Three-step biological process for the treatment of the liquid fraction of cattle manure

The liquid fraction of cattle manure was subjected to a biological treatment combining anoxic-anaerobic and oxic processes in order to stabilize the organic matter and reduce nitrogen and phosphorus so as to avoid problems of pollution when applying it to the land. The anoxic process was carried out at 30 degrees C in a CSTR reactor, the anaerobic process in a UASB reactor at 37 degrees C and the oxic treatment in another CSTR at 20 degrees C. The following results were obtained when working under optimum conditions (removal efficiencies in brackets): COD was reduced from 42 to 3.8 g/L (>90%); total solids from 41 to 14 (67%); total volatile solids from 22 to 7.0 (68%); total Kjeldahl nitrogen from 2.2 to 0.1 g/L (95%); NH4(-)-N from 1.10 to 0.02 g/L (98%) and Total-Phosphorus from 0.696 to 0.058 g/L (92%). Nitrates, undetected in the liquid fraction of cattle manure, were present in the final effluent as a result of nitrification. To reduce the amount of nitrates, different recirculation rates were tested. The minimum nitrate concentration achieved was 127 mg/L using a recirculation ratio of 4.     

Effect of compost temperature on oxygen uptake rate, specific growth rate and enzymatic activity of microorganisms in dairy cattle manure

Investigations were carried out to find out the relationship between temperature and microbial activity in dairy cattle manure composting using oxygen uptake rate, specific growth rate and enzymatic activities during autothermal and isothermal composting experiments. In autothermal composting, oxygen uptake rate and specific growth rate were found to be most intensive in order of 43 degrees C, 60 degrees C and 54 degrees C. Isothermal composting at 54 degrees C resulted highest levels of enzymatic activity and promoted the volatile solids reduction. Based on the maximum enzymatic activity, specific growth rate appeared to be more closely linked with microbial activity in compost than with oxygen uptake rate. The enhancement of specific growth rate, enzymatic activity and volatile solids reduction were induced at 54 degrees C in cattle manure composting.     

Vermicomposting of cattle and goat manures by Eisenia foetida and their growth and reproduction performance

Vermicomposting is commonly adopted for the treatment of livestock organic wastes. In the present study, two types of livestock manure were used for culturing of the earthworm, Eisenia foetida. Each treatment group consisted of six replicates and worm vermicasts were examined after 5 weeks. The concentrations of total C, P and K in goat manure vermicasts were higher than those in cattle manure vermicasts. Cattle vermicasts had a higher N content than goat vermicasts but the C:N ratio of fresh manure was higher than that of vermicasts for both materials. Earthworm biomass and reproductive performance, in terms of number of worms after 5 weeks of experiment, were higher in cattle manure than in goat manure. The cocoon production per worm in cattle manure was higher than in goat manure. However, the hatchability of cocoons was not affected by manure treatments. In conclusion, cattle manure provided a more nutritious and friendly environment to the earthworms than goat manure.     

宁夏西吉县养牛场粪污和周边土壤重金属及细菌群落特征

为了解宁夏肉牛养殖场粪污和周边土壤中重金属及细菌群落状况,在宁夏最大的肉牛养殖区西吉县采集了不同养殖期(哺乳期、犊牛期、育成期、育肥前期和育肥后期)的牛粪、施用牛粪蔬菜地及养殖场周边不同距离土壤样品,以远离养殖场的荒地土壤为对照,测定了7种重金属(Cu、Zn、Pb、Cd、Cr、Hg、As)含量和细菌群落组成及多样性。结果表明: 1)牛粪中Cu、Zn、Cd、Pb和Hg含量较全国平均值低33.8%～95.8%,而As含量比全国平均值高94.7%。随着养殖期的推移,牛粪中各重金属含量变化趋势不完全相同,育肥前期Cu、Cd、Hg和Cr含量高于其他4个时期,育肥前期和育肥后期牛粪重金属综合污染指数较大。2)施用牛粪的土壤Cu、Zn和Hg含量显著高于对照土壤,Zn含量与养殖场周边土壤差异显著,其他元素无显著差异,所有土壤重金属污染指数均在安全范围内。3)随着养殖期的推移,牛粪细菌多样性指数无特定变化趋势。施用牛粪的土壤序列、分类单元、Chao1指数显著高于养殖场周边土壤。4)牛粪中厚壁菌门的相对丰度最大,其次为拟杆菌门和变形菌门;育成期厚壁菌门的丰度显著低于其他养殖期,其他各菌门的丰度在不同养殖期间无显著差异。养殖场的存在对其周边土壤细菌群落的影响不明显,但施用牛粪后土壤Gp6、芽单胞菌属、溶杆菌属和Subdivision3_genera_incertae_sedis的数量显著高于对照和养殖场周边土壤。5)牛粪中有机质、pH、电导率、全氮、全钾、Cd、As含量对细菌多样性和各组分丰度的影响较显著;养殖场周边土壤pH、全磷和Hg含量对细菌多样性和各组分丰度的影响较显著。整体来讲,牛粪和土壤的理化性质对细菌群落的影响比重金属更显著。研究结果可为当地肉牛养殖饲料和兽药种类的选择、用量及有机肥的科学利用提供参考。     

Optimization of biogas production from cattle manure by pre-treatment with ultrasound and co-digestion with crude glycerin

Biogas production by co-digestion of cattle manure with crude glycerin obtained from biodiesel production was studied after pre-treatment of the cattle manure or mixtures of cattle manure with different amounts of added glycerin with ultrasound. Batch experiments with 1750 mL of medium containing 1760 g of screened cattle manure or mixtures of cattle manure (screened or ground) and 70-140 mL or crude glycerin were incubated under mesophilic and thermophilic condition in stirred tank reactors. Under mesophilic conditions, the addition of 4% glycerin to screened manure increased biogas production by up to 400%. Application of sonication (20 kHz, 0.1 kW, and 4 min) to a mixture of manure + 4% glycerin increased production of biogas by up to 800% compared to untreated manure. The best results were obtained under thermophilic conditions using sonicated mixtures of ground cattle manure with 6% added glycerin (348 L methane/kg COD removed were obtained).     

Chemical and biochemical variation in animal manure solids separated using different commercial separation technologies

Chemical and biochemical properties were investigated in 47 solids collected from commercial solids separation plants separating liquid manure into a nutrient-rich solid fraction and a nutrient-poor liquid fraction. The samples originated from five different types of separation technologies, separating primarily swine manure and anaerobically digested manure. The largest variations in measured chemical and biochemical characteristics between samples from the five different separation technologies were found for ash, total P, total C, DM and C distribution in the biochemical fractions (neutral detergent solubles (NDS), hemicellulose, cellulose and lignin). Principal component analysis (PCA) of the data obtained showed that the chemical and biochemical characteristics of the solids were dependent on the type of technology used for separation.     

Anaerobic digestion of animal waste: waste strength versus impact of mixing

We studied the effect of mode of mixing (biogas recirculation, impeller mixing, and slurry recirculation) and waste strength on the performance of laboratory scale digesters. The digesters were fed with 5% and 10% manure slurry, at a constant energy supply per unit volume (8 W/m3). The experiments were conducted in eight laboratory scale digesters, each having a working volume of 3.73 L, at a controlled temperature of 35+/-2 degrees C. Hydraulic retention time (HRT) was kept constant at 16.2 days, resulting in a total solids (TS) loading rate of 3.08 g/Ld and 6.2 g/Ld for 5% and 10% manure slurry feeds, respectively. Results showed that the unmixed and mixed digesters performed quite similarly when fed with 5% manure slurry and produced biogas at a rate of 0.84-0.94 L/Ld with a methane yield of 0.26-0.31 L CH4/g volatile solids (VS) loaded. This was possibly because of the low solids concentration in the case of 5% manure slurry, where mixing created by the naturally produced gas might be sufficient to provide adequate mixing. However, the effect of mixing and the mode of mixing became prominent in the case of the digesters fed with thicker manure slurry (10%). Digesters fed with 10% manure slurry and mixed by slurry recirculation, impeller, and biogas recirculation produced approximately 29%, 22% and 15% more biogas than unmixed digester, respectively. Deposition of solids inside the digesters was not observed in the case of 5% manure slurry, but it became significant in the case of 10% manure slurry. Therefore, mixing issue becomes more critical with thicker manure slurry.     

Effect of initial COD concentration, nutrient addition, temperature and microbial acclimation on anaerobic treatability of broiler and cattle manure

In this study, anaerobic treatability and biogas generation potential of broiler and cattle manure were investigated. For this purpose, seven sets of anaerobic batch reactor experiments were performed using broiler and cattle manure and their mixtures in five different ratios (100% broiler; 75% broiler, 25% cattle; 50% broiler, 50% cattle; 25% broiler, 75% cattle; 100% cattle). These manure mixtures had two different initial chemical oxygen demand (COD) (12,000 and 53,500 mg/l) concentrations. The effects of initial COD concentration, nutrient and trace metal supplementation, microbial acclimation and digestion temperature were investigated. Results revealed that the efficiency of total COD removal was 32.0-43.3% and 37.9-50% for initial COD concentrations of 12,000 and 53,500 mg/l, respectively. The biogas yields observed for initial COD concentrations of 12,000 and 53,500 mg/l were 180-270 and 223-368 ml gas/g COD added, respectively. A decrease in biogas yield was observed as the fraction of broiler manure increased in mixture of broiler and cattle manure at initial COD values of 53,500 mg/l.     

Manure sampling procedures and nutrient estimation by the hydrometer method for gestation pigs

Three manure agitation procedures were examined in this study (vertical mixing, horizontal mixing, and no mixing) to determine the efficacy of producing a representative manure sample. The total solids content for manure from gestation pigs was found to be well correlated with the total nitrogen (TN) and total phosphorus (TP) concentrations in the manure, with highly significant correlation coefficients of 0.988 and 0.994, respectively. Linear correlations were observed between the TN and TP contents and the manure specific gravity (correlation coefficients: 0.991 and 0.987, respectively). Therefore, it may be inferred that the nutrients in pig manure can be estimated with reasonable accuracy by measuring the liquid manure specific gravity. A rapid testing method for manure nutrient contents (TN and TP) using a soil hydrometer was also evaluated. The results showed that the estimating error increased from +/-10% to +/-30% with the decrease in TN (from 1000 to 100 ppm) and TP (from 700 to 50 ppm) concentrations in the manure. Data also showed that the hydrometer readings had to be taken within 10 s after mixing to avoid reading drift in specific gravity due to the settling of manure solids.     

Heavy metal leaching from mine tailings as affected by organic amendments

A column experiment was conducted to investigate Zn, Cd, and Pb leaching from mine tailings as affected by the addition of organic amendments. Composted yard waste, composted cattle manure, and cattle manure aged for one month increased heavy metal leaching from mine tailings when compared to an unamended control. Aged cattle manure and composted cattle manure significantly increased Zn concentration in the leachate. The maximum Zn concentration in leachate from the manure-amended treatments was as high as 3.7 mg/L, whereas Zn concentrations from the control were less than 0.7 mg/L. All organic amendments increased Cd leachate concentrations. The presence of aged cattle manure greatly increased Pb concentrations in the leachate from less than 10 microg/L for the control treatment to higher than 60 microg/L. Lead concentration in leachate was positively correlated with inorganic carbon, total organic carbon, total carbon and bicarbonate. Although organic amendments increased Zn, Cd, and Pb leaching when compared with the control treatment, Zn concentrations were lower than the 5 mg/L secondary drinking water standard, and Pb concentrations were only minimally higher than the 15 microg/L drinking water standard. Cadmium concentrations from manure treatments exceeded the 5 microg/L drinking water standard but only during the first 15 days. Organic amendments may encourage establishment of vegetation in mining areas that may minimize heavy metal contamination through runoff and erosion. However, increased risk due to heavy metal leaching in the presence of organic amendments should be carefully considered.     

Batch co-digestion of multi-component agro-wastes

In certain parts of the developing world conventional energy supplies such as electricity, gas, coal and petroleum by-products are either unavailable, too capital intensive to install, are unjustifiable due to low population densities in some semi-arid regions, or are simply unaffordable to the target population. In Zimbabwe, it has been assessed that only biomass energy can conveniently provide both lighting and space heating. Therefore, means of generating biogas from agricultural and other organic wastes, and to encourage their use is a policy which has been adopted by Zimbabwe's Department of Energy. In this study cattle slurry was mixed with a range of solid wastes and allowed to digest in 11 batch digesters. The mixtures which were used were selected on the basis of centroid design with the objective of determining whether there was either synergism or antagonism. Two trials were carried out, one based on cattle slurry, chicken manure (CM) and molasses (Mol), the other based on sheep and goat manure, chicken manure and surplus activated sludge. The criteria for judging the success of a co-digestion were volatile solids (VS) reduction, total methane production and methane yield. In the first trial, the analysis based on the methane yield showed that there was no antagonism and that the mixture of 30% cattle slurry/30% CM/40% Mol gave a synergistic effect. The analysis based on the VS destruction, however, did show that there was some very slight antagonism. In the second trial, the analysis based on the methane yield showed that there was both antagonism and synergism and that the synergism produced an extra 6.7% methane. The analysis based on the VS destruction also showed that there was both antagonism and synergism but that the effects were small.     

Seven years of repeated cattle manure addition to eroded Chinese Mollisols increase low-molecular-weight organic acids in soil solution

Background and aims

Organic amendments are an option in enhancing soil biological productivity. Limited research exists on the effects of long-term cattle manure addition on low-molecular-weight organic acids (LMWOAs) concentrations in corn (Zea mays L) and soybean (Glycine max L.) fields in the region of soil erosion. The purpose of this study was to investigate the potential influence of cattle manure on the LMWOAs concentration in erosion soil.

Methods

A field experiment was established in Hailun city, Northeast China to determine the impact of long-term cattle manure addition on the total amounts of main LMWOAs in eroded Mollisol fields. There were three levels of simulated-erosion, which removed 0, 10 and 30 cm of topsoil. Two soil amendments were: (1) chemical fertilizer at the rate normally used by farmers in the region and (2) chemical fertilizer plus 15,000 kg?ha^?1 (dry weight basis) of cattle manure. Main LMWOAs in soil were assessed at the flowering stage of soybean and the jointing stage of corn.

Principle results

Compared to chemical fertilizer alone, 7-years of repeated cattle manure addition significantly increased total amounts of main LMWOAs in rhizosphere about 9–70 times and bulk soil about 6–62 times. The magnitude of increase by cattle manure was in the order of oxalate>malate>malonate>lactate>maleate in corn plots, and oxalate>malate>malonate>lactate in soybean plots. In comparison, cattle manure and topsoil removal had larger effect on LMWOAs concentrations in corn plot than soybean plot. The addition of cattle manure application and top soil removal had significant independent influence on main LMWOAs concentration in soil solution.

Conclusion

This study suggested that addition of cattle manure would be an effective approach in modifying soil biological properties through the increases in low-molecular-weight organic acids to eroded Chinese Mollisols.     

老化和风干处理对蚓粪微生物学性质和结构稳定性的影响

蚓粪水稳性团聚体含量是结构稳定性表征之一,蚓粪中水稳性团聚体含量与其微生物学性质是紧密联系的,并且受到老化时问和有机质等因素的影响。国内将蚓粪水稳性团聚体含量与其微生物学性质联系,并结合施用不同有机物处理的研究很少见报道。研究通过室内短期培养试验,研究了在不同碳氮比有机物施用下蚓粪老化和风干处理对其微生物生物量、微生物活性和结构稳定性变化的影响。研究结果表明蚓粪经过老化处理后真菌数量、微生物生物量碳和微生物活性都显著降低。不同有机物的施用对蚓粪微生物学性质的影响主要表现在施用牛粪的处理中蚓粪细菌数量高于施用秸秆的处理,真菌数量相反。新鲜蚓粪经过老化处理后总的水稳性团聚体含量（〉0．053mm）增加,主要表现在水稳性大型大团聚体（〉2mm）含量增加,且在施用牛粪的处理中达到显著,可能是与牛粪比秸秆能分解产生更多的粘结物质有关。蚓粪的风于处理也显著增加各个处理中总水稳性团聚体含量,且风干后蚓粪中水稳性团聚体主要以微团聚体（0．25～0．053mm）形式存在。施用秸秆的处理中,新鲜蚓粪0．25～0．053mm粒级的水稳性团聚体含量显著高于施用牛粪的处理。经风干后,施用秸秆的处理0．25～0．053mm的水稳性团聚体含量显著低于施用牛粪的处理,而水稳性大型大团聚体含量显著高于施用牛粪的处理。蚓粪的不同粒级水稳性团聚体含量和蚓粪的生物学性质之间存在良好的相关性。     

Soil microbial populations, community composition, and activity as affected by repeated applications of hog and cattle manure in eastern Saskatchewan

A field site near Humboldt, Saskatchewan, was annually treated with hog or cattle manure and cropped to canola, spring wheat, barley, and canola from 1997 to 2000. During each growing season, soil was analyzed for microbial populations in terms of activity and community structure, and crops were assessed for root rot and foliar diseases. Microbial activity in soils treated with cattle manure was higher than in soils treated with hog manure or urea. Similarly, nitrous oxide emissions from soil increased with increasing rates of hog and cattle manure. Potential human pathogens, including Rahnella, Serratia, Proteus, Leclercia, and Salmonella species, were identified in soils that received cattle manure, whereas pseudomonads were the dominant species in the hog-manure-treated soil. Fecal coliforms were confirmed in soils that received hog or cattle manure. However, Enterobacteriaceae populations were 10-fold higher in soils receiving cattle manure than in soils receiving the other treatments. Increasing cattle manure rates increased fecal coliform population, but there was no indication that increased hog manure rates increased fecal coliform populations. Addition of urea, hog manure, or cattle manure to the soil did not increase foliar disease in wheat, barley, and canola and had variable effects on root rot incidence in cereals.     

Cattle Manure Enhances Methanogens Diversity and Methane Emissions Compared to Swine Manure under Rice Paddy

Livestock manures are broadly used in agriculture to improve soil quality. However, manure application can increase the availability of organic carbon, thereby facilitating methane (CH₄) production. Cattle and swine manures are expected to have different CH₄ emission characteristics in rice paddy soil due to the inherent differences in composition as a result of contrasting diets and digestive physiology between the two livestock types. To compare the effect of ruminant and non-ruminant animal manure applications on CH₄ emissions and methanogenic archaeal diversity during rice cultivation (June to September, 2009), fresh cattle and swine manures were applied into experimental pots at 0, 20 and 40 Mg fresh weight (FW) ha⁻¹ in a greenhouse. Applications of manures significantly enhanced total CH₄ emissions as compared to chemical fertilization, with cattle manure leading to higher emissions than swine manure. Total organic C contents in cattle (466 g kg⁻¹) and swine (460 g kg⁻¹) manures were of comparable results. Soil organic C (SOC) contents were also similar between the two manure treatments, but dissolved organic C (DOC) was significantly higher in cattle than swine manure. The mcrA gene copy numbers were significantly higher in cattle than swine manure. Diverse groups of methanogens which belong to Methanomicrobiaceae were detected only in cattle-manured but not in swine-manured soil. Methanogens were transferred from cattle manure to rice paddy soils through fresh excrement. In conclusion, cattle manure application can significantly increase CH₄ emissions in rice paddy soil during cultivation, and its pretreatment to suppress methanogenic activity without decreasing rice productivity should be considered.     

Effects of ammonia nitrogen of H2 and CH4 production during anaerobic digestion of dairy cattle manure

A number of researchers have verified the inhibitory effects of elevated H2 concentrations on various anaerobic fermentation processes. The objective of this work was to investigate the potential for using hydrogen gas production to predict upsets in anaerobic digesters operating on dairy cattle manure. In an ammonia nitrogen overload experiment, urea was added to the experimental digesters to obtain increased ammonia concentrations (600, 1,500, or 3,000 mg N/l). An increase in urea concentration resulted in an initial cessation of H2 production followed by an increase in H2 formation. Additions of 600, 1,500, or 3,000 mg N/l initially resulted in the reduction of biogas H2 concentrations. After 24 h, the H2 concentration increased in the 600 and 1,500 mg N/l digesters, but production remained inhibited in the 3,000 mg N/l digesters. Both methane and total biogas production decreased following urea addition. Volatile solids reduction also decreased during these periods. The digester effluent pH and alkalinity increased due to the increased NH4 formed with added urea. Based on these results, changes in H2 concentration could be a useful parameter for monitoring changes due to increased NH3 in dairy cattle manure anaerobic digesters.     

Comparison of two-stage thermophilic (68 degrees C/55 degrees C) anaerobic digestion with one-stage thermophilic (55 degrees C) digestion of cattle manure

A two-stage 68 degrees C/55 degrees C anaerobic degradation process for treatment of cattle manure was studied. In batch experiments, an increase of the specific methane yield, ranging from 24% to 56%, was obtained when cattle manure and its fractions (fibers and liquid) were pretreated at 68 degrees C for periods of 36, 108, and 168 h, and subsequently digested at 55 degrees C. In a lab-scale experiment, the performance of a two-stage reactor system, consisting of a digester operating at 68 degrees C with a hydraulic retention time (HRT) of 3 days, connected to a 55 degrees C reactor with 12-day HRT, was compared with a conventional single-stage reactor running at 55 degrees C with 15-days HRT. When an organic loading of 3 g volatile solids (VS) per liter per day was applied, the two-stage setup had a 6% to 8% higher specific methane yield and a 9% more effective VS-removal than the conventional single-stage reactor. The 68 degrees C reactor generated 7% to 9% of the total amount of methane of the two-stage system and maintained a volatile fatty acids (VFA) concentration of 4.0 to 4.4 g acetate per liter. Population size and activity of aceticlastic methanogens, syntrophic bacteria, and hydrolytic/fermentative bacteria were significantly lower in the 68 degrees C reactor than in the 55 degrees C reactors. The density levels of methanogens utilizing H2/CO2 or formate were, however, in the same range for all reactors, although the degradation of these substrates was significantly lower in the 68 degrees C reactor than in the 55 degrees C reactors. Temporal temperature gradient electrophoresis profiles (TTGE) of the 68 degrees C reactor demonstrated a stable bacterial community along with a less divergent community of archaeal species.     

Changes in microbial biomass indices after 10 years of farmyard manure and vegetal fertilizer application to a sandy soil under organic management

The main objective of the second Darmstadt trial was to investigate the effects of vegetal fertilizers on soil properties and crop yield in comparison with farmyard manure. The experiment consisted of seven treatments: (i) inorganic fertilizers, (ii) vegetal organic fertilizers, (iii) vegetal organic fertilizers equivalent to biodynamic preparations, (iv) cattle farmyard manure, (v) cattle farmyard manure with addition of biodynamic preparations, (vi) high level of cattle farmyard manure, and (vii) high level of cattle farmyard manure with biodynamic preparations. The soil properties analyzed were pH, soil organic C, N, P, and S, soil microbial biomass C, N, and P, basal respiration and fungal ergosterol. The application of vegetal fertilizers had slightly negative effects on soil organic C, no effects on crop yield (potato, winter rye) and microbial biomass, but positive effects on ergosterol in comparison with farmyard manure. The increase in ergosterol was caused by straw return in the vegetal, but also in the inorganic fertilizer treatments. The biodynamic preparations did not affect the contents of soil organic C and total N. The low effectiveness of vegetal fertiliser in maintaining soil organic C levels is of particular importance for organic cropping systems and should be examined further under different site conditions.     

煤矿区复垦土壤中有机肥的分解动态及其驱动因素

基于煤矿区不同复垦年限土壤,研究有机肥的分解动态及其驱动因素,可为有机肥合理施用和矿区土壤培肥提供科学依据。本研究以山西煤矿复垦区为试验平台,采用尼龙网袋填埋法,在复垦年限为1年(复垦初期阶段,R₁)、10年(复垦中期阶段,R₁₀)和30年(复垦长期阶段,R₃₀)的土壤中进行有机肥分解试验(有机肥碳量与土壤重量比例为4∶100)。供试有机肥为牛粪和猪粪,以不添加有机肥为对照(CK),填埋深度为15 cm。在填埋后的第12、23、55、218、281和365 d采集尼龙网袋样品,测定有机肥残留量、土壤微生物生物量碳(MBC)和可溶性有机碳(DOC)含量,采用方差分解分析(VPA)量化土壤性质、有机肥性质和水热条件对有机肥分解的贡献率。结果表明: 猪粪的分解速率显著高于牛粪。猪粪的腐殖化系数(46.3%)显著低于牛粪(71.7%);猪粪在复垦30年的土壤中的腐殖化系数(44.5%)显著低于复垦1年和10年的土壤(47.2%);而牛粪在3种复垦年限土壤中的腐殖化系数无显著差异。猪粪和牛粪的易分解碳库占总碳库的比例分别为52%和26%,易分解碳库分解速率常数分别为0.00085和0.00074 ℃^-1,且差异显著。在0~218 d填埋时间段内,猪粪还田对复垦土壤MBC和DOC的提升作用显著高于牛粪,在281~365 d填埋时间段内,两者差异不显著。有机肥还田下,3种复垦年限土壤中MBC和DOC的增长幅度均表现为R₁ >R₁₀ ≈ R₃₀。在土壤性质、物料性质和水热条件中,有机肥性质是其分解的主要影响因子,对有机肥分解的单独贡献率最大,为17.9%。综上,猪粪的分解受到土壤复垦年限的影响,而牛粪的分解不受土壤复垦年限的影响。在不同复垦年限土壤中,牛粪的腐殖化系数显著高于猪粪,在煤矿复垦区建议选择腐熟的牛粪进行有机肥还田,以提高土壤肥力。