Recycling of banana pseudostem waste for economical production of quality banana

Banana pseudostem biomass, traditionally incinerated and wasted, has been conserved and recycled by solid state fermentation (SSF) into plant growth stimulating soil conditioner (SC). This SC alone or combined with biofertilizers showed reduced mortality (10 and 12%) of planted suckers, enhanced chlorophyll contents (593 and 661 μg g⁻¹), gave biomass (35.0 and 36.6 kg) at par and improved yield (54.2 and 55.0 MT ha⁻¹), with that of the control (23%, 312 μg g⁻¹, 36.3 kg and 49.4 MT ha⁻¹, respectively). This has afforded (i) saving of chemical fertilizers by 50%, (ii) reduction in quantum (40%) and frequency (15%) of irrigation and (iii) reduction in cost of electricity and labor without sacrificing quality and quantity of banana. Thus, a voluminous agro-waste is converted into an eco-friendly agro-input for sustainable productivity.     

公路建设中水土流失影响及防治措施

公路建设中造成的水土流失越来越严重，水土流失范围呈线状，常常跨越多个流域和地貌类型，因此影响范围较广，且在公路的不同部位水土流失的程度不同，影响期限不同。在实际调查的基础上分析公路建设中水土流失的原因，并提出计算方法及一般性防护措施。     

Impact of four-dimensional seismic and production activities on the mangrove systems of the Niger Delta, Nigeria

Reconnaissance survey and laboratory appraisal of the mangrove system in seven communities in the Niger Delta (Nigeria) endangered by seismic and production operations revealed several alterations of soil, sediment, and vegetation. Hydrocarbon content in the range of 0.3-1.1 mg/100 g was extracted within the proximities of spill sources and seismic lines. The prospect area covered by our investigation was characterized by a mixed mangrove forest dominated by Rhizophora racemosa. It was observed that the construction of the seismic lines was responsible for the vegetal disorientation recurrent in the area. The grass, Paspalum vaginatum, and the saltwater fern, Acrostichum aureum, were found at the fringe of most dredge spoils. The characteristic tidal inundation which increases mobility of the substrate, salinity fluctuation, and anoxia may also have contributed, at least in part, to the observed despoliation of some of these species found within the vicinities of the seismic lines and hydrocarbon percolation. Extensive revegetation program is recommended to ensure an effective restoration process of this ecologically fragile zone.     

Phytocapping: An alternative technique to reduce leachate and methane generation from municipal landfills

Avoiding percolation of water into refuse is the key function of landfill covers. ‘Phytocapping’ has been considered as an effective, economical and environment-friendly technique for landfill remediation. In this technique, trees are established on a layer of soil cap placed over the refuse. Soil cover acts as a ‘storage’ and trees act as ‘bio-pump and filters’. For effective functioning of this technique, it is critical that an ‘optimum’ depth of soil is placed over the refuse, and ‘suitable’ plant species are used as plant cover. Preliminary results of a phytocapping trial (using 21 tree species and two depths of soil layers) show that the established trees can remove more water than that received via rainfall and rainfall interception can reduce up to 20% of the rain reaching the soil in a 1.5 year old plantation. The study is also trialling an US numeric model ‘STOMP’ (Subsurface Transport over Multiple Phases), to calculate daily water balance, to identify suitable plant species and to optimise thickness of the soil cover to be used in phytocapping.     

野鸭湖湿地不同植被类型土壤养分要素研究

以野鸭湖湿地自然保护区典型地段（样区一）及其附近受人为干扰因素较大的康西草原（样区二）为研究区,研究了野鸭湖湿地不同植被类型及其旅游干扰对土壤中有机质、速效氮、全氮、全磷含量的影响.     

An assessment of the effectiveness and impact of electrokinetic remediation for pyrene-contaminated soil

The effectiveness of electrokinetic remediation for pyrene-contaminated soil was investigated by an anode-cathode separated system using a salt bridge. The applied constant voltage was 24 V and the electrode gap was 24 cm. Two types of soil （sandy soil and loam soil） were selected because of their different conductive capabilities. The initial concentrations of pyrene in these soil samples were 261.3 mg/kg sandy soil and 259.8 mg/kg loam soil After treatment of the sandy soil and loam soil for seven days, 56.8% and 20.1% of the pyrene had been removed respectively. Under the same power supply voltage, the removal of the pollutant from the sandy soil was greater than that from the loam soil, due to the higher current and lower pH. Further analysis revealed that the effectiveness of electrokinetic remediation was affected by the energy expenditure, and was associated with changes in soil properties.     

Microencapsulated chlorpyrifos: Degradation in soil and influence on soil microbial community structures

Degradation kinetics of microencapsulated chlorpyrifos （CPF-MC） in soil and its influence on soil microbial community structures were investigated by comparing with emulsifiable concentration of chlorpyrifos （CPF-EC） in laboratory. The residual periods of CPF-MC with fortification levels of 5 and 20 mg/kg reached 120 days in soil, both of the degradation curves did not fit the first-order model, and out-capsule residues of chlorpyrifos in soil were maintained at 1.76 （±0.33） and 5.92 （±1.20） mg/kg in the period between 15 and 60 days, respectively. The degradation kinetics of CPF-EC fit the first-order model, and the residual periods of 5 and 20 mg/kg treatments were 60 days. Bacterial community structures in soil treated with two concentrations of CPF-MC showed similarity to those of the control during the test period, as seen in the band number and relative intensities of the individual band on DGGE gels （p 〉 0.05）. Fungal community structures were slightly affected in the 5 mg/kg treatments and returned to the control levels after 30 days, but initially differed significantly from control in the 20 mg/kg treatments （p 〈 0.05） and did not recover to control levels until 90 days later. The CPF-EC significantly altered microbial community structures （p 〈 0.05） and effects did not disappear until 240 days later. The results indicated that the microcapsule technology prolonged the residue periods of chlorpyrifos in soil whereas it decreased its side-effects on soil microbes as compared with the emulsifiable concentration formulation.     

铅污染土壤修复工艺技术研究

近年来,随着城市建设进程的加快,污染企业遗留下来的污染场地引起越来越多的关注,企业对土壤的污染产生很大不良的环境问题。自土壤重金属污染防治被关注开始,土壤污染的修复是很困难的,污染物处理费用非常昂贵,需要快速而有效的技术来加速修复土地的污染区。在本文中,选取一个典型铅污染土壤为研究方向,论述铅蓄电池中铅酸污染地块的修复工艺技术,对受污染场地土壤特性和环境风险进行评估,确定修复的可行性和修复的价值,通过土壤修复清洗技术,优化土壤修复基本参数,测试分析得出土壤修复最优工艺技术。     

企业周边地区土壤重金属环境质量及其影响因素的初探

分别选取化工企业和金属采选与冶炼企业各4家,测定其周边土壤砷、镉、汞、铬和铅5个重金属含量,与其对照点相比,并进行单项和综合污染指数评价。结果表明：化工企业周边土壤无重金属超标点位,未出现累积现象;而在金属企业周边重金属污染物有累积趋势,在4个金属企业周边监测点镉和汞均较对照点高,2个金属企业分别有60％和80％的点位镉轻微超标,1个企业全部监测点位砷轻微超标,这3个企业综合污染评价为轻度污染。相对化工企业而言,金属,台炼企业重金属污染防治更加重要。土壤中重金属含量受自然成土因素影响,同时也受企业排放污染物类别和排放量等人为因素的影响。     

Responses of greenhouse gas fluxes to experimental warming in wheat season under conventional tillage and no-tillage fields

Understanding the effects of warming on greenhouse gas(GHG, such as N_2O, CH_4 and CO_2 )feedbacks to climate change represents the major environmental issue. However, little information is available on how warming effects on GHG fluxes in farmland of North China Plain(NCP). An infrared warming simulation experiment was used to assess the responses of N_2O, CH_4 and CO_2 to warming in wheat season of 2012–2014 from conventional tillage(CT) and no-tillage(NT) systems. The results showed that warming increased cumulative N_2O emission by 7.7% in CT but decreased it by 9.7% in NT fields(p 0.05). Cumulative CH_4 uptake and CO_2 emission were increased by 28.7%–51.7% and 6.3%–15.9% in both two tillage systems,respectively(p 0.05). The stepwise regressions relationship between GHG fluxes and soil temperature and soil moisture indicated that the supply soil moisture due to irrigation and precipitation would enhance the positive warming effects on GHG fluxes in two wheat seasons.However, in 2013, the long-term drought stress due to infrared warming and less precipitation decreased N_2O and CO_2 emission in warmed treatments. In contrast, warming during this time increased CH_4 emission from deep soil depth. Across two years wheat seasons, warming significantly decreased by 30.3% and 63.9% sustained-flux global warming potential(SGWP) of N_2O and CH_4 expressed as CO_2 equivalent in CT and NT fields, respectively. However, increase in soil CO_2 emission indicated that future warming projection might provide positive feedback between soil C release and global warming in NCP.