Physical Characteristics of Miscanthus Composts Compared to Peat and Wood Fiber Growth Substrates

The physical parameters of four different Elephant grass “Miscanthus ogiformis” ‘Giganteus’ composts and four of the most used types of peat products in Denmark, along with a wood fiber growing medium (Culti), were compared to determine possible physical differences, and to test whether compost could be used as an alternative substrate to peat. The Miscanthus straw was composted with three different N sources: ammonium sulfate, liquid pig manure and urea plus tap water (as a control). Compared to peats, the composts tested had low total bulk density, high air-filled porosity and a high diffusion coefficient of oxygen. None of the 9 products tested had the optimum levels of all the different physical parameters. Mixing the tested compost and peat will possibly increase the air-filled porosity of the substrates compared to pure peat, and brings the substrates physical parameters closer to the ideal recommended range. These compost media require further investigation before they can be used directly as an alternative to peat in greenhouse production.     

C and N Turnover and Lignocellulose Degradation During Composting of Miscanthus Straw And Liquid Pig Manure

To obtain a peat substitute for pot plants, Miscanthus straw and liquid pig manure were composted in two different systems (open box and closed reactor) and examined for changes in pH, water content and chemical composition (nitrogen, carbon, hemicellulose, cellulose and lignin). Temperature maxima of 65-70°C were achieved within a few days in both systems. Composting and sampling were continued for 190 days in the box system and 150 days in the reactor. Major loss of nitrogen was found in a period of eight days after temperature maximum followed by stabilization. Accumulation of nitrate was observed during final weeks of composting in both systems. A marked decrease in content of hemicellulose was seen just after temperature maximum followed by slow, constant decrease throughout remaining composting period. The same pattern was observed for degradation of cellulose, though degradation was initiated later in the experiment. Degradation of hemicellulose was nearly 100% in both systems, whereas the cellulose decrease was 64 and 70% in the box and reactor, respectively. Lignin was not degraded during the experiments. Though initial C/N ratio was different in the two systems (25 in box and 16 in reactor), final ratios were the same (C/N=13). In spite of the similarities, the more complicated closed system is preferred if removal of ammonia from exit gas is considered.     

Growth of Hedera helix L. Container Plants in Compost Substrates Made with Miscanthus ogiformis Honda Straw and Various N-Sources

Ammonium sulfate or urea were added as N-source to shredded straw of Miscanthus ogiformis ‘Giganteus’ and water was included as control. The combined materials were composted for seven months, and the resulting composts were tested as growth substrates for nursery container plants and compared with fertilized and unfertilized peat substrates. The pH was below recommended level for the compost substrate made with ammonium sulfate and for the unfertilized peat substrate throughout the experiment. Electrical conductivity and concentrations of most nutrients were low and decreased throughout the experiment for all growth substrates. Shrinking of the growth substrates after 4, 12 or 17 months was larger for compost substrates than for peat substrates. Bulk density increased in compost substrates and decreased in peat substrates, while the total loss of C was greater in compost substrates than in peat. Water retention was lower and air volume greater for compost substrate made with ammonium sulfate than for fertilized peat. Algae and mosses did not occur on Miscanthus compost growth substrates in contrast to peat substrates. The shoot length and dry matter of Hedera helix, produced after four and 12 months of growth, and five months following cut back, showed that plants can grow well in compost substrates made of Miscanthus straw and ammonium sulfate or urea. However, the compost substrates could not fully substitute for fertilized or unfertilized peat substrate with respect to dry matter production.     

MSW Compost Reduces Nitrogen Volatilization During Dairy Manure Composting

Manures lose N through volatilization almost immediately after deposit. Attempts to control losses include the addition of a C source to stimulate nitrogen immobilization. Composting is a treatment process that recommends the addition of carbonaceous materials to achieve a C:N ratio of 30:1 to stimulate degradation and immobilize nitrogen. Dairies near cities may be able to reduce N loss from manures by composting with urban carbonaceous residues such as municipal solid waste (MSW) or MSW compost that, by themselves, have little agronomic value. Studies were conducted using a self-heating laboratory composter where dairy solids were mixed with MSW compost to determine the reduction of N loss during composting. One-to-one mixtures (v/v) of dairy manure solids and MSW compost were composted and NH₃ volatilization, CO₂ evolution and temperatures were compared to composting of manure alone. Addition of MSW compost resulted in increased CO₂ evolution and reduced N loss. Nitrogen loss from composting dairy manure alone was four to ten times greater than that from composting dairy manure mixed with MSW compost. Adjustment of the C:N ratio to 25 by adding MSW compost to manure appeared to be the major factor in reducing N losses.     

Chemical Amendments and Process Controls To Reduce Ammonia Volatilization During In-House Composting

Composting inside high-rise, caged layer facilities can produce atmospheric ammonia (NH₃) concentrations exceeding standards for human and poultry health. Control measures that reduce NH₃ volatilization are necessary for in-house composting to be sustainable. Due to differences specific to in-house composting — low carbon to nitrogen ratios of composting material, continuous manure addition, and frequent turning — it is not known whether NH₃ control measures used previously for poultry manure will work. The objectives of this study were to evaluate various amendment and process controls on NH₃ produced during simulated in-house composting in the lab, and to evaluate select chemical control measures during composting inside a high-rise layer facility. Ten amendments (aluminum sulfate; chloride salts of aluminum, calcium, magnesium, and potassium; gypsum; sodium bisulfate; zeolite (clinoptilolite); straw; and cellulose) and four process controls (moisture; temperature; turning frequency; and particle size) were evaluated in lab incubations in 1 L vessels wherein samples of poultry manure compost were incubated to simulate composting. Vials of boric acid solution were used to capture NH₃ evolved during incubations. With the exception of zeolite and cellulose, all amendments reduced NH₃ capture. Low moisture and temperature also reduced NH₃ capture, although managing temperature and moisture to achieve low NH_g would adversely impact microbial activity and other desired benefits of composting. When evaluated inhouse, aluminum sulfate, calcium chloride and magnesium chloride did not reduce NH evolution from compost measured on three different dates with a gas sensor. Spatial variability along treated segments of windrow apparently masked amendment effects. At the end of a six-week composting cycle, total nitrogen content was higher in compost treated with aluminum sulfate than control or chloride salt treatments. Aluminum sulfate and process controls such as moisture content, carbon source and particle size have potential to reduce NH₃ loss from poultry manure composted inside high-rise layer structures. In-house compost management to reduce NH₃ volatilization must consider the cost of amendments, effectiveness, and impacts on the composting process.     

不同畜禽粪便好氧堆肥过程中重金属Pb Cd Cu Zn的变化特征及其影响因素分析

畜禽粪便中的重金属含量及其生物有效性是限制其农业利用的重要因素。采用好气模拟培养方法对6种畜禽粪便好氧堆肥过程中Pb、Cd、Cu、Zn的总量以及生物有效性动态变化进行研究探讨,并分析了影响重金属生物有效性的因素。结果表明,根据现有的国际以及我国农用污泥农用标准,某些粪便中存在着Cd、Cu、Zn含量超标,由于饲料受重金属污染的不同,造成不同畜禽粪便中不同的重金属含量差异性较大。堆肥过程中,由于挥发性物质的挥发作用,4种重金属含量均呈现增加现象,尤其是在0～14 d的堆肥中增加量最高;而生物有效性重金属占其全量重金属的比例呈现先增加而后下降的趋势,除仔猪粪外,堆肥均能降低重金属生物有效性部分的比例,这将有利于降低其农业利用的风险。温度和水溶性碳对堆肥过程中4种重金属的生物有效性部分重金属相对含量的变化有着显著的影响。     

Application rate and composting method affect the immediate and residual manure fertilizer value in a maize–rice–rice–maize cropping sequence on a degraded soil in northern Vietnam

A field experiment was carried out in northern Vietnam to investigate the effects of adding different additives [rice (Oriza sativa L.) straw only, or rice straw with added lime, superphosphate (SSP), urea or a mixture of selected microorganism species] on nitrogen (N) losses and nutrient concentrations in manure composts. The composts and fresh manure were applied to a three-crop per year sequence (maize–rice–rice) on a degraded soil (Plinthic Acrisol/Plinthaquult) to investigate the effects of manure type on crop yield, N uptake and fertilizer value. Total N losses during composting with SSP were 20% of initial total N, while with other additives they were 30–35%. With SSP as a compost additive, 65–85% of the initial ammonium-N (NH₄-N) in the manure remained in the compost compared with 25% for microorganisms and 30% for lime. Nitrogen uptake efficiency (NUE) of fresh manure was lower than that of composted manure when applied to maize (Zea mays L.), but higher when applied to rice (Oriza sativa L.). The NUE of compost with SSP was generally higher than that of compost with straw only and lime. The mineral fertilizer equivalent (MFE) of manure types for maize decreased in the order: manure composted with SSP?>?manure composted with straw only and fresh manure?>?manure composted with lime. For rice, the corresponding order was: fresh manure?>?manure composted with SSP/microorganisms/urea?>?manure composted with lime/with straw alone. The MFE was higher when 5 tons manure ha^?1 were applied than when 10 tons manure ha^?1 were applied throughout the crop sequence. The residual effect of composted manures (determined in a fourth crop, with no manure applied) was generally 50% higher than that of fresh manure after one year of manure and compost application. Thus, addition of SSP during composting improved the field fertilizer value of composted pig manure the most.     

Changes in Availability of Plant Nutrients during Composting of Cow Manure with Poplar Leaf Litter

Safe management of animal and plant waste is one of the world's most important environmental challenges. Composting has been proposed as a useful technique for beneficially recycling wastes. This study showed that significant temporal changes in the nutrient availability occurred during the composting of cow manure with poplar leaf litter within 120 days. In particular, total C in the final compost was directly related to the addition of tree litter and inversely related to the time of composting, whereas extractable P and NO₃ increased with increasing amounts of tree litter and ammonium showed the opposite trend. During the later stages of the composting process higher concentrations of water soluble K, Ca, Mg, and Na were observed. The major benefit observed was that heavy metal concentrations initially present in the manure were significantly reduced during composting. Heavy metals in the final compost decreased in the order: Fe > Mn > Zn > Cu > Ni > Cd. The increased availability of plant nutrients following composting coupled with the lower extractability of heavy metals indicates that composting may be a sustainable option for agricultural waste recycling and increased productivity.     

有机辅料对猪粪堆肥中氨气挥发的抑制效应及其影响因素分析

选取稻草、油菜秸秆和食用菌渣作为猪粪堆肥的有机辅料,研究三种堆肥体系中氨气挥发释放规律及其影响因素。结果表明,经过65 d的堆腐,稻草－猪粪、油菜秸秆－猪粪和菌渣－猪粪堆肥氨气挥发量分别为5.084、6.483和3.013 g/kg,是对照（纯猪粪）处理（7.836g/kg）的64.88%、82.74%和38.45%。从氨气的释放量和释放速率看,菌渣是一种较好的有机辅料。从氨气释放的时间变化特征看,稻草对猪粪堆肥氨气排放高峰期影响最为明显,主要表现为氨气前期猛烈释放且持续时间短,是猪粪快速腐熟技术优选的高效有机辅料。堆腐完成后,三种有机辅料均能减少水溶性NH4+-N的累积,增加水溶性NO3--N的含量,引起pH和EC值下降,提高堆肥全氮含量,促进堆肥有机物和粗纤维的降解,且以稻草和菌渣处理效果最为显著。     

A comparison of the properties of manufactured soils produced from composting municipal green waste alone or with poultry manure or grease trap/septage waste

Manufactured soil for landscaping purposes was produced by composting for 6 weeks (1) municipal green waste alone, (2) green waste amended with 25% v/v poultry manure, or (3) green waste immersed in, and then removed from, a mixture of liquid grease trap waste/septage. Composting temperatures increased most rapidly and reached highest values (78oC) in the grease trap/septage-amended green waste. In comparison with green waste alone, addition of poultry manure prolonged the period of elevated temperatures and increased the maximum temperature attained from 52oC to 61oC. Following composting, each of the materials was split into (1) 100% compost, (2) 80% compost plus 20% v/v soil, and (3) 70% compost plus 20% soil plus 10% coal fly ash. Addition of poultry manure or grease trap/septage to green waste prior to composting increased bulk density and reduced total porosity of the composted product. Addition of soil, or soil and ash, to composts increased bulk density, reduced total porosity, decreased percentage macropores, and increased percentage mesopores and available water-holding capacity. Bicarbonate-extractable P, exchangeable NH₄⁺ and NO₃⁻, electrical conductivity (EC), soluble C, soluble C as a percentage of organic C, basal respiration, and metabolic quotient were all markedly greater in the grease trap/septage-amended than poultry manure-amended or green waste alone treatments. Values for extractable P and EC were considered large enough to be damaging to plant growth and germination index (GI) of watercress was less than 60% for all grease trap/septage composts. Extractable P and EC were also high, and GI was <100%, in the green waste alone and poultry manure-amended green waste alone treatments. Addition of soil or soil and ash to these composts resulted in GI values >100%.     

The Effects of Goat Manure,Sewage Sludge And Effective Microorganisms on the Composting of Pine Bark

This study investigated the cocomposting of pine bark with goat manure or sewage sludge, with or without inoculated effective microorganisms (EM). Composting was done for 90 days and parameters monitored over this period included temperature, pH, electrical conductivity (EC), C/N ratio, inorganic N, as well as tannin content. Changes in temperature, pH and EC during composting were consistent with those generally observed with other composting systems. The parameters were influenced by the feedstock materials used but were not affected by inoculation with effective microorganisms. The highest temperature measured from pine bark-goat manure composts was 60°C but much lower maximum temperatures of 40°C and 30°C were observed for pine bark sewage sludge and pine bark alone composts, respectively. The C/N ratios of the composts decreased with composting time. Ammonium levels decreased while nitrate levels increased with composting time. Tannin levels generally decreased with composting time but the extent of decrease depended on the contents of the composting mixtures. The trends observed showed that temperature, pH, EC, C/N ratio, tannin levels, and inorganic NH₄-N and NO₃-N were reliable parameters for monitoring the co-composting of pine bark with goat manure or sewage sludge. The pine bark-goat manure compost had more desirable nutritional properties than the pine bark and pine bark-sewage sludge composts. It had high CEC, near neutral pH, low C/N ratio, and high amounts of inorganic N and bases (K, Ca, and Mg) while pine bark compost had the least amounts of nutrients, was acidic, and had high C/N ratio and low CEC. The final tannin content of the pine bark-goat manure compost was below the 20 g/kg upper threshold level for horticultural potting media, implying that its use as a growing medium would not cause toxicity to plants.     

Effect of Woody Peat as an Additive on Maturity and Gaseous Emissions During Pig Manure Composting

Woody peat was used as an additive to compost with pig manure in 1.2 m³ composting reactors under aerobic conditions for a 77?days period to estimate the effect on the compost maturity and gaseous emissions (NH₃, N₂O, and CH₄). Pig manure was also composted with cornstalks (the traditional method) as a control treatment. The results showed that both cornstalks and woody peat composts reached the required maturity standard. Composting with woody peat as a bulking agent was found to reduced NH₃ emissions by 36% than the cornstalks amended treatment. Although CH₄ emission increased by adding woody peat, N₂O emission was considerably reduced, resulting in a slight decrease in total greenhouse gas emissions. More importantly, woody peat could reduce the losses of total carbon and total nitrogen, improve the compost quality as fertilizer.     

QUANTITY AND QUALITY OF CITRUS ON A CITROMELO ROOTSTOCK AS AFFECTED BY DIFFERENT TYPES OF N FERTILIZATION (CHEMICAL AND ORGANIC)

With respect to the important effects of nitrogen (N) on plant growth and fruit production, a five-year experiment was performed to evaluate the effects of different sources of N fertilization including chemical and organic on the quantity and quality of citrus fruit. Using five-year old trees, different types of fertilization including ammonium sulfate, urea coated with sulfur, ammonium nitrate and manure were tested using seven treatments in five replicates from 2002 to 2007. Different plant quantitative and qualitative parameters were determined. The most effective strategy on fruit yield production was the use of urea coated with sulfur and manure with 92.46 kg ha^?1 fruit yield followed by ammonium sulfate and manure (87.06 kg ha^?1) and ammonium sulfate (86.43 kg ha^?1). The combination of mineral and organic fertilization may be the most suitable fertilization strategy for citrus production.     

Compost Effect on Greenhouse Cucumbers and Suppression of Plant Pathogen Fusarium Oxysporum

Three windrows were constructed from a mixture of horse manure and soiled bedding collected from four equestrian centres in the Fraser Valley, British Columbia, where stables were bedded with hemlock, spruce, and fir wood shavings. Composting was accomplished by turning the windrows twice a week during the first four weeks and once a week for eight additional weeks. At the end of 12- week composting period, windrows were combined and allowed to cure for three months. The cured compost was tested for the ability to promote cucumber (cv Enigma) seedling growth, supply micronutrients, and suppress mycelial growth of plant pathogen Fusarium oxysporum f.sp. radicis cucumerinum (FORC). The heights and dry weights of cucumber seedlings grown in 20% compost in sawdust were significantly greater than those grown in sawdust alone. When fed with nutrient solutions lacking micronutrients, seedling grown in 20% compost gave significantly greater height, dry weight, and chlorophyll concentrations compared to seedlings grown in sawdust alone. The analysis of extractable micronutrients indicated that manganese, followed by zinc and boron, were the predominant micronutrients in horse manure compost. Both iron and molybdenum concentrations were present in less than one ppm and copper was present just above one ppm. There was a significant correlation (r² = 0.83) between in vivo chlorophyll measurements by SPAD-502 chlorophyll meter and the in vitro chlorophyll measurement by spectrophotometer. Thus in vivo measurements of SPAD-502 chlorophyll meter can be used to assess nutrient availability from compost to cucumber seedlings. Horse manure compost also contained bacteria that suppressed mycelial growth of FORC.     

中国东北地区畜禽粪污处理技术与资源化利用模式分析

为摸清东北地区畜禽粪污处理技术与资源化利用模式应用现状,该研究采用问卷调研与现场评估相结合的方式,对黑龙江、吉林和辽宁3省272个规模化养殖场进行了调研,分析了养殖畜种与存栏量、粪污产生量、粪污处理技术、粪污处理设施设备以及粪肥还田参数等数据,总结了东北地区畜禽粪污处理技术应用现状和资源化利用模式特点。结果表明：东北地区主要粪污收集工艺为干清粪,占比达94.35%。固体粪便以堆沤肥工艺为主,占所调研养殖场的86.93%,各畜种粪便存储设施面积符合畜禽规模化养殖场粪污资源化利用设施建设规范要求。液体粪污主要处理方式为粪水贮存,占所调研养殖场的68.18%;奶牛养殖场粪水贮存设施小于建设规范要求。东北地区粪肥还田主要种植作物为玉米,占所有种植作物的78.13%,现有配套土地面积普遍低于畜禽粪污土地承载力测算需求面积。固体粪肥主要施肥方式为人工施肥,占比达88.00%;液体粪肥主要施肥方式为漫灌和喷灌,占比分别为54.17%和37.50%。整体来看,东北地区粪污处理与资源化利用主要技术模式为“干清粪+粪便堆沤+粪水贮存”。研究结果可为东北地区粪污处理和资源化利用模式推广和政策制定提供参考。     

Aufnahme und Verteilung von 15N-markiertem Harnstoff bei Phaseolus vulgaris L

The Uptake and Distribution of ¹⁵N-Labelled Urea by Phaseolus vulgaris L The uptake of two-fold ¹⁵N-labelled urea via the root system of 21 days old plants of Phaseolus vulgaris in comparison with ¹⁵N-marked ammonium chloride has been investigated. The concentration of urea or ammonium resp. was 3 mmol/l. The plants were allowed to take up the labelled nitrogen for an 8 hours period. The determination of the ¹⁵N-frequency was carried out by emission spectrometry. The results demonstrate that urea is taken up as a whole undestructed molecule. Also there is evidence for a 7-fold enrichment of urea in the exsudation sap in comparison with the urea concentration in the nutrition solution. Inhibition of the metabolic activity of the roots (2,4-DNP, KCN, AsO₄, N₂) reduces both the urea and the ammonium absorption to a considerable rate. Variations of the transpiration, of the Ca/K ratios or p_H in the nutrition solution have none or only a very small influence on the uptake of urea. There may be the possibility for the existence of a common mechanism for the absorption of both urea and ammonium.     

青藏高原高寒牧区家畜粪便堆肥化处理技术研究

堆肥化处理是有效利用青藏高原高寒牧区牲畜粪便、减轻环境影响的可行途径。本文针对高寒牧区低温和劳动力资源缺乏的问题,研究了一种静态通气方式和保温措施对堆腐效果的影响。静态通气通过埋植于堆体中的通气管实现,而保温通过堆体外的双层塑料膜的温室效应实现。实验结果表明,埋入通气管与翻堆相比可以显著提高堆体内部和堆体外层的温度,有效加快腐熟速度,减少堆腐过程中养分的损失,降低劳动力投入,可以作为高寒牧区替代翻堆的更好通气手段。双层保温膜与单层膜相比能够有效辅助通气管维持堆体高温。堆肥原料中添加磷肥虽然可提高堆腐温度,但同时也增加了堆腐过程中有机质和氮素的损失,需要根据当地实际情况选用。     

Mass and Nutrient Losses During the Composting Of Dairy Manure Amended with Sawdust or Straw

Composting has become an increasingly popular manure management method for dairy farmers. However, the design of composting systems for farmers has been hindered by the limited amount of information on the quantities and volumes of compost produced relative to farm size and manure generated, and the impact of amendments on water, dry matter, volume and nitrogen losses during the composting process. Amendment type can affect the free air space, decomposition rate, temperature, C:N ratio and oxygen levels during composting. Amendments also initially increase the amount of material that must be handled. A better understanding of amendment effects should help farmers optimize, and potentially reduce costs associated with composting. In this study, freestall dairy manure (83% moisture) was amended with either hardwood sawdust or straw and composted for 110-155 days in turned windrows in four replicated trials that began on different dates. Initial C:N ratios of the windrows ranged from 25:1 to 50:1 due to variations in the source and N-content of the manure. Results showed that starting windrow volume for straw amended composts was 2.1 to 2.6 times greater than for sawdust amendment. Straw amended composts had low initial bulk densities with high free air space values of 75-93%. This led to lower temperatures and near ambient interstitial oxygen concentrations during composting. While all sawdust-amended composts self-heated to temperatures >55°C within 10 days, maintained these levels for more than 60 days and met EPA and USDA pathogen reduction guidelines, only two of the four straw amended windrows reached 55°C and none met the guidelines. In addition, sawdust amendment resulted in much lower windrow oxygen concentrations (< 5%) during the first 60 days. Both types of compost were stable after 100 days as indicated by CO₂ evolution rates <0.5 mg CO₂-C/g VS/d. Both types of amendments also led to extensive manure volume and weight reductions even after the weight of the added amendments were considered. However, moisture management proved critical in attaining reductions in manure weight during composting. Straw amendment resulted in greater volume decreases than sawdust amendment due to greater changes in bulk density and free air space. Through composting, farmers can reduce the volume and weights of material to be hauled by 50 to 80% based on equivalent nitrogen values of the stabilized compost as compared to unamended, uncomposted dairy manure. The initial total manure nitrogen lost during composting ranged from 7% to 38%. P and K losses were from 14 to 39% and from 1 to 38%, respectively. There was a significant negative correlation between C:N ratio and nitrogen loss (R₂=0.78) and carbon loss (R₂=0.86) during composting. An initial C:N ratio of greater than 40 is recommended to minimize nitrogen loss during dairy manure composting with sawdust or straw amendments.     

低蛋白饲喂技术对猪粪好氧堆肥腐熟度的影响

  【目的】  猪粪由于产生量大、碳氮比低、水分含量高等导致储存处理难度较大,好氧堆肥处理猪粪因原料所提供微生物活动环境较差,导致堆肥效率低下。低蛋白饲喂技术在不影响猪生长发育的同时降低了饲料中的氮投入,可以显著改变猪粪的养分组成。本研究通过多种有机肥腐熟指标判定,分析低蛋白含量日粮饲喂的猪粪通过不同堆肥方式是否可快速有效地达到腐熟,并符合安全施用标准。  【方法】  动物试验选取初始体重为60 kg的去势公猪72头,分高、低蛋白饲喂两个处理,每个处理6次重复,每个重复6头猪。试验饲料均适应喂养7天后,开始收集粪便,收粪期为60天。堆肥试验共设4个处理,分别是高蛋白饲喂静态堆肥 (MH)、低蛋白饲喂静态堆肥 (ML)、高蛋白饲喂好氧堆肥 (CH)、低蛋白饲喂好氧堆肥 (CL),堆肥周期为14天。监测了堆肥过程中堆体温度和碳、氮含量等指标,并测定堆肥处理的小白菜种子发芽指数 (GI)。  【结果】  以堆肥过程中高温持续时间、堆肥NH₄+-N含量、T值 (堆肥结束C/N与堆肥初始C/N的比值) 和GI (小白菜种子发芽指数) 4项为腐熟判断指标,在14天堆肥周期内,高蛋白饲喂产生的猪粪在静态堆肥情况下 (MH),高温持续时间为0天,NH₄+-N含量为0.43 g/kg、T值为0.91、GI指数为0,未能达到腐熟标准;高蛋白饲喂产生的猪粪堆肥在好氧堆肥条件下 (CH),高温持续时间为5天,NH₄+-N含量为0.33 g/kg、T值为0.70、GI指数为0.31,T值和GI值均未能达到腐熟标准;低蛋白饲喂产生的猪粪,在静态堆肥中 (ML) 高温持续时间为0 天,NH₄+-N含量为0.54 g/kg、T值为0.81、GI指数为0.25,均未能达到腐熟标准;而在好氧堆肥 (CL) 中,高温持续时间为6天,NH₄+-N含量0.14 g/kg、T值为0.57、GI指数为0.96,均达到腐熟标准。  【结论】  高蛋白饲养产生的猪粪在静态和好样发酵条件下堆放14天,都不能完全腐熟。低蛋白饲喂产生的猪粪在静态堆放条件下,堆肥14天也不能达到腐熟标准。而低蛋白饲养产生的猪粪在好样条件下,可以在堆放14天时达到腐熟,因为低蛋白饲喂技术使猪粪碳氮比提高了约15%,高温发酵时长延长了40%,极大提高了猪粪短时间内的腐熟程度。因此,在循环农业中,通过上游低蛋白饲喂技术可促进下游猪粪的快速处理和循环利用。     

生物过滤法去除死猪堆肥排放臭气效果的中试

为研究生物过滤法去除死猪堆肥发酵处理过程产生臭气以及挥发性有机物(volatile organic compounds,VOCs)的可行性,开展了死猪和猪粪混合堆肥试验,分析了死猪堆肥过程臭气浓度特性和VOCs组分特征,对生物过滤法去除臭气中VOCs的工艺关键参数-停留时间进行优化试验。死猪堆肥过程中排放VOCs种类达37种,其中主要致臭组分为三甲胺、二甲基硫、二甲基二硫、二甲基三硫;以腐熟猪粪堆肥作为滤料(添加3%活性污泥),在停留时间为30~100 s的条件下,生物过滤法对死猪堆肥排放臭气去除率达90%以上;停留时间60~100 s的条件下对VOCs中主要致臭组分的去除效率达82.2%~100%,生物过滤法去除死猪堆肥过程臭气浓度和VOCs的优化停留时间为60 s。研究结果能为死猪堆肥发酵过程排放臭气的处理和控制技术进一步研发提供科学依据。