菌、热及菌热联合对垃圾堆肥腐熟的比较分析

为研究菌剂、余热及其联合作用对堆肥腐熟度的影响,采用强制通风静态堆肥系统,以现有堆肥工艺为对照（CK）,比较研究了添加菌剂（T1）、余热利用（T2）、添加菌剂并利用余热（T3）3种工艺垃圾对堆肥过程中腐熟度的影响。结果表明：从温度、pH、电导率（EC）、腐植酸光学特性（E4/E6）、水溶性碳（WSC）、固相C/N和发芽率指数（GI）来看,4个处理均达到腐熟;添加菌剂（T1）对EC、E4/E6、WSC、C/N和GI有显著影响;除E4/E6、WSC和C/N外,循环热风（T2）对其余腐熟度指标有显著影响,菌剂和余热的联合作用可显著提高堆肥的腐熟度,且二者对堆肥腐熟度的影响是一种协同作用。     

城市生活垃圾堆肥过程中腐熟度指标及控制参数

以日处理400 t经马家楼筛分处理后的15～60 mm生活垃圾的北京南宫堆肥厂垃圾堆肥过程为研究对象,对堆肥过程中垃圾的理化性质、腐熟度指标与控制参数进行了研究。结果表明,堆肥过程中水分含量是下降的;不同季节堆肥pH值的总体变化均呈上升趋势;电导率(EC)降到了作物受抑制的限定值以下,不会对作物产生盐分毒害;堆肥水浸提的腐殖酸E₄/E₆值随着垃圾堆肥腐熟度升高呈增加趋势;24 h和96 h的发芽率指数(GI)表明垃圾堆肥时间可以从8周缩短到5周;有机碳、总氮和C/N比随着堆肥时间的增加均呈下降趋势;C/N比与E₄/E₆值和GI(24 h和96 h)值呈显著负相关关系,EC值与E₄/E₆值和GI(24 h和96 h)值呈极显著负相关,而E₄/E₆值与GI(24 h和96 h)值呈极显著正相关。     

Evaluation of Parameters During Composting of Two Contrasting Raw Materials

The aims of this work were: i) to evaluate, during a composting process, some parameters in two contrasting raw materials: one a ligneous material (C1) and the other (C2) a mixture of horse and poultry manure with a low straw percentage and ii) to compare results from microbiological and chemical analyses of both composting material during the process. Total carbon, total nitrogen, C: N ratio, ash, organic matter, organic matter destroyed, CEC, soluble organic carbon, soluble ammonium and nitrate, ammonium: nitrate ratio and respiration rate were evaluated during 18 weeks. C1 material showed a lower rate of organic matter mineralization probably due to the high proportion of ligneous material. This material reached a greater CEC during the experiment. Increase in CEC during composting is due to conversion of the remaining organic material into humic substances. These results would imply that C1 presented a greater humification level and consequently, a better quality. On the other hand, the greater decrease in soluble organic carbon and NH₄⁺-N values in C2 is in accordance with greater organic matter mineralization. A high decrease in soluble fractions, especially the more degradable ones (water soluble components) indicates a high mineralization of the organic matter during composting and a lower humification level. According to the data obtained in our experiment, some parameters such as CEC, soluble organic carbon and soluble NH₄⁺-N seem to achieve the stability level for both studied materials, while those parameters or indices such as C: N ratio, NH₄⁺-N: NO₃^?-N ratio indicated stability/maturity only in C2 material during the experimental time.     

Chemical and microbiological parameters for the characterisation of the stability and maturity of pruning waste compost

Composting of pruning waste, leaves and grass clippings was monitored by different parameters. A windrow composting pile, having the dimensions 2.5 m (height) x 30 m (length) was establish. The maturation of pruning waste compost was accompanied by a decline in NH₄ ⁺-N concentration, water soluble C (WSC) and an increase in NO₃ ^–-N content. Both organic matter (OM) content and total N (TN) losses during composting followed a first-order kinetic equation. These results were in agreement with the microbiological activity measured either by the CO₂ respiration or dehydrogenase (DH-ase) activity during the process. Statistically significant correlations were found between DH-ase activity, easily biodegradable organic C forms, NH₄ ⁺-N and NO₃ ^–-N concentrations and organic matter content and N losses. For this reason, DH-ase activity and the CO₂ evolution could be used as good indicators of pruning waste compost maturity. In contrast, humification parameters data from the organic matter fractionation did not agree with the initially expected values and did not contribute to the assessment of compost maturity. Neither the cation exchange capacity nor the germination index showed a clear tendency during the composting time, suggesting that these parameters are not suitable for evaluating the dynamics of the process.     

Evaluation of maturity and stability parameters of composts prepared from farm wastes

A composting experiment was carried out to study changes in physical [color, odor, temperature, organic matter (OM) loss], chemical [C:N ratio, water-soluble organic carbon (C_w):organic N (N_org) ratio, NH₄ ⁺-N and NO₃ ^?-N, humic acid (HA):fulvic acid (FA) ratio, humification index (HI) and cation-exchange capacity (CEC):total organic carbon (TOC) ratio)] and biological [seed germination index (GI)] parameters to assess compost maturity and stability over a period of 150 days. Five composts were prepared using a mixture of different farm wastes with or without enrichment of N, rock phosphate (RP) and microorganism (MO) inoculation. All the composts appeared to change to a granular and dark grey color without foul odor, and attained a constant temperature with no measurable changes (ambient level) at 120 days of composting. Correlation analysis showed that the optimal values of the selected parameters for our experimental conditions are as follows: organic matter loss > 42%, C:N ratio < 15, HA:FA ratio > 1.9, HI > 30%, CEC:TOC ratio > 1.7 and C_w:N_org ratio < 0.55. Composts enriched with N + RP or N + RP + MO matured at 150 and 120 days, respectively, whereas composts without any enrichment or enrichment with N or RP + MO did not mature even at 150 days of composting.     

Relating Compost Measures of Stability And Maturity to Plant Growth

Assessment of compost maturity is important for successful use of composts in agricultural and horticultural production. We assessed the “maturity” of four different sawdust-based composts. We composted sawdust with either cannery waste (CW), duck manure (DM), dairy (heifer) manure (HM) or potato culls (PC) for approximately one year. Windrows were turned weekly for the first 60 days of composting, covered for four winter months and then turned monthly for six more months. We measured compost microbial respiration (CO₂ loss), total C and N, C:N ratio, water soluble NO₃-N and NH₄-N, dissolved organic carbon (DOC), pH and electrical conductivity at selected dates over 370 days. Compost effects on ryegrass biomass and N uptake were evaluated in a greenhouse study. We related compost variables to ryegrass growth and N uptake using regression analysis. All composts maintained high respiration rates during the first 60 days of composting. Ammonium-N concentrations declined within the first 60 days of composting, while NO₃-N concentrations did not increase until 200+ days. After 250+ days, DM and PC composts produced significantly more ryegrass biomass than either CW or HM composts. Total C, microbial respiration and water-extractable NO₃-N were good predictors of compost stability/maturity, or compost resistance to change, while dissolved organic carbon, C:N ratio and EC were not. The compost NO₃-N/CO₂-C ratio was calculated as a parameter reflecting the increase in net N mineralization and the decrease in respiration rate. At ratio values >8 mg NO₃-N/mg CO₂-C/day, ryegrass growth and N uptake were at their maximum for three of the four composts, suggesting the ratio has potential as a useful index of compost maturity.     

堆肥含水量与腐熟度对其粉碎度的影响研究

以鸡粪和麦秸为原料，通过堆肥不同腐熟度和不同含水量下粉碎度的测定，表明堆肥含水量是控制粉碎度大小的首要因素，堆肥粉碎度随含水量的增加而降低，两者满足二级动力学方程。粉碎度的临界含水量为20％，含水量低于20％时，粉碎度的变化较小。含水量大于20％时，腐熟度对粉碎度的影响增强。腐熟的堆肥更容易粉碎。粉碎度与GI(发芽指数)、EC、pH值等腐熟度指标并不存在相关关系。但与TOC呈负线性相关，与全N、C/N比呈显著负二次相关。粉碎度与堆肥化学参数：纤维素、半纤维素含量呈负线性相关，与木质素无相关性。     

黄土高原半干旱区不同土地利用下的土壤有机碳、碳组分和土壤营养

Cropland (CP), native grassland (NG) and two shrub land treatments which were converted from cropland in 1985:seabuckthorn (Hippophae rhamnoides L. ) (ST), and branchytamarisk (Tamarix ramosissima) (BT) were investigated to evaluate effects of land use conversion on soil organic carbon (SOC) and soil nutrients in the semi-arid region of the Loess Plateau of China. Total organic carbon (TOC), light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), total N (TN), nitrate nitrogen (NO₃^--N) and nitrite nitrogen (NO₂^--N), ammonium nitrogen (NH₄⁺-N), total P, and available P (AP) were measured. The results showed that SOC in NG, ST and BT were 12.7%, 27.7% and 34.8% higher than that of the cropland, respectively. LFOC, light fraction (LF) dry matter, ratio of TOC to TN (C/N) and the ratio of TOC to AP (C/P) were higher in the shrub land or native grassland than in the cropland. Cropland had the highest TN, the sum of NO₃^--N and NO₂^--N, TP and AP due to the use of chemical fertilizers. TOC significantly correlated with LFOC, HFOC and C/N. LFOC significantly correlated with dry matter of the LF and C/N. TN, the sum of NO₃^--N and NO₂^--N and AP were significantly negatively correlated with TOC and LFOC. Therefore, land use conversion from cropland to shrub land, or maybe grassland, contributed to SOC sequestration and improved soil nutrients stabilization.     

调节C/N及添加菌剂与木酢液对园林绿化废弃物堆肥效果的影响

为探究C/N、菌剂、木酢液3因子及菌剂与木酢液交互作用对堆肥腐熟效果的影响,寻求最佳堆肥效果的因子水平组合。本研究以园林绿化废弃物为主要原料,通过L9（34）正交设计以鸡粪为C/N调理剂,菌剂和木酢液为添加剂进行堆肥试验。分析比较了各处理堆肥过程中温度、总有机碳、全氮、C/N、pH值、EC值、堆体体积等指标的变化情况,并以种子发芽率试验测定堆肥效果。结果表明,调节C/N比和添加适量菌剂与木酢液均能促使堆肥初温上升,高温期提前并延长,堆肥积温提高,发酵周期缩短,总有机碳降解量和总氮相对含量增加。适当调节C/N和添加适量菌剂均有利于堆肥pH值升高,防止EC值过高,而添加木酢液能明显降低堆肥pH与EC值。C/N、菌剂、木酢液、菌剂与木酢液交互作用对堆肥发芽指数的影响均达极显著水平,且影响效果表现为C/N菌剂木酢液。因素效应的差异显著性检验结果表明,C/N为30效果最好,0.4%菌剂与稀释500倍木酢液的交互作用最大,稀释50倍的木酢液对堆肥微生物活性存在一定的抑制作用。可见,基于种子发芽指数的园林绿化废物堆肥适宜参数组合为C/N30+0.4%菌剂+稀释500倍木酢液。     

Chemical and microbiological parameters for the characterization of maturity of composts made from farm and agro-industrial wastes

Bioconversion of farm wastes with agro-industrial wastes into enriched compost is an important possibility in need of research. In this article, changes in chemical and microbiological parameters were evaluated to determine the maturity of composts prepared from mixture of farm and agro-industrial wastes over a period of 150 days. Seven different composts were prepared by using a mixture of different farm wastes with or without enrichment with rock phosphate (RP), agro-industrial wastes and the inoculation of microorganisms. As composting proceeded, the organic C, water-soluble C (WSC), bacterial and fungal counts decreased, whereas total N, P, electrical conductivity (EC) and actinomycetes count increased gradually. Our results suggest that WSC <1%, C:N ratio < 20, neutral pH and a decrease in bacteria and fungal counts, along with an increase in actinomycetes count and stability at the end of composting, may be accepted as an indicator of compost maturity. Changes in organic C, EC, total N and P concentrations over time also proved to be reliable indicators of the progress of the composting process for establishing stability and compost maturity. Addition of RP, agro-industrial wastes and inoculation of microorganisms showed potential in improving the N and P contents of the composts.     

Humification-mineralization pyrolytic indices and carbon fractions of soil under organic and conventional management in central Italy

The aim of this study was to evaluate chemical changes in soil organic matter (SOM) in organically and conventionally managed fields, using pyrolytic indices and the extraction of different carbon fractions. Pyrolysis-gas chromatography (Py-GC) was used to study structural changes in SOM, whereas the different soil extractions gave a fractionation of C forms. Organic management increased both humic and labile C forms (microbial biomass C and water soluble organic C). A significant positive relationship was found between the living SOM fraction, expressed as microbial biomass/total organic C ratio (MBC/TOC) and humification rate. A negative relationship was found between the pyrrole to phenol ratio (O/Y) and total extractable C (TEC).An opposite trend has been observed for the second pyrolytic index (N/O), which represents the mineralization of fresh organic matter. Mineralization was higher in organically managed soil, probably because of consistent input of fresh material to the organic field. Carbon fraction pools and pyrolytic indices provided complementary indications of SOM quality under organic and conventional management.     

Using Thermogravimetry as a Simple Tool for Nutrient Assessment in Fire Affected Soils

Nutrient availability can be a limiting factor in the recovery of ecosystems after wildfire. Its evaluation is therefore critical for selecting appropriate restoration strategies in the post‐fire period. This study explores, for the first time, the use of thermogravimetry (TG) as a rapid proxy for nutrient availability and soil recovery. Soil samples from five burned and unburned sites in Andisols of Tenerife (Spain) were selected to examine the medium‐term impact of fire. Key soil chemical parameters [pH, electric conductivity, cation exchange capacity (CEC), main cation and anions in the soil solution, total organic carbon (TOC), total nitrogen (TN) and available phosphorus] were determined and thermogravimetry performed. Burned soils showed significantly higher pH, Ca²⁺ and Mg²⁺ and a lower CEC, TOC and TN than the unburned counterparts, and a site‐dependent response for soluble SO₄²⁻ and available phosphorus was observed in the medium term. Time elapsed since fire could have masked additional fire impacts. Thermogravimetry data allowed reasonable prediction of most soil properties and parameters, with r ² ranging from 0·4 to 0·9. The results demonstrate that soluble nutrient content is directly related to the amount of ash in the soil. The decrease of labile carboxyl‐C was associated with an increase of pH and decrease of CEC, whereas the increase of recalcitrant and refractory pools was associated with the amount of TOC and TN. The results suggest that this novel application of an established method can provide, following an initial calibration step, rapid and inexpensive proxies for key parameters necessary for assessing fire‐induced ecosystem degradation and designing suitable restoration strategies in the post‐fire period. Copyright © 2017 John Wiley & Sons, Ltd.     

用化学和生物学方法估测不同C/N比猪粪堆肥的腐熟度

Aerobic static pile composting(Mechanical turning every 3 days) of pig manure was prepared at 8 m^3 windrow heaps .Sawdust was used as the bulking aagent to provide additional carbon and to increase the porosity of the substrate Two treatments at initial C/N ratios of 30 and 15,respectively,were designed in the study,Dissolved organic carbon(DOC),soluble NH4^ -N,C/N ratios in solid and aqueous phases,E4/E6 ratios,and seed germination index(GI) were determined to evaluate the maturity of the co-composts.Seed germination index,a biological parameter,was suggested as one of the most reliable maturity indicators for organic compost.The results showed that the treatment at the initial C/N ratio of 30 reached maturity after 49 days of composting ;however,the treatment at the initial C/N ration of 15 should require composting time of longer than 63 days to obtain maturation.Chemical multi-indicator evaluation was necessary,and the GI measurement was the recommended approach for maturity evaluation in the study.     

Short‐term effect of biochar and compost on soil fertility and water status of a Dystric Cambisol in NE Germany under field conditions

Crop growth in sandy soils is usually limited by plant‐available nutrients and water contents. This study was conducted to determine whether these limiting factors could be improved through applications of compost and biochar. For this purpose, a maize (Zea mays L.) field trial was established at 1 ha area of a Dystric Cambisol in Brandenburg, NE Germany. Five treatments (control, compost, and three biochar‐compost mixtures with constant compost amount (32.5 Mg ha^–1) and increasing biochar amount, ranging from 5–20 Mg ha^–1) were compared. Analyses comprised total organic C (TOC), total N (TN), plant‐available nutrients, and volumetric soil water content for 4 months under field conditions during the growing season 2009. In addition, soil water‐retention characteristics were analyzed on undisturbed soil columns in the laboratory. Total organic‐C content could be increased by a factor of 2.5 from 0.8 to 2% (p < 0.01) at the highest biochar‐compost level compared with control while TN content only slightly increased. Plant‐available Ca, K, P, and Na contents increased by a factor of 2.2, 2.5, 1.2, and 2.8, respectively. With compost addition, the soil pH value significantly increased by up to 0.6 (p < 0.05) and plant‐available soil water retention increased by a factor of 2. Our results clearly demonstrated a synergistic positive effect of compost and biochar mixtures on soil organic‐matter content, nutrients levels, and water‐storage capacity of a sandy soil under field conditions.     

Carbon and nitrogen transformation during composting of sweet sorghum bagasse

Two types of compost, consisting of sweet sorghum bagasse with either sewage sludge or a mixture of pig slurry and poultry manure, were studied in a pilot plant using the Rutgers system. The total degradation of the piles as determined by the weight loss of organic matter during the bio-oxidative and maturation phases accounted for 64% of the organic matter applied and followed a first-order kinetic function. Concentrations of total and organic N increased during the composting process as the degradation of organic C compounds reduced the compost weight. Losses of N through NH₃ volatilization were low, particularly in the compost with sewage sludge due to pH values of <7.0 and the low temperatures reached in the compost during the first 2 weeks. The C:N ratio in the two composts decreased from 24.0 and 15.4 to values between 12 and 10. Increases in cation exchange capacity and in fulvic and humic acid-like C revealed that the organic matter had been humified during composting. The humification index, the C:N ratio, fulvic:humic acid-like C, and cation exchange capacity proved to be the most suitable parameters for assessing the maturity of these composts.     

Compost Maturity Effects on Nitrogen and Carbon Mineralization and Plant Growth

Improved predictive relationships between compost maturity and nitrogen (N) availability are needed. A total of 13 compost samples were collected from a single windrow over a 91 d period. Compost stability and maturity were assessed using both standard chemical analyses (total C and N, mineral N, total volatile solids) and other methods (CO₂ evolution, commercial maturity kits, and neutral detergent fiber, and lignin). Compost N and carbon (C) were evaluated during a 130 d aerobic incubation in a sandy loam soil after each compost was applied at 200 mg total kg^?1 soil. The effect of compost maturity on plant growth was evaluated by growing two ryegrass (Lolium perenne L.) crops and one barley (Hordeum vulgare L.) crop in succession in compost-amended soil under greenhouse conditions. Potential phytotoxicity from compost was assessed by growing tomato (Lypersicum esculentum L.) seedlings in compost-amended soil. Regression and correlation analyses were used to evaluate the relationship between compost maturity parameters, the rate and extent of net N and C mineralization, plant yield and N uptake, and phytotoxicity. Commonly used maturity parameters like total C, total N, and C:N ratio were poorly correlated with the rate and extent of mineralization, and with plant growth parameters. The N mineralization rate during the first 48 d of aerobic incubation was strongly correlated (r= ?0.82 to ?0.86) to compost fiber and lignin concentration, and to the Maturity Index (r=0.85). Trends in C mineralization were similar. There were few differences in C mineralization between composts after 48 d of aerobic incubation in soil. Ryegrass harvested 35 and 70 d after compost application was not strongly affected by compost maturity, and relatively immature composts were phytotoxic to tomato seedlings. Methods of characterizing compost maturity and stability that more realistically reflect the composting process are better predictors of N release and potential plant inhibition after incorporation into soil.     

The Effects of Short-Term Compost Application On Soil Chemical Properties and on Nutritional Status of Maize Plant

Compost may improve the soil quality and contribute to C sequestration. The short-term effects of compost application on soil properties of soil cropped with maize are reported here. Soil plots to which mature compost was added (at 50 Mg ha^?1 and 85 Mg ha^?1) were analyzed for total organic carbon (TOC), nutrients, heavy metals and other soil properties. In addition, maize plants were weighed at the end of the trial and analyzed for carbon (C), nitrogen (N), phosphorus (P) and heavy metals. The results demonstrate that soil amended with compost has an increased TOC content. The increase was proportional to the amount of compost used. At the highest dose used, compost also increased soil N and P content and the pH. Moreover, after compost application, the total heavy metal contents in soils did not increase. There was no difference between the maize yield from compost treated plots and the control plots. However, maize grains were found to be C, N and P enriched due to the increased nutrient status of the amended soil. In conclusion, the addition of mature compost improves soil properties by increasing the soil TOC content and this depends on the characteristics and the amount of compost used.     

Changes in total and labile carbon and nitrogen contents in a sandy soil after the conversion of a succession fallow to cultivated land

The content of soil organic matter (SOM) can be considered as an important factor for evaluating soil fertility, crop yields, and environmental effects. Sensitive measurements for the assessment of quantitative changes in SOM shortly after the conversion of the management practice would be helpful to understand the SOM‐transformation cycle in more detail. Changes in SOM are reflected in modifications of total organic‐carbon (TOC) and total organic‐nitrogen (TON) contents. They are initially detectable in the readily decomposable fraction. We used hot water–extractable carbon (HWC) and nitrogen (HWN) as measurement of labile pools of SOM and aimed to quantify changes in contents of these C and N fractions in a sandy soil already few years after changing management strategy. In this context, we examined the impact of the conversion of a succession fallow (F) to organic (O) and intensive (I) agriculture on TOC, total N (TN), HWC, and HWN. The conversion of succession fallow to cultivated land resulted in a significant decrease of TOC, TN, and HWC at 0–10 cm soil depth. On average, TOC decreased approx. 0.70 g C kg^–1 (approx. 9% of initial TOC), TN decreased approx. 0.13 g N kg^–1 (approx. 17% of initial TN), and HWC decreased approx. 0.05 g C kg^–1 (approx. 12% of initial HWC) within 3 years. Relatively rapid changes in TOC and TN contents indicated comparatively high proportions of decomposable C and N. These were reflected in comparable high HWC (ranging from 0.37 to 0.59 g C kg^–1 at 0–30 cm soil depth) and HWN (ranging from 0.04 to 0.10 g N kg^–1 at 0–30 cm) contents. These high contents as well as the high HWC : TOC and organic hot water–extractable N (HWN_org) : TN ratios (both between 5% and 7%) implied that the soil investigated has a high ability to provide short‐term available organic C and N compounds. Long‐lasting applications of high quantities of organic fertilizer in the past and high quantities of rhizodepositions were assumed as reasons for the high capability of soil to provide short‐term to medium‐term available C and N. Changes in the HWN content due to the fertilization or crop rotation were mainly based on changes in its inorganic part. This ranged between 10% and 30% of HWN. By discriminant function analysis, it could be shown that the HWN represents a suitably sensitive measurement for the determination of management‐specific impacts in terms of the N, but also of the C cycle. In combination with other C and particularly with other N parameters, the HWN allowed a statistically significant separation of comparable sites varying in management practice already 2 years after the conversion of the management system.     

Relationship between cation-exchange capacity and degree of maturity of city refuse composts

Abstract

An attempt was made to estimate the degree of maturity of city refuse composts by measuring their cation-exchange capacity (CEC).

The CEC of the city refuse compost increased for the first 7 days after commencement of the fermentation process, decreased for the next 2 days, and then increased again gradually up to the end of the piling period.

A highly significant negative correlation was noted between the CEC and C/N ratio of the city refuse composts (r=-0.903***). Regression analysis yielded the relationship: In CEC=7.02-1.02 In C/N

The CEC values of the city refuse composts, which were considered to have been sufficiently matured for application, were greater than about 60 me/ 100 g of ash-free material.     

Composting of Fish Waste with Wood By-Products and Testing Compost Quality as a Soil Amendment: Experiences in the Patagonia Region of Argentina

Composting experiments of fish processing wastes and wood by-products were conducted in the Andean-Patagonian Region. Fish wastes were mixed with sawdust + wood shavings (3:1 ratio by weight) with two replicates. Materials were mixed and placed in 220-liter PVC reactors. After 20 days, materials were remixed and reloaded in the reactors. Samples were taken at 20, 30, 40, 60, 80 and 100 day intervals and chemical analyses were made to assess predictors of compost stability. Thermophilic temperatures over 55°C were sustained long enough to satisfy the EPA requirements for pathogen reduction (72 hours). The decrease of NH₄+-N, water soluble carbon and the ratio of water soluble carbon to total nitrogen appeared to be the best parameters for predicting compost stability. Mature compost (CMP) and an organic commercial product, Lombriquen (LQN) were incubated with an Andisol and a Xeric Mollisol at a rate of lOg/kg for 16 weeks (20 to 30 percent soil moisture, 25°C) in order to estimate nitrogen and phosphorus release. Soils amended with LQN retained more P than CMP-amended soils (80 percent vs 60 percent of added Olsen-P in the Andisol and 50 vs 35 percent in the Xeric Mollisol). While N mineralization rates of LQN were variable (three to 11 percent of added total N), CMP showed constant rates for both types of soils (12 percent) and released more available N than LQN.