不同类型配生土与固体废弃物大田配施对绿地土壤理化性质和白玉兰生长的影响

为研究白玉兰配生土与固体废弃物配施对绿地土壤理化性质和白玉兰生长的影响,利用4种白玉兰配生土(降盐型、沃土型、消污型和疏松型)与3种固体废弃物(建筑废弃物、农林废弃物和餐厨垃圾有氧发酵初产物)进行大田配施,于白玉兰种植后180d、360d和720d分别测定表层土壤(0—30cm)pH、水溶性盐分含量、有机质含量、容重以及白玉兰相对生长率和叶绿素含量。结果表明:4种配生土和3种固体废弃物大田配施后,与原土处理(CK)相比,土壤pH和容重分别降低了8.53%—13.36%和22.62%—48.61%,水溶性盐分和有机质含量分别提高了182.9%—745.9%和38.45%—279.3%;种植后720d,白玉兰株高相对生长率提高了25.9%—102.9%,叶绿素含量提高了46.95%—67.38%。综合考虑土壤改良效果和固体废弃物消纳能力,处理降盐型Y2、沃土型F3、消污型M2和疏松型S2对土壤质量的改良及白玉兰植株生长作用较好,同时有助于固体废弃物的消纳和资源化利用。

超声提取-气相色谱-质谱法快速测定配生土中16种多环芳烃化合物

建立了一种快速测定配生土中16种多环芳烃化合物的超声提取-气相色谱-质谱方法。称取2.500 g配生土样品,于60℃超声波水浴中避光超声提取60 min,以4 000 r/min离心,移出上清液,残渣另用15 mL环己烷-丙酮(1∶1)超声提取30 min,重复提取2次,离心冷却后合并上清液。从上清液中准确移取10 mL,于30℃水浴,氮吹至约1 mL,溶液过硅酸镁净化小柱净化,过0.22μm尼龙有机针式滤膜,进样至气相色谱-质谱仪中测定。配生土中16种多环芳烃的检出限为0.01~0.02 mg/kg,16种多环芳烃样品加标回收率为71.2%~98.1%。该方法可快速测定绿化用配生土中16种多环芳烃化合物的含量。

关于园林绿化快速成景配生土的思考

目前我国正处于快速城市化进程之中,城市园林绿化面临环境污染、"垃圾围城"等许多新问题和新挑战,突出表现是"困难立地"不断增多。这对园林绿化特别是园林绿化土壤提出了更高的要求和标准,现有的园林绿化土壤已经不能满足城市发展和建设的需求。为此,提出了配生土的概念。配生土是指人为干预制成并满足植物健康快速生长营养需要的土壤。其主要特点是根据立地条件,对原土、客土、有机无机改良材料以及微生物菌剂进行科学配置,具有较好的物理性质和较高的生物活性以及环境调控能力,能够较为全面的满足植物生长发育的土壤条件,可以实现工厂化、规模化生产和园林绿化快速成景等。

上海花博会景观园林土壤改良及绿化种植技术

以上海花博会项目绿化工程为依托,响应生态发展理念,对园林景观绿化种植进行全方位研究。通过对地栽苗和容器苗两种苗木的种植土组成、配生土改良、苗木检疫、起苗运输、修剪包裹、种植工艺等内容的管理及研究,形成一套系统的园林绿化管理模式,实现上海花博园景观绿化快速成景,且苗木成活率高达97%。

城市困难立地条件下园林绿化植物病虫害的发生及其防控策略

城市困难立地园林绿化是近年来中国城市发展过程中面临的一个紧迫问题。文章通过介绍城市困难立地条件下植物病虫害发生概况和产生的变化,强调了城市困难立地园林绿化病虫害的防治方法和不同阶段的防治策略;结合病虫害防控新技术的开发和配生土技术的应用,对今后一段时间城市困难立地园林绿化植物病虫害防控技术进行了展望。

Adsorption properties of CFBC ash-cement pastes as compared with PCC fly ash-cement pastes

Circulating fluidized bed combustion （CFBC） ash can be potentially used as supplementary cementitious materials for concrete production due to its desirable pozzolanic activity. The adsorption properties of CFBC ash-cement pastes were studied, and ordinary pulverized coal combustion （PCC） fly ash-cement pastes were used as control. The water-adsorption and superplasticizer （SP）-adsorption properties of the pastes were evaluated by water demand and UV-visible absorption spectroscopy respectively. The results show that CFBC ash-cement system has greater compressive strength as compared with PCC fly ash-cement system at a given curing age, although the water demand of the former is significantly higher than that of the latter. CFBC ash-cement pastes possess higher adsorption ability of aliphatic SP than PCC fly ash-cement pastes and the adsorption amount increases with an increase in ash replacement ratio. CFBC ash- cement pastes exhibit lower workability with higher slump loss. It is concluded that CFBC ash can be potentially used as supplementary cementitious material in concrete production, but the mix design of CFBC ash concrete needs to be appropriately adjusted. It is suggested that CFBC ash is used for the production of the concrete needing low flowability.

Utilization of Recycled Coarse Aggregate in Concrete Mixes

In this paper, the effect of the source of recycled coarse aggregate on the properties of concrete is investigated. The tests were conducted on concrete made from three sources of recycled aggregates： （1） old concrete with unknown strength, （2） old concrete with a known compressive strength of 21 MPa, and （3） old concrete with a known strength of 42 MPa. The three sources of recycled aggregates were used to produce new concrete with a target compressive strength of 21 MPa. The first and third sources of recycled aggregates were used in producing concrete with target strength of 42 MPa. A control mix was designed with aggregates from natural sources. The research included two methods of making recycled concrete. One concrete mix was produced using the recycled aggregate and adding more water than the control mix, to reach the target slump, while the second concrete mix was produced using the same amount of water as the control mix but with additional superplasticizer to maintain the target slump. The results obtained in this research showed that the concrete compressive strength depends on the source of recycled aggregates; the stronger the source of recycled aggregate, the higher the compressive strength of the produced concrete. Furthermore, the compressive strength of the first concrete mix was about 10%-20% lower than the compressive strength of the control mix. However, when superplasticizers were used, the compressive strength was around the same value as the control mix.

Organochlorine pesticides in soils from the Issyk-Kul region in the western Tian Shan Mountains,Kyrgyzstan：Implication for spatial distribution,source apportionment and ecological risk assessment

As organchlorine pesticides(OCPs) may be an ecologic threat to mountain environments due to their tendency to deposit and accumulate in mountain regions undergoing long-range air transport, OCPs were analyzed in soils collected from an intermontane basin of the western Tian Shan Mountains, which is the UNESCO protected natural reserve of Issyk-Kul. Total OCP concentrations in the Issyk-Kul region ranged from 4.63 to 414 ng/g dw, of which two extraordinary high OCP concentrations(414 ng/g dw and 213 ng/g dw, respectively) influenced by an abandoned dumping site and urban sewage, respectively, were found. Principal component analysis(PCA) and correlation analysis inferred that the OCP inputs in the east of the Issyk-Kul region were mainly from local endogenous sources, and exogenous input via LRAT processes were prominent in the west and south. Additionally, the isomeric and parent substance/metabolite ratios revealed most pesticides accumulated in this region were from old usage, while DDTs had fresh input because of possibly illegal regional application and a slow degradation from the dumping site. Furthermore, ecological risk assessment revealed that no frequently adverse ecological effects were observed in the Issyk-Kul region, but potential risks on neighbouring organisms induced by p,p'-DDT and γ-HCH in dumping site and urban sewage should be considered when devising an efficient management plan to prevent secondary pollution.

Soil fungi of three native tree species inhibit biomass production and shift biomass allocation of invasive Mikania micrantha Kunth

Soil microbes contribute to native plant species successful resistance against invasive plant.Three native tree species,Heteropanax fragrans (HF),Cinnamomum burmanii (CB),and Macaranga tanarius (MT) were effective in controlling the notorious invasive vine Mikania micrantha (MM).Biomass production and allocation patterns (shoot/root biomass ratio (shoot/root)) are important indicators of MM climbing coverage and competitive light-capturing capacity.An investigation was conducted to test the role of soil microbes associated with the three native tree species to inhibit MM biomass production and shift MM shoot/root.Rhizosphere soils originating from preculture HF,CB,MT,and MM plots were collected separately for use as inocula.The inocula were mixed with sterilized river sand at a 1:9 (w/w) ratio to grow MM.The fungicide carbendazim (methyl benzimidazol-2-ylcarbamate) was applied to half the treatments to kill pathogenic soil fungi.Two nutrient levels were established based on the natural soil nutrient concentration from a field stand invaded by MM.MM were grown from seeds in a glasshouse,harvested 15 weeks after sowing,and separated into shoot and root portions.Results showed that under interaction of soil origin and nutrient levels,MM biomass production was unchanged,but biomass allocation patterns were significantly different.MM biomass production grown in the three native tree soils under two nutrient levels was similar or higher than MM biomass production in MM conspecific soil,indicating the absence of species-specific pathogens that inhibited MM biomass production in native tree soils.However,in both conspecific and tree soils,MM biomass production was significantly reduced in the presence of pathogenic soil fungi,i.e.MM experienced significant fungal inhibition,demonstrating the pathogenic soil fungi promoted native tree resistence to MM.MM exhibited decreased shoot biomass allocation when cultivated in native tree soil relative to MM conspecific soil under field stand nutrient level conditions.Reduced resource allocation to shoot biomass could result in diminished capacity to climb,cover,and subsequent smother to native trees,and reduced surface area exposed to available light.Following fungicide application,significant biomass allocation differences disappeared,suggesting the native tree soil fungi were responsible for decreasing MM shoot biomass.The overall results indicated tree soil fungi serve an integral role in controlling invasive MM through fungal inhibition on MM biomass production,and shifts in MM biomass allocation patterns.

Combined Applications of Nitrogen and Phosphorus Fertilizers with Manure Increase Maize Yield and Nutrient Uptake via Stimulating Root Growth in a Long-Term Experiment

Imbalanced application of nitrogen(N) and phosphorus(P) fertilizers can result in reduced crop yield,low nutrient use efficiency,and high loss of nutrients and soil nitrate nitrogen(NO_3^--N) accumulation decreases when N is applied with P and/or manure;however,the effect of applications of N with P and/or manure on root growth and distribution in the soil profile is not fully understood.The aim of this study was to investigate the combined effects of different N and P fertilizer application rates with or without manure on maize(Zea mays L.) yield,N uptake,root growth,apparent N surplus,Olsen-P concentration,and mineral N(N_(min)) accumulation in a fluvo-aquic calcareous soil from a long-term(28-year) experiment.The experiment comprised twelve combinations of chemical N and P fertilizers,either with or without chicken manure,as treatments in four replicates.The yield of maize grain was 82%higher,the N uptake 100%higher,and the N_(min) accumulation 39%lower in the treatments with combined N and P in comparison to N fertilizer only.The maize root length density in the 30-60 cm layer was three times greater in the treatments with N and P fertilizers than with N fertilizer only.Manure addition increased maize yield by 50%and N uptake by 43%,and reduced N_(min)(mostly NO_3^--N) accumulation in the soil by 46%.The long-term application of manure and P fertilizer resulted in significant increases in soil Olsen-P concentration when no N fertilizer was applied.Manure application reduced the apparent N surplus for all treatments.These results suggest that combined N and P fertilizer applications could enhance maize grain yield and nutrient uptake via stimulating root growth,leading to reduced accumulation of potentially leachable NO_3^--N in soil,and manure application was a practical way to improve degraded soils in China and the rest of the world.

Influence of Different Plant Materials in Combination with Chicken Manure on Soil Carbon and Nitrogen Contents and Vegetable Yield

The use of plant materials as soil amendments is an uncommon practice amongst major farming communities in Ghana, although it is necessary for soil fertility improvement. An examination of the effects of soil amendments is necessary to encourage the use of under-utilized organic resources in Ghana. Thus, a field experiment was conducted using 8 different tropical plant materials mixed with chicken manure as soil amendments for growth of tomato as a test crop. The plant materials included Leucaena leueocephala, Centrosema pubescens, Sesbania sesban, Gliricidia sepium, Mucuna pruriens, Pueraria phaseoloides, Azadirachta indiea, and Theo- broma cacao. There were two other treatments： one with equivalent amounts of chemical fertilizers and the other with no-fertilizer input （control）. Plant materials were mixed with chicken manure to obtain a uniform carbon-to-nitrogen （C：N） ratio of 5：1. Except the no-fertilizer control, all treatments received the same amount of nitrogen （N）. To clarify the decomposition pattern of the plant materials in soil, an incubation experiment was conducted using only the plant materials before the field experiment. The Glirieidia treatment released significantly more mineral N than the other plant materials in the incubation experiment. However, the tomato fruit yield was not enhanced in the Gliricidia treatment in the field experiment. The known quality parameters of the tested plant materials, such as total N, total carbon （C）, C：N ratio, and total polyphenols, had minimal effects on their mineralization dynamics. Azadirachta showed the best synergistic effect with chicken manure through significantly increasing soil microbial biomass and fruit yield of tomato. This result provides insights into the possible adoption of Azadirachta in combination with chicken manure as a soil amendment in small-scale agricultural holdings.