有机物料发酵流体和堆肥对苹果连作土壤环境及平邑甜茶幼苗生物量的影响

为探讨不同有机物料的发酵流体(厌氧发酵产物)和堆肥(有氧发酵产物)对苹果连作土壤环境的影响,以盆栽平邑甜茶幼苗为试验材料,分别设置猪粪+秸秆、鸡粪+秸秆、羊粪+秸秆、猪粪+鸡粪+羊粪+秸秆4个不同有机物料组合并进行厌氧发酵和有氧发酵,并将发酵产物分别施入连作土中,研究其对平邑甜茶幼苗生物量、连作土壤中微生物、土壤酶活性、土壤酚酸等的影响。结果表明:与有机物料堆肥相比,各有机物料发酵流体处理的平邑甜茶幼苗干重、鲜重较高,其中猪粪发酵流体处理显著提高了幼苗干、鲜重,7月份为对照的1.57、1.26倍,9月份为CK的1.55、1.86倍;两类发酵产物均增加了土壤微生物的数量,且发酵流体处理显著增加了土壤中细菌和放线菌的数量,其中羊粪发酵流体效果最明显,分别为CK的2.95倍和2.37倍,在堆肥处理中,真菌数量显著增高;两类发酵产物也影响了土壤中酚酸总量,表现为猪粪、鸡粪发酵流体和猪粪堆肥处理含量下降,至9月份分别下降到CK的0.45、0.39倍和0.36倍。     

Mobility and Translocation of Heavy Metals from Mine Tailings in Three Plant Species after Amendment with Compost and Biosurfactant

An experiment was performed to determine the effects of mine tailings alone mixed with compost or with compost plus crude biosurfactant on the accumulation of heavy metals (Pb, Zn, Cu, Cr, Cd, and Ni) in Acacia retinodes, Nicotiana glauca, and Echinochloa polystachya. The plants were grown in soil, mine tailings, and mine tailings containing compost over a period of seven and five months for shrubs or grass, respectively. The plants Acacia retinodes and Nicotiana glauca grown in mine tailings containing compost showed increases in dry biomass (from 62 to 79%) compared with plants in only tailings. Heavy metals accumulated in the roots and leaves showed high translocation rates of Cr in N. glauca, Cd in A. retinodes, and Ni in E. polystachya. Concentrations of heavy metals in the three plants irrigated with crude biosurfactant were not significantly different from those irrigated with water. Zn and Cd fractions within mine tailings containing compost were bound to carbonate, Pb was bound to residues, and Cu was bound to Fe-oxides. Cd had the highest mobility factor followed in order by Zn, Pb, and Cu. The elevated concentrations of Pb in roots and the low translocation rate for N. glauca and A. retinodes indicate that they are suitable for phytostabilizing Pb and Zn.     

物料预处理对堆肥减量化、腐殖化和稳定化的影响及其微生物机制

堆肥是有机固体废弃物处理与资源化的主要途径之一,包括矿化和腐殖化两个过程,且都和微生物活动有关。矿化过程会产生二氧化碳(CO2)等温室气体,是一个典型的温室气体释放过程。腐殖化过程则会产生稳定的腐殖质,则是优良的土壤改良剂。在堆肥稳定化的前提下,如何有效减少堆肥过程中的CO2释放,强化堆肥的腐殖化过程,增加作为优良土壤改良剂的腐殖质产量,对于发展低碳化堆肥技术,实现堆肥的资源化利用具有重要意义。本文选取水稻秸秆和餐厨垃圾作为堆肥原料,研究不同预处理对堆肥过程中矿化和腐殖化过程的影响,并探讨了不同预处理影响矿化和腐殖化过程的微生物机理。结果表明堆料加热预处理后,堆肥的矿化作用被明显削弱,总碳(TC)减量率仅为23.4%,并且最后形成了可观产量的稳定腐殖质(每kg堆料70 d后腐殖质含量为22.09 g±0.35 g,腐殖化系数达2.0),因此加热预处理后的堆肥过程在保证稳定腐殖质的产量前提下更低碳化。预处理通过影响堆料的性质和初始状态下堆料中微生物的种类和数量从而影响堆肥的矿化和腐殖化过程。活性微生物量与脱氢酶活性是矿化过程的主要决定因素,而多酚氧化酶活性主要影响堆肥的稳定腐殖化过程。     

城市污泥堆肥用作草皮基质对草坪草生长的影响

研究了城市污泥堆肥生产草坪基质的应用效果。试验结果表明,城市污泥堆肥基质能明显提高黑麦草的地上和地下生物量和叶绿素含量,与不施化肥和施用化学的对照相比,城市污泥堆肥可以增加土壤有效态氮、磷含量,促进植物叶片对氮的吸收,提高草坪的质量。用经过无害化处理的城市污泥生产草坪基质,既可以解决城市污泥的出路,又可以降低草坪的生产成本,是一条经济可行的途径。     

Field Demonstration of Acetone Pretreatment and Composting of Particulate-TNT-Contaminated Soil

Solid fragments of explosives in soil are common in explosives testing and training areas. In this study we initially sieved the upper 6 in of contaminated soil through a 3-mm mesh, and found 2,4,6-trinitrotoluene (TNT) fragments. These contributed to an estimated concentration of 1.7 kg per cubic yard soil, or for 2000 ppm TNT in the soil. Most of the fragments ranged 4 mm to 10 mm diameter in size, but explosives particles weighing up to 56 g (about 4 cm diameter) were frequently observed. An acetone pretreatment/composting system was then demonstrated at field scale. The amount of acetone required for a TNT-dissolving slurry process was controlled by the viscosity of the soil/acetone mix rather than the TNT dissolution rate. The amount needed was estimated at about 55 gallons acetone per cubic yard soil. Smaller, 5- to 10-mm-diameter fragments went into solution in less than 15 min at a mixer speed of 36 rpm, with a minimum of 2 g TNT going into solution per 30 min for the larger chunks. The slurries were then mixed with compost starting materials and composted in a vented 1 yd³ container. After 34 days incubation time TNT was below the site-specific regulatory threshold of 44 ppm. TNT metabolites and acetone were also below their regulatory thresholds established for the site.     

Production,economic viability and risks associated with switching dairy cows from drylots to compost bedded pack systems

The use of compost bedded pack systems (CBS) has increased over the past 5 years in tropical countries, and studies associating production traits with economical outcomes of this system are warranted. Our objectives were to evaluate productive traits, economic outcomes and the risks of losses of dairy farms that switched from a drylot system (DLS) to a CBS and to compare these with similar farms that did not change their system. We collected data from 18 farms over 36 consecutive months (August 2014 to July 2017). All farms started the study as DLS, and six farms switched to CBS in the second year. The other 12 farms kept their DLS during the 36 months of evaluation. Annual technical and economic indexes per farm were collected and calculated. Additionally, a risk analysis was performed based on a 10-year historical series of milk prices. The results were analysed using a regression model including year and herd as categorical variables (fixed), system and herd size as quantitative variables (fixed), and system × herd as a random variable. Furthermore, a non-metric multidimensional scaling plot was used to evaluate producers’ profiles in each year. Milk fat, milk total solids, and somatic cell count did not change when farms switched from DLS to CBS, and averaged 3.80%, 12.04%, and 256 500 cells/ml, respectively. However, milk protein (%) decreased in CBS farms. The majority of milk production variables were not affected. Nevertheless, farms that switched to CBS increased milk production per cow by 13.3% compared with DLS farms. Total operation costs (296 076.83 $/year) were not affected by the system, and neither were the costs of concentrates, roughage, labour or medicines. Net margin per litre (0.09 $/l), operating profit (14.95%), assets per litre (398.68 $/l per day) and return on assets (10.27%) did not change when farms switched from DLS to CBS. Net margin ($/l and $/cow) and asset turnover rate increased in CBS farms. Risk analysis indicated that the risk was reduced by 38% in CBS farms. Furthermore, our analysis showed that producers who switched to CBS had similar technical and economic indexes in the first year before switching their system. In conclusion, this study demonstrates that CBS systems might be promising for producers in tropical countries who are looking for a more productive and less risky system. We did not observe improvements in animal health as previously reported in the literature.     

Use of composts to manage corky root disease in organic tomato production

Corky root disease of tomato caused by Pyrenochaeta lycopersici is an economically important disease in organic tomato production. This study aimed to evaluate the effects of various composts consisting of green manure, garden waste and horse manure against corky root disease through bioassay under greenhouse conditions, where soil naturally infested with P. lycopersici was used as a root substrate. The various composts were mixed at a rate of 20% (v/v) with the infested soil. Disease severity (measured as infected roots) in the unamended soil was compared with that in the soil–compost mixtures. One of the composts made from garden waste significantly reduced the disease, whereas horse manure compost significantly stimulated it. Lower concentrations of NH₄‐N and total carbon and a higher concentration of Ca in the substrate were correlated with lower level of corky root disease. Addition of green manure or garden waste compost to the infested soil increased total microbial activity or population density of copiotrophic bacteria and actinomycetes, respectively. However, increased microbial activity or microbial population in soil–compost mixtures was not associated with a reduction in corky root disease severity in the present study.     

生活垃圾堆肥淋洗液培植无土草皮的生态特征

以生活垃圾堆肥淋洗液培植无土草皮,结果表明,垃圾堆肥淋洗液中有机质、全氮、有效磷及其它营养元素含量显著高于对照土壤淋洗液,能够充分满足草坪植物生长需要。高浓度淋洗液使黑麦草和高羊茅种子萌发高峰期推迟出现,但不影响发芽率,到萌发第11天,种子发芽率分别达到94％和92％以上。对黑麦草而言,80％的淋洗液可显著提高植株高度、地上生物量和叶绿素含量;对高羊茅,60％的淋洗液则为最佳浓度。当淋洗液培植的无土草皮进行田间铺坪90d时,黑麦草和高羊茅草皮地上生物量分别达到5．38g／块和7．89g／块,并显著高于对照草皮（P〈0．05）,而地下生物量和根长差异不显著。垃圾堆肥淋洗液改变了黑麦草和高羊茅植株地上／地下生物量的分配格局,使其根冠比降低,其分别为4．60和3．71,并明显低于对照。从坪用性状上看,铺坪后垃圾堆肥淋洗液培养的草皮叶色深绿,质地柔软光滑,明显优于土壤淋洗液培养的对照草皮。     

Immobilization of Heavy Metals in Soil Using Natural and Waste Materials for Vegetation Establishment on Contaminated Sites

Contaminated land is increasingly becoming an important issue worldwide. Many contaminants are persistent in soil for a large number of years. With the increase in public awareness regarding the consequences of contaminated soil, many researchers are concentrating on developing cost-effective and socially acceptable soil remediation technologies. Soils of many sites, which have been left derelict after industrial decline, harbor a broad suite of metal and organic contaminants. Land where such contaminants are deemed to pose a significant risk to receptors is considered contaminated under modern guidance. Remediation to break identified pollutant linkages would precede reclamation and plant establishment. One approach to break the pollutant receptor linkage is to utilize materials that effectively create soil conditions that immobilize contaminants whilst providing essential plant growth properties in terms of nutrition and water holding capacity. Materials that may achieve this include: 1) composts derived from materials such as sewage sludges and other municipal sources; 2) natural or synthetic zeolites; or 3) industrial by-products such as red-mud or other iron-rich materials such as iron grit or iron oxyhydroxides. Remediation techniques that utilize such materials may be cost-effective compared to more traditional methods and may effectively divert materials from the waste stream and could thereby make a dual contribution to sustainable development.