Accumulation and mobility of zinc in soil amended with different levels of pig-manure compost

Applying manure compost not only results in zinc accumulation in the soil but also causes an increase in zinc mobility and enhances zinc leaching. In this study, the physical and chemical characteristics of zinc, zinc profiles, and zinc balance were investigated to characterise the fate of zinc in fields where the quality and amount of pig manure compost applied have been known for 13 years. Moreover, we determined zinc fractionation in both 0.1 mol L^?1HCl-soluble (mobile) and -insoluble (immobile) fractions. Adsorption of zinc in the soil was enhanced with increasing total carbon content following the application of pig manure compost. The 159.6 mg ha^?1 year^?1manure applied plot (triplicate) exceeded the Japanese regulatory level after only 6 years of applying pig manure compost, whereas the 53.2 mg ha^?1 year^?1 manure applied plot (standard) reached the regulatory level after 13 years. The zinc loads in the plots were 17.0 and 5.6 kg ha^?1 year^?1, respectively. However, 5.9 % and 17.2 % of the zinc loaded in the standard and the triplicate pig manure compost applied plots, respectively, were estimated to be lost from the plough layer. Based on the vertical distribution of mobile and immobile zinc content, a higher rate of applied manure compost caused an increase in the mobile zinc fraction to a depth of 40 cm. Although the adsorption capacity of zinc was enhanced following the application of pig manure compost, a greater amount of mobile zinc could move downward through the manure amended soil than through non manure-amended soil.     

Microbial degradation of poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in compost

The microbial degradation of tensile test pieces made of poly(3-hydroxybutyrate) [P(3HB)] or copolymers with 10% [P(3HB-co-10%3HV)] and 20% [P(3HB-co-20%3HV)] 3-hydroxyvaleric acid was studied in small household compost heaps. Degradation was measured through loss of weight (surface erosion) and changes in molecular weight and mechanical strength. It was concluded, on the basis of weight loss and loss of mechanical properties, that P(3HB) and P(3HB-co-3HV) plastics were degraded in compost by the action of microorganisms. No decrease inM _w could be detected during the degradation process. The P(3HB-co-20%3HV) copolymer was degraded much faster than the homopolymer and P(3HB-co-10%3HV). One hundred nine microbial strains capable of degrading the polymersin vitro were isolated from the samples used in the biodegradation studies, as well as from two other composts, and identified. They consisted of 61 Gram-negative bacteria (e.g.,Acidovorax facilis), 10 Gram-positive bacteria (mainlyBacillus megaterium), 35Streptomyces strains, and 3 molds.     

Refuse treatment options: a case study

Records in public archives were evaluated for the period 1981-1991. Simple surveys of peoples and of technology and physical premises provided insight to gauge the attitudes of a local community in the Melbourne municipality and the Melbourne City Council towards composting of organic waste materials. There is a lag in perception and attitudes between the local community and the local government towards composting of organic refuse as a solid waste treatment option. The simple methodology of the study still made it possible to verify past and present perceptions and attitudes.     

Sustainable Agriculture: New Paradigms and Old Practices? Increased Production with Management of Organic Inputs in Senegal

Farmers in Sahelian countries are confronted with a variety of soil fertility and management problems. During the last two decades, NGOs have worked with farmers and research institutions to develop and test practices that will increase food production, while at the same time enhance the natural resource base.Since 1987, The Rodale Institute (RI) has worked closely with farmers' associations and government institutions to promote regenerative agriculture-farming systems that prioritize the use of local resources while improving them as they are used to grow food, using agro-ecological methods. The Senegalese Agricultural Research Institute has collaborated in this program as a partner of RI. The Senegal Regenerative Agriculture Resource Center model has been applied as a new and viable approach that builds on traditional knowledge and farmer-to-farmer exchange.Research results on soil conservation and improvement have shown that fields spread with amended animal manure or compost yield greater harvests than fields farmed with traditional methods.     

Environmental assessment of two home composts with high and low gaseous emissions of the composting process

A Life Cycle Assessment (LCA) of two home composts with low and high gaseous emissions of the composting process is presented. The study focused on the gaseous emissions of the composting process. Gaseous emissions of methane, nitrous oxides, ammonia and volatic organic compounds of the composting process were experimentally measured in field real trials. The results showed that the differences in gaseous emissions between the two home composts were 4.5, 5.8 and 52 for methane, nitrous oxides and ammonia, respectively. Higher emissions of nitrous oxides and methane affected significantly the category of global warming potential, while higher emissions of ammonia affected mainly the categories of acidification potential, eutrophication potential and photochemical oxidation. The differences found in the compost emissions were attributable to the composting production management (quality and composition of waste stream, frequency mixing of waste, humidity and temperature monitoring, among others) as well as weather conditions (temperature and humidity).     

Sorption of 2,4-D on Natural and Organic Amended Soils of Different Characteristics

The effect of one organic amendment consisting of an urban waste compost (UWC) was assessed on the sorption properties of the herbicide 2,4-D on four soils of different physicochemical characteristics. The soils chosen were a Typic Haphorthod (ST), a Typic Endoaquept (SR), an Entic Pelloxerert (TO), and a Typic Eutrochrept (AL). Adsorption experiments were performed on the original soils, and on mixtures of these soils with UWC at a rate of 6.25% (w/w). These mixtures were used just after preparation, and after aging for 8 and 25 weeks. 2,4-D adsorption was the highest on ST soil, whereas the lowest adsorption was for SR soil. This behavior is related to the high amount of organic matter (OM) and amorphous iron and aluminum oxides content on soil ST, whereas soil SR had the lowest OM content and specific surface area of the soils of this study. Addition of exogenous OM to soils caused an increase in the 2,4-D adsorption by three of the soils treated with UWC, with the only exception being ST soil, due to an observed decrease in its specific surface area. The adsorbed amounts of the herbicide on aged organic fertilized soils diminished in three of the amended soils, but was still greater than on unamended soils. In contrast, the ST soil showed the largest adsorption for unamended soil.     

不同堆沤处理对玉米秸秆厌氧发酵的影响

研究利用纤维素分解菌F2对玉米秸秆进行堆沤预处理,将经不同堆沤预处理时间后的秸秆与猪粪混合进行厌氧发酵产沼气试验。结果发现,堆沤15 d后秸秆的总有机碳含量降低了10.06%,VS去除率和纤维素降解率比未加菌堆沤预处理分别提高了10.74%、10.60%;加菌堆沤预处理后的秸秆厌氧发酵甲烷产气率、干物质产气率、发酵前后VS去除率均高于未加菌堆沤预处理后的秸秆,且产气效率也有明显的提高;加菌堆沤预处理10 d的秸秆比未加菌堆沤预处理15 d的秸秆提前了2 d达到产气高峰,累计产气量达到21 957 mL,比未加菌堆沤预处理15 d的秸秆增加了1 629 mL。实验结果表明:该纤维素分解菌对玉米秸秆纤维素有较强的降解能力,并在一定程度上促进了有机碳的矿化;有效地提高了秸秆的生物降解性能,缩短了预处理所需时间;同时提高了玉米秸秆的利用率和产气潜力。     

垃圾堆肥在北方潮土地区的农用研究

研究结果表明：垃圾堆肥具有促进作物增产的作用，并不会引起重金属污染。但在北方潮土地区，垃圾肥施用量以４０～５０ｔ·ｈｍ－２·茬－１为宜。过量施用垃圾肥不仅会引起施肥经济效益明显降低，且会引起土壤砂化。研究还表明，粘质土壤对垃圾肥有更大的容纳量。     

广州市污水污泥堆肥在环境绿化中的应用

将广州市大坦沙污水处理厂产生的脱水生污泥与粉煤灰、稻草按质量比例4∶1.2∶1混合堆制而成的污泥堆肥,堆肥总养分含量高于农家肥中的鸡粪,无论单独施用或与化肥结合使用应用于草坪等园林绿地,均有明显效果。污泥堆肥在草坪土壤应用的肥效试验表明,污泥堆肥与化肥结合使用效果较好,能缩短草坪草出苗和成坪时间,显著提高建植初期草坪草的生物量,但每公顷施用纯污泥堆肥30t与60t比较两者草坪草生物量没有显著差异;污泥堆肥施用污染风险初步分析表明,土壤中的重金属含量、渗滤液中的NO3--N和全P含量随着污泥堆肥施用量的增加而明显提高,考虑到广东地处热带、亚热带,雨量丰富且暴雨多,土壤呈酸性的特点,在园林绿地等相对封闭的体系中施用本项目堆制的污泥堆肥,只要将年施用量控制在30t/hm2以下,是基本安全的。     

城市垃圾堆肥制备专用肥对蔬菜生产和环境的效应

通过小区和大田试验方法，研究了城市生活垃圾肥制备有机。无机复合专用肥对蔬菜和土壤环境的效应。结果表明，施用该专用肥的辣椒、蕃茄或茄子、莴笋和青莱的小区和大田的产量，与对照相比分别增加２７．０％－８８．８％和２０．７％－９５．４％，其增产在Ｐ０．０１水平上达到显著，且蔬菜中一些营养成分的含量增加．而重金属Ｃｄ、Ｃｒ、Ｐｂ、Ａｓ元素的含量均未超有关卫生标准。长期施用，可补充土壤中有机质，且肥料中重金属元素不会引起菜地环境的污染。