Manure Loading Research Articles

Year-round methane emissions from liquid dairy manure in a cold climate reveal hysteretic pattern

Liquid dairy manure storage is favourable for methane (CH4) production and a significant source of this greenhouse gas. Manure storage in cold climates faces large temperature variations over the course of a year, and added on-farm complexities in manure loading require year-round measurements which are currently lacking. The objectives of this study were to 1) quantify CH4 emissions from farm-scale liquid dairy manure storage in a cold climate, 2) investigate the effect of manure temperature on CH4 emissions, and 3) compare measured CH4 emissions with values derived from the USEPA temperature model. Methane fluxes were measured from Aug 2010 to early Nov 2011 on a commercial farm in Ontario, Canada, using a micrometeorological mass balance method which relied on 3 towers with air intakes at 4 heights placed around the storage tank. Manure temperature and volatile solid content (VS) were also measured. Monthly CH4 emissions scaled by VS decreased from 43.8 g CH4 kg−1 VS in Sep 2010 to 5.3 g CH4 kg−1 VS in Jan 2011, and were correlated with temperature (r2 = 0.94). Manure temperature increased starting in Feb 2011, but the increase in CH4 emissions was delayed to Jul 2011. Hence, the response of CH4 emissions to temperature showed a hysteretic pattern where emissions in the warming branch after the winter (Apr-Jun) were significantly lower than emissions in the cooling branch after the summer (Sep-Nov) despite similar temperatures. The temperature model predicted emissions during the cooling phase well, but overpredicted emissions during the warming phase, indicating other limiting factors for microbial CH4 production. Thus, the annual predicted CH4 emissions were about 2.3× larger than the measured values. The newly observed hysteresis effect should be considered when predicting CH4 emissions from stored manure.

A 3-D model to predict the temperature of liquid manure within storage tanks

A numerical model was developed to determine the year-round temperature distribution within liquid manure storages, which is relevant for modelling temperature-dependent greenhouse gas and ammonia emissions. The model considers net short and long-wave radiation, heat conduction through walls and floor, surface convective heat transfer, evaporative heat loss, and manure loading. The model was implemented and validated for a circular concrete storage tank (40 m diameter; 2.5 m depth) on a dairy farm in Ontario, Canada, where it is assumed that heat transfer occurs in horizontal and vertical directions, and is symmetric in the angular direction. Annual root mean square error (RMSE), Nash–Sutcliffe model efficiency, coefficient of determination, and average bias between model estimates and measured values were 2.4 °C, 0.91, 0.95, and 0.12 °C, respectively. The model performed best in summer and autumn (lowest RMSE), which are the most important seasons for modelling temperature, as both temperature and manure volume are highest, leading to the greatest opportunity for gaseous emissions. A sensitivity analysis indicated that the most significant parameters were solar absorptivity, manure depth, incoming manure temperature, emissivity, and wind-speed. For every unit increase in depth (m), incoming manure temperature (°C), or wind-speed (m s −1 ), the peak summer temperature changed by −7.3, 0.3, or −2.4 °C, respectively. Parameters with little effect on temperature were the manure solids content and thermal conductivity of soil around the sides and the bottom of the tank. Results show that heat transfer is primarily 1-dimensional, and a simplified 1-D model would be sufficient for future applications.

Silvopasture—It's Not a Load of Manure: Differentiating between Silvopasture and Wooded Livestock Paddocks in the Northeastern United States

Silvopasture—It's Not a Load of Manure: Differentiating between Silvopasture and Wooded Livestock Paddocks in the Northeastern United States

Life cycle assessment of the environmental performance of conventional and organic methods of open field pepper cultivation system

PurposeAs the scale of the organic cultivation sector keeps increasing, there is growing demand for reliable data on organic agriculture and its effect on the environment. Conventional agriculture uses chemical fertilizers and pesticides, whilst organic cultivation mainly relies on crop rotation and organic fertilizers. The aim of this work is to quantify and compare the environmental sustainability of typical conventional and organic pepper cultivation systems.MethodsTwo open field pepper cultivations, both located in the Anthemountas basin, Northern Greece, are selected as case studies. Life cycle assessment (LCA) is used to quantify the overall environmental footprint and identify particular environmental weaknesses (i.e. unsustainable practices) of each cultivation system. Results are analysed at both midpoint and endpoint levels in order to obtain a comprehensive overview of the environmental sustainability of each system. Attributional LCA (ALCA) is employed to identify emissions associated with the life cycles of the two systems. Results are presented for problem-oriented (midpoint) and damage-oriented (endpoint) approaches, using ReCiPe impact assessment.Results and discussionAt midpoint level, conventional cultivation exhibits about threefold higher environmental impact on freshwater eutrophication, than organic cultivation. This arises from the extensive use of nitrogen and phosphorus-based fertilizers, with consequent direct emissions to the environment. The remaining impact categories are mainly affected by irrigation, with associated indirect emissions linked to electricity production. At endpoint level, the main hotspots identified for conventional cultivation are irrigation and fertilizing, due to intensive use of chemical fertilizers and (to a lesser degree) pesticides. For organic pepper cultivation, the main environmental hotspots are irrigation, machinery use, and manure loading and spreading processes. Of these, the highest score for irrigation derives from the heavy electricity consumption required for groundwater pumping associated with the fossil-fuel-dependent Greek electricity mix.ConclusionsOrganic and conventional cultivation systems have similar total environmental impacts per unit of product, with organic cultivation achieving lower environmental impacts in ‘freshwater eutrophication’, ‘climate change’, ‘terrestrial acidification’ and ‘marine eutrophication’ categories. Conventional cultivation has a significantly greater effect on the freshwater eutrophication impact category, due to phosphate emissions arising from application of chemical fertilizers.

Cost benefit assessment of a novel thermal stripping – acid absorption process for ammonia recovery from anaerobically digested dairy manure

Thermal stripping – acid absorption is a novel technology recently developed to recover ammonia as marketable ammonium sulfate granules from anaerobic digester effluent. Taking a large-size dairy farm in New York State, USA, as an example, this study evaluates the costs and benefits of ammonia recovery from a recirculation line of mesophilic anaerobic digesters. Option 1 is the baseline without ammonia recovery. Option 2 is to draw digester effluent at 28% of the liquid manure loading rate, heat to 101 °C for ammonia recovery, and return the ammonia-recovered dairy manure to the digesters. Under option 2, the returned hot manure eliminates the need to heat the digesters. Option 3 is similar to Option 2, but the recirculation rate is only 14% of the manure loading rate. In this case, additional heating is needed for the digesters. Engineering unit cost and revenue models are developed for the thermal stripping – acid absorption process. Options 2 and 3 have benefit/cost ratios of 1.90 and 1.86, respectively. Option 2 produces greater net present value (NPV) ($1.34 million) than Option 2 ($0.72 million), while Option 1 yields a negative NPV (−$0.23 million). Ammonia recovery on this farm can create 1.5–3 jobs. Labor costs account for 62–70% of the total operating costs. Option 2 can generate a benefit of $0.018/L manure digestate or $0.50/d/cow. Any uncertainties relating to NPV and benefit/cost ratio are mainly associated with the sale price of ammonium sulfate and hourly wage rate.

A Field Test of All-Weather Surfaces for Horse Paddocks

Abstract: This field study sought to determine the all-weather surface construction providing the least contaminated runoff and drainage effluent when exposed to moderate to heavy precipitation and different manure loads in horse paddocks during wintertime. Two different combinations of non-woven and woven geotextile together with two gravel fractions of 200 mm were exposed to precipitation and horse manure/urine for two years under two manure regimes (manure removal and manure accumulation). In a simulated rainfall (SR) study, the test areas were also exposed to 50 mm precipitation for 30 min and 15 kg of horse manure under the two manure regimes. Runoff, drainage effluent and leachate flow were measured and sampled for both regimes. The geotextile-gravel construction reduced runoff and drained the test area throughout the two-year period, confirming construction stability and a dry walking surface area at a mean drain flow of 3.65 L m-2 h-1. The concentrations of total N, total phosphorus (TP), chemical oxygen demand (COD) and total solids (TS) in fluids leaving the test areas in winter were lower than in previous studies, due to lower horse density. The mean drainage concentration of TP, COD and TS was 3.4, 231, 739 mg L-1, respectively, due to manure removal in the SR study. The TP (1.9 mg L-1) concentration in drain fluids was reduced by 47% in the test area consisting of a single geotextile compared with previously reported values (3.6 mg L-1). With the paddock designs tested here, non-point pollution from paddocks could be controlled and reduced.

Comparison on batch anaerobic digestion of five different livestock manures and prediction of biochemical methane potential (BMP) using different statistical models

There is a lack of literature reporting the methane potential of several livestock manures under the same anaerobic digestion conditions (same inoculum, temperature, time, and size of the digester). To the best of our knowledge, no previous study has reported biochemical methane potential (BMP) predicting models developed and evaluated by solely using at least five different livestock manure tests results. The goal of this study was to evaluate the BMP of five different livestock manures (dairy manure (DM), horse manure (HM), goat manure (GM), chicken manure (CM) and swine manure (SM)) and to predict the BMP using different statistical models. Nutrients of the digested different manures were also monitored. The BMP tests were conducted under mesophilic temperatures with a manure loading factor of 3.5g volatile solids (VS)/L and a feed to inoculum ratio (F/I) of 0.5. Single variable and multiple variable regression models were developed using manure total carbohydrate (TC), crude protein (CP), total fat (TF), lignin (LIG) and acid detergent fiber (ADF), and measured BMP data. Three different kinetic models (first order kinetic model, modified Gompertz model and Chen and Hashimoto model) were evaluated for BMP predictions. The BMPs of DM, HM, GM, CM and SM were measured to be 204, 155, 159, 259, and 323mL/g VS, respectively and the VS removals were calculated to be 58.6%, 52.9%, 46.4%, 81.4%, 81.4%, respectively. The technical digestion time (T80–90, time required to produce 80–90% of total biogas production) for DM, HM, GM, CM and SM was calculated to be in the ranges of 19–28, 27–37, 31–44, 13–18, 12–17days, respectively. The effluents from the HM showed the lowest nitrogen, phosphorus and potassium concentrations. The effluents from the CM digesters showed highest nitrogen and phosphorus concentrations and digested SM showed highest potassium concentration. Based on the results of the regression analysis, the model using the variable of LIG showed the best (R2=0.851, p=0.026) for BMP prediction among the single variable models, and the model including variables of TC and TF showed the best prediction for BMPs (R2=0.913, p=0.068–0.075) comparing with other two-variable models, while the model including variables of CP, LIG and ADF performed the best in BMP prediction (R2=0.999, p=0.009–0.017) if three-variable models were compared. Among the three kinetic models used, the first order kinetic model fitted the measured BMPs data best (R2=0.996–0.998, rRMSE=0.171–0.381) and deviations between measured and the first order kinetic model predicted BMPs were less than 3.0%.

Start-up strategies in manure-fed biogas reactors: Process parameters and methanogenic communities

Four start-up strategies were assayed in 75 dm3 continuous stirred-tank reactors to select the optimal conditions for the start-up of the demonstration BIO4GAS® plant. Two reactors were completely filled with manure and their temperature increased from 20 to 37 °C at either a slow or fast rate. The other two reactors were started at 37 °C with a seed sludge from a stably operating plant and their load (cattle manure) increased at a low or high rate. Reactor performance was monitored for 35 days. The composition and abundance of the methanogenic communities was determined using a phylogenetic microarray and quantitative PCR. All reactors performed successfully in terms of biogas production and experienced a steady start-up, with pH values above 7.3 and VFA/alkalinity ratios below 0.3, denoting stability. Similar methanogenic loads (averaging 5 × 107 g-1 of 16S rRNA gene copies) were detected in the cattle manure and seed sludge, however the methanogenic diversity was higher in the manure with dominance of Methanosarcina and subdominance of Methanocorpusculum and Methanobrevibacter. Starting-up the reactors with an initial full load of manure and progressively increasing the temperature entailed less changes in the sludge chemical environment and in the dynamics of the dominant methanogens. Using a rate of temperature increase of 0.61 K d−1 proved better than1.21 K d−1 with a methane yield of 103.8 dm3 kg−1 VS and a COD mass removal efficiency of 28.3%. The diverse methanogenic community in the manure easily adapted to reactor upsets due to forced overload conditions.

Effects of Biosolids and Manure Application on Microbial Water Quality in Rural Areas in the US

Most of the waterborne disease outbreaks observed in North America are associated with rural drinking water systems. The majority of the reported waterborne outbreaks are related to microbial agents (parasites, bacteria and viruses). Rural areas are characterized by high livestock density and lack of advanced treatment systems for animal and human waste, and wastewater. Animal waste from livestock production facilities is often applied to land without prior treatment. Biosolids (treated municipal wastewater sludge) from large wastewater facilities in urban areas are often transported and applied to land in rural areas. This situation introduces a potential for risk of human exposure to waterborne contaminants such as human and zoonotic pathogens originating from manure, biosolids, and leaking septic systems. This paper focuses on waterborne outbreaks and sources of microbial pollution in rural areas in the US, characterization of the microbial load of biosolids and manure, association of biosolid and manure application with microbial contamination of surface and groundwater, risk assessment and best management practice for biosolids and manure application to protect water quality. Gaps in knowledge are identified, and recommendations to improve the water quality in the rural areas are discussed.

Leaching of veterinary antibiotics in calcareous Chinese croplands

Veterinary antibiotics reach the soil environment by manure application, where they accumulate or are prone to vertical translocation. We assumed that a high pH value at slightly calcareous soil properties should retain tetracyclines and fluoroquinolones even at high manure loads, whereas it should facilitate leaching of sulfonamides. Hence, we investigated the transport of manure-added antibiotics in a soil developed from calcareous parent material on a farm in peri-urban Beijing, China. Leachate was collected from zero-tension samplers, installed at 40cm depth under undisturbed soil, which was treated according to (i) routine farm practice and (ii) worst-case conditions (high antibiotic concentrations, irrigation imitating heavy rainfall). Additionally, the soil depth distribution of pharmaceuticals at the end of the leaching experiment was analysed. Under routine farm practice, sulfamethazine was repeatedly detected in the leachate with a maximum concentration of 0.12μgL−1. All applied substances were still detected in soil after 53days, suggesting that there was no overall rapid and complete dissipation. Worst-case conditions enhanced vertical translocation; all leachate samples contained sulfonamides (up to 653μgL−1 sulfamethazine), and even tetracyclines were found in the leachate once, with doxycycline reaching the highest concentration (0.19μgL−1). The concentrated simultaneous occurrence of sulfonamides with the bromide tracer in leachate samples pointed to preferential flow as underlying transport process. The high pH values did not prevent the single leaching event for tetracyclines and hardly affected overall leaching behaviour. The applied fluoroquinolones were not significantly translocated below 4cm depth, irrespective of irrigation and high manure addition.

우사깔짚에서 발생되는 온실가스 배출량 산정: 모의 실험결과

우사바닥깔짚으로부터의 온실가스 배출량을 산정하기 위해 깔짚으로의 분뇨부하량을 정확히 조절할 수 있는 모의우사바닥에서의 깔짚두께별 <TEX>$CH_4$</TEX>와 <TEX>$N_2O$</TEX> 가스 발생량을 조사하였다. 톱밥이 10, 15cm 높이로 깔린 <TEX>$0.2583m^2$</TEX>(L 0.63 m<TEX>${\times}$</TEX>W 0.41 m) 크기의 우사바닥으로의 한우와 젖소의 분뇨부하는 친환경 축사표준모델의 축사면적과 축종별 일일 분뇨배설량 자료를 기준으로 한우는 <TEX>$1.586kg/m^2/d$</TEX>, 젖소는 <TEX>$3.588kg/m^2/d$</TEX>로 정하고 24시간 주기로 분뇨를 투입/혼합하면서 깔짚으로부터 발생하는 온실가스 발생량을 조사하였다. 총 12개의 모의우사바닥을 이용하여 모든 실험은 3반복으로 3회에 걸쳐 수행되었다(5~7월, 9~11월, 2~4월). 그 결과 단위면적당 <TEX>$CH_4$</TEX> 발생량은 한우, 젖소 모두에서 깔짚이 두꺼운 경우 적게 발생하는 경향을 보였으나 통계적으로 유의적인 차이가 없었으며(p<0.05), <TEX>$N_2O$</TEX> 발생량의 경우에도 깔짚두께에 따른 차이가 없는 것으로 나타났다. 한우와 젖소를 비교할 때 단위면적당 온실가스 발생량은 젖소가 <TEX>$CH_4$</TEX>는 약 7.5배, <TEX>$N_2O$</TEX>는 약 1.2배 많았으며 연간 배출되는 <TEX>$CH_4$</TEX>는 한우 7.4 g/head/year, 젖소 130.4 g/head/year로 젖소가 한우에 비해 21배 높은 것으로 나타났다. 또한 <TEX>$N_2O$</TEX>는 한우 3,267 g/head/year, 젖소 14,719 g/head/year로 젖소가 약 4.5 배 많았으나 배설된 N 대비 <TEX>$N_2O$</TEX>-N은 한우 0.2148 kg <TEX>$N_2O$</TEX>-N/kg N, 젖소 0.1632 kg <TEX>$N_2O$</TEX>-N/kg N으로 오히려 한우가 높았으며 IPCC 2006 GL값 0.07 kg <TEX>$N_2O$</TEX>-N/kg N과 비교시 한우는 약 3.07배, 젖소는 약 2.33배 높은 것으로 나타났다. To know the emission amount of greenhouse gases from bedding materials of cowshed floor, the emission rates of methane (<TEX>$CH_4$</TEX>) and nitrous oxide (<TEX>$N_2O$</TEX>) gases from a simulated cowshed floor (SCF) with sawdust that manure loading rate into the bedding material could be accurately controlled were assessed in this study. The manure loading rates of Korean beef and Holstein dairy cattle into the SCF of <TEX>$0.258m^2$</TEX> surface area with 10 to 15 cm height sawdust were <TEX>$1.586kg/m^2/d$</TEX> and <TEX>$3.588kg/m^2/d$</TEX>, respectively, and those were calculated on the basis of "Standard model for sustainable livestock" and "Data for excretion amount of manure from livestock". All experiments were done in triplicates in three different seasons (May to July, Sep. to Nov., and Feb. to Apr.) using 12 SCFs. The effects of bedding material thickness on <TEX>$CH_4$</TEX> and <TEX>$N_2O$</TEX> emission from SCFs for both Korean beef cattle and Holstein dairy cattle were not statistically significant (p<0.05). Emission amount of <TEX>$CH_4$</TEX> and <TEX>$N_2O$</TEX> per square meter of SCF for Holstein dairy cattle was 7.5 and 1.2 times higher than that of Korean beef cattle, respectively. The yearly <TEX>$CH_4$</TEX> amount per head was 17.7 times higher in Holstein dairy cattle, obtaining 130.4 g/head/year from SCF for Holstein dairy cattle and 7.4 g/head/year from SCF for Korean beef cattle, and <TEX>$N_2O$</TEX> was also 3.8 times higher in Holstein dairy cattle (3,267 g/head/year in Korean beef cattle and 14,719 g/head/year in Holstein dairy cattle). However, the <TEX>$N_2O$</TEX>-N per loaded nitrogen into SCF was higher in Korean beef cattle, having 0.2148 and 0.1632 kg <TEX>$N_2O$</TEX>-N/kg N in Korean beef cattle and Holstein dairy cattle, respectively, and those values were 3.07 and 2.33 times higher than that of Intergovernmental Panel on Climate Change (IPCC) 2006 guideline (GL) (0.07 kg <TEX>$N_2O$</TEX>-N/kg N).

Assessment of the Nitrogen Estimation of Fecal Residue and Waste Water Production Amount and its Risk Predict in Nanning City

The computational parameter and statistical methods of pig fecal equivalent of the livestock and poultry manure in nanning County is determined in the current project based on the several surveys of local farming conditions, and pig excrement equivalent number from 2004 to 2009 are calculated. Based on pig fecal equivalent, we forecast poultry excrement load of early warning value from 2010 to 2015 year by using the GM (1, 1) model. The result indicates that from 2010 to 2015 the livestock manure emissions in nanning city increase from 18063400 tons to 19168900 tons, the average farm manure load reached 27.70 t/ha from 26.11 t/ha, the R value increases gradually, the agricultural non-point pollution thereat degree of animal manure actually assures the tendency of aggravating.

Management model for assessment of nitrogen flow from feed to pig manure after storage in Vietnam

Nitrogen (N) losses from pig production and the recycling of N from manure to crops can harm the atmosphere, soil and ground water quality. This study intended to build a dynamic management model, adapted to the Vietnamese context, that links the N flow at all stages along the manure management chain from the N in the diets fed to grower-finisher pigs to the application of the manure in the field. The model assesses N contents and losses at each stage of manure management so that application of manure N can be adjusted to ensure optimal fertilizer value, while at the same time minimizing environmental damage. This model provides a tool for examining the N flow on pig farms, to adjust the N content of feeds, the pig population, and to minimize N discharge and emissions. The model is developed using Powersim® software and data from feed-excretion, storage and composting experiments. For validation and performance of the model we used sub-datasets from feed-excretion experiments in Denmark and Vietnam that were not used to parameterize in the model. This article presents the development of the model and trial of the model through scenario analyses of pig production in livestock production zones. The objective is that policy makers, extension officers or agricultural advisors will use the model as a support management tool to formulate and adjust manure management practices. This includes assessment of the land carrying capacity in existing livestock production areas and of maximum acceptable manure loads in planned livestock production zones.

Selective reduction of the pathogenic load of cow manure in an industrial-scale continuous-feeding vermireactor

Vermicomposting is a suitable technology for processing different wastes, to produce a valuable end product (vermicompost). However, the pathogenic load of the waste must be greatly reduced in order to prevent risks to human health. Although Eisenia andrei may reduce the levels of several pathogens, the feasibility of vermicomposting, with regard to pathogen reduction, has not been tested on an industrial scale. This work studied whether vermicomposting in a continuous feeding vermireactor, is able to reduce the pathogenic load of cow manure. The effect of E. andrei on pathogens depended on the type of pathogen; thus, levels of Clostridium, total coliforms and Enterobacteria were not modified, but levels of faecal enterococci, faecal coliforms and Escherichia coli were reduced to acceptable levels. Pathogens could have maintained their levels in continuous feeding vermireactors, as fresh layers of manure are added to the top, which allows the vertical spread of pathogens through leaching.

Determining Seasonal Greenhouse Gas Emissions from Ground-Level Area Sources in a Dairy Operation in Central Texas

ABSTRACT Greenhouse gas (GHG) emissions from agricultural production operations are recognized as an important air quality issue. A new technique following the U.S. Environmental Protection Agency Method TO-14A was used to measure GHG emissions from ground-level area sources (GLAS) in a free-stall dairy operation in central Texas. The objective of this study was to quantify and report GHG emission rates (ERs) from the dairy during the summer and winter using this protocol. A weeklong sampling was performed during each season. A total of 75 and 66 chromatograms of air samples were acquired from six delineated GLAS (loafing pen, walkway, barn, silage pile, settling basin, and lagoon) of the same dairy during summer and winter, respectively. Three primary GHGs—methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O)—were identified from the dairy operation during the sampling periods. The estimated overall ERs for CH4, CO2, and N2O during the summer for this dairy were 274, 6005, and 7.96 g head−1day−1, respectively. During the winter, the estimated overall CH4, CO2, and N2O ERs were 52, 7471, and 3.59 g head−1day−1, respectively. The overall CH4 and N2O ERs during the summer were approximately 5.3 and 2.2 times higher than those in the winter for the free-stall dairy. These seasonal variations were likely due to fluctuations in ambient temperature, dairy manure loading rates, and manure microbial activity of GLAS. The annualized ERs for CH4, CO2, and N2O for this dairy were estimated to be 181, 6612, and 6.13 g head−1day−1, respectively. Total GHG emissions calculated for this dairy with 500 cows were 2250 t of carbon dioxide equivalent (CO2e) per year. IMPLICATIONS The agricultural sector, especially concentrated animal feeding operations (CAFOs) contribute a considerable amount of GHGs to the atmosphere. To develop abatement strategies to reduce GHG emissions, it is important to learn to collect, analyze, verify, and report real data on actual emissions. Therefore, there is a need for a robust and accurate technique/protocol to measure GHGs from CAFOs. It is important to obtain direct estimates of GHG emissions from different GLAS in CAFOs to compile emission inventories and to develop GLAS-specific abatement strategies.

Anaerobic ammonia oxidation in a fertilized paddy soil

Evidence for anaerobic ammonium oxidation in a paddy field was obtained in Southern China using an isotope-pairing technique, quantitative PCR assays and 16S rRNA gene clone libraries, along with nutrient profiles of soil cores. A paddy field with a high load of slurry manure as fertilizer was selected for this study and was shown to contain a high amount of ammonium (6.2-178.8 mg kg(-1)). The anaerobic oxidation of ammonium (anammox) rates in this paddy soil ranged between 0.5 and 2.9 nmol N per gram of soil per hour in different depths of the soil core, and the specific cellular anammox activity observed in batch tests ranged from 2.9 to 21 fmol per cell per day. Anammox contributed 4-37% to soil N2 production, the remainder being due to denitrification. The 16S rRNA gene sequences of surface soil were closely related to the anammox bacteria 'Kuenenia', 'Anammoxoglobus' and 'Jettenia'. Most of the anammox 16S rRNA genes retrieved from the deeper soil were affiliated to 'Brocadia'. The retrieval of mainly bacterial amoA sequences in the upper part of the paddy soil indicated that nitrifying bacteria may be the major source of nitrite for anammox bacteria in the cultivated horizon. In the deeper oxygen-limited parts, only archaeal amoA sequences were found, indicating that archaea may produce nitrite in this part of the soil. It is estimated that a total loss of 76 g N m(-2) per year is linked to anammox in the paddy field.

Combined effects of the antibiotic sulfadiazine and liquid manure on the soil microbial‐community structure and functions

AbstractSulfonamides are the second most used antibiotic class in veterinary medicine and applied to livestock to treat bacterial infections. Subsequently, they are spread onto agricultural soils together with the contaminated manure used as fertilizer. Both manure and antibiotics affect the soil microbial community. However, the influence of different liquid manure loads on effects of antibiotics to soil microorganisms is not well understood. Therefore, we performed a microcosm experiment for up to 32 d to clarify whether the function and structure of the soil microbial community is differently affected by interactions of manure and the antibiotic sulfadiazine (SDZ). To this end selected concentrations of pig liquid manure (0, 20, 40, 80 g kg–1) and SDZ (0, 10, 100 mg kg–1) were combined. We hypothesized that incremental manure amendment might reduce the effect of SDZ in soils, due to an increasing sorption capacity of SDZ to organic compounds. Clear dose‐dependent effects of SDZ on microbial biomass and PLFA pattern were determined, and SDZ effects interacted with the liquid manure application rate. Soil microbial biomass increased with incremental liquid manure addition, whereas this effect was absent in the presence of additional SDZ. However, activities of enzymes such as urease and protease were only slightly affected and basal respiration was not affected by SDZ application, while differences mostly depended on the concentration of liquid manure. These results illustrated that the microbial biomass and structural composition react more sensitive to SDZ contamination than functional processes. Furthermore, effects disproportionally increased with incremental liquid manure addition, although extractable amounts of SDZ declined with increasing liquid manure application.

Performance of geotextile-gravel bed all-weather surfaces for cattle

A cost-effective way of producing all-weather surfaces for cattle is to use a combined geotextile-gravel pad construction, which allows pavement depth to be reduced. This study sought to determine the pavement construction that would offer the least runoff, best drainage effect and highest quality runoff and drainage effluent after exposure to heavy precipitation under different manure loads in high animal density areas. The study also examined whether any pavement construction gave acceptable sealing to the underlying soil surface. Three different combinations of non-woven and woven geotextile together with two gravel fractions of 200 mm were exposed to 50 mm precipitation for 30 min and 15 kg of cattle manure under two manure regimes (manure removal and manure accumulation). Runoff, drainage effluent and leachate flow were measured and sampled in buckets as they exited their respective pipes for both regimes. The pad surface layer reduced runoff flow rate and stabilised drain flow throughout the experiments, confirming pad stability. Manure removal reduced total N, total P, chemical oxygen demand (COD) and total solid (TS) concentrations in drainage effluent. One pad construction proved better at oxidising NO 2 –N and another at trapping TS. One pad construction met the sealing liner norm to the underlying soil. The drainage effluent produced was acceptable for wetland treatment. The results show that geotextile and gravel pad constructions not only have a supporting and draining function, but also a filtering, aerating and sealing effect.

Removing the pollution load of manure by mixed bacterial cultures and environmental yeasts

Removing the pollution load of manure by mixed bacterial cultures and environmental yeasts

Loading capacity estimation and risk assessment of livestock manure in cultivated lands around Dongting Lake

Based on the status of animal husbandry in Dongting Lake area, the quantity of livestock manure was estimated using the excretive coefficient method and the loading capacity and risk conditions evaluated. The results show that the output of livestock manure, urine, BOD5, COD and NH3-N in Dongting Lake area in 2006 are 1 616.93×104 t, 1 248.30×104 t, 72.41×104 t, 79.33×104 t and 7.48×104 t respectively. The average loading capacity of livestock manure reaches 19.25 t·hm-2. Forewarning average risk level of livestock manure loading is 0.47. On the average, there is no environmental pollution, and there is still room to develop animal production in Dongting Lake area. However, some cultivated lands already show livestock manure pollution, a trend that can not be ignored.