were: manure storage, delay between manure application and rainfall, manure incorporation by tillage, and increased hayland vegetation height. Storage of manure for 30 d or more consistently and dramatically lowered E. coli counts in our experiments, with longer storage providing greater reductions. Manure E. coli declined by > 99% after approximately 90 d of storage. On average, levels of E. coli in runoff were 97% lower from plots receiving 30-d-old and > 99% lower from plots receiving 90-d-old manure than from plots where fresh manure was applied. Runoff from hayland and cornland plots where manure was applied 3 d before rainfall contained approximately 50% fewer E. coli than did runoff from plots that received manure 1 d before rainfall. Hayland vegetation height alone did not significantly affect E. coli levels in runoff, but interactions with rainfall delay and manure age were observed. Manure incorporation alone did not significantly affect E. coli levels in cornland plot runoff, but incorporation could reduce bacteria export by reducing field runoff and interaction with rainfall delay was observed. Extended storage that avoids additions of fresh manure, combined with application several days before runoff, incorporation on tilled land, and higher vegetation on hayland at application could substantially reduce microorganism loading from agricultural land.     

Exploring management strategies for community-based forests using multi-agent systems: A case study in Palawan, Philippines

This paper describes the experiences and lessons learned in applying a multi-agent systems (MAS) model to study the dynamics and complex interactions among stakeholders in the management of community-based forests. The MAS model is developed using the companion modelling (ComMod) approach, which allows for a collaborative development of the model between the stakeholders and researchers. This approach involves the development and application of role-playing games (RPGs) and computer simulation as learning tools and to validate the model. Inferences are drawn from the learning and negotiation processes that the stakeholders and researchers underwent in the collaborative development of the MAS model. These processes ultimately led to the development of a collaborative resource management plan. The approach and the MAS model were applied to a case study involving a community-based forest managed by three villages in the island of Palawan, Philippines.     

Emissions of ammonia, methane, carbon dioxide, and nitrous oxide from dairy cattle housing and manure management systems

Concentrated animal feeding operations emit trace gases such as ammonia (NH?), methane (CH?), carbon dioxide (CO?), and nitrous oxide (N?O). The implementation of air quality regulations in livestock-producing states increases the need for accurate on-farm determination of emission rates. The objective of this study was to determine the emission rates of NH?, CH?, CO?, and N?O from three source areas (open lots, wastewater pond, compost) on a commercial dairy located in southern Idaho. Gas concentrations and wind statistics were measured each month and used with an inverse dispersion model to calculate emission rates. Average emissions per cow per day from the open lots were 0.13 kg NH?, 0.49 kg CH?, 28.1 kg CO?, and 0.01 kg N?O. Average emissions from the wastewater pond (g m(-2) d(-1)) were 2.0 g NH?, 103 g CH?, 637 g CO?, and 0.49 g N?O. Average emissions from the compost facility (g m(-2) d(-1)) were 1.6 g NH?, 13.5 g CH?, 516 g CO?, and 0.90 g N?O. The combined emissions of NH?, CH?, CO?, and N?O from the lots, wastewater pond and compost averaged 0.15, 1.4, 30.0, and 0.02 kg cow(-1) d(-1), respectively. The open lot areas generated the greatest emissions of NH?, CO?, and N?O, contributing 78, 80, and 57%, respectively, to total farm emissions. Methane emissions were greatest from the lots in the spring (74% of total), after which the wastewater pond became the largest source of emissions (55% of total) for the remainder of the year. Data from this study can be used to develop trace gas emissions factors from open-lot dairies in southern Idaho and potentially other open-lot production systems in similar climatic regions.     

Conservation strategies for effective land management of protected areas using an erosion prediction information system (EPIS)

This research demonstrates the predictive modeling capabilities of a geographic information system (GIS)-based soil erosion potential model to assess the effects of implementing land use change within a tropical watershed. The Revised Universal Soil Loss Equation (RUSLE) was integrated with a GIS to produce an Erosion Prediction Information System (EPIS) and modified to reflect conditions found in the mountainous tropics. Research was conducted in the Zenzontia subcatchment of the Río Ayuquíla, located within the Sierra de Manantlán Biosphere Reserve (SMBR), México. Expanding agricultural activities within this area will accentuate the already high rate of soil erosion and resultant sediment loading occurring in the Río Ayuquíla. Two land-use change scenarios are modeled with the EPIS: (1) implementation of soil conservation practices in erosion prone locations; and (2) selection of sites for agricultural expansion which minimize potential soil loss. Confronted with limited financial resources and the necessity for expedient action, managers of the SMBR can draw upon the predictive capacity of the EPIS to facilitate rapid and informed land-use planning decisions.     

Assessing watershed transport of atrazine and nitrate to evaluate conservation practice effects and advise future monitoring strategies

Continued public support for U.S. taxpayer funded programs aimed at reducing agricultural pollutants depends on clear demonstrations of water quality improvements. The objective of this research was to determine if implementation of agricultural best management practices (BMPs) in the Goodwater Creek Experimental Watershed (GCEW) resulted in changes to atrazine and nitrate (NO₃–N) loads during storm events. An additional objective was to estimate future monitoring periods necessary to detect a 5, 10, 20, and 25% reduction in atrazine and NO₃–N event load. The GCEW is a 73 km² watershed located in northcentral Missouri, USA. Linear regressions and Akaike Information Criteria were used to determine if reductions in atrazine and NO₃–N event loads occurred as BMPs were implemented. No effects due to any BMP type were indicated for the period of record. Further investigation of event sampling from the long-term GCEW monitoring program indicated errors in atrazine load calculations may be possible due to pre-existing minimum threshold levels used to trigger autosampling and sample compositing. Variation of event loads was better explained by linear regressions for NO₃–N than for atrazine. Decommissioning of upstream monitoring stations during the study period represented a missed opportunity to further explain variation of event loads at the watershed outlet. Atrazine requires approximately twice the monitoring period relative to NO₃–N to detect future reductions in event load. Appropriate matching of pollutant transport mechanisms with autosampling protocols remains a critical information need when setting up or adapting watershed monitoring networks aimed at detecting watershed-scale BMP effects.