Dry Manure Research Articles

How shallow water table conditions affect N2O emissions and associated microbial abundances under different nitrogen fertilisations

Globally, agriculture is the largest source of nitrous oxide (N2O), a potent greenhouse gas (GHG). A recognised tool to prevent its loss from agricultural soils is the presence of a shallow water table. A four-year lysimeter experiment (2011–2014) was conducted in northeast Italy to investigate how water table levels affect N2O emissions after different N fertilisation techniques. Soil surface flux and groundwater-dissolved N2O were studied under free drainage and at two shallow water table levels (60 cm and 120 cm) and at two levels of N input (250 and 368 kg N ha−1 y−1), using dry manure in 2011 and 2012 and fresh manure in 2013 and 2014. DNA was extracted from soils and quantitative PCR (qPCR) was used to assess the size of nitrifying, denitrifying and N2-fixing bacterial communities. at three soil depths. The day after pre-seeding fertiliser incorporation, N2O emission started to be detected and continued for two-three weeks; brief measurable emissions also followed top–dressing fertilisation events. Cumulative N2O emission measured between 0.97 and 2.33 kg N2O-N ha−1 y−1, corresponding to emission factors from 0.4% to 1.1%. Manure fertilisation significantly affected the N dose only when applied as fresh manure. Water-filled pore space (WFPS) affected daily N2O emissions with a significant interaction with fertilisation level. The two N input levels showed differences only when WFPS was >40%, which revealed N availability as key to increased N2O emissions at high water content, supposedly by fostering anaerobic denitrification. No significant relationships were observed between peak N2O emissions and the values of the temperature or irrigation variables recorded during the experimental observation period. Groundwater dissolved N2O-N concentrations measured about 1.7 μg L−1 with some peak variability from nitrate leaching. Quantitative PCR assays demonstrated that shifts in microbial population that can be involved in oxidation processes and heterotrophic denitrification occurred in the soil, even though the contributions of the different N pathways on N2O emissions were indistinguishable. Indeed, both nitrifying and denitrifying genes were simultaneously promoted by the high fertilisation input and hindered by the high water table level. Shallow groundwater conditions appeared to reduce N2O emissions probably by favouring complete denitrification. These results suggest that in the Po Plain, regulated by the Nitrate Directive, shallow groundwater conditions, with a balanced N input, may mitigate air and water pollution.

Analysis of selected economic and environmental impacts of long distance manure transports to biogas plants

In regions with high livestock density, manure supply often exceeds demand and complete local deployment would lead to severe environmental damage due to over-nutrification. One solution is to use the surplus in other regions, which have lower nutrient-levels. To decrease costs associated with transport the manure can first be used in biogas plants of those regions. To date, however, the economic and ecological consequences of this solution are unclear. Here, we develop a model of the consequences from the perspective of a biogas plant owner and apply it to a case study in Lower-Saxony, Germany. The model determines the maximal profitable manure transport distance from a financial point of view. Furthermore, it examines selected environmental impacts for various scenarios with an assumed transport range of 150 km, a typical distance. For dry poultry manure transport distances up to 700 km and more can be financially advantageous. Emission reductions occurred in all scenarios in the impact categories Greenhouse Gas and Acidification. The model can support decision-makers in the livestock and biogas industries in determining whether to transport manure and, if so, how far.

Methane/Gasoline Bi-fuel Engines as a Power Source for Standard Agriculture Tractors: Development and Testing Activities

Abstract. Promoting energy efficiency in agriculture means supporting economic growth by reducing both pollution and greenhouse gas (GHG) emissions while minimizing waste and the inefficient use of natural resources. Biomethane presents an interesting option given its possibility to be produced from livestock waste or other organic residues, with GHG emission savings ranging from 84% to 86% (wet or dry manure). Moreover, experiences with methane-fueled engines are widely available, thus leading to considering the possibility of using such a fuel in the agricultural sector as well. The aim of this research was to develop a first-generation tractor prototype provided with a commercially available bi-fuel engine adapted for the purpose and tested both in laboratory and field conditions. The main design aspects are depicted while the performance results show similar values of engine power and torque (87 kW maximum power for the diesel fuel tractor and 88 kW for the methane-fueled version; 1172 Nm maximum torque at 550 min-1 for the methane and 1155 Nm at 400 min-1 for the diesel tractor) with an autonomy of the methane prototype which is, at present, 40% of a comparable standard tractor. The possible role in farm fleet is also presented. Keywords: Agricultural machinery, CNG, Gaseous bio-fuels, Renewable fuels.

How Do Temperature and Rainfall Affect Nitrous Oxide Emissions from Open-Lot Beef Cattle Feedyard Pens?

Abstract. Temperature is a primary factor affecting greenhouse gas (GHG) emissions from agricultural soils, but little is known about how temperature affects nitrous oxide (N2O) emissions from manure. The majority of grain-fed cattle in the Texas Panhandle are finished in large, earthen-surfaced, open-lot feedyards. Manure accumulates in feedyard pens and creates an environment high in nitrogen (N) and carbon (C) that can lead to N2O losses. In previous studies, N2O-N emissions from feedyard manure have been highly variable, ranging from negligible amounts from dry manure to 200 mg m-2 h-1 after a simulated rainfall event. The objective of this research was to determine how temperature affects N2O emissions from feedyard manure following rainfall. A recirculating flow-through, non-steady-state (RFT-NSS) chamber system with 1 m2 pans was used to monitor N2O emissions from beef cattle manure following a single 25.4 mm simulated rainfall event. Emissions were monitored at manure temperatures of 5.0°C, 11.2°C, 17.2°C, 21.5°C, 26.8°C, 31.0°C, 38.1°C, and 46.2°C. At all temperatures, a single N2O episode was observed following rainfall, peaking 2 to 11 h after rainfall with duration of 2 to 3 d. A second N2O episode was observed at temperatures =31.0°C, peaking 3 to 4 d after rainfall with duration of 18 d. When present, the second N2O episode accounted for 72% to 83% of the 20 d cumulative emissions. A step-increase in cumulative N2O emissions was observed between 26.8°C and 31.0°C, believed to be due to a major shift from denitrification to nitrification as the primary process of N2O production. Empirical regression models were developed for predicting cumulative N2O emissions based on temperature, which showed 88% agreement between predicted and field-observed N2O-N flux rates. These regression models will be useful for further quantification of N2O emissions from open-lot beef cattle feedyards in the U.S. Southern High Plains and for assessment of practices for reducing GHG emissions. Keywords: Beef cattle, Chamber, Greenhouse gas, Manure, Nitrous oxide, Precipitation.

Evaluation of phytoplankton diversity in periphyton based aquaculture system

This study was done to determine the impact of rice straw as a substrate for periphyton production and phytoplankton biodiversity in earthen fish ponds belongs to the world fish center. The ponds have the same area of Six 1000 m2 and the depth of water 1m. The ponds cultured with mono six Nile tilapia fry in the rate of 3 fry/ m2. All ponds were fertilized with dry chicken manure in the rate of 15 kg/pond/week, and divided into two treatments, each of 3 replicates; the first treatment (T1), the substrate free control, while second treatment (T2) received 45 kg dry rice straw/pond. The samples were collected monthly from May to December 2017. The quantitative measurements for phytoplankton showed that total count of phytoplankton in water was higher in T1 than T2. The rice straw was effective for controlling growth of cyanophyceae compared to controls, and was capable for inhibiting the growth of Microcystis. Phormidium, Merismopediam, Gloeocapsa, Lyngbya and Chlorella, but Chrococcus, Synedra and Navicula sp. had improved growth in the presence of rice straw.Concerning periphyton the total count was (2103.68 x 106 org. /m2 as an average). And Chlorophyceae represent the dominant group with average (1577.07 x 106 org. /m2). The biodiversity index of overall phytoplankton genera Taxa evenness were (1.95 and 0.51) respectively in T2 which indicates that there is a high biodiversity of algae compared to T1 (1.76 and 0.42). The results of this investigation indicated that rice straw could introduce an accessible practical and commercial method to increased phytoplankton biodiversity.

Effects of dairy manure-derived biochar on psychrophilic, mesophilic and thermophilic anaerobic digestions of dairy manure

Effects of dairy manure-derived biochar (M-BC) on methane production in anaerobic digestion (AD) of dry dairy manure were investigated with three different concentrations of biochar (0, 1 and 10 g/L) and temperatures (psychrophilic, 20 °C; mesophilic, 35 °C; thermophilic, 55 °C). Compared with the AD without any biochar, the cumulative methane and yield in the AD with 10 g/L biochar were increased to 27.65% and 26.47% in psychrophilic, 32.21% and 24.90% in mesophilic and 35.71% and 24.69% in thermophilic digestions. The addition of M-BC shortened the lag phases of AD at all temperatures in the study while it lowered the concentration of total VFAs and propionic acid. It was suggested that the high nutrients and alkalinity potential of M-BC (i.e. 9.1% Ca, 3.6% Mg, 1.3% N, 0.14% P) would play significant roles in enhancing methane production and shortening lag phases from the AD of dairy manure.

Effect of ultrasonic pretreatment of the dairy manure on the electricity generation of microbial fuel cell

Microbial fuel cells (MFCs) represent a promising emerging technology for organic waste treatment and bioelectricity could be obtained simultaneously. In order to effectively develop the resource and energy in dairy manure, two-compartment MFC using dairy manure as main substrate (DMMFC) were proposed and the effect of ultrasonic pretreatment on the electricity generation of DMMFC was studied comprehensively. The results showed that when the ultrasonic power for the pretreatment of dairy manure was 600W, DMMFC showed the highest closed-circuit voltage (CCV) of 212mV at solid content of 10%. With external loading of 1000Ω, the power densities reached 29.9mW/m2, 56.2mW/m2, 102mW/m2 and 72.6mW/m2 at the ultrasonic power of 0, 300, 600, and 900W, respectively. The maximum current density arrived 102mA/m2 on the 14th day when the dairy manure was treated 20min under the ultrasonic of 600W. After 203 d, removal rate of chemical oxygen demand (COD) arrived 74.6%, and the energy of over 10.5kJ/kg (dry manure) was obtained.

SUITABILITY OF DRIED POULTRY MANURE FOR USE AS ANIMAL FEED

The aim of this study was to determine the optimum quality of poultry manure dried at various layer thickness and temperatures. The effects of the depth of manure layer (1, 2 and 3 cm) and dryer temperature (40, 50 and 60°C) on the drying time and the quality of the dried manure as a safe animal feed were investigated. The results indicate that the optimum depth and temperature to dry manure in a heated air dryer is 3 cm and 60 °C, respectively. Increasing the temperature and/or decreasing the depth of manure layer decrease the concentration of protein and amino acids in the dried manure. The temperature and depth of the manure layer did not affect the elemental composition of the dried manure. The presence and offensiveness of odour were reduced by 63.3% and 69.3%, respectively. The majority of the panel members described the odour of the dried manure as that of grain. The drying process reduced the number of bacteria, yeast and mould, and E. Coli by 65.62%-99.83%, 74.07%-99.63%, and 99.97% respectively. The Salmonallae were destroyed completely at temperatures above 50 °C.

Farm-scale greenhouse gas balances, hotspots and uncertainties in smallholder crop-livestock systems in Central Kenya

Abstract Climate-smart approaches have gained momentum in tropical, agricultural development. However, to date, few studies have examined whole-farm greenhouse gas (GHG) balances in smallholder crop-livestock systems. This study aimed to quantify GHG balances at farm-scale, identify GHG hotspots and assess mitigation options in coffee-dairy farms undergoing agricultural intensification in Central Kenya. In recent decades, decreasing farm size has forced the shift from extensive practices to zero-grazing systems and higher nitrogen (N) inputs. We hypothesised that different farm strategies and intensification levels determine the farm’s GHG balance. A farm typology was constructed through principal component analysis (PCA) and hierarchical clustering from 125 farms surveyed. Four farm types were identified ranging relatively from small to large farms, low to high livestock intensities, and low to high N input rates. Whole-farm GHG balances were estimated using an adapted version of the Cool Farm Tool (CFT). Farms were found to be net sources of GHG, averaging from 4.5 t CO 2 eq ha −1 yr −1 in less intensive farms to 12.5 t CO 2 eq ha −1 yr −1 in high intensive farms. Within the farm GHG hotspots identified, methane (CH 4 ) from enteric fermentation processes accounted for 26–39% of total farm GHG emissions; nitrous oxide (N 2 O) and CH 4 from manure management systems (MMS) for 26–38%; soil background and fertilizer induced N 2 O emissions for 24–29%; off-farm production of feeds and agrochemicals for 10–22%; and crop residue management (CRM) for the remaining 1–3%. Within the mitigation practices assessed, zero-grazing stalls already lowered the livestock maintenance energy requirements, reducing enteric fermentation emissions. Stall-feeding, however, brings the necessity-opportunity to manage the manure and our results showed that MMS can be a determining factor in the GHG balance. Increasing the frequency of manure collection from stalls in favour of solid storage systems can reduce N 2 O emissions by up to 75%. Furthermore, dry manure storage reduced the CH 4 emissions of liquid slurry systems by more than 70%. Further benefits in terms of carbon (C) sequestration were identified along farm types from manure and crop residues applications in soils (with averages of −1.3 to −2.3 t CO 2 eq ha −1 yr −1 ) and biomass growth in agroforestry systems (−1.2 to −2 t CO 2 eq ha −1 yr −1 ). Together, soils and woody biomass offset 25–36% of farm emissions. We conclude that reduced farm size and increased livestock density lead to higher emissions per unit area, though this increase is smoothed by larger negative fluxes in soils (by higher C inputs) and woody biomass (by higher tree densities) until a steady state is reached. Average yield-scaled emissions, or product carbon footprints (CFs), resulted in 1.08 kg CO 2 eq kg coffee berry −1 , 0.64 kg CO 2 eq kg maize −1 and 1.05 kg CO 2 eq kg milk −1 on average. CFs did not always differ between farm types and intensification levels, meaning that increases in productivity were not higher than increases in GHG fluxes from intensification. This may be due to: 1) increases in productivity are the result of more processes other than N inputs; and/or 2) emissions from N inputs are overestimated by EFs and GHG calculators. Smallholders may benefit in the near future from climate initiatives and further field characterisation, models calibration and monitoring are required to overcome critical levels of uncertainty and provide more accurate estimations of GHG balances at farm-scale.

Potentials of Waste and Wastewater Resources Recovery and Re-Use (RRR) Options for Improving Water, Energy and Nutrition Security

Under increasing demand for water, fertilizer and energy, waste and wastewater treatment can be potential options for considerably enhancing not only the supply of these valuable economic assets but also for improving sanitation and ecological conditions. Effluents and treated wastewater are important for meeting water demands for agricultural irrigation, landscape irrigation, and environmental system enhancement. Fertilizer and nutrients recovered though recycling organic waste and filtering wastewater, or embedded in effluents can be essential inputs for increasing crop biomass, timber output, and production of aquatic crops and marine species such as fish. Similarly, energy recovered from waste and wastewater recycling (including dry manure for cooking and heating) is important for enhanced energy supply especially in remote rural areas of the developing countries. Yet, the utilization of the waste and wastewater resources for additional gains should consider the accepted safety measures in order to prevent environmental and health risks. Focusing on potential benefits from resources recycling and recovery yet being cautious on their external effects, this review critically assesses the available waste and wastewater treatment options, and their economic, environmental and health benefits and risks.

Life cycle assessment of superheated steam drying technology as a novel cow manure management method

Common methods of managing dairy manure are directly applying it to the farm field as a fertilizer. For direct application without any type of treatment, the majority of nutrients in the manure run off to the local river and lake during precipitation periods. The algae bloom is one of the environmental outcomes due to eutrophication of the lakes, which may jeopardize the quality of drinking water. In this study, superheated steam drying (SSD) technology is investigated as an alternative manure management method. Rapidly dried cow manure can be used as alternative fuel. Evaluations of energy payback time (EPBT) and life cycle assessment (LCA) of the SSD technology are presented in the SSD scenario and the results are compared with those of the direct field application (FA) of fresh manure and anaerobic digestion (AD). The heat required for the generation of superheated steam in the SSD scenario is provided from combustion of the dry manure to reduce energy costs. The results for the SSD process show 95% and 70% lower eutrophication and global warming potential in comparison to the FA scenario. Acidification potential for SSD turned out to be 35% higher than FA. The comparison of SSD with AD for their EPBT and normalized impacts indicated that the proposed SSD scenario has higher environmental sustainability than AD (70% lower impact), and is likely an economically better choice compared to conventional AD method (87% lower EPBT) for the future investment.

PRODUCTION, MANAGEMENT AND THE ENVIRONMENT SYMPOSIUM: Measurement and mitigation of reactive nitrogen species from swine and poultry production.

Reactive nitrogen (Nr) species include oxides of nitrogen [N; nitric oxide, nitrogen dioxide and nitrous oxide (NO)], anions (nitrate and nitrite), and amine derivatives [ammonia (NH), ammonium salts and urea]. Of the different Nr species, air emissions from swine and poultry facilities are predominantly NH followed by NO. Excreta emissions are NH, ammonium ions, and urea with trace amounts of nitrate and nitrite. Farm systems and practices that handle manure as a wet product without pH modification favor almost exclusive NH production. Systems and practices associated with dry manure handling and bedded systems emit more NH than NO. Results from a turkey grow-out study estimated that just under 1% of consumed N was emitted as NO from housing, compared with just under 11% emitted as NH. Despite generally less NO emissions from animal housing compared with crop field emissions, NO emissions from housing are often greater than estimated. Lagoon systems emit more NO than either slurry or deep pit swine systems. Deep pit swine buildings emit only one-third the NO that is emitted from deep bedded swine systems. Laying hen, broiler chicken, and turkey buildings emit over 4 times as much NO as swine housing, on a weight-adjusted basis. Critical control points for mitigation center on: 1) reducing the amount of N excreted and, therefore, excreted N available for loss to air or water during housing, manure storage, or following land application of manures; 2) capturing excreted N to prevent release of N-containing compounds to air, water, or soil resources; or 3) conversion or treatment of N-containing compounds to non-reactive N gas.

Mechanisms and effects of arsanilic acid on antibiotic resistance genes and microbial communities during pig manure digestion

High concentrations of residual arsanilic acid occur in pig manure due to its use in feed to promote growth and control diseases. This study compared the effects of arsanilic acid at three concentrations (0, 325, and 650mg/kg dry pig manure) on the abundance of antibiotic resistance genes (ARGs) and the microbial community during anaerobic digestion. Addition of 650mg/kg arsanilic acid enhanced the absolute abundances of tetC, sul2, ermB, and gyrA more than twofold in the digestion product. Redundancy analysis indicated that the change in the microbial community structure was the main driver of variation in the ARGs profile. The As resistance gene arsC co-occurred with four ARGs and intI1, possibly causing the increase in ARGs under pressure by arsanilic acid. High arsanilic acid concentrations can increase the risk of ARGs occurring in anaerobic digestion products. The amount of arsanilic acid used as a feed additive should be controlled.

Development of a charcoal-fuelled dryer for the production of organic fertilizer from hog waste

The negligence of livestock farmers regarding waste disposal and inadequate waste control facilities are becoming a serious health and environmental hazard. In this study, a charcoal-fuelled dryer was developed to eliminate the moisture content in hog waste for easy conversion into organic fertilizer. The dryer is made up a drying chamber and a heating chamber. The drying chamber consists of a stirrer and a frame, while the heating chamber consists of a charcoal heat source and a high heat conducting frame. The dryer was positioned between the two chambers and was heated directly from a charcoal pot placed below the drying chamber. Waste was continuously rotated by rotating blades attached to the stirrer’s shaft. A pulley, 100 mm diameter, was mounted on the stirrer’s shaft and it was powered by a low-speed electric motor. The dryer was tested and evaluated under varying moisture contents of hog waste and operational conditions. The drying efficiency was found to be 98.25% and the mean time for drying 5 kg of hog waste was determined to be 55.61 minutes at a moisture content drying rate of 5.4 J/min (0.0899 kg/min). The sticky-marshy waste was eliminated and coarse dry manure, which could be easily converted into organic fertilizer, was obtained.

Effect of Climatic Conditions on Differences in Thermo-Technical Properties of Organic Bedding in Laboratory Testing

Abstract The aim of this experiment was to analyse the influence of climatic factors on the thermal performance of separated liquid manure. The samples of organic bedding were collected from the lying area of dairy housing and preparatory store. The measurement of properties of recycled manure solids (RMS) was carried out in laboratory conditions. Samples were examined with determining the temperature effect on the thermal conductivity λ of ’dry‘ separated liquid manure (with a dry matter content of 60%) and ’wet‘ liquid manure (with a dry matter content of 26%), in air temperatures ranging from 0 °C to 40 °C. Subsequently, the thermal resistance of three selected types of cows lying structures was calculated for winter and summer boundary values. Based on the results of thermal conductivity and thermal resistance, it was observed that dry separated liquid manure as an alternative bedding has, in low temperature (up to 5 °C), the most suitable thermal performance if it is maintained in a dry condition (with a dry matter content of 60%). With increasing temperature (above 20 °C) and increasing humidity of bedding (below 26%), thermo-technical properties get worse; however, when comparing the thermal resistance of the cow bed structure with sandwich mattresses with a 50 mm layer of organic bedding and the deep cubicle filled with 200 mm of organic bedding, the thermal resistance of floor structure decreases by 7.6% or 18.4%, respectively. With a proper handling of the recycled organic bedding, it is possible to use its economic advantages.

Improved Chamber Systems for Rapid, Real-Time Nitrous Oxide Emissions from Manure and Soil

Abstract. Nitrous oxide (N2O) emission rates have traditionally been measured using non-flow-through (NFT), non-steady-state (NSS) chambers, which rely on measuring the increase in N2O concentration in the sealed chamber headspace over time. These flux measurements are very labor- and time-intensive, requiring three to four gas samples collected over a 30 to 60 min period, followed by laboratory N2O measurement with a gas chromatograph (GC) and subsequent flux rate calculation. The objective of this research was to develop and evaluate improved, real-time flux chamber designs that rapidly quantify N2O emissions from manure and soil. The first chamber system consisted of six square 0.95 m2 chamber pans. The chamber pans were mounted on a rail system to facilitate controlled indoor/outdoor laboratory research at a pilot scale. An aluminum lid was moved among the chamber pans. A second portable chamber system with a circular footprint (0.49 m internal dia.) was designed for use in field measurements. With both systems, N2O concentrations were measured each second with 0.1 ppb resolution by recirculating sample air through a real-time continuous N2O analyzer with return flow into the recirculating-flow-through (RFT-NSS) chamber. Performance and observational data are presented for different chamber vent designs, sealing mechanisms between the chamber pan and lid, recirculation pumps, and presence/absence of an internal fan that mixes headspace air within the sealed chamber. As examples of the repeatability and precision of the methodology, ten consecutive flux measurements were obtained using moist manure (32.6% wet basis water content, WCWB) within a 15 min period in which chamber pans were fitted with lids for 60 s and removed for 30 s. The mean calculated N2O flux was 43.08 ±0.89 mg N2O m-2 h-1. Using dry manure (WCWB = 10.8%), five consecutive flux measurements showed a very low, but consistent, flux that averaged 0.025 ±0.0016 mg N2O m-2 h-1. Five case study experiments demonstrate the usefulness of these chamber systems and highlight discoveries and lessons learned to enhance future research efforts. Major discoveries and observations include: (1) installation of a small internal fan within the chamber lids decreased N2O fluctuation over small time periods, allowing precise measurement of manure N2O fluxes as low as 0.0073 mg N2O m-2 h-1 during a 60 s measurement period; (2) two distinct N2O peaks were observed at 1 and 21 d following the addition of water to manure (initial WCWB = 32.6%), with the second peak accounting for 83% of the total N2O emitted over 45 d; and (3) there was notable diurnal variation in N2O fluxes due to temperature variation, even when the manure was dry (WCWB = 10.8%). These flux chamber systems proved to be more rapid, precise, and repeatable than traditional flux chamber methods and offer promise for future greenhouse gas emissions research on manure and soil. Keywords: Cattle, Chamber, Diurnal, Fan, Feedlot, Greenhouse gas, Manure, Precision.

Effect of Different Doses of Rabbit Manure on the Abundance, Growth Rate and Production of Zooplankton in Plurispecific System for Fish Larvae Feeding

In order to determine the optimal dose of rabbit manure for plurispecific production of fresh water zooplankton in controlled area, the effects of six different doses of dry rabbit manure (T 1 = 300 g/m 3 , T 2 = 600 g/m 3 , T 3 = 900 g/m 3 , T 4 = 1200 g/m 3 , T 5 = 1500 g/m 3 , T 0 = 0g/m 3 ) on physico-chemical and biological parameters of areas were monitored for 27 days in cultures realized in plastic buckets of 80 L capacity each. Manures are from rabbits fed with diet previously revealed favorable to their growth, and is made of 2% of dried cassava, 30% of maize bran, 10% of palmist cake, 10% of soya cake, 5% of cotton cake, 2% of shell, 10% of malt, 5% of beer yeast, 10% of Panicum maximum and 1% of salt. Six days after fertilization, buckets were seeded with zooplankton by 26 individuals per liter (ind/L). Results obtained show that the supply of rabbit manure has improved chemical properties and microalgae production (phytoplankton) with treatments T 1 , T 2 , T 3 , T 4 and T 5 . Optimal conditions of zooplankton production through phytoplankton are obtained with doses in T 2 and T 4 which present the best specific growth rate. The daily production through the highest phytoplankton biomass (chlorophyll-a) has been obtained with dose in T 5 . Thus, doses 600 g/m 3 and 1200 g/m 3 of rabbit manure may be considered optimal for a plurispecific production of fresh water zooplankton. It was noted that Rotifers were predominant in abundance in almost the different culture areas.

Evaluation N2O Emissions from Intensive Manure Managements in a Dairy Area

To investigate N2O emissions from intensive manure managements, eight farmer’s fields covering paddy rice and uplands cropping systems in a livestock watershed of central Japan has been selected. The manure was popular applied with PIAF (Ploughing Immediately after Fertilization), FKSSL (Fertilizer Keeping on the Surface Soil for a Longer Time) and only applied in winter fallow season for paddy rice under the application rate of 200-800 kg N ha-1yr-1. Field gas samples were conducted by static chamber method. The result showed that N2O flux varied from 0 to 1607 μg N m-2h-1 in upland crop systems and from 0 to 924 μg N m-2 h-1 in paddy fields. And the annual emission ranged from 1.91- 9.26 kg N ha-1 yr-1 accounting for 0.48 ± 0.41% of input N in uplands and 1.28-1.91 kg N ha-1 yr-1 accounting for 0.43 ± 0.27% of input N in paddy rice, respectively. In rice/fallow system, more N2O emitted and the emission factor was 0.59 ± 0.07% due to the manure applied in fallow winter season. The N2O emission from FKSSL was 0.85 ± 0.79% of input N, and 3.4 times higher than PIAF. Slurry application contributed N2O emission 0.71 ± 0.37% of input N with 2 times higher than that of dry compost manure plots.

Temperature influence on the fast pyrolysis of manure samples: char, bio-oil and gases production

Fast pyrolysis characterization of three dry manure samples was studied using a pyrolyzer. A heating rate of 600°C/s and a holding time of 10 s were selected to reproduce industrial conditions. The effect of the peak pyrolysis temperature (600, 800 and 1000°C) on the pyrolysis product yield and composition was evaluated. Char and bio-oil were gravimetrically quantified. Scanning electron microscopy (SEM) was used to analyse the char structure. H 2 , CH 4 , CO and CO 2 were measured by means of gas chromatography (GC). A decrease in the char yield and an increase of the gas yield were observed when temperature increased. From 800°C on, it was observed that the char yield of samples Dig R and SW were constant, which indicated that the primary devolatilization reactions stopped. This fact was also corroborated by GC analysis. The bio-oil yield slightly increased with temperature, showing a maximum of 20.7 and 27.8 wt.% for samples Pre and SW, respectively, whereas sample Dig R showed a maximum yield of 16.5 wt.% at 800°C. CO 2 and CO were the main released gases whereas H 2 and CH 4 production increased with temperature. Finally, an increase of char porosity was observed with temperature.

A Multivariate Approach to Evaluate Biomass Production, Biochemical Composition and Stress Compounds of Spirulina platensis Cultivated in Wastewater.

The study was performed to investigate the effects of using cow effluent for the cultivation of Spirulina platensis on its biomass production and cell physiology. S. platensis was cultivated in three different cow effluents (CE) used as cultivation medium during 15days. CE was prepared using dry cow manures, and it was further modified with supplement of NaNO3 (CEN) and NaNO3+NaCl (CENS). High nitrate value stimulated chlorophyll-a and total protein content of the cyanobacterium and also biomass production in standards medium (SM) and CEN media. Total carbohydrate content of S. platensis grown in CE media was found to be higher (p<0.05) than that of SM. Productions of biomass and biochemical compounds by the cyanobacterium grown on the CE and SM media were evaluated by using multivariate approach. Conductivity, oxidation reduction potential (ORP), salinity, pH, and TDS played important role (p<0.01) in the biochemical composition. As an effective explanatory factor, ORP had a significant positive correlation with H2O2, whereas negatively correlated with chlorophyll-α, biomass production, filament length, and proline. Canonical correspondence analysis proposed that biochemical compounds of S. platensis were not only affected by salinity and nutrition of media but also by pH and ORP. The present study indicated that CEN as a low cost model medium had high potential for the production of biomass by S. platensis with high protein content.