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Yield and quality improvements in Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.) are increasingly difficult to attain, which behooves a systems approach to unlock genotype (G) × environment (E) × management (M) synergies. This 25 site-year study was designed to assess a G × E × M systems approach to improve CWRS agronomics, quality, and N use efficiency (NUE). The investigation consisted of genetics (AAC Viewfield vs. AC Stettler), N source (untreated urea; urea + urease inhibitor, N-(n-butyl) thiophosphoric triamide (NBPT); urea + nitrification inhibitor, nitrapyrin; urea + dual-inhibitor (NBPT + dicyandiamide); and polymer-coated) and N timing/placement (all-banded at planting, two-split applications and three-split applications), deployed across diverse soil zones in western Canada. Differential yield responses were observed between cultivars as AAC Viewfield produced superior yield over AC Stettler (+4.3%) in black and grey soils, while yield attainment was similar in dark brown soils. Genetic improvement over AC Stettler seemed most apparent in water abundant environments; however, AC Stettler was often superior in drier conditions. All N sources produced comparable outcomes for yield, quality, NUE, and net returns. In black and grey soils, adopting either all-banded or two-splits improved grain yield due to augmented seedling vigor, heads per plant, and N recovery. The timing of split-applications introduces more risk to yield and is likely attributed to a poorly developed source:sink relationship in the critical growth period if applied late to optimize grain protein. This highlights the complexity of the system and balance needed to harness the potential synergy between G, E, and M components. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) colonize biochar in soils, yet the processes governing their colonization and growth in biochar are not well characterized. Biochar amendment improves soil health by increasing soil carbon, decreasing bulk density, and improving soil water retention, all of which can increase yield and alleviate environmental stress on crops. Biochar is often applied with nutrient addition, impacting mycorrhizal communities. To understand how mycorrhizas explore soils containing biochar, we buried packets of non-activated biochar in root exclusion mesh bags in contrasting agricultural soils. In this greenhouse experiment, with quinoa (Chenopodium quinoa) as the host plant, we tested impacts of mineral nutrient (as manure and fertilizer) and biochar addition on mycorrhizal colonization of biochar. Paraglomus appeared to dominate the biochar packets, and the community of AMF found in the biochar was a subset (12 of 18) of the virtual taxa detected in soil communities. We saw differences in AMF community composition between soils with different edaphic properties, and while nutrient addition shifted those communities, the shifts were inconsistent between soil types and did not significantly influence the observation that Paraglomus appeared to selectively colonize biochar. This observation may reflect differences in AMF traits, with Paraglomus previously identified only in soils (not in roots) pointing to predominately soil exploratory traits. Conversely, the absence of some AMF from the biochar implies either a reduced tendency to explore soils or an ability to avoid recalcitrant nutrient sources. Our results point to a selective colonization of biochar in agricultural soils. [ABSTRACT FROM AUTHOR]

Granular urea fertilizer applied at planting is prone to nitrogen (N) losses in certain environments. Enhanced efficiency fertilizers (EEFs) are developed to mitigate losses and optimize plant uptake. To determine the benefits of EEFs in grain yield and quality enhancement in Canada Western Red Spring (CWRS) wheat, an experiment was conducted from 2019 to 2022 at eight sites in Alberta and Saskatchewan, Canada. The effects of five N sources [urea; urea + urease inhibitor, N-(n-butyl)thiophosphoric triamide (NBPT); urea + nitrification inhibitor, nitrapyrin; urea + dual-inhibitor, NBPT + dicyandiamide; and polymer-coated urea, ESN® (Environmentally Smart Nitrogen®)] and four N rates (60, 120, 180, and 240 kg N ha−1) on CWRS wheat production were examined. Results indicated that N source affected grain yield in Dark Brown Chernozem soils but not in Black Chernozem or Dark Grey Luvisol soils. In Dark Brown Chernozem soils, a dual inhibitor increased grain yield by 3.1% and 3.9% relative to urea and polymer-coated urea, respectively, while all other EEFs attained similar results. The use of a dual inhibitor EEF led to greater net returns compared to urea and polymer-coated urea in the Dark Brown Chernozem soils. Grain protein concentration increased linearly with increasing N rate from 60 to 240 kg N ha−1. Generally, a rate of 120 kg N ha−1 was optimal for CWRS wheat grown in Canadian prairie conditions when coupled with EEFs, particularly a dual inhibitor, and grain yield and protein were often responsive. [ABSTRACT FROM AUTHOR]

Efforts to reduce greenhouse gas (GHG) emissions from cattle production have led to modifications of livestock diet composition aimed at reducing CH4 emissions from enteric fermentation. These diet modifications can result in varied manure types that may differentially affect GHG emissions when applied to soil. The purpose of this experiment was to examine the effect of different manure types on GHG emissions. We conducted an incubation experiment, comparing the manure from livestock fed a corn-based diet (CM) to that from livestock fed a traditional barley-based diet (BM). The manures were applied to three soil types (with varied soil fertility and pH) and compared to a control (without manure application). Carbon dioxide (CO2) emissions were greater from CM than from BM across all soil types (29.1 and 14.7 mg CO2-C kg−1, respectively). However, CM resulted in lower N2O emissions relative to BM in the low fertility soil (4.21 and 72.67 μg N2O-N kg−1, respectively) and in lower CH4 emissions relative to BM in the two acidic soils (0.5 and 2.5 μg CH4-C kg−1, respectively). Total GHG emissions (sum of CO2, N2O, and CH4) were similar between CM and BM across all soil types, but CM (unlike BM) had 52–66% lower emissions in the low fertility soil relative to both CM and BM in the high fertility soil. Our study shows that manure and soil type interact to affect GHG emissions and that CM may mitigate N2O emissions relative to BM when applied to low fertility soils. [ABSTRACT FROM AUTHOR]

Wastewater has been widely reclaimed to irrigate crops where freshwater resources are scarce. Therefore, predicting the impacts of wastewater irrigation on soil moisture and soil salinity is critical for sustainable wastewater irrigation management. In this study, the denitrification‐decomposition (DNDC) model was modified to couple wastewater irrigation with a water balance equation (SALT‐DNDC). Secondly, the SALT‐DNDC model was verified against the measured soil moisture, temperature, and nitrous oxide emission during the barley‐growing season at Lethbridge, Alberta, Canada. Third, the SALT‐DNDC model was used to predict the effects of one‐time and split wastewater irrigation with varying quantity and quality on transpiration and soil salinity. The results showed that split irrigation of wastewater with an electrical conductivity of 6 dS m−1 reduced the peak soil salinity from 52–55 dS m−1 to a range of 8–20 dS m−1, compared to one‐time irrigation. Therefore, the split irrigation of wastewater could substantially reduce peak soil salinity. In this regard, optimal split wastewater irrigation with elevated salt concentration can limit soil salinity to acceptable salt tolerance levels for crop growth. The SALT‐DNDC model can simulate dynamics of split irrigation wastewater and offers a new tool for assessing the effects of wastewater reuse on soil salinity. [ABSTRACT FROM AUTHOR]

Wastewater has been widely reclaimed to irrigate crops where freshwater resources are scarce. Therefore, predicting the impacts of wastewater irrigation on soil moisture and soil salinity is critical for sustainable wastewater irrigation management. In this study, the denitrification‐decomposition (DNDC) model was modified to couple wastewater irrigation with a water balance equation (SALT‐DNDC). Secondly, the SALT‐DNDC model was verified against the measured soil moisture, temperature, and nitrous oxide emission during the barley‐growing season at Lethbridge, Alberta, Canada. Third, the SALT‐DNDC model was used to predict the effects of one‐time and split wastewater irrigation with varying quantity and quality on transpiration and soil salinity. The results showed that split irrigation of wastewater with an electrical conductivity of 6 dS m−1 reduced the peak soil salinity from 52–55 dS m−1 to a range of 8–20 dS m−1, compared to one‐time irrigation. Therefore, the split irrigation of wastewater could substantially reduce peak soil salinity. In this regard, optimal split wastewater irrigation with elevated salt concentration can limit soil salinity to acceptable salt tolerance levels for crop growth. The SALT‐DNDC model can simulate dynamics of split irrigation wastewater and offers a new tool for assessing the effects of wastewater reuse on soil salinity. [ABSTRACT FROM AUTHOR]

Anaerobic fungi produce extracellular hydrolytic enzymes that facilitate degradation of cellulose and hemicellulose in ruminants. The purpose of this work was to study the impact of three different anaerobic fungal species (Anaeromyces mucronatus YE505, Neocallimastix frontalis 27, and Piromyces rhizinflatus YM600) on hydrolysis of two different lignocellulosic substrates, corn (Zea mays L.) silage and reed (Phragmites australis (Cav.) Trin. ex Steud.). Biomass from each plant species was incubated anaerobically for 11 days either in the presence of live fungal inoculum or with heat-inactivated (control) inoculum. Headspace gas composition, dry matter loss, soluble chemical oxygen demand, concentration of volatile fatty acids, and chemical composition were measured before and after hydrolysis. While some microbial activity was observed, inoculation with anaerobic fungi did not result in any significant difference in the degradation of either type of plant biomass tested, likely due to low fungal activity or survival under the experimental conditions tested. While the premise of utilizing the unique biological activities of anaerobic fungi for biotechnology applications remains promising, further research on optimizing culturing and process conditions is necessary. [ABSTRACT FROM AUTHOR]

Optimizing nitrogen fertilizer management can reduce nitrous oxide (N2O) emissions. This study tested if split applying enhanced efficiency fertilizers (EEFs) resulted in lower N2O emissions than applying equivalent rates of urea at planting. In semiarid southern Alberta, field trials were conducted during three years (planting to harvest) in rainfed winter wheat crops. Annual fertilizer rates ranged from 146 to 176 kg N ha−1. Fertilizer types were urea, and three EEFs (polymer-coated urea, urea with urease and nitrification inhibitors, and urea with a nitrification inhibitor). Each fertilizer type was applied three ways: 100% banded at planting, split applied 30% banded at planting and 70% broadcast in late fall, and split applied 30% banded at planting and 70% broadcast at Feekes growth stage 4 (GS4, post-tiller formation, wheat entering the greening up phase in the early spring). Nitrous oxide was measured using static chambers between sub-weekly and monthly from planting to harvest. Over three years, cumulative N2O emissions ranged from 0.16 to 1.32 kg N ha−1. This was equivalent to emissions factors between 0.009 and 0.688%. Cumulative N2O emissions and emissions factors did not differ between fertilizer types, but they were lower when fertilizer was split applied at GS4 compared to in late fall (P ≤ 0.10). Our study suggests that EEFs do not reduce N2O emissions from rainfed winter wheat crops, but a well-timed split application with a majority of fertilizer applied after winter can minimize N2O emissions. [ABSTRACT FROM AUTHOR]

Purpose: Grasslands play a crucial role in offsetting greenhouse gas emissions and mitigating climate change. A moderate change in grassland carbon (C) and nitrogen (N) stocks may substantially alter the global C and N cycle and thereby influence climate. But how grassland C and N stocks respond to grazing and slope position remains uncertain. This research investigates how C and N stocks respond to cattle grazing along a landscape slope.Materials and methods: We studied a grassland that has been grazed by cattle at four cattle stocking rates (0, 1.2, 2.4, and 4.8 animal unit months (AUM) ha−1) since 1949, representing control (CK), light (L), heavy (H), and very heavy (VH) grazing intensities, respectively. Samples were taken from the top and bottom slope positions within each paddock (only the top position in CK); C and N stocks in soil, roots, litter, and standing crop were estimated. Soil C and N stocks were estimated based on equivalent mass (1500 Mg ha−1). Root C and N stocks were estimated to the depth of 15 cm.Results and discussion: All parameters, except for litter N stock and standing crop C stock, significantly responded to the interaction of grazing intensity and slope position. In the bottom position, soil and standing crop C and N stocks as well as litter C stock were higher with the L treatment than with VH, while no significant differences were found among the three grazed treatments for root C and litter N stocks. In the top position, soil and root C and N stocks were higher with the VH treatment than with L, whereas litter C and N stocks and standing crop C stock were lower with VH than with L.Conclusions: Our results provide evidence that slope position plays an important role in regulating the response of C and N stocks to grazing and may need to be considered when developing optimal grazing management strategies. [ABSTRACT FROM AUTHOR]

Given the rising nitrous oxide (N2O) concentration in the atmosphere, it has become increasingly important to identify hot spots and hot moments of N2O emissions. With field measurements often failing to capture the spatiotemporal dynamics of N2O emissions, estimating them with modeling tools has become an attractive alternative. Therefore, we incorporated several semi-empirical equations to estimate N2O emissions with the Soil and Water Assessment Tool from nitrification and denitrification processes in soil. We then used the model to simulate soil moisture and the N2O flux from grassland soils subjected to long-term grazing (> 60 years) at different intensities in Alberta, Canada. Sensitivity analysis showed that parameters controlling the N2O flux from nitrification were most sensitive. On average, the accuracy of N2O emission simulations were found to be satisfactory, as indicated by the selected goodness-of-fit statistics and predictive uncertainty band, while the model simulated the soil moisture with slightly higher accuracy. As expected, emissions were higher from the plots with greater grazing intensity. Scenario analysis showed that the N2O emissions with the recommended fertilizer rate would dominate the emissions from the projected wetter and warmer future. The combined effects of fertilization and wetter and warmer climate scenarios would increase the current N2O emission levels by more than sixfold, which would be comparable to current emission levels from agricultural soils in similar regions. [ABSTRACT FROM AUTHOR]

We analyzed soil prokaryotic and fungal community composition in soils with varying histories of cattle manure application. The manure treatments were (i) annual application for 43 years (MF), (ii) annual application for 14 years followed by 29 years without application (MF14), and (iii) annual application for 30 years followed by 13 years without application (MF30). An annual application of chemical nitrogen (N) fertilizer (CNF) and a non-amended control (Con) were also included. Soil prokaryotic evenness and diversity significantly decreased in MF relative to other treatments in fall, but were similar to the other fertilizer treatments in spring and summer. Distinct prokaryotic and fungal community composition was observed in MF compared to other treatments across fall, spring, and summer seasons. The MF treatment significantly increased the relative abundance of Firmicutes, Gammaproteobacteria, and Gemmatimonadetes, but significantly decreased the relative abundance of Acidobacteria. In fall, the soil prokaryotic and fungal community composition with MF30 was significantly different than the other fertilization treatments. Overall, the study showed that annual manure application (MF) led to a different microbial community composition than the other fertilizer treatments. Soil without manure application for 13 years (MF30) had a significantly different microbial community composition from other fertilizer treatments in fall, while the soil without manure application for 29 years (MF14) resembled a microbial community that had never received manure. [ABSTRACT FROM AUTHOR]

Abstract: Long‐term cattle grazing may degrade grassland soils, but how soil CO2, CH4 and N2O fluxes respond to long‐term cattle grazing is poorly understood. Therefore, we quantified soil CO2, CH4 and N2O fluxes in response to four levels (none, light, heavy, very heavy) of long‐term (>65 years) cattle grazing on a rough fescue grassland in the foothills of the Rocky Mountains, Canada over three grazing seasons. The grazed grassland soils emitted 37 to 51% more CO2 than non‐grazed soils. Grazed grassland soils were small CH4 sinks and small N2O sources each season, and their cumulative fluxes were significantly affected by a cattle stocking rate × year interaction, indicating the grazing effect was influenced by environmental conditions. Soil CH4 uptake was negatively correlated with soil moisture (r = −0·59). The 2013 grazing season had about 41% greater precipitation than average and grazing significantly decreased CH4 uptake 31 to 38% compared with non‐grazed soils. The N2O emissions were 122 to 179% greater with heavy and very heavy grazing than none in the wet season, unaffected by grazing in the normal precipitation season and 72% lower with light grazing than none in the dry season. Predicting trace gas fluxes from grazed grassland soils across space and time is difficult because of interactions among weather conditions, edaphic properties and grazing intensity. However, long‐term cattle grazing increased soil CO2 fluxes, while the grazing effect on CH4 uptake depended on precipitation and the soil N2O flux responded as a function of grazing intensity and precipitation. © 2016 Her Majesty the Queen in Right of Canada. Land Degradation & Development Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Phytoextraction of excess nutrients by crops in soils with a long history of manure application may be a viable option for reducing the nutrient levels. This greenhouse study examined the effectiveness of six growth cycles (40 d each) of barley, canola, corn, oat, pea, soybean, and triticale at extracting nitrogen (N) and phosphorus (P) from a Dark Brown Chernozem that had received 180 Mg ha−1 (wet wt.) of beef cattle feedlot manure annually for 38 years. Moisture content during the study was maintained at either 100% or 50% soil field capacity (SFC). Repeated cropping resulted in an overall decrease in dry matter yield (DMY). The decrease in N and P uptake relative to Cycle 1 was fastest for the cereal grains and less pronounced for the two legumes. However, cumulative N uptake values were significantly greater for corn than the other crops under both moisture regimes. The reduction in soil N was greater under the 100% than the 50% SFC. These results indicate that repeated cropping can be a useful management practice for reducing N and P levels in a heavily manured soil. The extent of reduction will be greater for crops with high biomass production under adequate moisture supply. [ABSTRACT FROM AUTHOR]

While some countries disaggregate NO emission factors for urine and dung deposited onto pastures, in Canada, distinct NO emission factors for beef cattle urine and dung have not been defined. To help address this knowledge gap, we conducted a 1-year study to quantify NO fluxes from beef cattle urine and dung patches on a semiarid tame pasture in western Canada, as well as to quantify the NO emission factors (EF3) for urine and dung as the percentage of applied N emitted as NO-N. Urine and dung were deposited when soil water-filled pore space was nearly 60%, a wet soil condition for the grazing season in the semiarid study region, which led to a burst of NO from urine in the first 14 days of the study (42% of total N emitted). Urine emitted more cumulative NO ( P < 0.001) and had a greater NO emission factor ( P = 0.002) than dung. The urine patch emitted 1.30 ± 0.47 g NO-N m year, while the dung patch emitted 0.083 ± 0.020 g NO-N m year (mean values ± SD). The NO emission factor for urine was 1.32 ± 0.49%, while for dung it was 0.03 ± 0.02%. We conclude that more study is needed to determine if distinct NO emission factors are required for urine and dung deposited onto pasture in western Canada to more accurately estimate national NO inventories. [ABSTRACT FROM AUTHOR]

Managing the stocking rate is considered one of the most important practices influencing carbon storage on rangeland. The effects of four stocking rates consisting of a non-grazed control (CK), light (0.15 sheep ha month), moderate (0.30 sheep ha month) and heavy (0.45 sheep ha month) were evaluated for impacts on carbon storage taking place on the Desert Steppe of Inner Mongolia, China. Carbon storage was measure in aboveground vegetation, roots and soil in August of 2009, 2011 and 2013. Both aboveground biomass (AGB) and below-ground biomass (BGB) increased significantly as stocking rate decreased. Stocking rate also had a significant effect on both the aboveground and below-ground carbon storage in plant biomass, but had no effect on the soil carbon. Compared to the heavy stocking rate typically practiced by local herders, lower stocking rates increased the total above- and below-ground biomass carbon storage by ≥ 7%. Over the 3 year study, compared to the moderate stocking rate, the rate of carbon sequestration with a light stocking rate was 0.7 Mg C ha year. Thus, reducing stocking rate has the potential to increase C sequestration and storage, as well as maintaining animal numbers at a more sustainable level suitable for the Desert Steppe ecosystem. [ABSTRACT FROM AUTHOR]

This study investigates the effects of residue incorporation coupled with plant growth and soil moisture level on wheat biomasses, soil nutrients, labile organic carbon (LOC), microbial metabolic profiles, and community composition. Four management practices were used in a 180-day pot experiment: (1) control (CON), (2) maize ( Zea mays L.) residue incorporation without plants (MR), (3) wheat ( Triticum aestivum L.) plants without maize residue (WP), and (4) maize residue incorporation with wheat plants (MRWPs). Each management practice included soil moisture at both 40 and 80% of field capacity. At wheat harvest, soil nutrient contents in the WP and MRWP treatments were significantly lower than in the CON and MR treatments. In comparison with the CON treatment, MR, WP, and MRWP treatments resulted in 35, 23, and 67% increases in dissolved organic carbon content; 17, 12, and 34% increases in hot-water extractable organic carbon content; and 78, 50, and 150% increases in microbial biomass carbon content. Furthermore, microbial utilizations of carboxylic acids and polymer carbon sources in the MR, WP, and MRWP treatments were 261 and 88%, 239 and 105%, and 300 and 126% higher than in the CON treatment. The MR and CON treatments had similar phospholipid fatty acid (PLFA) content but the WP and MRWP treatments had significantly increased gram-negative content and changes to community composition compared with the CON and MR treatments. The wheat biomass, LOC, and PLFA contents significantly increased with greater soil moisture. Overall, these results suggest an additive effect of residue incorporation and plant growth on LOC contents, primarily due to the changes in microbial utilization of carbon sources and community composition. [ABSTRACT FROM AUTHOR]

We investigated whether nitrification inhibitor nitrapyrin can reduce nutrient leaching and increase nutrient uptake by corn (Zea maysL.) in cattle manure amended soil. Amendments included non-amended check (CK), urea (Urea), REG (manure from cattle fed barley grain), and DDGS (manure from cattle fed 60% dried distillers grains with solubles), co-applied with or without nitrapyrin and leached or unleached with water. Nitrapyrin reduced (P < 0.01) leaching of nitrate by 56, 32, and 24% from DDGS, REG, and Urea treatments, respectively, and also reduced (P < 0.05) leaching of phosphate (58%), potassium (39%), calcium (39%), and magnesium (39%) from DDGS treatment. While nitrapyrin reduces the rate of ammonium conversion to nitrate, higher magnesium and phosphate levels in DDGS-amended soil favor struvite formation and reduce their leaching. Corn biomass and nutrient uptake were higher (P < 0.01) in DDGS and Urea than CK and REG treatments, but remained unaffected by nitrapyrin. The benefits of nitrapyrin should be further investigated under field conditions. Abbreviations: DCD, dicyandiamide; DDGS, dried distillers grains with solubles; NI, nitrification inhibitor; TP, total P; TN, total N. [ABSTRACT FROM PUBLISHER]

Effectively utilizing composts requires that their nitrogen (N) and phosphorus (P) contents be used as fertilizer, but how this is best accomplished is not fully understood. The authors' objective was to quantify N and P availability of a calcareous clay loam soil receiving composts derived from four contrasting beef cattle feedlot feedstocks applied at 50, 150, and 450 mg total P kg−1and supplemented twice with fertilizer N for a 42-week greenhouse plant bioassay. Three composted manures from beef cattle fed distinct diets and a composted mix of slaughterhouse and construction waste were applied. Inorganically fertilized and non-amended soils were included as controls. Canola (Brassica napusL.) and pea (Pisum sativumL.) were grown in pots containing 1.5 kg air-dried soil for six alternating 7-week cycles. Soils amended with composted manure from beef cattle fed typical finishing diets had the lowest apparent N recovery (31%) and the greatest soil nitrate after 42 weeks (25 mg N kg−1). Phosphorus availability was greater with composted manure from beef cattle fed distillers' dried grains than composted manure from beef cattle fed typical finishing diets and a composted mixture of slaughterhouse and construction waste. Apparent P recovery (66%) was greatest from composted manure of beef cattle fed corn (Zea maysL.) distillers' dried grains applied at 50 mg total P kg−1. Composted manure from beef cattle fed distillers' dried grains had greater P availability than conventional composted beef cattle feedlot manure. Overall, performance of the composted mixture of slaughterhouse and construction waste was similar to the composted beef cattle manures. [ABSTRACT FROM AUTHOR]

The influence of 15 annual applications of composted (CM) or stockpiled (SM) beef feedlot manure with straw (ST) or wood-chip (WD) bedding on electrical conductivity (EC), soluble cations and anions (Na, K, Ca, Mg, SO4-S, Cl), sodium adsorption ratio (SAR), potassium adsorption ratio (PAR), and pH of a clay loam soil (0–15 cm) in southern Alberta was examined in an irrigated barley silage cropping system. Manure type (CM versus SM) had a significant effect on certain soil salinity parameters. Calcium, Mg, Na, K, and SO4-S were significantly (p≤ 0.05) greater for SM- than CM-amended soils for certain bedding materials and rates. Electrical conductivity, concentration of soluble cations and anions (Na, K, SO4-S, Cl), SAR, PAR, and pH in the surface soil were greater for ST than WD bedding. Two exceptions were Ca and Mg, where soil concentrations were generally greater for WD than ST. Salinity parameters were greater with increased application rate, and greater for amended than unamended soils. Overall, bedding had considerably more significant effects on soil salinity parameters compared to manure type. Wood-chip bedding may be a management tool for feedlots to lower EC, soluble cations and anions, and pH of surface soils. [ABSTRACT FROM AUTHOR]

Organic amendments recycle nutrients, but N2O emissions are both environmental and agronomic concerns. We conducted a 4-year field experiment to determine no-till barley (Hordeum vulgareL.) yield and nutrient uptake and soil N2O emissions following a single application of six amendment treatments: (1) no amendment (Check); (2) synthetic N fertilizer (Fert); (3) fresh beef cattle feedlot manure (ManureF); (4) beef cattle feedlot manure compost (CompostR); (5) beef cattle feedlot manure composted with cattle mortalities (CompostM); and (6) separated solids from anaerobically digested cattle feedlot manure (ADM). Barley grown in Year 1 (2006), Year 2 (2007), and Year 4 (2009) (with Year 3 (2008) under fallow) had higher grain yields from ManureF (4.73 Mg ha−1) in Year 2 and ADM (6.30 Mg ha−1) in Year 4 (p< 0.05) than other treatments. The grain N and P contents were not affected (p> 0.05), but N uptake over 3 years (112.8 kg N ha−1yr−1), and P uptake in Year 1 (19.1 kg ha−1yr−1) and Year 2 (14.3 kg ha−1yr−1) from ManureF, were higher (p< 0.05×) than other treatments. The cumulative N2O emissions from ManureF in Year 1 (1.488 kg N ha−1) and from ADM in Year 2 (1.072 kg N ha−1) were higher (p< 0.05) than other treatments while the fraction of applied N emitted as N2O was small (0.00 to 0.79%) and not affected by treatment. However, the percentages of applied N emitted as N2O from compost and ADM were similar to synthetic fertilizer and livestock manure. [ABSTRACT FROM PUBLISHER]

Livestock manure and compost are commonly used to supply nutrients for crops and improve soil quality. However, excess application may increase the risk of nutrient loss and eutrophication. We investigated the potential leaching losses of nitrogen (N), phosphorus (P), and non-purgeable organic carbon (NPOC) over 105 days in the laboratory. Soils were amended with four treatments: (1) manure (BM) and (2) compost (BC) from cattle fed a typical finishing diet, (3) manure (DDGSM), and (4) compost (DDGSC) from cattle fed diets containing 60 % wheat dried distillers' grains with solubles (DDGS) replacing barley grain. A non-amended control soil was included for comparison. Leachate samples were collected 0, 7, 21, 42, 70, and 105 days after amendment application. Amendment application significantly increased leaching loss of total nitrogen (TN), NO -N, NH -N, total phosphorus (TP), ortho-P (PO -P), and NPOC from soils by 2.2 to 154.8 times compared with the control. Regardless of whether DDGS was included in cattle diet, cumulative leaching losses of TN, NO -N, TP, and PO -P were significantly higher, while NH -N and NPOC were lower from compost-amended soil than manure-amended soil. The proportion of cumulative N leaching losses relative to the total N applied was greater with DDGSM and DDGSC than BM and BC, while a greater proportion of total P was leached from DDGSM and DDGSC than BM. Based on the results, more attention should be paid to the potential risk of soil nutrient leaching posed after applying manure and compost, and the higher risk of N and P leaching losses from soil amended with DDGS manure and compost than manure from beef cattle fed typical finishing diets. [ABSTRACT FROM AUTHOR]

Returning crop residue may result in nutrient reduction in soil in the first few years. A two-year field experiment was conducted to assess whether this negative effect is alleviated by improved crop residue management (CRM). Nine treatments (3 CRM and 3 N fertilizer rates) were used. The CRM treatments were (1) R0: 100 % of the N using mineral fertilizer with no crop residues return; (2) R: crop residue plus mineral fertilizer as for the R0; and (3) Rc: crop residue plus 83 % of the N using mineral and 17 % manure fertilizer. Each CRM received N fertilizer rates at 270, 360, and 450 kg N ha year. At the end of the experiment, soil NO-N was reduced by 33 % from the R relative to the R0 treatment, while the Rc treatment resulted in a 21 to 44 % increase in occluded particulate organic C and N, and 80 °C extracted dissolved organic N, 19 to 32 % increase in microbial biomass C and protease activity, and higher monounsaturated phospholipid fatty acid (PLFA):saturated PLFA ratio from stimulating growth of indigenous bacteria when compared with the R treatment. Principal component analysis showed that the Biolog and PLFA profiles in the three CRM treatments were different from each other. Overall, these properties were not influenced by the used N fertilizer rates. Our results indicated that application of 17 % of the total N using manure in a field with crop residues return was effective for improving potential plant N availability and labile soil organic matter, primarily due to a shift in the dominant microorganisms. [ABSTRACT FROM AUTHOR]

Agricultural operations generate large quantities of manure which must be eliminated in a manner that is consistent with public health guidelines. Meanwhile, construction and demolition waste makes up about 25% of total solid municipal waste. Co-composting of manure with construction and demolition waste offers a potential means to make manure safe for soil amendment and also divert construction and demolition waste from municipal landfills. Therefore, the archaeal, bacterial, and fungal microbiota of two different types of composted cattle manure and one co-composted with construction and demolition waste, were assessed over a 99-day composting period. The microbiota of the three compost mixtures did not differ, but significant changes over time and by sampling depth were observed. Bacillus and Halocella, however, were more relatively abundant in composted manure from cattle fed dried distillers’ grains and solubles. Proteobacteria and Bacteroidetes were enriched at day 0 and Firmicutes at day 99. The fungal genus Kernia was the most relatively abundant overall and was enriched at day 0. The concentration of 12 antimicrobial resistance determinants in the compost mixtures was also determined, and 10 of these determinants decreased significantly from days 0 to 99. The addition of construction and demolition waste did not affect the persistence of antimicrobial resistance genes or community structure of the compost microbiota and therefore co-composting construction and demolition waste with cattle manure offers a safe, viable way to divert this waste from landfills. [ABSTRACT FROM AUTHOR]

We investigated the effect of environmentally smart nitrogen (ESN) fertilizer on nitrous oxide (N2O) emissions under no-till barley (Hordeum vulgareL.) production over 3 years at three sites in Alberta, Canada. Treatments included two barley cultivars, with ESN and urea applied at 1× and 1.5× the recommended rate, and herbicide at 50% and 100% of registered in-crop rates. Cumulative N2O emissions over the growing season were low (0.11 to 1.32 kg nitrogen (N) per hectare or 0.05–0.22 g N kg−1grain yield), and not affected by barley cultivars or herbicide rates in all nine site-years, nor by fertilizer type or rate in seven out of nine site-years. However, average N2O emissions from ESN were 15% lower (P = 0.05) than urea across all site-years. Our results suggest ESN could play a role in reducing N2O emissions, but the reduction will depend on rainfall events and crop N utilization. [ABSTRACT FROM AUTHOR]

The influence of annual applications of composted (CM) or stockpiled (SM) beef feedlot manure with straw (ST) or wood-chip (WD) bedding on cation exchange capacity (CEC) of a clay loam soil in southern Alberta was examined after 1, 8, and 15 years. The hypotheses in our study were that soil CEC should be greater for amended than unamended soils; manure type and bedding should have no effect on soil CEC; and soil CEC should increase with greater manure application rate. After fifteen applications, the CEC was significantly greater for amended than unamended soils. Manure type had no significant (P > 0.05) effect on soil CEC after fifteen applications, and the mean soil CEC was 5% greater for WD than ST. Mean CEC was significantly greater by 7 to 12% for the 77 than the 13 and the 39 Mg ha−1 rates after fifteen applications. The soil CEC was increased by 0.061 cmolc kg−1 for a unit increase in application rate (Mg dry wt. ha−1 yr−1), and 96% of the variation in CEC for amended soils could be explained by application rate. Overall, bedding, rate, or adjusting both bedding type and manure rate (but not manure type), may be possible practices for feedlot producers to manage soil CEC. [ABSTRACT FROM AUTHOR]

A 2-year field trial was conducted to evaluate crop and soil responses to application of manure from cattle fed distillers’ grain (DGM) in comparison with manure from cattle fed regular barley grain (BGM). Manure addition in general promoted grain and straw yield and increased plant nitrogen (N) and phosphorus (P) uptake in both years by approximately 30–50%. In the first year, effect of manure type on crop responses was insignificant, which is consistent with the similar chemical composition of both manures. In the second year, P recovery was greater in DGM treatments, presumably related to a relatively greater P in DGM. Manure application in general increased soil residual nitrate nitrogen (NO3–N) and available P contents at 0–15 cm deep. The high background fertility of studied soil together with the excess moisture during the second year may have masked the significant effects of manure type on most crop and soil responses during this study. [ABSTRACT FROM PUBLISHER]

Grassland communities occupy about 25 % of global land area and global warming could alter grassland plant community coverage. A field study was conducted to investigate the impact of soil warming (surface soil temperature increased by 1.3 °C) and nitrogen addition (100 kg N ha year) on a desert steppe community in Inner Mongolia, China, from 2006 to 2011. Although there were strong intra- and inter-annual variations, in general, warming had little effect on coverage of the four major species (two cool season C species: Convolvulus ammannii and Stipa breviflora, and two warm season C species: Cleistogenes songorica and Kochia prostrata) over six growing seasons. The C/C coverage ratio consistently decreased with warming, with the decrease being statistically significant for one-third of sampling dates. Warming caused a reduction (from 27.6 to 25.1 %) in peak season total plant community coverage. N addition did not affect the four main species, four functional groups (perennial grass, perennial forb, shrub and annual-biennial) or the total plant community over the 6 years, except when precipitation was high (231 mm in 2008). The small reduction in plant community coverage demonstrated the resilience of desert steppe to warming. There could be a shift of C to C species because of warming, as indicated by the decrease in C/C ratio, but confirmation of this trend requires further study. [ABSTRACT FROM AUTHOR]

This study investigated CO2and N2O emissions from soil receiving long-term cattle feedlot manure applications under rainfed and irrigated conditions in semi-arid southern Alberta, Canada. Soil available N and CO2and N2O fluxes were measured after fall crop harvesting and prior to next spring's seeding from plots that had received 0 and 60 t ha−1yr−1cattle feedlot manure application with (Mi0 and Mi60) or without irrigation (Mr0 and Mr60) for 27 years. Both CO2and N2O fluxes varied considerably over the 7-month nongrowing season. Cumulative CO2emissions from manured treatments (Mr60 at 2.20 t ha−1and Mi60 at 2.36 t ha−1) were 2.6 times values from nonmanured treatments (Mr0 at 0.83 t ha−1and Mi0 at 0.92 t ha−1). Similarly, cumulative N2O emission from manured treatments (Mr60 at 4.54 kg ha−1and Mi60 at 5.34 kg ha−1) were 8–12 times values from nonmanured treatments (Mr0 at 0.40 kg ha−1and Mi0 at 0.70 kg ha−1). Growing season irrigation had no effect on CO2and N2O emission over the nongrowing season. [ABSTRACT FROM AUTHOR]

Soil cultivation changes and usage of agricultural wastes can have profound impacts on greenhouse gas (GHG) emission from soil. In this study, the effects of soil cultivation and organic amendment on GHG emission were investigated using aerobic incubation. Surface soil (0–20 cm) from (1) rice–legume consecutive rotation (Rice) and (2) recently (<3 years) converted from rice field to plastic-covered intensive vegetable and flower production (VegC) were collected in Kunming, P.R. China. Rose (Rosa rugosaThunb.) residues and cattle manure were applied at 5% by weight. Results indicated that N2O and CO2fluxes were significantly influenced by soil cultivation, organic amendment, incubation time and their interaction (p <0.05). Applying cattle manure increased, while rose residue decreased, cumulative N2O emissions from soil (84 days). Rose residue application significantly increased cumulative CO2emissions with peak values of 6371 (Rice) and 7481 mg kg−1(VegC), followed by cattle manure addition figure of 2265 (VegC) and 3581 mg kg−1(Rice). Both were significantly higher (p <0.05) than the un-amended Control at 709 (VegC) and 904 mg kg−1(Rice). Our study demonstrates that a low C/N ratio in cattle manure is better than a high C/N ratio in rose residue in regard to reducing the global warming potential of agricultural soil. [ABSTRACT FROM AUTHOR]

Accumulation of thin stillage (TS), a byproduct resulting from ethanol production, has led to a need to explore all possible means of its utilization. The objective of this research was to evaluate the effectiveness of TS derived from wheat ( Triticum aestivum L.)-based ethanol production plant as a fertilizer. The experiment was conducted over a 2-year period in east-central Saskatchewan, Canada. Treatments included three rates of TS: 50, 100, and 200 kg N ha using two methods of application: broadcast, and incorporation and injection. For comparison, conventional fertilizer urea (46-0-0) was applied at the same rates of N as the TS. Responses of crop yield (wheat and canola ( Brassica napus L.), N and P uptake, and apparent N recovery were measured over two growing seasons on a Black Chernozemic soil. For both seasons, at equivalent N rate, the TS produced similar or greater crop yield and nutrient recovery compared to urea fertilizer, especially when injected. This is caused by the presence of other plant nutrients, such as P and S in TS, and its relatively high plant-available NH-N content. The injection of TS appears to be a more effective application method compared to broadcasting, likely through reducing volatile N loss and placing nutrients closer to the growing crop roots when injected in bands in soil. The TS did not show any adverse effect on measured crop parameters even at the high rate of application. The results of this study suggest that land application of TS can be an effective solution for TS management that recycles nutrients in the feedstock grain for the ethanol production. [ABSTRACT FROM AUTHOR]

The impact of fertilization on maize ( Zea mays L.) yield and soil properties was investigated in a long-term (> 18 y) experimental field in N China. A completely randomized block design with seven fertilizer treatments and four replications was used. The seven fertilizer treatments were (1) compost (COMP), (2) half compost plus half chemical fertilizer (COMP1/2), (3) balanced NPK fertilizer (NPK), (4-6) unbalanced chemical fertilizers without one of the major elements (NP, PK, and NK), and (7) an unamended control (CK). In addition to maize yield, soil chemical and biological properties were investigated. Compared to the balanced NPK treatment, maize yield from the COMP treatment was 7.9% higher, from the COMP1/2 was similar, but from the NP, PK, NK, and CK treatment were 12.4%, 59.9%, 78.6%, and 75.7% lower. Across the growing season, microbial biomass C and N contents, basal soil respiration, and fluorescein diacetate hydrolysis, dehydrogenase, urease, and invertase activities in the COMP and COMP1/2 treatments were 7%-203% higher than the NPK treatment. Values from all other treatments were up to 60% lower than the NPK treatment. Maize yield is closely related to the soil organic C (OC) and biological properties, and the OC is closely related to various biological properties, indicating that OC is a suitable indicator for soil quality. Our results suggest the most limiting nutrient for improving the yield or soil quality was P, followed by N and K, and balanced fertilization is important in maintaining high crop yield and soil quality. Additionally, increases in OC, N, and biological activities in COMP and COMP1/2 treatments imply that organic compost is superior to the chemical fertilizers tested. [ABSTRACT FROM AUTHOR]

Livestock manure applied to agricultural land is one of the ways natural steroid estrogens enter soils. To examine the impact of long-term solid beef cattle (Bos Taurus) manure on soil properties and 17β-estradiol sorption and mineralization, this study utilized a soil that had received beef cattle manure over 35 years. The 17β-estradiol was strongly sorbed and sorption significantly increased (P < 0.05) with increasing soil organic carbon content (SOC) and with an increasing annual rate of beef cattle manure. The 17β-estradiol mineralization half-life was significantly negatively correlated, and the total amount of 17β-estradiol mineralized at 90 days (MAX) was significantly positively correlated with 17β-estradiol sorption. The long-term rate of manure application had no significant effect on MAX, but the addition of fresh beef cattle manure in the laboratory resulted in significantly (P < 0.05) smaller MAX values. None of the treatments showed MAX values exceeding one-third of the 17β-estradiol applied. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the response of δ15N in herbage and cattle tail switch hair to long-term grazing pressure on a rough fescue grassland (Festuca campestris Rydb.) near Stavely, Alberta, Canada. Cattle have grazed the paddocks from 15 May to 15 November annually since 1949. Stocking rates were 0, 2.4 and 4.8 animal unit months ha−1 for non-grazing (Control), moderate grazing (MG) and heavy grazing (HG), respectively. Green standing crop (GSC) was sampled monthly throughout the grazing season in 2007. The GSC was fractioned into neutral detergent fiber (NDF), acid detergent fiber (ADF), and their total nitrogen (TN) concentration and δ15N values in NDF, ADF and GSC were determined. Tail switch hair samples from cows (>2 years old) and calves (<1 year) were collected at the end of the grazing season in 2007 and 2008 and analysed for δ15N values. The TN concentrations in NDF and δ15N values in herbage NDF and ADF fractions were higher (P < 0.05) in MG and HG than the Control, and decreased over the grazing season. The δ15N values in tail hair also decreased (P < 0.05) over the grazing season but were not affected by grazing intensity. However, as expected, δ15N values in tail hair increased with herbage δ15N values. The δ15N values in tail hair were enriched by +5.2‰ compared to herbage δ15N values in 2007. Changes in δ15N value in GSC and cattle hair reflect the influence of grazing practices on N cycles through the animal/plant/soil system on this rough fescue grassland. [ABSTRACT FROM PUBLISHER]

Purpose: Since substrate quality can influence the C mineralization pattern of compost in soils, proper selection of compost is important in increasing soil organic carbon (SOC) levels. This study investigated the effect of substrate quality of livestock manure composts on compost C mineralization and retention in soils. Materials and methods: A laboratory incubation experiment using four livestock manure composts (with different degrees of stability and other substrate qualities) and three soils (Inceptisol, Ultisol, and Andisol) was conducted for 100 days. Emission of CO from the compost-amended soils was periodically measured and cumulative CO emission was calculated as the percentage of total organic C (TOC) of applied compost (% C). The % C patterns were fitted with a double exponential first-order kinetics model to obtain the mineralizable C pool size and potentially retainable C in the soils. Results and discussion: The compost stability degree (SD) ranged from 31.4 to 61.5%, indicating a wide range of recalcitrance to microbial decomposition in the four composts used in our study. Among other compost quality indices, the KSO extractable organic C concentration and molar ratio of NH/NO decreased with increasing SD values. The % C ranged from 1.6 to 11.4% and decreased as SD increased, suggesting that compost C mineralization in soils can be predicted using SD. The pool size (rapid pool + slow pool) of mineralizable organic C estimated using a first-order kinetic model ranged from 1.7 to 28.5% and tended to decrease with increasing SD. Among the three soils, Andisol showed relatively low % C and mineralizable C pool size due to its inherent SOC protection mechanism via Al-organic matter complex. Conclusions: Our results suggest that application of compost with high SD and low extractable organic C would be more efficient in increasing SOC level due to a higher retention of compost C in the soils. The different patterns of C mineralization and retention among the three soils also suggest that not only compost quality but also soil characteristics should be considered when estimating CO emission from compost-amended soils. [ABSTRACT FROM AUTHOR]

A column leaching experiment using three soils (Inceptisol, Ultisol, and Andisol) and seven livestock manure composts that had different characteristics was conducted for 19 weeks to investigate the interactive effects of composts and soils on the phosphorus (P) leaching potential of compost-amended soils and to identify the principal variables that affect P leaching. Cumulative total P leaching (TPcum) tended to increase with increasing total and available P concentration in the soils. Among various compost properties, total P concentration was positively correlated with TPcum from the compost-amended soils, except for the Andisol, which has a high P-sorption capacity. There was no significant relationship between TPcum and water-extractable P concentration of the composts, suggesting that total P rather than inorganic P concentration of composts may be successfully used in predicting P leaching potential from compost-amended soils except for soils that have a high P-sorption capacity, as in Andisol. [ABSTRACT FROM AUTHOR]

We investigated the effect of increasing soil temperature and nitrogen on greenhouse gas (GHG) emissions [carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O)] from a desert steppe soil in Inner Mongolia, China. Two temperature levels (heating versus no heating) and two nitrogen (N) fertilizer application levels (0 and 100 kg N ha−1 year−1) were examined in a complete randomized design with six replications. The GHG surface fluxes and their concentrations in soil (0 to 50 cm) were collected bi-weekly from June 2006 to November 2007. Carbon dioxide and N2O emissions were not affected by heating or N treatment, but compared with other seasons, CO2 was higher in summer [average of 29.6 versus 8.6 mg carbon (C) m−2 h−1 over all other seasons] and N2O was lower in winter (average of 2.6 versus 4.0 mg N m−2 h−1 over all other seasons). Desert steppe soil is a CH4 sink with the highest rate of consumption occurring in summer. Heating decreased CH4 consumption only in the summer. Increasing surface soil temperature by 1.3°C or applying 100 kg ha−1 year−1 N fertilizer had no effect on the overall GHG emissions. Seasonal variability in GHG emission reflected changes in temperature and soil moisture content. At an average CH4 consumption rate of 31.65 µg C m−2 h−1, the 30.73 million ha of desert steppe soil in Inner Mongolia can consume (sequestrate) about 85 × 106 kg CH4-C, an offset equivalent to 711 × 106 kg CO2-C emissions annually. Thus, desert steppe soil should be considered an important CH4 sink and its potential in reducing GHG emission and mitigating climate change warrants further investigation. [ABSTRACT FROM AUTHOR]

Agricultural land currently is used not only for producing food, fiber, and other bioproducts, but also for disposing of and recycling industrial, municipal, and agricultural wastes. Because such uses may potentially have negative effects on the environment, the fate of applied elements or of those originally present in the soil are under intensive scrutiny. Temporal change in the mass of a given soil element or constituent per unit area typically is calculated as the difference between constituent masses in a fixed soil depth at two sampling times. This method, however, is adequate for only rare cases when soil volume remains unchanged (i.e., when there are no changes in soil bulk density or thickness). Other methods based on "fixed soil mass," "equivalent soil depth," or "cumulative mass coordinate" have been developed to account for bulk density changes but they still do not account for changes in soil mass, such as those associated with waste inputs or soil redistribution through erosion and deposition, or imports and exports. We propose an alternative method based on elevation-based soil sampling to account for the effects of changes in both soil bulk density and soil mass. Unlike methods that assume soil mass remains unchanged, the proposed method would also be applicable to sites with appreciable additions or removals of soil mass or volume. We discuss the merits of elevation-based soil sampling to assess temporal changes in soil constituents, and present an example of its application to a site receiving heavy applications of livestock manure for 30 yr. [ABSTRACT FROM AUTHOR]