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Paper mill biosolids (PB) are recognized as a valuable source of carbon for the physical improvement of arable soils. However, little is known about the composition of carbohydrates of these materials and their breakdown in soil, which contributes to soil structural stability. The objectives of this study were to characterize the carbohydrates in PB and to determine under controlled conditions and in the field the soil carbohydrate content and water-stable aggregation. The field experiment consisted of PB applied every year (2000–2008) at 0, 30, and 60 Mg wet weight·ha−1 to annual row crops with soils collected after 3, 6, and 9 yr. The other experiment consisted of PB added at 50 Mg wet weight·ha−1 to two soils, a clay and a sandy loam, and incubated at 25 °C and 60% water-filled pore space for 16 wk. The PB differed in their content in galactose, mannose, and arabinose for total fraction and sum of carbohydrates for water-soluble fraction. In the field, repeated annual PB application increased most of soil total carbohydrates (sum and individuals) after 3 yr and the proportion of >1 mm stable aggregates. The incubation study confirmed results obtained in the field, where the PB richest in carbohydrates induced the highest increases in soil total carbohydrates in both soil types. Soil total and microbial (galactose and mannose)-derived carbohydrates were closely correlated with the percentage of large aggregates, while with water-soluble carbohydrates, they are highly correlated to the amount of microbial carbohydrates applied, thus further contributing to improve soil C quality.

In recent decades, there has been a growing interest in the recycling of organic materials such as paper mill biosolids (PB) and biochar for use as soil amendments. However, the benefits of co-application of PB and biochar and its effects on soil phosphorus (P) availability remain unknown. An incubation study was conducted on two acidic soils to assess the effect of two PB types (2.5% w/w) co-applied with three rates (0%, 2.5%, and 5% w/w) of pine (Pinus strobus L.) biochar on soil P fractions. An unfertilized control and a mineral NP fertilizer were used as a reference. Soil P fractions were determined by Hedley procedure after 2 and 16 wk of incubation. Material fractionation indicated that the PB containing the highest total P and the lowest Al content had the highest proportion of labile P, whereas most P in the biochar was in a stable form. The incubation study revealed that the P-rich PB increased P availability in both soils to a level comparable to mineral fertilizer at the end of the incubation. The addition of biochar to PB, however, did not affect soil P availability, but the highest rate induced a conversion of P fixed to Al and Fe oxides towards recalcitrant forms, particularly in the sandy loam soil. We conclude that co-applying biochar and PB could be more beneficial than application biochar alone and soils amended with such a mixture would be expected to release part of their P slowly over a longer period of time.

Amending croplands with forest residues may help in restoring soil properties in fields subject to intensive land management. Despite their known benefits when applied separately, co-application of wood biochar with paper mill biosolids (PB) has seen little investigation under field conditions. A study was initiated in Québec, QC, Canada, to determine the effect of a single application of wood biochar with and without PB on the nitrogen (N) and phosphorus (P) availability of two pH-neutral to alkaline loamy soils. Biochar at 0, 10, and 20 Mg dry weight·ha−1 and PB at 30 Mg wet weight·ha−1 were applied before planting of corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] in 2018. Residual effect of this co-application was determined under soybean and corn in the subsequent year. In both years, corn received supplemental N and P from mineral fertilizers according to local agronomic recommendations. Co-applying biochar and PB reduced soil NO3-N availability in the year of application and decreased corn yield by 1.0 Mg·ha−1 compared with biochar or PB applied alone, but these amendments did not affect soybean yields. In the following year, the previous biochar addition increased soybean yield by 0.6 Mg·ha−1 but had little effect on corn. For both years, biochar addition induced a large increase in soil Mehlich-3 P. This study revealed that wood biochar positively impacted P status of these soils but was not a source of N to crops even when co-applied with PB.

Combined papermill biosolids (PB) and forest-derived alkaline by-products are known for their direct benefits to agricultural crops, but their residual effects after several years of application have received little attention. A 10 yr field study was initiated on a loamy soil at Yamachiche, QC, to assess the residual effects of PB application after nine consecutive years, either alone or with several liming by-products, on nitrogen (N), phosphorus (P), and metal accumulation in plant and crop yield. The treatments consisted of PB at 0, 30, 60, and 90 Mg wet·ha−1, three liming by-products (calcitic lime, lime mud, and wood ash), each at 3 Mg wet·ha−1 with 30 Mg wet PB·ha−1, and a mineral N fertilizer (MIN). During the residual years, only the MIN treatment was carried out every year according to crop needs. Grain yield and total plant N and P accumulation were evaluated each year, whereas metal accumulation was determined on a 3 yr cycle. The residual effects of PB applications increased crop yields in some years, but the effects were generally lower than with MIN. Plant N recovery in the first three residual years was half of that recorded during years of application (15% vs. 30%), whereas P recovery was at 6%. Residual PB applications had little effect on metal accumulation in grain. Soil liming decreased zinc and cadmium concentrations in grain but increased molybdenum. This study showed that repeated applications of PB and alkaline materials continued to have a positive effect on field crops 3–5 yr after their cessation.

Plusieurs dirigeants croient a tort que formuler une strategie est un exercice long, couteux et futile dans le monde instable actuel. Persuades qu’il est illusoire d’investir dans une telle demarche, ils en concluent que leur seule planche de salut consiste a reagir rapidement a toutes les occasions qui se presentent sur le marche. Ils mettent ainsi de cote une activite essentielle au succes de leur organisation.

Combined paper mill biosolids (PB) are a well-known fertilizing source of nitrogen (N) and phosphorus (P). Many jurisdictions have established default values for estimating their agronomic N and P contribution, but nutrient release can vary with their chemical properties, and this has been little studied. The objective of this incubation study was to compare four PB of different sources along with a de-inking paper sludge (DPS) for their N and P release in three contrasting soils under controlled conditions (25 °C, 60% water-filled pore space). Treatments consisted of PB or DPS at 50 Mg fresh mass ha−1, PB at 30 Mg fresh mass ha−1 plus inorganic N to supply 100 kg available N ha−1, inorganic NP fertilizer, and an unfertilized control. Measurements of NO3 + NH4-N were made after 3 d and 1, 2, 3, 4, 6, 8, 12, and 16 wk of incubation. Mehlich-3 P was measured after 2 and 16 wk of incubation. Nitrogen mineralization generally declined a few days after PB addition and then gradually and constantly increased. The P mineralization of PB also increased with time. By the end of incubation, net N and P release averaged 30% (7%–49%) and 75% (16%–116%) of the NP fertilizer, respectively. The intensity of release, however, varied with material characteristics and soil type. Mineral N addition to the 30 Mg PB ha−1 promoted N release to a level comparable to NP fertilizer. Soil N immobilization occurred with the DPS application. Current default N value used for PB in Quebec and Ontario is appropriate but not P.

Resume Les reformes du systeme electoral dans les democraties liberales ont permis aux personnes ayant une deficience intellectuelle, historiquement depouillees de leur citoyennete, d’exercer leurs droits politiques. S’inspirant du contenu de la Convention relative aux droits des personnes handicapees (2008), de nombreux gouvernements nationaux ont etendu le principe de l’inclusion universelle au droit de vote aux personnes ayant une deficience intellectuelle, et ce, malgre certaines resistances institutionnelles. Differentes approches de l’ethique et de la theorie politique ont donne des justifications a ce processus de reforme, mais elles demeurent partagees a l’idee de determiner un seuil de competences intellectuelles requises pour l’exercice des droits politiques. Le concept de vulnerabilite developpe par Martha Fineman aborde l’enjeu differemment, en mettant l’accent sur les dimensions relationnelles et collaboratives de l’institution politique et de la citoyennete.

This research aimed to classify 16 horticultural composts collected across Canada into management group according to their phosphorus (P) fractions and carbon (C) content using isometric log ratio (ilr) and to interpret the clusters against the total P content and C-to-P ratio indices. The ilr approach was found to be more discriminant for grouping the composts compared with the conventional statistical analysis. The C-to-P ratio index was representative of cluster 1 only. This cluster included organic amendments with C-to-P ratios higher than 100 and high capacity to increase soil organic matter content without excessive P dosage. Total P separated clusters 2 and 3 despite the amalgamation of P forms into total P. Cluster 2 showed high total P (>10 g P kg−1) and low C-to-P ratios (24–38), whereas cluster 3 showed variable C-to-P ratios (18–78) and total P −1after excluding one compost close to cluster 2. Clusters 2 and 3 were considered as potential sources of plant-available P. The ilr approach suggests that composts made of municipal biosolids and poultry manures in cluster 2 have the highest potential as plant-available P source compared with those made of other livestock manures or food processing wastes.

De 50 % a 90 % des efforts strategiques des entreprises sont en definitive consideres comme des echecs1. Par consequent, peu d’entreprises reussissent a creer et a maintenir un avantage concurrentiel ainsi qu’a assurer leur croissance de facon durable. Les entreprises peuvent toutefois eviter le naufrage grâce a un systeme rigoureux et agile de gestion de la strategie.

Industrial by-products such as paper mill biosolids (PBs) have been used as fertilizers and amendments in agriculture for many decades. However, their content of plant essential nutrients including phosphorus (P) varies largely with sources, and availability of these nutrients once applied to soil still remains unknown. Five PBs differing in their C/N ratio (12–47) were used in an incubation study to assess the P forms and availability from both PBs and PB-amended soils. Biosolids were added to three contrasting soils varying in texture and pH in 500-ml jars at the rate of 50 Mg wet ha–1, supplying between 45 and 112 kg total P ha–1. An unfertilized control and a mineral NP treatment (30 kg P ha–1) were also included. Biosolids and soil P fractions were determined by a modified Hedley fractionation method following 2 and 16 weeks of incubation. Phosphorus forms in PBs varied across type of materials with labile P ranging from 20 to 72% and organic P (Po) ranging from 28 to 66% of total P. Soil incubated with PB showed changes in all P fractions due to amendment, soil type, and duration of incubation. Resin-P and labile P, the most available forms, were significantly higher with addition of high PB–P content. Soil labile P represented up to 50% of total P added by PB. Overall, most inorganic P (Pi) fractions and labile P further increased with incubation duration. Close relationships were established between resin-P and labile P content in PB and the increases of those fractions in incubated soils, notably after 2 weeks. The P recovery as labile P represented on average 34% of total P added or 68% in terms of mineral P. We concluded that PB could be used as an efficient source of P for fertilizing crops.

Continuous assessment of soil heavy metal concentrations in agricultural soils is critical for ensuring ecosystem health and minimizing potential adverse effects. However, conventional laboratory determinations are time-consuming, expensive and involve hazardous chemicals. We evaluated the potential of visible near infrared reflectance spectroscopy (VNIRS) to rapidly and simultaneously predict total, Mehlich-3 (M3), DTPA, and water-soluble (H 2 O) soil heavy metal concentrations. Soil samples were collected from a loam soil ( n = 64) and a loamy sand ( n = 32) after repeated annual applications (3–9 years) of paper mill biosolids (PB) and liming by-products. Models were developed using modified partial least squares regression on 75% of the total sample set and also for each soil, after removal of the spectral outliers ( n = 3), with the remainder used for validation. The coefficient of determination in validation (R 2 V ) and the ratio of performance to deviation (RPD) were used to assess model accuracy. Predictions for the total set were excellent for total Zn and Cd, M3-Cu and -Cd, and DTPA-Cd (R 2 V > 0.90, RPD > 3.0), good for total Cu, Ni and Mo, M3-Ni, DTPA-Cu and -Ni, and H 2 O-Cu and -Ni (R 2 V = 0.70 to 0.90, RPD = 1.70 to 3.0), but poor for M3-Zn, DTPA-Zn, and H 2 O-Zn, -Cd and -Mo (R 2 V

Improvement in use efficiency of N fertilizers can potentially better sustain agriculture by reducing N2O emissions from soils, but little is known about its impact on soil CO2 emissions. A study, involving both a field experiment and a laboratory incubation, was conducted in eastern Canada to determine the N fertilization effect on soil CO2 emissions. In laboratory, we incubated nine different types of soil with and without 150 kg N ha−1 as KNO3 or (NH4)2SO4. The N-fertilized soils had lower CO2 emissions compared with the no-N control soils for six of them. Among fertilizer sources, emissions of CO2 were on average 22% lower with KNO3 than with (NH4)2SO4. The field experiment conducted on a clay soil included three sources of N (urea-NH4NO3, CaNH4NO3, and aqua NH3) at 0–200 kg N ha−1 band-incorporated at the six-leaf corn stage. Under field conditions, most CO2 was emitted between N application and grain maturity with cumulative seasonal soil emissions greater in the control (4.9 Mg C ha−1) than in the N treatments (average of 4.0 ± 0.3 Mg C ha−1). Evidence suggested that both heterotrophic and autotrophic respiration seemed affected, whereas the NO3-based source had a more depressing effect on CO2 emissions than did the NH4 source.

Depuis l’adoption de la Convention des Nations Unies relative aux droits des personnes handicapées (2006), les États signataires sont appelés à réformer leurs lois électorales. D’abord, les lois qui retirent systématiquement le droit de vote aux personnes ayant une déficience intellectuelle (DI), sans procéder à une évaluation individuelle de leur capacité à voter, sont considérées comme discriminatoires. De plus, il importe de mettre l’accent sur la responsabilité des pouvoirs publics de veiller au respect et à l’exercice des droits politiques. Dans un premier temps, le présent texte aborde la question de la légitimité des tests d’aptitude visant à déterminer la capacité à voter et, ensuite, la question des devoirs des autorités électorales dans le but de permettre le vote des personnes ayant une DI. D’un point de vue formel, le texte appuie le principe d’un droit de vote inconditionnel, tout en reconnaissant, d’un point de vue pratique, qu’il existe des limitations légitimes à l’exercice de celui-ci. Since the adoption of the Convention on the Rights of Persons with Disabilities (2006), the signatory States were called upon to engage in electoral reforms. Considering intellectual disability (ID), all law systematically withdrawing the right to vote without previously examining individual ability to vote has been declared discriminatory. The Convention’s focus has also been placed on states’ responsibilities toward the exercise of political rights. The analysis will first explore the legitimacy of cognitive tests imposed on potential voters. Then, it will examine the duties of the states toward persons with ID. From a formal point of view, the text proposes an unconditional right to vote, while recognizing, from a practical point of view, legitimate limitations of that right.

We used visible near-infrared reflectance spectroscopy (VNIRS) to characterize a set of organic materials (n = 75). Good predictions for total carbon, excellent predictions for total nitrogen, but ...

Few studies have assessed the common, yet unproven, hypothesis that an increase of plant nitrogen (N) uptake and/or recovery efficiency (NRE) will reduce nitrous oxide (N2O) emission during crop production. Understanding the relationships between N2O emissions and crop N uptake and use efficiency parameters can help inform crop N management recommendations for both efficiency and environmental goals. Analyses were conducted to determine which of several commonly used crop N uptake-derived parameters related most strongly to growing season N2O emissions under varying N management practices in North American maize systems. Nitrogen uptake-derived variables included total aboveground N uptake (TNU), grain N uptake (GNU), N recovery efficiency (NRE), net N balance (NNB) in relation to GNU [NNB(GNU)] and TNU [NNB(TNU)], and surplus N (SN). The relationship between N2O and N application rate was sigmoidal with relatively small emissions for N rates

Repeated annual application of paper mill biosolids (PB) and liming materials may impact soil functioning, such as nutrient cycling, organic matter decomposition, and microbial activities. The objective of this study was to evaluate the residual effect of 9 yr annual applications of PB and different liming materials on soil microbial community structure and microbial biomass C, N, and P. Treatments consisted of PB at four rates (0, 30, 60, and 90 wet Mg ha−1), three liming by-products (calcitic lime, lime mud, and wood ash, each at 3 wet Mg ha−1 with 30 Mg PB ha−1), and a mineral N fertilizer surface-applied after annual crop seeding. Three years after treatment application ended, soils were sampled from 0–15 to 15–30 cm layers in each plot after corn harvest. Soil microbial community and microbial biomass C, N, and P were higher in the surface layer than deeper. Application of PB significantly increased soil microbial biomass C, N, and P and fungal biomass in both layers and induced changes in microbial ...

The application of industrial residuals in agriculture may raise concerns about soil and crop metal accumulation. A complete study using a fractionation scheme would reveal build-up in metal pools occurring after material addition and predict the transformation of metals in soil between the different forms and potential metal release into the environment. An experimental study was conducted from 2000 to 2008 on a loamy soil at Yamachiche, Quebec, Canada, to evaluate the effects of repeated annual addition of combined paper mill biosolids when applied alone or with several liming by-products on soil Cu, Zn, and Cd fractions. Wet paper mill biosolids at 0, 30, 60, or 90 Mg ha and calcitic lime, lime mud, or wood ash, each at 3 Mg ha with 30 Mg paper mill biosolids ha, were surface applied after seeding. The soils were sampled after 6 (soybean [ (L.) Merr.]) and 9 [corn ( L.)] crop years and analyzed using the Tessier fractionation procedure. Results indicated that biosolids addition increased exchangeable Zn and Cd, carbonate-bound Cd, Fe-Mn oxide-bound Zn and Cd, organically bound Cu and Zn, and total Zn and Cd fractions but decreased Fe-Mn oxide-bound Cu in the uppermost 30-cm layer. With liming by-products, there was a shift from exchangeable to carbonate-bound forms. Even with very small metals addition, paper mill and liming materials increased the mobility of soil Zn and Cd after 9 yr of application, and this metal redistribution resulted into higher crop grain concentrations.

Land application of residuals from the forest industry can help to restore soil fertility, but few studies have assessed the effects of metal accumulation in plants. An experimental study was initiated in 2000 on a loamy soil at Yamachiche, QC, Canada, to evaluate the effects of repeated annual applications of combined paper mill biosolids, when applied alone or with several liming by-products. This study assessed the accumulation of Cu, Zn, Mo, and Cd in plants and soil after 6 (soybean [ (L.) Merr.]) and 9 [corn ( L.)] crop yr. Wet paper mill biosolids at 0, 30, 60, or 90 Mg ha were surface applied after seeding. Calcitic lime, lime mud, and wood ash were applied wet each at 3 Mg ha with 30 Mg wet paper mill biosolids ha. Repeated applications of paper mill biosolids increased plant and soil metal concentrations after 6 and 9 yr in the order of Cd > Mo (soybean) > Zn > Cu. Liming increased soil pH and Mo availability and decreased Zn and Cd availability. Metals in crop stover responded more positively to applications than those in grains, but the concentrations in plant tissues were generally well below critical values. The Cu/Mo ratio of soybean plants at pH > 6.8 fell below 2:1, however, and may pose a risk for inducing Cu metabolism disorder in ruminants. Results of this study indicate that paper mill biosolids and alkaline residuals, when applied with respect to regulations and soil pH, have a limited effect on metal accumulation in plants and soil.

No-tillage systems contribute to physical, chemical and biological changes in the soil. The effects of different tillage practices and phosphorus (P) fertilization on soil microbial biomass, activity, and community structure were studied during the maize growing season in a maize–soybean rotation established for 18 years in eastern Canada. Soil samples were collected at two depths (0–10 and 10–20 cm) under mouldboard plow (MP) and no-till (NT) management and fertilized with 0, 17.5, and 35 kg P ha−1. Results show that the duration of the growing season had a greater effect on soil microbiota properties than soil tillage or P fertilization at both soil depths. Seasonal fluctuations in soil microbial biomass carbon (SMB-C) and nitrogen (SMB-N), in dehydrogenase and alkaline phosphomonoesterase activities, and in total phospholipids fatty acid (PLFA) level, were greater under NT than MP management. The PLFA biomarkers separated treatments primarily by sampling date and secondly by tillage management, but were not significantly affected by P fertilization. The abundance of arbuscular mycorrhizal fungi (AMF; C16:1ω5) and fungi (C18:2ω6,9) was lower under NT than MP at the 10–20-cm soil depth in July. Phosphorus fertilization increased soil microbial biomass phosphorus (SMB-P) and Mehlich-3 extractable P, but had a limited impact on the other soil properties. In conclusion, soil environmental factors and tillage had a greater effect on microorganisms (biomass and activity) and community structure than P fertilization.

Synthetic N fertilizers are a major source of N 2 O emissions from soil. A field experiment was conducted during three growing seasons (2004-2006) on a clay soil (fine, mixed, frigid Typic Humaquept) under corn (Zea mays L.) to evaluate the impact of N fertilizer source and application rate on N 2 O emissions. Treatments consisted of three sources of N fertilizer (urea-NH 4 NO 3 32% [UAN], Ca-NH 4 NO 3 [CAN], and aqua NH 3 [AA]) at four different rates (0, 100, 150, and 200 kg N ha ―1 ). Fertilizers were banded 5 cm below the soil surface between corn rows at the six-leaf stage and N 2 O emissions were measured weekly. For all 3 yr of this study, cumulative N 2 O emission decreased in the order UAN ≥ CAN ≥ AA. Averaged across years, fertilizer-induced post-sidedress emissions were greater than the Intergovernmental Panel on Climate Change default factor (0.01 kg N 2 O-N kg ―1 N), with values of 0.038, 0.033, and 0.027 kg N 2 O-N kg ―1 N for UAN, CAN, and AA, respectively. The N 2 O emissions increased linearly with N rate, even at rates exceeding the optimum level for grain yield. Peaks of N 2 O flux occurred on the days following fertilizer application and in early fall when the soil was re-wetted. Emissions of N 2 O were higher at water-filled pore space >0.57 m 3 m ―3 and were also related to soil inorganic N and water-extractable organic C contents. Our results confirm that N fertilizer source and application rate can impact N 2 O emissions but these effects are modulated by soil environmental conditions.

Industrial by-products such as paper mill biosolids (PB) and different liming materials have been used as fertilizers and amendments in agricultural soils for many decades. However, little is known about the effects of their repeated application on soil nutrient availability, particularly phosphorus (P). A 6-yr field study (2000-2005) was conducted in the province of Quebec to investigate the effect of repeated annual applications of different PB and industrial by-products on selected soil chemical properties, especially soil P fractions. Different PB rates (0 to 90 Mg wet ha-1) and several liming products (lime mud, wood ash, calcitic lime, and Mg by-products) were annually applied to field crops after seeding. Soils were sampled before seeding in May 2003 and at harvest in October 2005. Results showed that HCl-P was the largest P pool, accounting for about 64% of the total P fraction, and that the repeated applications of liming products significantly increased this pool and decreased the organic P pools. The NaOH-Po and residual-P were significantly lower in 2005 than in 2003, indicating that PB application without supplemental P fertilizer inputs enhanced the mobility and/or mineralization of NaOH-Po and the transformation of recalcitrant P to more labile forms with time. Lime mud (LM) was found to be the best liming material owing to its high neutralization capacity and positive effect on soil P availability over time. Key words: Paper mill biosolids, alkaline residuals, lime, wood ash, soil P fractions

Paper mill biosolids (PB) may provide benefits for crop yields and soil nutrients. However, few data are available on metal accumulation and pathogenic populations resulting from applications in silage corn production. A study was initiated to determine the effect of annual spring application of combined PB during 3 consecutive years, with or without calcitic lime, on yield and on the environmental risk posed by N, P, heavy metals (Cu, Zn, Cd, Mo) and Escherichia coli to a silage corn cropped in a loamy sand in eastern Ontario, Canada. Treatments consisted of complete mineral NPK fertilization (PB0), 30 Mg wet weight ha-1 with supplemental N and K, and 60 and 120 Mg wet ha-1 supplemented with K, either with or without 2.5 Mg ha-1 calcitic lime. The PB at 30 Mg wet ha-1 with reduced mineral N and PB at 60 Mg wet ha-1 provided comparable yields to the mineral N fertilization in all years, whereas application of PB at 120 Mg wet ha-1 increased corn yield by 6.0 Mg ha-1 in the third year. After 3 yr, contents of soil NO3-N and the P saturation index (P/Al) were increased, indicating a possible risk of nitrate and P leaching. Lime increased soil pH by 0.8 unit, which in turn caused a large increase in the tissue Mo concentration and Mo uptake by silage corn. The PB, particularly at 120 Mg wet ha-1, produced significant accumulations of Cd and Zn in soil, plant tissue and uptake. The PB showed small counts of E. coli, and consequently very little contamination was observed in the soil and on the harvested crop. Based on these results, the PB used are a good source of nutrients that benefits silage corn yields and represent as well a low risk for human and animal health and for the environment when the application does not exceed 60 Mg wet ha-1 yr-1.Key words: Zea mays L., paper mill biosolids, lime, heavy metals, cadmium, molybdenum, Escherichia coli

Soil acidity is a major problem in agriculture because it limits plant growth and reduces crop productivity. The neutralizing potential of industrial by-products and their impact on soil properties were evaluated in two acidic soils characterized by contrasting textures, and submitted to intensive agriculture practices. Soil pH, microbial (dehydrogenase and alkaline phosphatase) activity, and Mehlich-3 extractable P, K, Ca and Mg were monitored in the year of soil incorporation of eight liming products and in the following 2 yr. In the sandy loam, liming products did not result in significant increases in soil pH in the 0- to 7.5-cm soil layer. Lime mud (LM) significantly increased soil pH by 0.4 units in the 7.5- to 20-cm layer compared with cement kiln dust (CKD). In the silty clay, calcium-phosphate-magnesium (CalPoMag) significantly raised pH by 0.65 units over both natural calcitic lime (NCa) and the magnesium dissolution product (MgD) in the first soil layer, and by 0.5 units over carbide lime (CL) treatment in the second soil layer. Activities of dehydrogenase and alkaline phosphatase were increased to various degrees by all liming materials, especially on the silty clay; LM and CalPoMag were the most beneficial materials. The exception was MgD, which did not result in any impact on microbial activity relative to the control. Both enzymatic activities were related to the increase in soil pH, particularly the alkaline phosphatase. Ion leaching was more pronounced in the sandy loam than in the silty clay soil, where large differences in the Ca and Mg ion levels were still detected in the 20- to 40-cm layer of the sandy loam. In this study, LM and CalPoMag are interesting liming products, particularly in the silty clay soil. Key words: Enzymatic activity, soil pH, lime, soil cations

Régis Simard and his colleagues developed a research program focussing on the agronomic and environmental impacts of nutrients in agricultural systems. The success of this program resulted from an integrated approach, linking assessment of nutrient availability to an understanding of nutrient dynamics in the soil, and applying this understanding to development of improved management practices for a variety of nutrient sources. Research into nutrient availability conducted by Régis and his co-workers led to improvements in quantification of nutrient supply, using traditional soil analysis with batch chemical extraction as well as ionic exchange membranes (IEMs) and electro-ultrafiltration (EUF). Ion exchange membranes are now used as a tool in routine soil fertility assessments and in agronomic and environmental research to study nutrient ion release rates. Additionally, intensive analytical techniques, such as sequential extraction and X-ray absorption near-edge structure (XANES) were developed and used to characterize the forms and relative availability of soil nutrients for plant uptake or environmental effects. Characterization of nutrient pools improved understanding of nutrient dynamics in the soil, allowing a more accurate assessment of the agronomic value and environmental risk of nutrients applied to agricultural systems. Building on this knowledge, Régis and his colleagues developed improved methods of utilizing manures, composts, paper mill sludge (PMS) and liming by-products, effectively diverting nutrients from the waste stream into a resource for crop production. This paper describes the contributions of Régis and his colleagues to the improvement of agronomically and environmentally sustainable nutrient management practices, based on an integrated research approach that provided a clear understanding nutrient availability and soil nutrient dynamics. Key words: Chemical extraction, integrated nutrient management, ion exchange membranes, paper mill sludge, soil phosphorus, soil potassium

Inductively coupled plasma (ICP) emission spectroscopy is routinely used in laboratory testing to determine soil P extracted by Mehlich 3 (M3P). The effectiveness of ICP, however, has been questioned, particularly when used to detect soil P. Our objective was to compare ICP (M3P‐ICP) with colorimetric (M3P‐Col) methods of determining soil M3P. Soil samples (488; 0–20 cm deep) were collected from five experimental sites in eastern Canada that varied in soil texture, organic matter (OM) content, pH, and previous use of organic or mineral phosphorus (P) fertilizer and were cropped to annual or perennial species. Soil P content ranged from 9.4 to 189.5 mg P kg−1 when ICP was used and from 1.9 to 210.3 mg P kg−1 for the colorimetric method. Although there was a significant (R2 = 0.91; P < 0.001) relationship between the two methods, soil P measured by ICP was, on average, 36% higher. Large differences between M3P‐ICP and M3P‐Col occurred primarily for soils under perennial forage species, indicating the impo...

La démocratie moderne est marquée par une opposition fondamentale entre individu et communauté. Le concept de tradition d’Alasdair Maclntyre offre une solution à ce conflit, mais dont les sources rendent problématique une justification démocratique des normes sociales. Maclntyre va à l’encontre de l’idéal démocratique moderne et doit, sur cette base, être dissocié d’une éthique communautarienne pour laquelle l’idée de communauté suppose le respect intégral de l’autonomie rationnelle des individus. Cet article rend compte du problème de légitimité que pose la théorie de Maclntyre., The conflict between individual and community is fundamental to modern democracy. Alasdair Maclntyre's concept of tradition offers a solution to this conflict, but one where the democratic justification of social norms becomes problematic. Maclntyre goes against the modern democratic ideal and, on this basis, must be distinguished from the communitarian ethic in which the idea of community presupposes the integral respect of an individual's rational autonomy. This article provide an account of the legitimacy problem in Maclntyre's theory.

Manure is known to increase soil N2O emissions by stimulating nitrification and denitrification processes. Our objective was to compare soil-surface N2O emissions following the application of liquid and solid dairy cattle manures to a loamy and a clay soil cropped to silage maize. Manures were applied in 2 consecutive years at rates equivalent to 150 kg total N ha-1 and compared with a control treatment receiving an equivalent rate of synthetic N. Soil-surface N2O fluxes, soil temperature, and soil water, nitrate and ammonium contents were monitored weekly in manured and control plots. From 60 to 90% of seasonal N2O emissions occurred during the first 40 d following manure and synthetic fertilizer applications, indicating that outside that period one or several factors limited N2O emissions. The period of higher emissions following manure and fertilizer application corresponded with the period when soil mineral N contents were highest (up to 17 g NO3−-N m-2) and water-filled pore space (WFPS) was greater than 0.5 m3 m-3. The absence of significant N2O fluxes later in the growing season despite high WFPS levels indicated that the stimulating effect of organic and synthetic N additions on soil N2O production was relatively short-lived. Fertilization of silage maize with dairy cattle manure resulted in greater or equal N2O emissions than with synthetic N. This was observed despite lower overall soil mineral N contents in the manured plots, indicating that other factors affected by manure, possibly additional C substrates and enhanced soil respiration, resulted in greater denitrification and N2O production. Silage maize yields in the manured soils were lower than those receiving synthetic N, indicating that the N2O emissions per kilogram of harvested biomass were greater for manures than for synthetic N. Our results also suggest that the main source of N2O was nitrification in the loam and denitrification in the clay soil. There was no clear difference in N2O emissions between liquid and solid manures. The variable effects of liquid and solid manure addition reported in the literature on soil N2O emissions likely result from the variable composition of the manures themselves as well as from interactions with other factors such as soil environment and farming practices. A better characterization of the availability of manure C and N is required to assess the impact of manure application on soil N2O emissions under field conditions. Key words: Greenhouse gases, N2O, maize, manure

Democratie et diversite sont-elles conciliables ? Et, si oui, a quelles conditions ? Selon un discours dominant, le modele liberal, pluraliste et multiculturel serait le seul veritablement en mesure de repondre a ce defi. Mais le prix a payer serait un renoncement a l'ideal republicain du bien commun et a l'idee d'une communaute de citoyens qui s'autogouvernent. Les auteurs de ce livre, qu'ils s'inscrivent dans les courants republicain, liberal ou radical, ne partagent pas ce constat. La conciliation entre democratie et diversite n'a pas le liberalisme multiculturel comme seul horizon. Au contraire, c'est en reposant les fondements de la democratie, et en conservant a l'arriere-plan un certain heritage republicain, que peut emerger une nouvelle approche de la diversite. Pour certains auteurs, cet heritage republicain est celui de posseder une grammaire culturelle commune afin d'assurer une cohesion collective, pour d'autres, il s'exprime comme liberte de non-domination ou encore comme modele d'autodetermination democratique. Un heritage qui est pluriel, mais qui a encore un role aujourd'hui pour repondre aux problemes politiques des societes democratiques, dont celui de la diversite et de la reconnaissance des differences."

Water-extractable organic C (WEOC) is a determinant driver of several soil and environmental processes, and can be influenced by management practices such as organic amendment. Our objective was to study the dynamics of soil WEOC following application of liquid and solid dairy cattle manures to a loamy and a clay soil under field conditions. Manures were applied in 2 consecutive years to silage corn fields at rates equivalent to 150 kg total N ha-1. Soil WEOC was monitored the day after application and weekly or biweekly thereafter in manured and control (mineral fertilizers) plots. Liquid and solid manure S brought on average 39 and 13 g WEOC m-2, respectively. These amounts are much larger than the increases measured in soil WEOC during the hours and days following manure application (0 to 30 mg kg-1, equivalent to 0 to 3 g m-2). Moreover, manure addition had little effects in the 10- to 30-cm soil layer. The rapid and extensive adsorption of manure WEOC onto mineral surfaces likely explains the limited effects of manure on soil WEOC. This adsorption process was presumably exacerbated by the mixing of manure and soil resulting from the tillage operation. Soil temperature and respiration appeared to have determinant influence on the level of soil WEOC content in the post-harvest period. Overall, temporal variations in soil WEOC contents were large and generally greater than the fluctuations directly attributable to manure addition. Key words: Soil organic C, extractable C, dairy manure, silage corn